WO2014085626A1

WO2014085626A1 - Light modulation of plants and plant parts

Info

Publication number: WO2014085626A1
Application number: PCT/US2013/072295
Authority: WO
Inventors: Kevin Michael Folta; David G. Clark; Thomas A. COLQUHOUN
Original assignee: University of Florida; University of Florida Research Foundation Inc
Current assignee: University of Florida; University of Florida Research Foundation Inc
Priority date: 2012-11-27
Filing date: 2013-11-27
Publication date: 2014-06-05
Anticipated expiration: 2015-05-27

Abstract

In one embodiment, the present invention provides methods for applying light to plants and plant parts (such as flowers, fruits) to modulate pigment accumulation, (i.e., color), stature, photomorphogenic responses, nutraceutical content, flavor, and/or aroma of plants or plant parts. Also provided are software and/or control devices for plant lighting systems (such as light-emitting diodes (LEDs)) that can be used to modulate pigment accumulation, stature, photomorphogenic responses, nutraceutical content, flavor, and/or aroma of plants or plant parts.

Description

DESCRIPTION

LIGHT MODULATION OF PLANTS AND PLANT PARTS CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Applications Serial No. 61/730,329, filed November 27, 2012 and Serial No. 61 /794,406; filed March 15, 2013, both of which are incorporated herein by reference in their entirety. BACKGROUND OF INVENTION

Plant growth and development is a product of the genetic potential contained in a plant and how it responds to stimuli from the ambient environment. An element of this interaction (genetic potential and environment) is facilitated by a suite of plant photosensory receptor proteins, each adapted to sense and relay information about the incident light spectrum. In the case of horticultural crops, light quantity, quality, and duration inform the plant of current conditions that ultimately contribute to plant productivity and product quality.

Specific wavelengths of light provide discrete information to the plant leading to particular responses. For instance, blue light (400-500 nm) controls phototropic growth, leaf expansion, stem growth inhibition and accumulation of anthocyanin pigments. Red light (-660 nm) controls many responses including germination, functions of the chloroplast, stem and petiole growth. Far-red light (>700 nm) is an important signal in a shaded environment, and has a central role in modulating red light responses. All of these light wavelengths have effects on flowering and gene expression.

In plants, light signals are transduced through well-described pathways that can control the many aspects of plant growth and development (Chen, M et al, 2004). These pathways have been translated to a large number of crop species, where genetic and photophysiological analyses demonstrate the effects of various wavelengths of light on plant productivity (Frantz et al, 2004; Singh et al, 201 1 ; Barrero et al, 2012; Li & Ma, 2012; Preuss et al, 2012; Reynolds et al, 2012).

Although yield is often affected, qualities such as ripening, color and nutraceutical content are also affected by the light environment. In practice, light is a passive entity, driving plant processes based on the available photon energy from the sun, greenhouse, or artificial environment.

Numerous aspects of plant organic compound metabolism are influenced by overall light conditions, such as, the cellular redox state, cyclic nucleotide metabolism in bean, and phenylpropanoid production in Arabidopsis (Brown et al, 1989; Jin et al, 2000; Dietz & Pfannschmidt, 201 1).

There is strong interest in understanding plant-human interaction with regard to plant produced volatile organic compounds (Dudareva & Pichersky, 2008; Du et al, 2011; Miyazaki et al, 2012; Tieman et al, 2012). In particular, plant volatile contributions to flavor during gustation (retro-nasal), and fragrance during inhalation (ortho-nasal) have high intrinsic value for product quality and human liking (Goff & Klee, 2006). Floral fragrance, the quality of having a sweet and pleasant scent, is composed of volatile organic compounds (VOCs) that are generally lipophilic liquids with high vapor pressures and low molecular weights. The floral VOCs are commonly separated into three main categories: benzenoids/phenylpropanoids, fatty-acid derivatives, and terpenoids. Additionally, carotenoid derivatives, as well as nitrogen containing and sulfur containing floral VOCs have been identified.

Fruit flavor and aroma, which are important factors that drive consumer-liking, are also generated by a diverse set of chemicals including organic volatile compounds such as phenolics and carotenoids. For example, in tomato fruits, flavor intensity is associated with twelve different compounds, seven of which are independently significant for tomato flavor even after accounting for fructose: 2-butylacetate, cis-3-hexen-l-ol, citric acid, 3-methyl-l -butanol, 2-methylbutanal, l-octen-3- one, and trans,trans-2,4-decadienal. Sweetness of tomato fruits is associated with twelve compounds, eight of which overlap with those flavor compounds and three of which are independent predictors of sweetness even after accounting for fructose: geranial, 2-methylbutanal, and 3 -methyl- 1-butanal (Tieman et al., 2012).

Plant volatile production can be influenced by light quantity over the course of fruit development in strawberry (Watson et al, 2002). For example, terpenoids have been shown to be modulated by the photosensory receptor proteins, phytochromes (Peer & Langenheim, 1998; Tanaka et al, 1998). A USDA group demonstrated that when sweet basil plants were grown on colored mulches, the volatile compounds emitted from fresh leaves varied with the color of mulch used (Loughrin & Kasperbauer, 2003).

Studies have also examined light effects during de-etiolation, that is, the molecular and biochemical events occurring throughout a seedling's transition from darkness to light, termed "photomorphogenesis". Research in this area has primarily been performed in Arabidopsis thaliana seedlings, as ample genetic resources and well-described physiology allow an opportunity to dissect light-regulatory networks.

Relatives to Arabidopsis are frequently consumed as nutrient-dense vegetables, often as seedlings shortly after germination, or "sprouts". Brassica sprouts have been shown to be rich in many phytonutrients including anthocyanins, glucosinilates, sulforaphane, carotenoids, flavonoids, general antioxidants, and terpenes (Manchali et al, 2012; Bjorkman et al, 201 1 ). It has also been demonstrated that cruciferous sprouts had 10-100 times the quantity of chemoprotective compounds than mature plants (Fahey et al, 1997). Qualitative and quantitative differences in phytonutrients are also observed during germination and seedling development (Gu et al, 2012). Some of these compounds have been shown to have potential anti-cancer properties, as demonstrated by in vitro assays (Abbaoui et al, 2012; Brooks et al., 2001) and in mice (Dinkova-Kostova et al., 2010). Consumption of broccoli sprouts is associated with a risk reduction in populations exposed to environmental pollutants (Kensler et al., 2012). Many studies document the chemoprotective effects of compounds derived from sprouts, and clinical trials indicate that they may be consumed without any ill effects (Shapiro et al, 2006).

It has been shown that secondary metabolite networks do change in response to environmental cues such as heat stress (Lee et al, 2012), nitrogen and sulfur availability (Li et al, 2007) and UV-B irradiation (Mewis et al , 2012). Narrow bandwidth LED light has been used to analyze changes in carotenoid and glucosinolate levels in mature kales (Lefsrud et al, 2008) and broccoli sprout nutrient levels could be increased with specific treatments of blue light (Kopsell and Sams, 2013).

Different combinations of altered C0₂, salinity and light levels influence lettuce antioxidant activity (Perez-Lopez et al, 2013). Salinity stress has also been shown to influence different metabolites in radish sprouts (Yuan et al, 2010).

Light studies in mature plants have demonstrated that specific light treatments can influence accumulation of carotenoids (Lefsrud et al, 2008; Becatti et al, 2009; Tuan et al, 2012; Lee et al, 2013), anthocyanins (Samuoliene et al, 2013 ; Zhou et al, 2007) and chlorophyll (Fan et al, 2013).

BRIEF SUMMARY

The present invention provides methods for applying controlled, narrow-spectrum light treatments to plants and plant parts (such as flowers, fruits) to modulate size, color, stature, nutraceutical content, flavor, and/or aroma of plants or plant parts.

The present invention further provides software and/or control devices for plant lighting systems (such as light-emitting diodes (LEDs)) that can be used to modulate size, stature, nutraceutical content, flavor, and/or aroma of plants or plant parts.

BRIEF DESCRIPTION OF DRAWINGS

Figures 1A-1B illustrate ( A ) Spectroradiometer readings of the light qualities used in the experiments described in Examples 1-5. All treatments represent the waveform generated at a

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fluence rate of 50 μηιοΐ m s . B = blue, R = red, FR = far-red, HBW = half-bandwidth. (B) Histograms of petunia FVBP emission under white and far-red wavelengths of light (50 umol*s^" 2 -2

*m ) quantitatively represent detected 2-phenylethanol and phenylacetaldehyde compounds. Y- axis is in ng*gfw ^~^ *h and the X-axis is general white light (black bar) and far-red treatment (gray bar) over a time course (mean ± se; n = 3). MD flowers are treated for eight hours (same as in Fig. 1A) then placed in white light conditions; volatiles are collected every four hours afterward until the next day.

Figure 2 illustrates the Petunia x hybrida cv 'Mitchel Diploid' (MD) FVBP metabolic pathway beginning with phenylalanine, and FVBP compound emission under varying light conditions. Histograms of petunia FVBP emission under different wavelengths of light (50 -2 -2

umol*s *m ) quantitatively represent detected FVBP compounds. For the histograms, the Y-axis is in ng*gfw^~' *h^~ , and the X-axis is general white light (W), blue light (Bl), red (R), far-red (F-R), and dark (D) lighting conditions (mean ± se; n = 3). Lower case letters above the standard error bars are the results of a one-way ANOVA (t-distribution). Inset picture is a representative MD flower.

Figure 3 illustrates the Petunia x hybrida cv 'Mitchel Diploid' (MD) FVBP metabolic pathway beginning with phenylalanine, and FVBP compound emission under varying treatment time of far-red light conditions. Histograms of petunia FVBP emission under white and far-red

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wavelengths of light (50 umoI*s *m ) quantitatively represent detected FVBP compounds. Y-axis is in ng*gfw^"^ *h^~^ , and the X-axis is general white light (W), 2 hours under far-red treatment (2H), 4 hours (4H), 6 hours (6H), and eight hours (8H) (mean ± se; n = 3). Lower case letters above the standard error bars are the results of a one-way ANOVA (t-distribution). Inset picture is a representative MD flower.

Figure 4 shows an example of Solatium lycopersicum cv 'M82' volatile organic compound emission under varying light conditions. Histograms of tomato volatile compound emission under

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different wavelengths of light (50 umol*s *m ) quantitatively represent select volatile compounds. For the histograms, the Y-axis is in ng*gfvv^~^ *h and the X-axis is general white light (W), blue light (Bl), red (R), far-red (F-R), and dark (D) lighting conditions (mean ± se; n =3). Lower case letters above the standard error bars are the results of a one-way ANOVA (t- distribution). Inset picture is a representative of tomato fruit used in these experiments.

Figure 5 shows an example of Fragaria ananassa cv 'Strawberry Festival' volatile organic compound emission under varying light conditions. Histograms of Festival volatile

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compound emission under different wavelengths of light (50 umo *s "*m ) quantitatively represent select volatile compounds. For the histograms, the Y-axis is in

and the X- axis is general white light (W), blue light (Bl), red (R), far-red (F-R), and dark (D) lighting conditions (mean ± se; n =3). Lower case letters above the standard error bars are the results of a one-way ANOVA (t- distribution). Inset picture is a representative of Festival fruit used in these experiments.

Figure 6 shows an example of Vaccinium corymbosum cv 'Scintilla' volatile organic compound emission under varying light conditions. Histograms of Scintilla volatile compound emission under different wavelengths of light (50 umol*s~ *m^" ) quantitatively represent select volatile compounds. For the histograms, the Y-axis is in ng* gfw *h , and the X -axis is general white light (W), blue light (Bl), red (R), far-red (F-R), and dark (D) lighting conditions (mean ± se; n =3). Lower case letters above the standard error bars are the results of a one-way ANOVA (t- distribution). Inset picture is a representative of Scintilla fruit used in these experiments.

Figure 7 shows that light modulates plant growth. Green light promotes stem growth. Arabidopsis seedlings are imaged every five minutes using high-resolution CCD cameras. After stabilizing dark growth rates, light is applied. Blue, red and far-red light conditions inhibit growth, while green light increases plant growth rate. The results are observed in all receptor mutant backgrounds, indicating that green light modulates plant growth via a novel receptor.

Figure 8A-8B show that while exposure to light generally increases the level of transcripts required for photosynthesis, green light reduces the level of transcripts required for photosynthesis. The results show that the levels of three key transcripts required for photosynthesis decrease in response to a green light pulse in an etiolated seedling.

Figure 9 shows that green light induces shade-like responses. Plants adapting to shade typically grow with elongated petioles and less leaf expansion. The response to low light environments can be mimicked by increasing green light. The addition of green wavebands induces a shade-like phenotype in Arabidopsis rosettes. The shade -like responses are observed in all photomorphogenic mutants, indicating that the shade-like response is mediated by a novel green light sensor.

Figure 10A-10F show that the application of green light reverses the effects of red and/or blue light in developing seedlings. (A) and (B) show that the application of green light reverses the inhibition effect of red light on plant growth. However, examination of photoreceptor mutants shows that phototropin 1 blue light receptor mediates the pathway in which green light reverses the effects of red and/or blue light on plant growth. The results indicate that green wavebands oppose the effects of red and blue light; green light indicates to plants the presence of non-optimal photosynthetic conditions, invoking plant adaptive response.

Figure 11 shows that applications of light of desired wavelengths can be used to modulate the size, color and nutraceutical contents in plants.

Figure 12 shows methods of volatile collection useful in the present invention.

Figure 13 shows various pathways for synthesis of volatile compounds in plants.

Figures 14A-14D show phenotypes of 4-day old Red Russian kale seedlings under selective light conditions. Shown are representative seedlings grown for (A) 4 days under dark, white (1, 10 and 100 pmol m^"2 s^"1) , red (1 , 25 and 100 μιηοΐ m^"2 s^"1), far-red (1, 10 and 100 μηιοΐ m^"2 s^"1) or blue light (1 , 20 and 100 μηιο m^"2 s^"1), (B) 1 day of darkness and 3 days of light, (C) 2 days of darkness and 2 days of light, and (D) 3 days of darkness and 1 day of light.

Figures 15A-15E show hypocotyl elongation of Red Russian kale seedlings under selective light conditions. Hypocotyl length is shown in graphs after (A) 4 days of exposure to white, far-red, red or blue light with the indicated fluence rates, (B) 1 day of darkness and 3 days of light, (C) 2 days of darkness and 2 days of light, and (D) 3 days of darkness and 1 day of light. (E) Hypocotyl elongation during 4 days of exposure to 0 (closed circles) or 10 μηιοΐ m^"2 s^"1 of white (opened circles), far-red (grey circles), red (closed triangles) or blue (opened triangles) light. Results are representative of three independent experiments. Means ± SE, n = 18.

Figures 16A-16D show anthocyanin content in 4-day old Red Russian kale seedlings under selective light conditions. Anthocyanin levels are shown graphically after (A) 4 days of exposure to white, far-red, red or blue light with the indicated fluence rates, (B) 1 day of darkness and 3 days of light, (C) 2 days of darkness and 2 days of light, and (D) 3 days of darkness and 1 day of light. Results represent the average of three independent experiments. Means ± SE.

Figures 17A-17D show chlorophyll levels in 4-day old Red Russian kale seedlings under selective light conditions. Chlorophyll content is shown graphically after (A) 4 days of exposure to white, far-red, red or blue light with the indicated fluence rates, (B) 1 day of darkness and 3 days of light, (C) 2 days of darkness and 2 days of light, and (D) 3 days of darkness and 1 day of light. Results represent the average of three independent experiments. Means ± SE.

Figures 18A-18D shows the effect of simultaneous red and far-red light irradiance on the growth of Red Russian kale seedlings. Shown are (A) hypocotyl length (representative of three independent experiments; means ± SE, n = 18.), (B) anthocyanin content (average of three independent experiments, means ± SE), (C) chlorophyll levels (average of three independent experiments, means ± SE), and (D) a representative picture of 4-day old seedlings exposed for 1 day to darkness and 3 days to the indicated red and far-red light fluence rates.

Figures 19A-19B show the effect of simultaneous red, far-red and blue light irradiance on the growth of Red Russian kale seedlings. (A) Anthocyanin and (B) chlorophyll levels of 4-day old seedlings exposed for 1 day to darkness and 3 days to the indicated red, far-red and blue light fluence rates are illustrated. Results represent the average of three independent experiments. Means ± SE.

Figure 20 shows the effect of light wavelength on the anti-oxidant capacity of Red Russian kale seedlings. Trolox equivalents (TE) in 4-day old seedlings grown under continuous darkness or 50 μπιοΐ m^"2 s^"' fluence rate of the indicated light conditions are graphically illustrated. Results are representative of three independent experiments. Means ± SE., n = 3.

Figures 21A-21F show the growth of Red Russian kale under optimized sequential light treatments. (A) Scheme representing the four treatments (Tl to T4) of light used on seedlings grown for four days is shown. Transitions every 24 h are indicated and a change in color represents a change in a light condition; D, dark, W, white light (50 μηιοΐ m^"2 s^"1), R, red light (25 μηιοΐ m^"2 s^"1), FR, far- red light (50 μηιοΐ m^"2 s^"1), and B, blue light (50 μηιοΐ m^"2 s^"1). (B) Representative pictures are shown. (C) Hypocotyl elongation, (D) anthocyanin accumulation, (E) chlorophyll levels, and (F) antioxidant capacity of kale seedlings from all four treatments are graphically illustrated. Scale bars represent 1 cm.

DETAILED DISCLOSURE

In various embodiments, the present invention provides methods for applying controlled, narrow-spectrum light treatments to plants and plant parts (such as flowers, fruits) to modulate color, stature, nutraceutical content, flavor, and/or aroma of plants or plant parts.

In additional embodiments, the present invention provides software and/or control devices for plant lighting systems (such as light-emitting diodes (LEDs)) that can be used to modulate color, stature, nutraceutical content, flavor, and/or aroma of plants or plant parts. In one embodiment, the present invention provides a specific "prescription" that improves colors, size, and/or shape of plants and plant products. In certain embodiments, the light treatments of the present invention substantially increase various beneficial plant chemicals.

In certain embodiments, the present invention can be utilized by specialty crop growers such as greenhouse growers of lettuces and sprouts. The present invention can also be applied to high- value crops and produce such as, but certainly not limited to, strawberry and tomato.

Plant growth, development and metabolism are controlled by light acting through discrete photosensors and associated transduction pathways. Specific metabolic nodes (regulated by genes and proteins they encode) are known to be affected by light.

In accordance with the present invention, treatment of fruits, flowers and herbs with narrow- bandwidth LED light can be used to alter the accumulation of flavor and aroma compounds. The results show that the accumulation of various volatiles in plants can be modulated in accordance with the light treatment methods of the present invention.

The present invention offers the opportunity to re-shape flavor and aroma of plant products using light treatment, and can be used to transform how fruits, vegetables and flowers are treated before and after harvest. In certain embodiments, the present invention provides specialized lighting systems composed of controllable LED light sequences. In a specific embodiment, software is used to attain improved flavor and aroma of plant products, and to enhance qualities of plant products post-harvest.

Grow lights and other light sources used in plant growth are passive and do not impart active control of growth, development or metabolism. The use of LED light in specific combination of wavelengths, intensities and durations that dynamically changed based on empirical data, to specifically control discrete metabolic systems, is unique to this invention. In one embodiment, the present invention provides a method of altering (e.g., increasing) the emission level of an organic volatile compound in a plant cell, plant tissue, or plant part, wherein the method comprises: applying a narrow-bandwidth light to a plant cell, plant tissue, or plant part capable of producing an organic volatile compound of interest, wherein the narrow-bandwidth light is from an artificial light-emitting source or is obtained from filtering natural or artificial light.

In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm (such as less than l Onm).

In one embodiment, the narrow-bandwidth light is a monochromatic light or has a bandwidth of less than lOOnm, or any value less than l OOnm (such as less than lOnm).

In one embodiment, the narrow-bandwidth light has a bandwidth of less than l OOnm, or any value less than 1 OOnm (such as less than 1 Onm).

In certain embodiments, the narrow-bandwidth light can be applied, before or after harvest of the flowers or fruits, to a floral or fruit cell, tissue or a whole flower or fruit. In one preferred embodiment, the narrow-bandwidth light is applied after harvest of flowers or fruits, to a floral or fruit cell, tissue, or a whole flower or fruit.

In one embodiment, two, three, or multiple narrow-bandwidth lights, are applied to a plant cell, plant tissue, plant part, or a whole plant, before or harvest of the plant cell, plant tissue, or plant part.

In one embodiment, two, three, or multiple narrow-bandwidth lights, each has a half- bandwidth of less than 50nm, or any value less than 50nm (such as less than l Onm), are applied before or after harvest of the flowers or fruits, to a floral or fruit cell, tissue or a whole flower or fruit. In one embodiment, two, three, or multiple narrow-bandwidth lights, each has a half-bandwidth from 3nm to 50nm, or any value therebetween, are applied before or after harvest of the flowers or fruits, to a floral or fruit cell, tissue or a whole flower or fruit.

In certain embodiments, the present invention provides a method for modulating color, stature, and/or nutraceutical content of plants, wherein the method comprises: applying a narrow- bandwidth light to a plant cell, plant tissue, plant part, or a whole plant, before the plant is harvested, wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light. In some embodiments, the methods are carried out while the plant is a seedling. In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm (such as less than lOOnm).

In certain embodiments, the narrow-bandwidth light has a half-bandwidth from 3nm to 5 Onm, or any value therebetween, including, but not limited to, 5nm to 45nm, lOnm to 40nm, 15nm to 30nm, and 20nm to 25nm.

In one embodiment, two, three, or multiple narrow-bandwidth lights, each has a half- bandwidth of less than 50nm, or any value less than 50nm (such as less than lOnm), are applied a plant cell, plant tissue, plant part, or a whole plant, before the plant is harvested, in order to modulate color, stature, and/or nutraceutical content of the plant.

In one embodiment, two, three, or multiple narrow-bandwidth lights, each has a half- bandwidth from 3nm to 50nm, or any value therebetween, are applied a plant cell, plant tissue, plant part, or a whole plant, before the plant is harvested, in order to modulate color, stature, and/or nutraceutical content of the plant.

In certain embodiments, the light comprises, or consists of, a monochromatic light selected from near ultra-violet (UV-A), blue, green, yellow, orange, red, and far-red.

UV-A light has a frequency within the range of approximately 668THz to 789THz and a wavelength within the range of approximately 320nm to 400nm.

Blue light has a frequency within the range of approximately 606THz to 668THz and a wavelength within the range of approximately 400nm to 495nm.

Green light has a frequency within the range of approximately 526THz to 606THz and a wavelength within the range of approximately 495nm to 570nm.

Yellow light has a frequency within the range of approximately 508THz to 526THz and a wavelength within the range of approximately 570nm to 590nm.

Orange light has a frequency within the range of approximately 484THz to 508THz and a wavelength within the range of approximately 590nm to 620nm.

Red light has a frequency within the range of approximately 400THz to 484THz and a wavelength within the range of approximately 620nm to 700nm.

Far-red light has a wavelength within the range of approximately 700nm to 760nm.

In one embodiment, the present invention does not encompass the application of a white light from an artificial or natural source to plant cells, tissues, parts, or a whole plant.

In one embodiment, the present invention does not encompass placing or storing plant cells, tissues, parts, or a whole plant in darkness (with no visible light). In another embodiment, the present invention embodies placing or storing plant cells, tissues, parts, or a whole plant in darkness (with no visible light).

In one embodiment, the present invention does not encompass the application of an electromagnetic radiation with a wavelength shorter than that of visible light (e.g., ultraviolet light (such as ultraviolet A, ultraviolet B, ultraviolet C), and X-rays) to plant cells, tissues, parts, or a whole plant.

In another embodiment, the present invention embodies the application of an electromagnetic radiation with a wavelength shorter than that of visible light (e.g., ultraviolet light (such as ultraviolet A, ultraviolet B, ultraviolet C), and X-rays) to plant cells, tissues, parts, or a whole plant. In one embodiment, the present invention does not encompass the application of an electromagnetic radiation with a wavelength longer than that of visible light (e.g., infrared) to plant cells, tissues, parts, or a whole plant.

In another embodiment, the present invention embodies the application of an electromagnetic radiation with a wavelength longer than that of visible light (e.g., infrared) to plant cells, tissues, parts, or a whole plant.

In certain embodiments in accordance with the present invention, plants or parts thereof (including cells and tissues) are exposed to a narrow-bandwidth light for a period of more than 5 minutes, or any time period more than 5 minutes including, but not limited to, more than 30 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 24 hours, 30 hours, 36 hours, 40 hours, or 48 hours, and 5 days.

In certain embodiments in accordance with the present invention, plants or parts thereof (including cells and tissues) are exposed to a narrow-bandwidth light for a period of less than 90 days, or any time period less than 90 days including, but not limited to, more than 60 days, 30 days, 20 days, 15 days, 10 days, 9 days, 8 days, 7 days, 6 days, 5 days, 4 days, 3 days, 2 days, or 1 day.

In certain embodiments in accordance with the present invention, an artificial light is applied to a plant cell, plant tissue, plant part, or whole plant at a photo fluence rate of at least 0.1 umol-m^_2-s^_1, or any value higher than 10 umol-m^~2-s^-1, including, but not limited to, higher than 1, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 150, 180, 200, 250, 300, 350, 400, 450, 500, 700, 800, or lOOO umol m ² s^_1.

In certain embodiments, in accordance with the present invention, an artificial light is applied when a plant cell, plant tissue, plant part, or whole plant is placed at a temperature from 2°C to 40 °C, or any temperature between, including refrigerator temperature (about 4°C) and room temperature (about 15 - 25°C).

In certain embodiments, to modulate a plant trait, a narrow-bandwidth light can be applied to plant parts including, but not limited to, flowers, fruits, seeds, leaves, and stems.

In one embodiment according to the present invention, light applied to plants or parts thereof (e.g., flowers, fruits) consists of a single waveband having a narrow-bandwidth. In another embodiment according to the present invention, light applied to plants or parts thereof (e.g., flowers, fruits) comprises or consists of more than one wavebands (such as, a red waveband and a blue waveband), each having a narrow-bandwidth.

Monochromatic light is of one wavelength or a narrow range of wavelengths. If the wavelength is in the visible range, monochromatic light will be of a single color. As used herein, "monochromatic" refers to light that has a bandwidth of less than about 100 nm. More preferably, the bandwidth will be less than about 10 nm, and most preferably less than about 1 nm. 5

1 1

Half-bandwidth refers to the range of wavelengths present in a light sample at 50% of peak amplitude.

Light Modulation of Plant Flavor and Aroma Compounds in Flowers and Fruits

Volatile compounds contribute to the aroma and flavor profiles of plant products.

Coordinated synthesis and release of dozens to hundreds of compounds produces the aromatic signature of fruits and flowers. The volatile compounds are produced through several biochemical pathways in plants (e.g., phenylpropanoids, fatty acid derivatives, and terpenes). Multiple enzymatic steps in each pathway regulate the flow of substrates to subsequent catalysis leading ultimately to the emission of a volatile product.

In one embodiment, the present invention utilizes monochromatic light treatments to modulate the organoleptic qualities of common flowers and fruits that produce diverse aromatic products. Light modulates the expression of enzymes involved in the synthesis and release of volatile and aroma compounds in plants.

In one embodiment, the present invention shows that in a post-harvest setting, the flux of substrates through discrete biochemical nodes can be modulated by applying specific quantities and qualities of light, thereby modulating the production and release of volatile compounds in flowers and fruits. Thus, light treatments can be used to modulate the flavor or aroma qualities of a given genotype of plant, creating a range of phenotypes from a common genetic background. Light treatments can also be employed to stabilize or induce desirable flavors and aromas of fruits and flowers post-harvest.

In certain specific embodiments, emission levels of volatile compounds in petunia flowers, tomato, strawberry, and blueberry fruits are modulated by the application of different wavelengths of light post-harvest. The results show that narrow band- width light modulates the emission of various volatiles important to plant product quality.

In one embodiment, far-red light increases rose oil emission in petunia. In another embodiment, red, far-red, and dark treatments increase emission of flavor and sweet volatiles in tomato.

In one embodiment, the present invention provides a method of altering (e.g., increasing) the emission level of an organic volatile compound in a plant cell, plant tissue, or plant part, wherein the method comprises: applying a narrow-bandwidth light, or multiple lights, from an artificial light- emitting source to a plant cell, plant tissue, or plant part capable of producing an organic volatile compound of interest.

In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm (such as less than lOnm). In another embodiment, the present invention provides a method of altering (e.g., increasing) the emission level of an organic volatile compound in a plant cell, plant tissue, or plant part, wherein the method comprises: applying a narrow-bandwidth light to a plant cell, plant tissue, or plant part capable of producing an organic volatile compound of interest, wherein the narrow-bandwidth light is obtained by filtering natural or artificial light.

In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm (such as less than lOnm).

In certain embodiments, the narrow-bandwidth light has a half-bandwidth from 3nm to 50nm, or any value there between, including, but not limited to, 5nm to 45nm, l Onm to 40nm, 15nm to 30nm, and 20nm to 25nm.

In one embodiment, the narrow-bandwidth light has a wavelength within the range of 300nm to 900nm, or any range therebetween, such as between 350nm to 800nm.

In certain embodiments, the present invention provides a method of altering (e.g., increasing) the emission level of organic volatile compounds including, but not limited to, benzenoids/phenylpropanoids; fatty acid derivatives; esters; carotenoids (such as beta carotene and lycopene); and terpenes.

Phenylpropanoids represent the largest pool of secondary metabolites, and more than 7000 phenylpropanoid compounds have been documented in plants. Floral volatile benzenoid/phenylpropanoid (FVBP) compounds are putatively derived from the aromatic amino acid L-phenylalanine (Phe), which is synthesized in the plastid from metabolites originating in the shikimate pathway. The characteristic benzene ring (derived from Phe) can be modified with multiple and varying side-groups.

In certain embodiments, the present invention provides a method of altering (e.g., increasing) the emission level of volatile benzenoids/phenylpropanoids including, but not limited to, phenylacetaldehyde, phenylethylalcohol, benzaldehyde, phenylacetaldehyde, isoeugenol, eugenol, 2- phenylethanol, benzyl alcohol, methyl benzoate, benzylacetate, ethyl benzoate, vanillin, phenylpropanoid, benzyl benzoate, 2-phenylethanol, methyl salicylate, 2-phenethyl acetate, and phenethyl benzoate.

Fatty-acid derived VOCs are saturated and unsaturated hydrocarbons. Volatile fatty-acid derivatives are produced from the breakdown of, for example, CI 8 unsaturated fatty acids, primarily linolenic and linoleic acids, and include an assorted group of volatiles including green leaf volatiles and methyl jasmonate. Fatty-acid derived VOCs appear to be synthesized in membranous structures of plant cells.

Terpenoids are derived from isopentyl diphosphate and dimethylallyl diphosphate. Terpenoids are produced through two alternative pathways, the cytosolic mevalonic acid pathway and the plastidic methyl-erythritol pathway. Terpenoids are subdivided into five classes based on structure: hemiterpenes (C5), monoterpenes (CI O), sesquiterpenes (CI 5), homoterpenes (C 1 1 -CI 6), and diterpenes (C20).

In one specific embodiment, the present invention provides a method of increasing the emission level of a floral volatile benzenoid/phenylpropanoid (FVBP) compound in a floral cell or tissue, wherein the method comprises: applying a narrow-bandwidth light from an artificial source to a floral cell or tissue capable of producing a FVBP compound of interest. In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm, such as less than l OOnm.

In one specific embodiment, the present invention provides a method of increasing the emission level of a floral volatile benzenoid/phenylpropanoid (FVBP) compound in a floral cell or tissue, wherein the method comprises: applying a narrow-bandwidth light to a floral cell or tissue capable of producing a FVBP compound of interest, wherein the narrow-bandwidth light is obtained by filtering natural or artificial light. In one embodiment, the narrow-bandwidth light has a half- bandwidth of less than 50nm, or any value less than 50nm, such as less than l Onm.

In one further embodiment, the narrow-bandwidth light is a red light and/or a far-red light. In certain embodiments, FVBP compounds, whose emission level is increased by the application of a red light and/or far-red light (as compared to the application of white light that contains the entire visible spectrum without absorption), include, but are not limited to, phenylacetaldehyde, 2-phenylethanol, isoeugenol, eugenol, 2-phenethyl acetate, benzyl alcohol, benzaldehyde, methyl benzoate, and methyl salicylate.

In one embodiment, a narrow-bandwidth light of a selective spectrum is applied to one or more floral organs including stigma, style, petal, sepal, receptacle, and ovary.

In certain embodiments, the present invention can be used to alter (e.g., increase) the emission level of organic volatile compounds in floral organs of angiosperm species including, but not limited to, Solanaceae, Asteraceae, Orchidaceae, Scrophulariaceae, Cucurbitaceae, Leguminosae, Solanaceae, Rosaceae, Cruciferae, Rutaceae, Myrtaceae, Liliaceae, Passifloracae, Oxalidaceae, Vitaceae, Actinidiaceae, and Caricaceae.

In certain embodiments, the present invention can be used to alter (e.g., increase) the emission level of organic volatile compounds in floral organs of angiosperm species including, but not limited to, petunias, roses, chrysanthemums, carnations, daisies, petunias, torenia, bellflowers, tulips, gladiolas, snapdragons, orchids, lilies, lavenders, cherry flowers, and camellias. In one specific embodiment, the present invention can be used to alter the emission level of organic volatile compounds in Petunia.

In certain embodiments, the present invention provides a method of increasing the emission level of a volatile organic compound in a fruit cell or tissue, wherein the method comprises: applying a narrow-bandwidth light to a fruit cell, tissue, or a whole fruit, wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light.

In certain embodiments, the present invention can be used to alter (e.g., increase) the emission level of organic volatile compounds in fruits including, but not limited to, tomatoes; citrus fruits such as oranges, grapefruits, lemons, and limes; grapes; apples; pears; peaches; plums; cherries; bananas; berries such as blackberries, blueberries, raspberries, cranberries, and strawberries; pineapples; dates; avocadoes; olives; Passiflora edulis; melons such as watermelons, cantaloupes, and honeydews; figs; kiwi fruits; mangos; and pomegranate fruits.

Petunia

Petunia x hybrida cv 'Mitchell Diploid' (MD) is an established floral volatile model system with a relatively low metabolic background and a comparatively small number of emitted volatiles (Verdonk et al, 2003; Schuurink et al , 2006; Colquhoun et al, 2010; Colquhoun & Clark, 201 1). Major volatile compounds are generated in large quantities from the petal limb tissue (Underwood et al, 2005). The genetic regulation and biochemical formation of MD floral volatile benzenoids/phenylpropanoids has been well described.

Petunia x hybrida cv 'Mitchell Diploid' (MD) is useful for examining light-quality-mediated regulation of specific control points in regard to plant secondary metabolism. MD also has the advantage of few other screening pigments in the petals, since the flowers are white. Compared to the other plant products, the white flowers should not reflect incident light in the visible spectrum, which allows for full illumination with the photon energies applied.

In general, the blue light treatment of MD flowers has little to no effect on volatile emission, except a slight decrease of benzaldehyde emission relative to white light conditions is observed (Fig. 2).

Benzaldehyde production in MD floral limb cells is putatively catalyzed by a BALDH enzyme, which is localized to the mitochondria (Long et al , 2009). Currently, benzaldehyde is the only MD volatile compound thought to originate from the mitochondrial subcellular compartment. Mitochondrial cellular localization varies with light spectrum in mesophyll cells of Arabidopsis (Islam et al, 2009). Blue light induces an early acceleration of mitochondria movement that is fluence rate dependent. If this latter phenomenon exists in petunia, transport of substrates from other cellular compartments (plastids, peroxisomes, and cytoplasm) may be affected under different light conditions, which may provide a differential situation to examine trafficking mechanisms of floral volatile substrates.

In contrast to blue treatments, red and far-red light affect the emission of phenylacetaldehyde, 2-phenylethanol, benzyl alcohol, and benzyl benzoate. For the emission of these compounds, both red and far-red had comparable effects, indicating that the response to light is not phytochrome reversible.

Figure 2 also shows that methyl salicylate is significantly reduced only by far-red light treatment, indicating that methyl salicylate production may be repressed by active phytochrome. Multiple mechanisms may be responsible for the affect red and far-red light treatments have on MD floral fragrance.

Tomato

In one embodiment, the present invention provides a method of increasing the emission level of a volatile organic compound in tomato, wherein the method comprises: applying a narrow- bandwidth light to a tomato fruit or part thereof, wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light.

In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm, such as less than lOnm.

In one embodiment, a narrow-bandwidth red light and/or far-red light is applied to tomato fruits to enhance the emission of volatile organic compounds and to improve aroma and/or taste.

Tomato fruit volatile profiles are much more complex when compared to petunia, yet tomato is also a well-established system for characterization of plant volatiles (Buttery el al, 1987; Goff & Klee, 2006; Tieman et al, 2012). There are a number of reports regarding the role of light in fruit phytonutrient content (Azari et al , 2010). For example, some of these reports show how light affects the storage of juices (Hashizume et al, 2007), or the effect of light treatments on lycopene accumulation during fruit ripening (Alba et al , 2000).

In one embodiment, the present invention examines the effect of spectral light treatments on a subset of volatiles that contribute significantly to tomato flavor (Tieman et al, 2012). The compounds cis-3-hexenal (grassy), cis-3-hexen-l-ol ("green", leafy), 2-methyl butanal (cocoa, coffee-like), and 3 -methyl- 1 -butanol (amyl alcohol) have important roles in shaping the flavor of tomato, with the latter two providing a perception of sweetness (Tieman et al, 2012).

Compared to white light controls, treatment of tomatoes with far-red light results in significant differences of all four compounds examined, while dark treatments result in increases in 2-methyl butanol and 3-methyl-l -butanol (Fig. 4). Some of the most significant increases in volatile emission, compared to white light treatments, are when fruits ripen in far-red light or darkness. The results indicate that light is driving a process (either dependent on photosynthesis, metabolism, or development) that actually decreases the accumulation of these compounds.

The results are consistent with previous reports that show how genes known to participate in light-driven responses affect tomato pigmentation and nutritional quality. Liu et al. (2004) identified high pigmentation mutants as HY5 and a COP-like gene. HY5 is known for its role in phytochrome and cryptochrome signaling. COPl and COP-like genes have defined roles in light signaling as well. Although flavors are not assessed in the hpl and hp2 mutants, it is postulated that the increased carotenoids may give rise to changes in key volatiles (like beta-ionone) that can affect flavors (Chen, G et al, 2004; Vogel et al , 2010; Tieman et al, 2012).

Red light treatment of the tomatoes results in a significant increase in 2-methyl butanol and

3 -methyl- 1-butanol, while levels of cis-3-hexenal are reduced, all compared to white light treatments (Fig. 4). The results show that significant changes in tomato flavor volatiles can be attained by altering the ripening light environment. These findings are important because two volatiles that contribute to sweet flavor perception (without the contribution of sugars) are present at higher levels after red light treatment than in white light, indicating that the likability of tomato may be increased due to a perceived sweeter flavor.

In certain embodiments, a narrow-bandwidth far-red light is applied to a tomato fruit or part thereof before and/or after harvest of the tomato fruit, thereby increasing the emission level of one or more volatile compounds including cis-3-hexenal, cis-3-hexen-l-ol, 2-methyl- butanol, and 3-methyl- 1-butanol (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, a narrow-bandwidth red light is applied to a tomato fruit or part thereof before and/or after harvest of the tomato fruit, thereby increasing emission level of volatile compounds including 2-methyl butanol and 3 -methyl- 1-butanol (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, before and/or after harvest of a tomato fruit, the tomato fruit is placed in dark (no light), and the emission level of volatile compounds including 2-methyl butanol and 3 -methyl- 1-butanol is increased (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, the present invention is used to increase sweetness and/or aroma intensity of a tomato fruit.

In certain embodiments, a narrow-bandwidth light is applied to a tomato fruit or part thereof to enhance the emission of one or more volatile compounds including, but not limited to, 2- butylacetate, cis-3-hexen- l-ol, citric acid, 3-methyl-l-butanol, 2-methylbutanal, l -octen-3-one, trans,trans-2,4-decadienal, geranial, 2-methylbutanal, and 3 -methyl- 1-butanal. In certain embodiments, a narrow-bandwidth light is applied to a tomato fruit or part thereof to enhance the emission of one or more volatile compounds including, but not limited to, trans-2- penetenal, trans-2-heptenal, isovaleraldehyde, 3-methyl-l -butanol, methional, isovaleric acid, 2- isobutylthiazole, 6-methyl-5-hepten-2-one, β-ionone, phenyl acetaldehyde, geranylacetone, 2- phenylethanol, isobutyl acetate, cz^'s-3-hexen-l-ol, l-nitro-2-phenylethane, trans, trans-2,4-decadienal,

2- methylbutanal, hexyl alcohol, guaiacol, hexanal, l-octen-3-one, c i-3-hexenal, methylsalicylate, /ra¾s-2-hexenal, β-damascenone, and 2-methyl-l-butanol.

In one embodiment, a narrow-bandwidth light that does not comprise blue light is applied to a tomato fruit or part thereof.

The present invention can be used to modulate flavors of fruits without changing the genetics, adding transgenes or hormones, or affecting plant nutrition. By changing red and far-red mixtures or the daily duration of red and far-red treatments post-harvest in accordance with the present invention, the flavor of tomato fruits can be remodeled. Strawberry

In one embodiment, the present invention provides a method of increasing the emission level of a volatile organic compound in strawberry, wherein the method comprises: applying a narrow- bandwidth light to a strawberry fruit or part thereof, wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light.

In one embodiment, a narrow-bandwidth red light and/or far-red light is applied to strawberry fruits to enhance the emission of volatile organic compounds and to improve aroma and/or taste.

C ultivar "Strawberry Festival" fruits exposed to various spectral light treatments are assayed for the abundance of cis-2-hexen-l -ol (green, grassy), methyl butyrate (apple, pineapple), ethyl caproate (pineapple, banana) and hexyl butyrate (fruity, sweet).

Exposure to various light conditions does not significantly affect the accumulation of cis-

3- hexen-l-ol. Methyl butyrate emission increases significantly in response to far-red light, and to a lesser extent to red light and dark treatment (Fig. 5). Ethyl caproate is most abundant under white light conditions. Exposure to narrow-bandwidth light decreases the levels of ethyl caproate by 4 to 50 folds, and there is a greater decrease in ethyl caproate under complete dark treatment.

The results indicate that the pathways leading to production of ethyl caproate contain regulatory nodes that require active participation of blue and red (and possibly far-red) signaling systems. Conversely the independent steps may depend on blue, then red light cues (or vice-versa) to produce the enzymes necessary for synthesis of ethyl caproate. The emission of hexyl butyrate is unaffected in all light conditions except for blue light. Monochromatic blue light decreases hexyl butyrate accumulation by approximately fivefold, indicating that activation of cryptochromes (or possibly other blue light sensors) regulates expression, stability, or activity of enzymes required for its synthesis.

When strawberry is compared to tomato for light control of cis-3-hexen-l-ol accumulation, the data indicate that light has an effect in tomato, but not in strawberry fruit tissue. In tomatoes, the levels of cis-3-hexen-l-ol are clearly affected by far-red light (Fig. 4), in a manner indicative of phytochrome control. This same pattern is not observed in strawberry where the compound is present in similar quantities across treatments (Fig. 5). In these cases the enzymes that underlie production are not regulated in the same way or their substrates are not comparably available.

In certain embodiments, a narrow-bandwidth far-red light is applied to a strawberry fruit or a part thereof before and/or after harvest of the strawberry fruit, thereby increasing the emission level of volatile compounds including methyl butyrate and hexyl butyrate (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, a narrow-bandwidth red light is applied to a strawberry fruit or a part thereof before and/or after harvest of the strawberry fruit, thereby increasing emission level of volatile compounds including methyl butyrate (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, the present invention is used to increase sweetness and/or aroma intensity of strawberry.

In certain embodiments, a narrow-bandwidth light is applied to strawberry or parts thereof to enhance the emission of one or more volatile compounds including, but not limited to, cis-2-hexen-l- ol, methyl butyrate, ethyl caproate, hexyl butyrate, and cis-3-hexen-l-ol.

In certain embodiments, a narrow-bandwidth light is applied to strawberry or parts thereof to enhance the emission of one or more volatile compounds including, but not limited to, esters including methyl butanoate, ethyl butanoate, methyl hexanoate, butyl butanoate, ethyl hexanoate, 3- methylbutyl butanoate, hexyl acetate, hexenyl acetate, methyl anthranilate; terpenes including, linalool, myrtenyl acetate; nerolidol; decalactone, undecalactone; benzaldehyde, undecanon, and hexanoic acid.

In one embodiment, a narrow-bandwidth light that does not comprise blue light is applied to a strawberry fruit or a strawberry fruit cell.

Blueberry

In one embodiment, the present invention provides a method of increasing the emission level of a volatile organic compound in blueberry, wherein the method comprises: applying a narrow- bandwidth light to blueberry fruit or a part thereof, wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light.

In one embodiment, a narrow-bandwidth red light and/or far-red light is applied to blueberry fruits to enhance the emission of volatile organic compounds and to improve aroma and/or taste.

Similar to strawberry and tomato fruits, blueberry fruits present a complex profile of flavor volatiles. However, unlike strawberry and tomato, blueberry fruit volatiles have not been as extensively characterized.

The effect of light on the emission of key volatiles likely to affect blueberry flavors, including trans-2-hexenol, trans-2-hexenal, linalool, a-terpineol, geraniol, limonene, cis-3-hexen-l-ol, nerol, l-penten-3-ol, hexanal, and 1,8-cineole are exam i ned (Parliment & Kolor, 1975; Hirvi & Honkanen, 1983; Horvat & Senter, 1985; Baloga ei al, 1995; Du et ai , 201 1).

In response to light, the levels of hexenal emission are highest after far-red treatment, but are not significantly affected by other treatments or darkness. The results indicate that reversion of phytochrome to an inactive state may increase the levels of this compound.

Trans-2 -hexanal is not significantly changed by light treatment, while 1-hexanol and trans-2-hexen-l-ol levels are decreased by blue and far-red treatment. When considered against petunia, tomato, and strawberry, blueberry exhibits the least change in response to monochromatic light environments.

In certain embodiments, a narrow-bandwidth far-red light is applied to blueberry or a part thereof before and/or after harvest of the blueberry fruit, thereby increasing the emission level of volatile one or more compounds including hexenal and trans-2-hexenal (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, a narrow-bandwidth red light is applied to blueberry or a part thereof before and/or after harvest of the blueberry fruit, thereby increasing the emission level of one or more volatile compounds including hexenal and trans-2-hexenal (as compared to the application of white light that contains the entire visible spectrum without absorption).

In certain embodiments, the present invention is used to increase sweetness and/or aroma intensity of blueberry. In certain embodiments, a narrow-bandwidth light is applied to blueberry or part thereof to enhance the emission of one or more volatile compounds including trans-2 -hexenol, trans-2-hexenal, linalool, a-terpineol, geraniol, limonene, cis-3-hexen-l-ol, nerol, l-penten-3-ol, hexanal, and 1,8-cineole.

In one embodiment, a narrow-bandwidth light that does not comprise blue light is applied to blueberry. The present invention shows that the level of a group of compounds central to flavors and aromas of fruits and flowers are modulated by monochromatic light in a post-harvest system. The present invention can be applied in post-harvest treatments or retail-level storage of fresh fruits and vegetables. The present invention can be used to enhance flavor in plant produce by designing simple, safe, and inexpensive light treatment programs that manipulate the quality of compounds that affect consumer liking.

Light Modulation of Color, Stature, and Nutraceutical Content of Plant Products

Plant growth and development depend on specific wavelengths of light. The light-directed control of size/height, color and nutraceutical content presents a means to alter plant-product quality without necessitating the application of growth regulators, other chemicals or extra labor.

In one embodiment, the present invention provides a method comprising placing plants into specific light environments in order to modulate plant traits (such as color and stature of plants), along with certain phytonutrients.

In another embodiment, the present invention provides a method for modulating color, stature, and/or nutraceutical content of plants, wherein the method comprises: applying a narrow- bandwidth light to a plant cell, plant tissue, plant part, or a whole plant, before the plant is harvested, wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light. In some embodiments, the methods are carried out at the plant's seedling stage of development.

In certain embodiments, the narrow-bandwidth light has a half-bandwidth from 3nm to 50nm, or any value therebetween, including, but not limited to, 5nm to 45nm, 1 Onm to 40nm, 15nm to 30nm, and 20nm to 25nm.

In one embodiment, the narrow-bandwidth light is a monochromatic light or has a bandwidth of less than lOOnm, or any value less than lOOnm (such as less than lOnm).

In one embodiment, the narrow-bandwidth light has a bandwidth of less than 1 OOnm, or any value less than 1 OOnm (such as less than lOnm).

In one embodiment, a narrow-bandwidth green light is applied to increase growth rate of stem and/or to induce shade-like responses in seedlings. It is postulated that plants have photoreceptors that respond to green light. A novel sensor receptor contributes to plant responses to green light, which is different from plant normal responses to blue and red light. While exposure to light generally makes stems grow at a slower rate, green light increases stem growth (Fig. 7). Also, exposure to light nonnally increases the accumulation of plastid transcripts, whereas green wavebands decrease the abundance of plastid transcripts (Fig. 8). Similar to far-red light, green light is an indicator of shade, thereby inducing adaptive shade-like responses in seedlings (Fig. 9). Genetic studies show that while a majority of plant responses to green light are mediated by a novel green receptor, certain responses to green light also are mediated by cryptochrome and phototropin blue light receptors.

In one embodiment, the narrow-bandwidth light has a wavelength within the range of 300nm to 900nm, or any range therebetween, such as between 350nm to 800nm. In certain embodiments, the light comprises, or consists of, a monochromatic light selected from violet, blue, green, yellow, orange, red, and far-red.

In certain embodiments, the present invention uses light treatments to modulate colors in plants including radish, kale, mung bean, broccoli, and spouts.

In one embodiment, a narrow-bandwidth light is applied to modulate nutraceutical content, such as, but not limited to, glucosinolate levels, anthocyanin levels, antioxidant capacity, and combinations thereof. In certain embodiments, the narrow-bandwidth light is selected from a far- red light, a blue light, and a combination thereof, when used to promote levels of anthocyanins. In other embodiments, the narrow-bandwidth light applied is a far-red light when used to promote antioxidant capacity.

In one embodiment, the present invention does not encompass the application of a white light from an artificial or natural source to plant cells, tissues, parts, or a whole plant. In one embodiment, the present invention does not encompass placing or storing plant cells, tissues, parts, or a whole plant in darkness (with no visible light). In another embodiment, the present invention embodies placing or storing plant cells, tissues, parts, or a whole plant in darkness (with no visible light).

In certain embodiments, plant species whose traits can be modulated by light treatment in accordance with the present invention include, but are not limited to, monocots, dicots, crop plants (e.g., any plant species grown for purposes of agriculture, food production for animals including humans), trees (e.g., fruit trees, trees grown for wood production, trees grown for decoration, etc.), and flowers of any kind (e.g., plants grown for purposes of decoration, for example, following their harvest).

In certain embodiments, examples of plant species whose traits can be modulated by light treatment in accordance with the present invention include, but are not limited to, Viridiplantae, Streptophyta, Embryophyta, Tracheophyta, Euphyllophytes, Spermatophyta, Magnoliophyta, Liliopsida, Commelinidae, Poales, Poaceae, Oryza, Oryza sativa, Zea, Zea mays, Hordeum, Hordeum vulgare, Triticum, Triticum aestivum, Eudicotyledons, Core eudicots, Asteridae, Euasterids, Rosidae, Eurosids II, Brassicales, Brassicaceae, Arabidopsis, Magnoliopsida, Solananae, Solanales, Solanaceae, Solanum, and Nicotiana.

In certain embodiments, examples of plant species whose traits can be modulated by light treatment in accordance with the present invention include, but are not limited to, radish, kale, mung bean, broccoli, spouts, lettuce, tomato, asparagus, cabbage (including green cabbage, red cabbage, white cabbage), corn, Brussels sprouts, cauliflower, sugarcane, sorghum, millet, rice, wheat, sweat pea, green bean, spinach, eggplant, basil, chives, parsley, celery, cucumber, barley, oat, soybean, grape, canola, Arabidopsis, Brassica sp., cotton, tobacco, bamboo, sugar beet, and sunflower.

In accordance with the subject invention, narrow bandwidth light can be used to shape the growth and metabolic content in commercially important plant species, including those that are closely related to Arabidopsis. Brassica sprouts have the genetic ability to produce an array of phytonutrients; alteration of the light environment can be used according to the current invention to enhance this potential.

Embodiments of the present invention utilize narrow bandwidth light sources provided by custom LED arrays to modulate size, pigment accumulation and nutraceutical content in Red Russian Kale {Brassica napus L.subsp. napus var pabularia). Red Russian kale is utilized in certain embodiments since it is a healthful food and exhibits significant phenotypic plasticity. The results show that kale seedlings follow the general rules defined by Arabidopsis, with some exception in the response to far-red light. The seedlings demonstrate wavelength-dependent alterations in anthocyanin content, glucosinolates and general antioxidant qualities. These findings demonstrate that a vocabulary of specific light treatment sequences may be applied to derive remarkably different outcomes from one genetic background.

In one embodiment, the present invention provides light-driven changes to Red Russian kale sprouts, seedlings that show great phenotypic variation. Manipulation of time in darkness, light wavelengths and fluence rates induce changes in several features, such as stem length, pigment accumulation, antioxidant capacity and glucosinolate content.

In one embodiment, the present invention examines how conspicuous seedling traits like hypocotyl growth rate, chlorophyll accumulation, anthocyanin levels, and cotyledon expansion are affected by time of growth in darkness followed by transfer to various fluence rates of light. Generally, typical photomorphogenic responses are observed with respect to inhibition of stem elongation, cotyledon expansion and accumulation of pigments, in end-point analyses. Such findings are consistent with what has been observed in Arabidopsis thaliana seedlings. However, kale seedlings show some important differences. Observation of the panels in Fig. 14 and quantitative results in Fig. 15 show that most of the elongation growth is occurring after two days in darkness. In contrast, Arabidopsis grows rapidly in darkness shortly after germination and elongation rates slow thereafter (Gendreau et at, 1997). Red Russian kale elongates slowly at first and then more rapidly with establishment (Fig. 15E). The effects of white, red and blue light are generally comparable when comparing seedling morphology, with a few exceptions. White light has limited effects on hypocotyl elongation at low fluence rates. This finding is important because application of narrow bandwidth light can potentially use lower fluence rates and less energy to obtain a stronger effect. Like Arabidopsis, far-red light has a strong effect on stem growth rate inhibition, yet the effect is even observed here at the lowest fluence rates. This suggests a hypersensitivity to far-red light.

Pigmentation is also measured in embodiments of the invention. Fig. 16 shows the effects on anythocyanin accumulation. Anthocyanins have been associated with healthful benefits and provide an attractive coloration to fruit and vegetable products. Black raspberry promoter demethylation- mediated cancer protective effects have been shown to be in part based on anthocyanin bioactivities (Wang et al, 2013). In the mulberry plant and in sweet potato anthocyanins are known to act as hypoglycemic agents, suggesting their use in diabetes prevention (Zhao et al., 2013; Gao et al, 2004). Demonstrated anti-inflammatory and anti-microbial activities of black soybean anthocyanins suggest these pigments as good candidates for a synergistic usage with administered antibiotics (Yoon et al, 2013). The natural availability of anthocyanin metabolic enzymes in different human tissues further potentiates the use of anthocyanin-rich products in target site therapies (Mallery et al, 2011)

While most light conditions have comparable fluence-rate response effects, far-red light induces robust accumulation even at low fluence rates. Embodiments of the invention also show that one day is sufficient to add substantial anthocyanin pigmentation to the seedling. Chlorophyll accumulation is comparable in all light conditions, both in respect to seedling developmental competence and in fluence-rate response. The exception is that red light causes significantly more accumulation under a lower fluence rate (25 μιηοΐ m^"2 s^"1), as shown in Fig. 17.

The application of narrow-bandwidth technology according to the subject invention to control of plant growth and development lies in application of precise mixes of light through time to optimize the production of desired traits. The concept of 'steady signaling states' implies that a given light condition may bring gene expression and metabolism into a predictable range (Folta and Childers, 2008). Consistent with this concept, the ratio of red to far-red light was tested in embodiments of the invention, as a steady-state equilibrium of active phytochrome and input through phyA may allow optimization of pigment accumulation. The results in Fig. 18 show that far-red and red with a balance of 3: 1 at these fluence rates provides the optimal balance of anthocyanins and chlorophylls. Chlorophyll does not accumulate well under far-red light alone, owing to the effect of far-red light on chloroplast development (Barnes et al, 1996). In combination with blue light (Fig. 19) far-red light produces more anthocyanins per g tissue than with far-red light alone (Fig. 16). Again, far-red light induces the strongest anthocyanin response, while having an inhibitory effect on chlorophyll accumulation.

The accumulation of specific secondary metabolites can be controlled by light (Samuoliene et al, 2013). General antioxidants are induced by some light conditions. For example, UV-B and UV-C stimulates phenolics, stilbenes and overall antioxidant activity in pigeon pea {Cajanus cajan) leaves (Wei et al, 2013; Coiquhoun et al, 2013). A supplementary UV-B treatment also affects the total antioxidant activity in basil (Sakalauskaite et al, 2013). In one embodiment, the ORAC-FL method was employed to estimate general antioxidant capacity in light-treated brassica seedlings. The results in Fig. 20 show that far-red light also elevates the anti-oxidant potential of treated seedlings, with white light also producing high levels. The latter result suggests that input through multiple light sensory pathways is required to maximize production, while the former shows that activation of phyA is sufficient to attain the same effect.

Brassicas are known to be particularly enriched in glucosinolates, compounds that contribute to their flavors and have been associated with healthful effects (Cartea and Velasco, 2008). Glucosinolates have been shown to be affected by light treatments in mature kales (Lefsrud et al, 2008) and in radish hypocotyls (Hasegawa et al, 2000), with blue light supplementation leading to higher levels. In one embodiment, light increased the levels of most aliphatic glucosinolates, with the exception of 40HI3M, which is dark abundant (Table 1). Overall these results indicate that only minor differences are observed in response to different light treatments, and are likely not physiologically relevant. In addition, it is possible that the glucosinolate levels in mature kale plants differ from the numbers measured in young seedlings.

Embodiments of the invention examined an integrative approach to generate in the end a kale sprout with an acceptable size, a desirable color and optimized antioxidant levels. Fig. 21 A shows the sequence of light treatments employed with the goal of producing variations in the final product that enhance produce quality. The first treatment matches standard production characteristics - germination in darkness followed by greening and cotyledon development under white light. Another group of seedlings is germinated in darkness to promote stem elongation, and is then transferred to an intermediate fluence rate of red light. Red light promotes chlorophyll accumulation, while still allowing elongation growth, leading to green sprouts with long stems and some accumulation of anthocyanins. The similar chlorophyll levels obtained in the two treatments using blue and far-red- light can either reflect the inclusion of a 24 h red-light pulse or the combination of blue and far-red light inductive effects on this pigment accumulation, despite the fact that this red-light pulse was insufficient to prevent stem elongation inhibition to a large extent. The addition of blue light leads a strong production of anthocyanins and total glucosinolates (Table 2) and a final far-red treatment drives the production of antioxidants but decreases glucosinolate concentrations. This result contrasts with the measurements under single light- wave lengths (Table 1), where the higher antioxidant capacity (Fig. 20) correlates with the highest glucosinolate levels.

A significant aspect of embodiments of the present invention is that this limited set of conditions can produce a variety of plant products from a single genetic background. A small grower with a simple light infrastructure can modulate colors, size and nutrition to add value to a single genotype. It allows one set of seeds, management and production practices to be maintained, with an end product of remarkably different seedlings. Screening Methods

In another embodiment, the present invention provides a method for identifying a particular narrow-bandwidth for increasing the emission level of a volatile organic compound of interest, from flower or fruit of an angiosperm species, wherein the method comprises:

applying a narrow-bandwidth light of a test spectrum to a plant cell, plant tissue, or plant part

(e.g., flower, fruit) capable of producing a volatile organic compound of interest;

determining the emission level of the volatile organic compound of interest; and

identifying the test spectrum that increases the emission level of the volatile organic compound of interest.

In certain embodiments, the present invention can be used to identify specific wavelengths of light for modulating (e.g., increasing, reducing) the emission level of organic volatile compounds including, but not limited to, phenylacetaldehyde, phenylethylalcohol, benzaldehyde, phenylacetaldehyde, isoeugenol, eugenol, 2-phenylethanol, benzyl alcohol, methyl benzoate, benzylacetate, ethyl benzoate, vanillin, phenylpropanoid, benzyl benzoate, methyl salicylate, 2- phenethyl acetate, phenethyl benzoate, l-penten-3-one, trans-2-hexenol, trans-2-hexenal, linalool, a- terpineol, geraniol, limonene, cis-3-hexen-l -ol, nerol, l-penten-3-ol, 1,8-cineole, methyl butanoate, ethyl butanoate, methyl hexanoate, butyl butanoate, ethyl hexanoate, 3-methylbutyl butanoate, hexyl acetate, hexenyl acetate, methyl anthranilate, linalool, myrtenyl acetate; nerolidol, decalactone, undecalactone, benzaldehyde, undecanon, hexanoic acid, cis-2-hexen-l-ol, methyl butyrate, ethyl caproate, hexyl butyrate, cis-3-hexen-l-ol, trans-2-peneten&\, ?rans-2-heptenal, isovaleraldehyde, 3- methyl- l-butanol, methional, isovaleric acid, 2-butylacetate, cis-3-hexen-l-ol, citric acid, 3-methyl-l - butanol, 2-methylbutanal, l-octen-3-one, trans,trans-2,4-decadienal, geranial, 2-methylbutanal, 3- methyl-l-butanal, 2-isobutyIthiazole, 6-methyl-5-hepten-2-one, β-ionone, geranylacetone, isobutyl acetate, cw-3-hexen-l-ol, 1 -nitro-2-phenyl ethane, 2-methylbutanal, hexyl alcohol, guaiacol, 1-octen- 3-one, methylsalicylate, irara-2-hexenal, β-damascenone, 2-methyl-l-butanol, (S)-linalool, 8- hydroxylinalool, linalool glycoside, nerolidol, limonene, methylbenzoate, bl-nitro-2-phenylathane, 2- benzyl acetate, phenylethyl acetate, pseudoionene, geranylacetone, β-ionone, hexanol, (Z)-3-hexenol, trans-2,4-hexadienal, c s-3-hexenol, 1-hexanol, hexanal, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, cz^'s-3-hexenal, ira«5^,-2,4-hexadienal, 2-ethylhexanol, β-caryophyllene, cembrene, nerolidol, furanoid, cw-linalool oxide, 4-methyl-l-pentanol, 6-methyl-hept-5-en-2-ol, hexenal, and hexenol.

In another embodiment, the present invention provides methods for identifying a particular narrow-bandwidth, or light spectrum, useful for modulating a plant trait (such as plant color, growth rate (including growth rate of stems, leaves, fruits, and/or flowers), stature, nutraceutical content, flavor, and/or aroma) of interest. Methods include applying a narrow-bandwidth light of a test spectrum to a plant (or cell, tissue, or part of the plant); growing the plant; determining the effect the test spectrum has on the plant trait; and identifying the test spectrum that modulates the plant trait of interest.

In certain embodiments, the screening method comprises applying a narrow-bandwidth light. In one embodiment, the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm (such as less than 1 Onm).

In one embodiment, the narrow-bandwidth light is a monochromatic light or has a bandwidth of less than lOOnm, or any value less than lOOnm (such as less than l Onm).

In one embodiment, the narrow-bandwidth light has a bandwidth of less than 1 OOnm, or any value less than lOOnm (such as less than lOnm).

In certain embodiments, the screening method comprises applying a narrow-bandwidth the light comprising, or consisting of, a monochromatic light selected from violet, blue, green, yellow, orange, red, and far-red.

In certain embodiments, the screening method comprises applying a narrow-bandwidth the light having a wavelength within the range of 3 OOnm to 900nm, or any range therebetween, such as between 35 Onm to 800nm.

In certain embodiments, the nutraceutical content that is modulated includes anthocyanin levels (also associated with coloration in plants), glucosinolate levels and general antioxidant levels.

Lighting Systems for Modulating Plant Traits

In another embodiment, the present invention provides a plant lighting system for modulating plant traits, including color, stature, nutraceutical content, flavor, and/or aroma.

In another embodiment, the present invention provides software and/or control devices that can be used to modulate color, stature, nutraceutical content, flavor, and/or aroma of plants. In one embodiment, the present invention provides materials and methods for controlling custom conditions that can be used to improve the growth of specific crops, allowing farmers to grow, for example, high- value crops, with less input.

In one embodiment, the present invention provides a plant lighting system for altering the emission level of a volatile organic compound of interest, from plants or plant parts (such as fruits and flowers), wherein the lighting system comprises: a light source capable of emitting a narrow- bandwidth light to a plant part of interest; and a controlling device for controlling the bandwidth of the light emitted from the light source so that when the narrow-bandwidth light is applied to the plant part (such as flowers and fruits), the emission level of a volatile organic compound of interest from the plant part is altered (such as increased or decreased).

In one embodiment, the present invention provides a plant lighting system for modulating a plant trait (such as plant color, growth rate, stature, nutraceutical content, flavor, and/or aroma) of interest, comprising: a light source capable of emitting a narrow-bandwidth; and a controlling device configured to control the frequency, range of wavelength, and/or bandwidth of the light emitted from the light source so that when the narrow-bandwidth light is applied to a plant or plant part, the plant trait of interest is modulated. In some embodiments, the plant trait of interest includes, but is not limited to, anthocyanin levels, chlorophyll levels, and glucosinolate levels.

In one specific embodiment, the present invention provides a plant lighting system for altering (e.g., increasing) the emission level of a volatile organic compound of interest from a floral organ or a fruit, comprising: a light source capable of emitting a narrow-bandwidth; and a controlling device configured to control the frequency, range of wavelength, and/or bandwidth of the light emitted from the light source so that when the narrow-bandwidth light is applied to a floral organ or a fruit, the emission level of the volatile organic compound of interest from the floral organ or the fruit is altered (e.g., increased).

In one specific embodiment, the volatile organic compound of interest increases the intensity of aroma and/or flavor (such as sweetness) of the fruit.

In another embodiment, the volatile organic compound of interest increases the intensity of floral fragrance or scent of a flower.

In a further embodiment, the lighting system comprises a sensor for determining the emission level of one or more volatile organic compounds of interest.

In one specific embodiment, the present invention provides a plant lighting system for increasing the intensity of aroma and/or flavor (such as sweetness) of a fruit, comprising: a light source capable of emitting a narrow-bandwidth; and a controlling device configured to control frequency, range of wavelength, and/or bandwidth of the light emitted from the light source so that when the narrow-bandwidth light is applied to a fruit, the intensity of aroma and/or flavor (such as sweetness) of the fruit is increased.

In one specific embodiment, the present invention provides a plant lighting system for the intensity of floral fragrance or scent of a flower, comprising: a light source capable of emitting a narrow-bandwidth; and a controlling device configured to control the frequency, range of wavelength, and/or bandwidth of the light emitted from the light source so that when the narrow-bandwidth light is applied to a flower, the intensity of floral fragrance or scent of the flower is increased.

Light sources useful according to the present invention can be of any suitable conventional source including, but not limited to, light-emitting diode (LED), organic light-emitting diode (OLED), and a natural or artificial white light source comprising filters that let through light of the desired wavelength(s). The light source may be placed at any distance from the plants or parts thereof, before or after harvest, provided that the light energy used is sufficient to influence.

In certain embodiments, the controlling device can be a computer and/or a device-control software program, and preferably, having a specific "prescription" or program for modulating a trait of interest (e.g., the emission level of volatile organic compounds, color, stature, nutraceutical content, flavor, aroma, growth rate of plants or parts thereof) for a particular plant species.

In certain embodiments, the controlling device is in the form of a data-processing system or apparatus (such as a computer) within which a set of instructions, when executed, may cause the system or apparatus to perform any one or more of the methodologies discussed above. The methods and processes described herein can be embodied as a software code.

In one embodiment, the controlling device comprises a software code that can be stored on one or more computer-readable media (e.g., non-transitory computer-readable media). When a data- processing system or apparatus reads and executes the code and/or data stored on a machine-readable medium, the data-processing system or apparatus system performs the methods and processes embodied as the software code stored within the machine-readable medium.

In certain embodiments, the methods and processes described herein can be implemented in hardware modules. For example, the hardware modules can include, but are not limited to, application-specific integrated circuit (ASIC) chips, field programmable gate arrays (FPGAs), and other programmable logic devices. When the hardware modules are activated, the hardware modules perform the methods and processes included within the hardware modules.

In certain embodiments, machine-readable media useful according to the present invention can include computer-readable storage media and communication media accessible by the computer system. A computer-readable storage medium includes, but is not limited to, volatile memory such as random access memories (RAM, DRAM, SRAM); and non-volatile memory such as flash memory, various read-only-memories (ROM, PROM, EPROM, EEPROM), magnetic and ferromagnetic/ferroelectric memories (MRAM, FeRAM), and magnetic and optical storage devices (hard drives, magnetic tape, CDs, DVDs); or other media now known or later developed that are capable of storing computer-readable information/data for use by a computer system.

In certain embodiments, the plant lighting system of the invention is capable of emitting light with a half-bandwidth of less than 50nm, or any value less than 50nm, including, but not limited to, less than 45nm, less than 40nm, less than 35nm, less than 30nm, less than 25nm, less than 20nm, less than 15nm, less than l Onm, less than 5nm, and less than 3nm.

In certain embodiments, the half-bandwidth of the emission-line spectrum of the light source is less than 50nm, or any value less than 50nm (such as less than l Onm).

In certain embodiments, the half-bandwidth of the emission-line spectrum of the light source is from 3nm to 50nm, or any value therebetween, including, but not limited to, 5nm to 45nm, lOnm to 40nm, 15nm to 30nm, and 20nm to 25nm.

In one embodiment, the narrow-bandwidth light is a monochromatic light or has a bandwidth of less than l OOnm, or any value less than l OOnm (such as less than l Onm). In one embodiment, the narrow-bandwidth light has a bandwidth of less than 1 OOnm, or any value less than lOOnm (such as less than lOnm).

In one embodiment, the narrow-bandwidth light is a monochromatic light or has a bandwidth of less than 1 OOnm, or any value less than lOOnm (such as less than lOnm).

In certain embodiments, the plant lighting system of the invention is capable of emitting light having a wavelength within the range of 3 OOnm to 900nm, or any range therebetween, such as, between 350nm to 800nm.

In certain embodiments, the plant lighting system can be placed in green houses, processing compartments in processing factories, refrigerators, or shipping containers. In one embodiment, the light source can be manually or automatically activated by, for example, employing a timing means and thereby emitting wavelengths of light in accordance with the present invention.

Alternatively, an independent container specifically designed for exposing plant parts or cells to light of wavelengths as described herein may be employed. In a further alternative, the number of light sources may be as little as one to a whole "battery" of light sources arranged in series and/or in parallel, each light source being suitably distanced one from the other at appropriate intervals in such a manner as to effect exposure of the plant material to light of wavelengths in accordance with the present invention.

MATERIALS AND METHODS

Narrow-Bandwidth LED Light Platform

The light treatments are generated using a light emitting diode (LED) platform (Zhang et al, 2011) (Fig. IB). A dark treatment and four light treatments are tested: white, blue, red, and far-red

-2 -1

(Fig. 1A-B). In all cases, light treatments are 50 μηιοΐ m s in separate illumination chambers o o

within an environmentally-controlled area (22 C ± 1.5 C). The control treatment (white light) is generated by T8 cool white fluorescent bulbs, while the dark treatments are performed in an actively ventilated light-tight enclosure under the same ambient conditions. The light treatments are generated using the Flora Lamp LED arrays (Light Emitting Computers, Victoria, B.C.). Fruits and flowers are treated without photoperiod. Spectroradiometer readings are taken with a StellarNet device and visualized on SpectraWiz software (Stellar et, Tampa, FL).

For experiments involving Brassica napus pabularia, LED light is provided by Plant Whisperer light units (Light Emitting Computers, Victoria BC Canada). Principle wavelengths tested are 470, 660, 730 nm and white light supplied by Philips Cool White Fluorescent bulbs. Experimental trials are conducted in ventilated experimental chambers lined with reflective mylar. Light is applied at various fluence rates without photoperiod.

Petunia

In all cases of petunia experimentation, Petunia x hybrida cv 'Mitchell Diploid' (MD) plants (Mitchell et al, 1980) are grown in a glass greenhouse from seeds to reproductive maturity. Developing MD flowers are tagged at stage 6 and allowed to grow to stage 8 (Colquhoun el al, 2010). In the morning of stage 8 open flowers, tagged flowers are excised at the petiole, and placed in a 4 ml glass vial with 2 ml of tap water.

In the initial experiment (Fig. 2), the prepared MD flowers are placed in each of five light environments: white, blue, red, far-red, and dark. Six flowers are exposed to each light condition for eight hours and removed at 18:00 h. The corollas are then removed from the receptacle and two corollas are each inserted into a single glass tube for volatile collection, for three biological replicates. Multiple replications of this experiment are performed with similar results observed.

To determine the length of time required to obtain a light-induced volatile response, a time course experiment is subsequently conducted. Samples of eight flowers are exposed to a far red light environment for 0, 2, 4, 6, or 8 hours. Flowers are kept under white light (control) conditions until entering the far red light treatment.

A dark environment control is also included. At 18:00 h, all flowers are removed from their respective light treatments. Receptacle is detached, and two flowers are each inserted into a single glass tube for volatile collection, for four biological replicates. Multiple replications of this experiment are performed with similar results observed.

Tomato

Field grown tomatoes (Solanum lycopersicum, M82) are harvested at breaker stage and allowed to ripen under five different light conditions: white, blue, red, far-red, and dark. After 10 days, fruit are diced and lOOg samples are loaded into glass tubes in triplicate for volatile collection. Multiple replications of this experiment are performed with similar results observed. Strawberry

Field grown mature Fragaria x ananassa cv 'Strawberry Festival' fruit are harvested in the morning and chilled at 4°C overnight in dark conditions. Seven uniformly selected berries per treatment are placed into clear plastic containers the next morning, and allowed treatment conditions for 8 h. Light environments tested are white, blue, red, far-red, and dark. After 8 h, light- treated fruit samples are homogenized in a blender and 20 g of homogenate is loaded in triplicate into glass tubes for volatile collection. Multiple replications of this experiment are performed with similar results observed.

Blueberry

Field grown Vaccinium corymbosum cv 'Scintilla' fruit are harvested one day prior to light treatments. Mature blueberry fruits are harvested in the morning and chilled at 4°C overnight in dark conditions. The next morning selected uniform fruit are spread in a single layer and placed in the light treatments for eight hours. After the treatments, the berries are removed, blended 15 s, and volatiles are collected in triplicate (30 g homogenate per tube). Multiple replications of this experiment are performed with similar results observed.

Volatile Collection

Samples are loaded as described previously into thin walled glass tubes attached to a dynamic headspace volatile collection system with a column containing HaySep Q 80-100 porous polymer adsorbent (Hayes Separations Inc., Bandera, TX) at the tube outlet to capture volatile organic compounds over a period of one hour. Volatiles are eluted from the column with 150 μΐ methylene chloride spiked with 5 μΐ of nonyl acetate as an elution standard. Elutions are run on an Agilent 7890 A Series Gas Chromatograph Flame Ionization Detector.

Peaks from the chromatography traces of compounds within a sample elution are identified using Chemstation software (Agilent Technologies, Santa Clara, CA). Peak areas of detected VOC are used to determine the mass of said compound within a sample via calculations that adjust for nonyl acetate elution standard and original biological sample mass (Underwood et al., 2005; Dexter et al, 2007). GC-MS is used to confirm the presence of compounds and identify retention times that are not associated with a GC standard. Red Russian Kale

Seeds for Red Russian kale (Brassica napus pabularia; Johnny's Selected Seeds, Waterville ME) are surface sterilized in 25% (v/v) bleach for ten minutes followed by a brief treatment with 70% ethanol and then are placed on vertical water-agar plates or on horizontal water-agar magenta boxes for the final sequential treatments. The seeds are stratified at 4°C for 48 h, exposed to white light for one hour and transferred to darkness for 24-96 h prior to light treatments.

Fluence rate response / Developmental competence

Seeds on agar plates are transferred to complete darkness and then moved to light conditions on sequential days. Seedlings are grown under various fluence rates and wavelengths, alone or in combination as described. All experiments analyzed end-point hypocotyl length after 96 h. Seedlings are imaged on a flat-bed scanner and then measured using Image Tool 3.0.

Extraction and measurement of anthocyanins and chlorophyll

4-day old seedlings grown under different light conditions are collected, roots excised, immediately frozen in liquid nitrogen, reduced to powder using a mortar and a pestle, and transferred to an eppendorf tube where the weight is measured. Around 60 mg and 20 mg of powder weight are used for anthocyanins and for chlorophyll extraction, respectively.

Anthocyanins extraction follows the method described by Neff and Chory (1998). Three hundred microliters of methanol-1 % (v/v) HC1 is added to each tube and incubated overnight at 4°C under dark. 200 μΐ of water and 500 μΐ of chloroform are then added and the tubes centrifuged for 5 min at maximum speed at room temperature. The supernatant is transferred to a new tube and the volume adjusted to 800 μΐ with 60% methanol-1% HC1. The absorbances at 530 nm and 657 nm are read with a SmartSpec 3000 spectrophotometer (Bio-Rad), using 60% methanol-1% HC1 as the blank. The amount of anthocyanins per seedling weight is calculated using the following equation:

Antho = (Abs₅₃₀ - Abs₆57) x 1000 x powder weight (mg)^"1

For chlorophyll extraction the method is described by Moran and Porath (1980). Ground leaf tissue is added to 800 μΐ of dimethylformamide incubated overnight at 4°C in darkness. The next day the absorbance is recorded at 647 nm and 664 nm in a quartz cuvette, using dimethylformamide as the blank. The total level of chlorophyll per seedling weight is calculated using the following equation:

Ch= 0.8 x (17.67 x Abs₆47 + 7.17 x Abs₆₆₄) x powder weight (mg)^"1

Measurement of total antioxidant capacity

The antioxidant capacity is determined following the ORAC-FL (oxygen radical absorbance capacity-fluorescein) method described by Cao et al. (1993) and modified by Ou et al. (2001). Four- day old seedlings, grown for 1 d under darkness and 3 d under light at 50 μιηοΐ m^"2 s^"1 fluence rate, are collected, roots excised and frozen in liquid nitrogen. The material is ground to powder and the weight registered. Around 150 mg is used per sample. Five milliliters of ice-cold PBS (pH 7.0) is added to the powder and incubated for 1 h on ice, under dark. Each solution is centrifuged for 30 min at 4000 rpm and 4°C, the supernatant transferred to three microcentrifuge tubes, and then centrifuged for 20 min at 20000 xg and 4°C. The supernatants are collected again into three new tubes, used as three technical replicates in each independent experiment. These solutions are kept on ice and immediately used for antioxidant capacity analysis or frozen at -80°C.

The ORAC-FL is conducted at 37°C in a 3 ml final volume (PBS solvent). The fluorescence is recorded every 5 min in a FluoroMax-3 fluorometer (Jobin Yvon Horiba) using 480 nm and 514 nm as the excitation and emission wavelengths, respectively. The reactions are conducted for 90 min or until a reaction has stopped (considered when the decay in fluorescence would be lower than 5% of the previous reading). Next, 300 μΐ of the diluted kale extracts are added to the cuvette containing fluorescein (sodium salt, Sigma) to a final concentration of 100 nM and equilibrated at 37°C for 15 min. AAPH (2,2'-azobis(2-methylpropionamidine) dihydrochloride, Sigma) is then added to a final concentration of 12 mM and the reaction started. To build the calibration curve the Trolox reagent (±- 6-hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid, Sigma) replaces the kale extracts in the reaction volume and the fluorescences of eight solutions with known Trolox concentrations from 1 to 8 μΜ are measured. Fluorescein and AAPH constitute the blank.

The area under the fluorescence decay curve, AUC, in a plot of the relative (to time zero, FL₀) fluorescence over time is calculated using the following equation, where ¾ is the fluorescence level read at a time point i and At is the interval between reads (5 minutes in our experimental conditions):

AUC = (FL₀/FL₀+FL₁/FLo+FL₂/FL₀+...+FL FL₀) x At (min) The difference between the A UC for a given sample and the blank, A UC _ank, gives the net area, Net A UC:

Net AUC = AUC-AUC_blank

Plotting the Net A UC of the Trolox samples versus the known Trolox concentrations allows to build a calibration curve and to extrapolate a concentration of Trolox equivalents in the kale extracts.

Measurement of glucosinolate content

For glucosinolates extraction around 100 mg of 4-d old seedlings (roots excised) are frozen in liquid nitrogen and reduced to powder in an eppendorf tube. 1 ml 70% methanol at 80°C and 30 μΐ of 5 mM benzylglucosinolate (glucotropaeolin potassium salt, ChromaDex) is added to each sample tube, vortexed and incubated at 80°C for 10 minutes. The tubes are centrifuged at 4000 rpm for 10 minutes (room temperature) and the supernatant transferred to a 15 ml falcon tube. This methanol extraction is repeated twice, the supernatants combined and the volume adjusted to 4 ml with 70% methanol.

For glucosinolates purification, 1 g DEAE sephadex A-25 resin (Sigma) is incubated overnight in 30 ml 0.5 M acetate buffer (pH 5.0) and 1 ml applied to a Bio-Rad column. The column is washed once with 5 ml water , the glucosinolate extract is then added, and the column is washed again twice with 2 ml 70% methanol, five times with 2 ml water and once with 2 ml 20 mM acetate buffer. 15 mg of sulfatase (Sigma) is dissolved in 6 ml 20 mM acetate buffer and 500 μΐ applied to each column, which are then left overnight at room temperature. The columns are eluted three times with 1 ml water, the eluted fractions dried in a speed-vac and the pellets resuspended in 100 μΐ water, from which 15 are used for the FTPLC analysis.

The glucosinolates studied are previously described in Arabidopsis. HPLC peaks are identified from absorbance at 229 nm with a UV detector and retention time, in comparison to known standards. Results are presented as μηιοΐ g^"1 fresh weight based on pure de-sulfoglucosinolate standards at 229 nm. Each treatment is analyzed in triplicate. Compounds are analyzed on a C-18 column using a 6 min gradient from 1.5 to 5.0% (v/v) acetonitrile (AN), a 2 min gradient using 5-7% AN, followed by a 7 min gradient from 7-25% AN and a 2 min gradient transitioning from 25-92% AN, then 6 min at 92% AN, then 1 in from 92-1.5% AN and lastly 5 min at 1.5% AN.

EXAMPLES

Following are examples that illustrate procedures and embodiments for practicing the invention. The examples should not be construed as limiting. EXAMPLE 1 - PETUNIA FLORAL VOLATILE EMISSION AFTER VARYING SPECTRAL LIGHT QUALITY TREATMENTS

This Example shows the effects of spectral light treatments on Petunia x hybrida cv 'Mitchell Diploid' (MD) floral volatile benzenoid/phenylpropanoid (FVBP) emission. MD floral fragrance production is a well characterized biological system consisting of a relatively simple, but robust fragrance bouquet (Verdonk et al, 2003; Schuurink et al, 2006; Colquhoun et al, 2010; Colquhoun & Clark, 2011).

Flowers from MD plants are excised at stage 8 (Colquhoun et al, 2010), placed in tap water, and moved from greenhouse conditions to specific lighting conditions. Detected amounts of FVBPs under white light treatments, which are comparable to what has been commonly reported in the literature (Boatright et al, 2004; Underwood et al, 2005; Verdonk et al, 2005; Colquhoun et al, 2010), are used as the control treatment.

Dark treatment of MD flowers results in the significant reduction of most of the FVBP compounds like: methyl benzoate, benzaldehyde, phenylacetaldehyde, isoeugenol, and eugenol (Fig. 2). No light treatments significantly affect the emission of MD floral volatile phenylpropanoids, isoeugenol and eugenol. The blue light treatment only results in a significant change of benzaldehyde emission, which is slightly reduced as compared to white light treated flowers. The most obvious manipulation of FVBP emission is observed with the red and far-red light treatments, which increase phenylacetaldehyde emission by 2.7 fold (red) and 2.3 fold (far-red), and increase 2-phenylethanol emission by 9.9 fold (red) and 5.8 fold (far-red). These treatments also result in an increased benzyl alcohol and benzyl benzoate emission. Methyl salicylate emission is significantly reduced after the far-red light treatment (Fig. 2). EXAMPLE 2 - PETUNIA FLORAL VOLATILE EMISSION AFTER TREATMENT WITH FAR- RED LIGHT OVER A TIME COURSE

Because treatment of MD flowers with far-red light results in an increase in volatile emission in largest number of FVBP compounds, far-red light is u sed in a time dependent manner to test for a rate of affective induction of change in volatile emission.

In this Example, MD flowers are placed under white light to far-red light conditions for 8 hours, and FVBP emission level is compared (Fig. 3). Similar differences in specific FVBPs affected and intensity of effect are observed when compared to the results shown in the previous experiment (Fig. 2), indicating reproducibility throughout experiments.

The results show that, under far-red light treatment, phenylacetaldehyde emission is elevated after 2 h and 4 h, then remained constant for the duration of the experiment, while emission of 2-phenylethanol increases over time with a similar profile as phenylacetaldehyde (Fig. 3). 2- phenethyl acetate and phenethyl benzoate, which are compounds derived from 2-phenylethanol, are also emitted at elevated levels compared to control conditions (Fig. 3) (emission of 2-phenethyl acetate and phenethyl benzoate is not detected in the previous experiment, Fig. 2). Benzyl alcohol e m i s s i o n is elevated by 2 h of far-red light treatment and reaches a maximum level after 8 h of treatment. Benzyl benzoate and benzaldehyde emissions are elevated by the far-red light treatment and both reach a maximum level after 4 h of treatment (Fig. 3). Methyl salicylate emission is reduced after 2 h of far-red light treatment, and remained consistent afterward. No significant change is detected for methyl benzoate or isoeugenol emission through any time-point of far-red treatment compared to the white light treatment.

This example also investigates the effect of the duration of the far-red light on the emission of phenylacetaldehyde and 2-phenylethanol. Briefly, MD flowers are exposed to the far-red light conditions for 8 hours, removed from the far-red light conditions, and placed into white light conditions; volatiles are collected every 4 hours for a total of five volatile collections (Fig. IB). Emission of phenylacetaldehyde and 2-phenylethanol from MD flowers directly after the 8 h far-red light treatment is similar to previous results as shown in Fig. 2, 3), indicating reproducibility throughout experiments. As the diurnal rhythm of MD volatile emission increases towards midnight, the effect of far-red light treatment on these volatiles is diminished when compared to the controls (Fig. IB).

EXAMPLE 3 - TOMATO FRUIT VOLATILE EMISSION AFTER VARYING SPECTRAL LIGHT QUALITY TREATMENTS

This Example examines the effect of varying spectral light on volatile emission in Solatium lycopersicum cv 'M82' fruit. Tomato fruit volatile compound production is a well characterized biological system. Unlike petunia fragrance, tomato fruit volatile profiles can consist of a large and complex number of volatile chemical species (Buttery et al, 1987; Tieman et al, 2012).

This Example focuses on emission of a simple set of volatile compounds cis-3-hexenal, cis- 3-hexen-l -ol, 2-methyl- butanol, and 3 -methyl- 1-butanol, which can be of commercial importance. Cis-3-hexenal is present in tomatoes in large amounts, and can generate a robust signal for our analytical techniques; cis-3 -hexen-l-ol, 2-methyl- butanol, and 3 -methyl- 1-butanol have been empirically demonstrated to contribute to overall tomato flavor intensity (Tieman et al, 2012).

Tomato fruits are harvested at breaker stage and allowed to ripen under white light, blue, red, far-red, and dark conditions. Compared to white light treatments, the blue light treatment does not result in significant differences in the emission of cis-3 -hexenal, cis-3 -hexen-l-ol, 2-methyl- butanol, and 3 -methyl- 1-butanol (Fig. 4). In contrast, the dark treatment results in a 5 fold increase in 3-methyl- 1-butanol, a 2.6 fold increase in 2-methyl butanol, and a significant increase of cis-3- hexen-l-ol, when compared to white light conditions. Red light treatment results in significant increases of 2-methyl butanol and 3-methyl-l -butanol, along with a reduction of cis-3-hexenal (Fig. 4). Far-red light treatment results in significant increases of cis-3 -hexenal, cis-3-hexen-l-ol, 2-methyl- butanol, and 3 -methyl- 1-butanol, with a notable 2.2 fold increase of cis-3-hexenal.

EXAMPLE 4 - STRAWBERRY FRUIT VOLATILE EMISSION AFTER VARYING SPECTRAL

LIGHT QUALITY TREATMENTS

This Example examines the effect of varying spectral light on volatile emission in Fragaria χ ananassa cv 'Strawberry Festival' fruit. Strawberry Festival fruit volatile profile can consist of a large array of volatile compounds (Maarse, 1991 ; Du et al, 201 1).

This Example focuses on a simple set of volatile compounds - cis-3-hexen-l -ol, ethyl caproate, methyl butyrate, and hexyl butyrate, which can be of commercial importance. Cis-3- hexen-l -ol is present in large amounts in strawberries; ethyl caproate and methyl butyrate production is well d o c u m e n t e d in the literature (Hakala et al, 2002; Jetti et al, 2007;

Olbricht et al , 2008); hexyl butyrate, a five carbon extension of methyl butyrate, has chemical similarity with methyl butyrate.

Mature strawberry fruit is harvested in the morning and chilled at 4°C overnight in dark conditions. Compared to white light treatments in strawberry, cis-3-hexen-l-ol emission is not significantly altered in any of the other light treatments (Fig. 5). In contrast, ethyl caproate emission is dramatically reduced in all light treatments compared to white light. Methyl butyrate emission is significantly increased after far-red light treatments, while hexyl butyrate emission is detected at significantly reduced amounts under blue light treatments (Fig. 5). EXAMPLE 5 - BLUEBERRY FRUIT VOLATILE EMISSION AFTER VARYING SPECTRAL LIGHT QUALITY TREATMENTS

This Example examines the effect of varying spectral light on volatile emission in Vaccinium corymbosum cv 'Scintilla' fruit. S i m i l ar to tom atoe s and strawberri es, blueberry fruits e m it a relatively large array of volatile compounds. Whi l e among various Vaccinium species and blueberry cultivars, significant variation in volatiles has been reported, a subset of volatiles, including trans-2-hexenol, trans-2-hexenal, linalool, a-terpineol, geraniol, limonene, cis-3-hexen-l- ol, nerol, l-penten-3-ol, hexanal, and 1,8-cineole, are reported in the literature as blueberry aroma compounds commonly emitted from various blueberry species (Hirvi & Honkanen, 1983; Horvat & Senter, 1985; Baloga e/ a/., 1995; Du el al, 201 1).

This Example shows the effect of varying spectral light on volatile emission on a simple set of volatile compounds: hexenal, trans-2-hexenal, 1 -hexanol, trans-2-hexen-l-ol, which are of putative importance in blueberry. Compared to white light treatments, blueberries exposed to far-red light conditions emit higher levels of hexenal, and reduced levels of 1-hexanol and trans-2- hexen-l-ol emissions (Fig. 6). The blue light treatment also results in significant reduction of 1- hexanol and trans-2-hexen-l-ol emissions, when compared to white light controls.

EXAMPLE 6 - MODULATION OF PLANT TRAITS BY LIGHT

This Example shows that light treatments can be used to modulate color, stature, and/or nutraceutical content of plants. In certain embodiments, light treatments can be used to modulate colors in plants including radish, kale, mung bean, broccoli, and sprouts.

In one embodiment, green light is applied to Arabidopsis seedlings. The results show that green light promotes stem growth (Fig. 7), decreases the abundance of plastid transcripts and inhibits seedling growth responses (Fig. 8), and induces adaptive shade-like responses in seedlings (Fig. 9). Genetic studies show that while a majority of plant responses to green light are mediated by a novel green receptor, certain responses to green light also are mediated by cryptochrome and phototropin blue light receptors.

EXAMPLE 7 - STEM GROWTH RESPONSES DURING DE-ETIOLATION IN RED RUSSIAN KALE SEEDLINGS DEPEND ON LIGHT WAVELENGTHS

This Example examines stem growth responses during de-etiolation to various light wavelengths in Brassica napus seedlings. Red Russian kale seedling development is first assessed under different light conditions and a variety of fluence rates. Seedlings are allowed to germinate in darkness and then moved to various wavelengths and three fluence rates, at 24 h intervals (light/dark; 0 D/96 L, 24 D/72 L, 48 D/48 L, 72 D/24 L). Fig. 14, panels A-D, shows the typical seedling response to light with expanded cotyledons and greening and also the repression of hypocotyl elongation. The effect of light on hypocotyl elongation is quantified in Fig. 15, A-D. White, blue and red light all have comparable effects on the kale responses over the duration of the experiment, leading to stronger stem growth inhibition under higher fluence rates. Far-red light, however, exerts a different effect and promotes the most robust repression, almost independently of the fluence rate, of stem growth rate (Fig. 15, A-D), with seedlings approximately 10% the length of dark-grown controls, even at 1 umol.m^.s^"1 after 0 D/96 L treatment (Fig. 15, A).

Comparison of the differences of hypocotyl length between panels C and D in Fig. 15 suggests the existence of a developmental switch during this time period, which prompts investigation of the response to light every 24 h during 4 days of exposure to an intermediate (10 μ ιοΐ m^"2 s ) fluence rate. As seen in Fig. 15, E, seedling growth rate under white, red and blue light is relatively slow over the first 48 h and begins to increase after this time point. Here again an exception is made for far-red, which inhibits growth rate after 2 d of exposure to continuous light (Fig. 15, E).

EXAMPLE 8 - ACCUMULATION OF ANTHROCYANINS AND CHLOROPHYLL IS REGULATED BY THE LIGHT WAVELENGTH AND FLUENCE RATE

In this Example, the combination of different treatments of altered darkness/light periods and/or different light wavelengths and fluence rates not only represses stem elongation to different extents but also promotes additional different phenotypic behaviors (Fig. 14, A-D). The typical seedling response to light is seen in all four conditions tested but appears to be stronger under 96 h of light (Fig. 14, A), with seedlings exhibiting the most cotyledon expansion, and all appearing green compared to other time points. In addition, generally, higher fluence rates promote darker colors, independently of the wavelength, whereas lower fluence rates result in greener seedlings. These observations suggest that kale seedlings are accumulating different pigments, namely anthocyanins and chlorophyll, hallmarks of photomorphogenic development. Having in mind consumer-desired colors and potential nutraceutical content, it is important to understand the parameters of pigmentation upon specific light conditions. Therefore, seedlings are grown as described in Fig. 14 and anthocyanins and chlorophyll are extracted and measured. The quantitative results from three independent trials of 18 seedlings are shown in Figs. 16 and 17. In all cases the pigments increase with fluence rate, as expected. Anthocyanins accumulate to similar levels under white, red and blue light but reach much higher levels under the exposure of any fluence rate of far-red light (Fig. 16). Chlorophyll accumulates to approximately the same levels in each seedling set (Fig. 17). The exception is that accumulation in red light is higher at 25 μηιοΐ m^"2 s^"1 than at an intermediate rate in any other light quality (Fig. 17).

EXAMPLE 9 - BALANCE OF RED AND FAR-RED LIGHT ON THE DE-ETIOLATION OF RED RUSSIAN KALE SEEDLINGS The modulation of plant growth and development by light is dictated by phytochromes, plant pigments that are generally activated by red light and inactivated by far-red light (reviewed in Chen and Chory, 2011). Under the presence of both wavelengths a dynamic equilibrium is established, allowing plants to rapidly optimize their response to that particular environment. In this Example, Figs. 15- 17 reveal that far-red and red light exert almost antagonistic effects on photomorphogenic development. Seedlings under far-red light exhibit a stronger suppression of hypocotyl elongation, accompanied by greater accumulation of anthocyanins, as opposed to longer and greener hypocotyls under red light. To further explore the interaction between these two wavelengths on kale growth, seedlings are grown for 4 d under different combinations of simultaneously applied red and far-red light (Fig. 18). Consistent with what is observed in Fig. 15, A-D, irradiance with a relatively small amount of far-red light, is sufficient to repress hypocotyl elongation (Fig. 18, A). In addition, the accumulation of anthocyanins is also dramatically higher with decreasing levels of the red to far-red light ratio (Fig. 18, B). Conspicuous effects are seen in Fig. 18, D, with seedlings showing substantial purple pigment accumulation with less green at lower red/far-red ratios. The presence of far-red light does not revert the induction of chlorophyll accumulation (Fig. 18, C) except when far-red light alone is applied. Here, chlorophyll levels decrease to almost half their levels when red light is present (Fig. 18, C).

EXAMPLE 10 - ADDITION OF BLUE LIGHT TO A RED/FAR-RED BACKGROUND ALTERS PIGMENT ACCUMULATION IN RED RUSSIAN KALE SEEDLINGS

Blue light typically induces anthocyanin accumulation. This Example examines the effect of blue supplementation on mixtures of red and far-red light. Seedlings are grown as in Fig. 18, except that blue light is added. Consistent with the effect of combinations of red and far-red light on hypocotyl elongation (Fig. 18, A), the presence of blue light does not augment the strong hypocotyl growth inhibition under high fluence rates (data not shown). The addition of blue light along with red and/or far-red light promotes increased levels of anthocyanins (Fig. 19, A). Increasing fluence rates of blue light on a red background leads to higher levels of anthocyanins. When blue light is applied together with far-red light anthocyanin accumulation is 30% higher than when far-red light is provided alone (Fig. 19, A and Fig. 16, B). The presence of high fluence rates of blue light under a red background is sufficient to induce a 50% increase in chlorophyll content when compared to the seedlings grown under red light (25 μηιοΐ m^"2 s^"1) alone, promoting the highest levels of chlorophyll accumulation measured in this study (Fig. 19, B and Fig. 17, B).

EXAMPLE 1 1 - TOTAL ANTIOXIDANT CAPACITY AND GLUCOSINOLATE ACCUMULATION IN RED RUSSIAN KALE IS AFFECTED BY THE LIGHT WAVELENGTH Wavelength-specific effects on anthocyanins and chlorophyll are conspicuous and quantifiable. Data from this Example suggest that there may be concomitant changes in antioxidant agents and/or glucosinolates (GL), two classes of compounds with reported health benefits (Gulcin, 2012; Traka and Mithen, 2009; Prakash and Gupta, 2012). To test this hypothesis, total antioxidant capacity of kale seedlings grown under different light wavelengths is assessed in this Example using the ORAC-FL (oxygen radical absorbance capacity-fluorescein) assay (Cao et al, 1993; Ou et al, 2001). This method is based on the capacity of any putative antioxidant agent to quench the activity of a peroxyl radical generator that induces a decay in fluorescence emitted by a fluorescent compound. The calculations are made using as a standard the Trolox reagent, a vitamin C analogue, and therefore the quantitative results indicate the antioxidant capacity of any sample by giving its concentration of Trolox equivalents (TE). For this test, kale seedlings are grown for 4 days in darkness or under a single fluence rate (50 μιηοΐ m^"2 s^"1) of different light wavelengths. The results show that far-red induces the highest TE accumulation (Fig. 20), approximately 25% higher than under white or blue light. In contrast, red light-grown seedlings have a TE concentration much lower than in any other light regime, albeit double the basal level of dark-grown seedlings.

Glucosinilate composition in light-grown kale seedlings is determined by HPLC. Light treatments are the same as those used for the ORAC-FL tests. GLs may be classified based on their side chain structure into groups (Dinkova-Kostova et al, 2010; Prakash and Gupta, 2012). In these trials two groups are identified - the aliphatic and the indole - and we observe differences in the accumulation of total and specific GLs (Table 1 ). Furthermore, within each group every specific GL is found to be present in kale grown under all treatments tested.

Treatment with far-red light increases the total aliphatic GL levels by 25% over dark controls, whereas white light, decreases them. Red and blue light does not induce any difference compared to darkness. When looking into specific aliphatic GL, light treatments generally decrease the levels of 4- hydroxy-indolyl-3-methyl-GL (40HI3M), but increase "unknown" GL species (which cannot be precisely resolved) to approximately 100-200%) under white light, red light or blue light conditions compared to dark controls. The only aliphatic species that is significantly modified by a single light treatment is 4-methylsulfinylbutyl-GL (4MSOB), which shows similar levels in all conditions except under far-red light, where a 50% increase is observed when compared to the dark level.

Total indole-based GLs are generally at their highest levels in etiolated seedlings (Table 1 ) and about double of what is present with any narrow-bandwidth treatment. Far-red, red and blue light all generate similar total indole GL levels, whereas white light lowers this amount about 40%. The substantial effect of white light on decreasing indole GLs is also visible when looking at specific species, as seen by the 67%, 50% and 85% decrease in indole-3-ylmethyl-GL (13 M), 4-methoxyindol- 3-ylmethyl-GL (4MTI3M), and l -methoxyindol-3-ylmethyl-GL (1MTI3M), respectively, when compared to dark-grown kale. This effect is observed to a similar extent under the rest of the light conditions except for DM, where far-red, red and blue light actually decreases it to lower levels than in darkness but still reaches a level 50% higher than what is measured under white light.

Finally, when total GL levels are examined across all light treatments, the accumulation is highest in far-red light, with approximately 15-42% accumulation compared to other light treatments or darkness.

Table 1. Steady-state accumulation of glucosinolates (GL) in specific light conditions. Data are presented as the mean of three independent biological replicates with standard error of the mean.

Letter notations indicate significantly different values based on a t-test (p < 0.05).

Glucosinolat Light condition

e (μηιοΐ g^" ) Dark White Far-Red Red Blue

1.72 ± 1.68 ± 2.48 ± 1.88 ±

4MSOB a a b ab 1.77 ± 0.05 a

0.15 0.12 0.16 0.35

0.17 ± 0.12 ± 0.28 ± 0.17 ±

5MSOP a a a a 0.17 ± 0.08 a

0.01 0.02 0.16 0.01

0.58 ± 0.17 ± 0.27 ± 0.15 ±

¾ 40HI3M a b b b 0.29 ± 0.10 ab

0.09 0.01 0.05 0.02

< 0.21 ± 0.25 ± 0.27 ± 0.16 ±

4MTB ab a ab b 0.37 ± 0.23 ab

0.01 0.02 0.04 0.02

0.12 ± 0.26 ± 0.20 ± 0.28 ±

unknown a be ab be 0.34 ± 0.05 c

0.01 0.02 0.03 0.03

Total 2.80 ± 2.48 ± 3.50 ± 2.64 ±

ab a b ab 2.94 ± 0.18 ab aliphatic 0.26 0.15 0.37 0.17

3.12 ± 2.57 ± 3.65 ± 2.81 ±

Total ab a b ab 3.07 ± 0.18 ab

0.29 0.15 0.40 0.14

4MSOB: 4-methylsulfmylbutyl-GL; 5MSOP: 5-methylsulfinylpentyl-GL; 40HI3M: 4-hydroxy- indolyl-3-methyl-GL; 4MTB: 4-methylthiobutyl-GL; DM: indole-3-ylmethyl-GL; 4MT13M: 4- methoxyindol-3-ylmethyl-GL; 1 MTDM: l-methoxyindol-3-ylmethyl-GL. EXAMPLE 12 - A SEQUENTIAL PROGRAM TO CONTROL END-POINT PRODUCTS

Examples herein show that controlling light conditions affects different physiological parameters in Red Russian kale. For instance, stem elongation, pigment accumulation and nutrient density are modulated by changing light wavelengths and fluence rates. This Example integrates the information gained to explore kale sprout plasticity during growth, to reach an "ideal" kale sprout for market. Four different combinations of light are tested over a period of four days. The sequence of treatments (Fig. 21, A) is designed to promote specific outcomes in the final product. The first treatment (Tl ) is a control, and includes three days of white light treatment following a 24 h-dark period to promote stem elongation. Treatment 2 (T2) serves as a transition from Tl to Treatment 3 (T3) and 4 (T4) and uses red instead of white light, at an intermediate fluence rate (25 μιηοΐ m^"2 s^"1) that does not repress stem elongation to a strong extent (Fig. 15, A-C) but is still able to promote chlorophyll accumulation (Fig. 17). In T3, the red-light treatment lasts one day and the other two are used for a combination of simultaneous far-red and blue light, which promote darker purple seedling colors (Fig. 14) and anthocyanin accumulation (Fig. 19, A) to a stronger level than other light treatments, and also increase the antioxidant capacity of kale (Fig. 20). Given the fact that far-red light has a stronger effect on the accumulation of GLs (Table 1), the blue light is switched off in the last day of growth in T4 when compared to T3.

Both white (Tl) and red (T2) light treatments repress hypocotyl elongation (Fig. 21, B and C) as described above (Fig. 15, B). Exposure to blue and far-red light in T3 and T4 treatments result in shorter seedlings. All four sequential treatments lead, in contrast, to the accumulation of similar chlorophyll levels (Fig. 21, E). The equal chlorophyll pigmentation is consistent with the similar leaf green coloration seen in all four treatments (Fig. 21, B), although leaves from T3 and T4 seedlings also show a higher content of purple pigments. The hypocotyls themselves also develop a dark purple color, in contrast to the mild and light purple seen in Tl and T2, respectively. Consistently, anthocyanin levels in T3 and T4 (Fig. 21, D) are increased, and 50% higher than in Tl and just slightly lower than the levels obtained with a one day darkness/three days of constant far-red or simultaneous far-red and blue wavelengths (Figs. 16, B and 19, A).

Tl and T3 treatments result in seedlings with similar antioxidant capacities (Fig. 21, F), with more than 100% of the TE measured in T2 but significantly lower than the nearly 100 μιηοΐ TE g^"1 registered in T4. Both aliphatic and indole-specific and total GL concentrations show a peak under the T3 treatment but decrease in T4.

When comparing GL levels under white light (Table 1) and Tl (Table 2), where the same white light fluence rate is used during the same period of time, it is observed that performing the sequential treatments in magenta boxes results in higher GL concentrations as opposed to the vertical agar plates. All GL concentrations are induced in T3, as seen by the 45% increase of aliphatic species from Tl to T3, 83% in indole GLs and 45% of the total GLs.

Table 2. Steady-state accumulation of glucosinolates (GL) in sequential light treatments. Data are presented as the mean of three independent biological replicates with standard error of the mean. Letter notations indicate significantly different values based on a t-test (p < 0.05). 43

Glucosinolate Sequential treatment

(μmol g^" ) Tl T2 T3 T4

4MSOB 3.42 ± 0.70 a 3.92 ± 0.33 a 4.98 ± 0.38 a 4.49 ± 0.35 a

5MSOP 0.34 ± 0.07 ab 0.36 ± 0.04 a 0.53 ± 0.07 a 0.1 1 ± 0.07 b te

40ffl3M 1.1 1 ± 0.27 ab 1.18 ± 0.11 ab 1.47 ± 0.09 a 0.73 ± 0.19 b

< 4MTB 0.76 ± 0.1 1 ab 0.98 ± 0.08 a 1.16 ± 0.11 ab 0.52 ± 0.07 b unknown 0.05 ± 0.01 a 0.13 ± 0.01 b 0.08 ± 0.01 a 0.03 ± 0.02 a

Total aliphatic 5.67 ± 1.16 ab 6.57 ± 0.55 ab 8.21 ± 0.50 a 5.89 ± 0.34 b

DM 0.01 ± 0.00 a 0.02 ± 0.00 b 0.03 ± 0.00 c 0.01 ± 0.01 abc

4MT13M 0.02 ± 0.00 a 0.02 ± 0.00 a 0.02 ± 0.00 a 0.01 ± 0.01 a

1MTI3M 0.03 ± 0.01 a 0.07 ± 0.01 b 0.06 ± 0.01 ab 0.02 ± 0.01 a

Total indole 0.06 ± 0.01 a 0.10 ± 0.01 b 0.11 ± 0.01 b 0.03 ± 0.03 a

Total 5.73 ± 1.17 ab 6.67 ± 0.55 ab 8.33 ± 0.51 a 5.92 ± 0.35 b

4MSOB: 4-methylsulfinylbutyl-GL; 5MSOP: 5-methylsulfinylpentyl-GL; 40HI3M: 4-hydroxy- indolyl-3-methyl-GL; 4MTB: 4-methylthiobutyl-GL; I3M: indole-3-ylmethyl-GL; 4MTI3M: 4- methoxyindol-3-ylmethyl-GL; 1MTI3M: 1 -methoxyindol-3-ylmethyl-GL.

Embodiments of the invention utilize narrow-bandwidth light to control several valued traits of a nutrient dense food. The present invention applies the basic biology derived from a laboratory plant to a specialty crop, translating principles learned to generate attractive novel colors and nutraceuticals to consumers. The present invention also demonstrates the range of phenotypes that may be extracted from a given genotype, simply by modulating ambient light conditions, and paves the way for additional experiments that use narrow bandwidth lighting or supplementation to affect traits that add value to small format crops. Such environmental modification may add substantial value, novelty and profitability to already nutrient-dense fresh vegetables. In terms of basic science, it is a demonstration of how to extract "more" phenotype from a given genotype by altering the ambient light environment.

All references, including publications, patent applications and patents, cited herein are hereby incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety herein.

The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise indicated. No language in the specification should be construed as indicating any element is essential to the practice of the invention unless as much is explicitly stated.

The description herein of any aspect or embodiment of the invention using terms such as "comprising", "having", "including" or "containing" with reference to an element or elements is intended to provide support for a similar aspect or embodiment of the invention that "consists of, "consists essentially of, or "substantially comprises" that particular element or elements, unless otherwise stated or clearly contradicted by context (e.g., a composition described herein as comprising a particular element should be understood as also describing a composition consisting of that element, unless otherwise stated or clearly contradicted by context).

It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application.

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Claims

CLAIMS We claim:

1. A method of increasing the emission of a volatile organic compound from a floral organ, wherein the method comprises:

applying a narrow-bandwidth light to a floral organ capable of producing a volatile organic compound of interest,

wherein the narrow-bandwidth light is emitted from an artificial light-emitting source or is obtained from filtering a natural or artificial light,

wherein the narrow-bandwidth light has a half-bandwidth of less than 50nm,

whereby the emission of the volatile organic compound of interest is increased.

2. The method, according to claim 1 , wherein the narrow-bandwidth light has a half- bandwidth of less than lOnm.

3. The method, according to claim 1, wherein the narrow-bandwidth light is a red light or far-red light.

4. The method, according to claim 1 , wherein the narrow-bandwidth light is applied after the flower is harvested.

5. The method, according to claim 1 , wherein the volatile organic compound is a floral volatile benzenoid/phenylpropanoid (FVBP) compound.

6. The method, according to claim 5, wherein the floral volatile benzenoid/phenylpropanoid (FVBP) compound is selected from the group consisting of phenylacetaldehyde, phenylethylalcohol, benzaldehyde, phenylacetaldehyde, isoeugenol, eugenol, 2- phenylethanol, benzyl alcohol, methyl benzoate, benzyl acetate, ethyl benzoate, vanillin, phenylpropanoid, benzyl benzoate, 2-phenylethanol, methyl salicylate, 2-phenethyl acetate, and phenethyl benzoate.

7. The method, according to claim 1 , wherein the floral organ is from a flower selected from the group consisting of petunia, rose, chrysanthemum, carnation, daisy, torenia, lavender, bellflower, tulip, gladiola, snapdragon, orchid, lily, cherry flower, and camellia.

8. The method, according to claim 1 , used to enhance flower fragrance.

9. A method of increasing the emission of a volatile organic compound from a fruit, wherein the method comprises:

applying a narrow-bandwidth light to a fruit or a part thereof capable of producing a volatile organic compound of interest,

wherein the narrow-bandwidth light has a half-bandwidth of less than 50nm,

whereby the emission of the volatile organic compound of interest is increased.

10. The method, according to claim 9, wherein the narrow -bandwidth light has a half- bandwidth of less than lOnm.

11. The method, according to claim 9, wherein the narrow-bandwidth light is applied after the fruit is harvested.

12. The method, according to claim 9, wherein the fruit is tomato.

13. The method, according to claim 12, wherein the narrow-bandwidth light is a far-red light, and the volatile organic compound is selected from cis-3-hexenal, cis-3-hexen-l-ol, 2-methyl- butanol, and 3-methyl- 1 -butanol.

14. The method, according to claim 12, wherein the narrow-bandwidth light is a red light, and the volatile organic compound is selected from 2-methyl- butanol and 3 -methyl -1 -butanol.

15. The method, according to claim 9, wherein the fruit is strawberry.

16. The method, according to claim 15, wherein the narrow-bandwidth light is a far-red light, and the volatile organic compound is selected from methyl butyrate and hexyl butyrate.

17. The method, according to claim 15, wherein the narrow-bandwidth light is a red light, and the volatile organic compound is methyl butyrate.

18. The method, according to claim 9, wherein the fruit is blueberry.

19. The method, according to claim 18, wherein the narrow-bandwidth light is a red light or a far-red light, and the volatile organic compound is selected from hexenal and trans-2-hexenal.

20. The method, according to claim 9, used to enhance the taste and/or aroma of the fruit.

21. A method for modulating a plant trait selected from color, stature, nutraceutical content, flavor, and aroma, wherein the method comprises:

applying a narrow-bandwidth light to a plant or a part thereof, and

growing the plant after application of the narrow-bandwidth light,

wherein the narrow-bandwidth light has a half-bandwidth of less than 50nm, or any value less than 50nm.

22. The method, according to claim 21, wherein the narrow-bandwidth light is a green light, and the method is used to promote stem growth and/or to induce shade-like responses.

23. The method, according to claim 21, wherein the nutraceutical content modulated is selected from glucosinolate levels, anthocyanin levels, antioxidant capacity, and combinations thereof.

24. The method, according to claim 21, wherein the narrow-bandwidth light is selected from a far-red light, a blue light, and a combination thereof, and the method is used to promote levels of anthocyanins.

25. The method, according to claim 21, wherein the narrow-bandwidth light is a far-red light, and the method is used to promote antioxidant capacity.

26. A method for identifying a particular narrow-bandwidth light capable of modulating a plant trait of interest selected from color, stature, nutraceutical content, and flavor, wherein the method comprises:

applying a narrow-bandwidth light of a test spectrum to a plant, or a part thereof, capable of modulating the plant trait of interest;

determining the effect the test spectrum has on the plant trait of interest; and

identifying the test spectrum that modulates the plant trait of interest.

27. A method for identifying a light spectrum capable of increasing the emission level of an volatile organic compound of interest, from flower or fruit of an angiosperm species, wherein the method comprises:

applying a narrow-bandwidth light of a test spectrum to a fruit or flower, or a part thereof capable of producing a volatile organic compound of interest;

28. The method, according to claim 27, wherein the volatile organic compound of interest is selected from the group consisting of phenylacetaldehyde, phenylethylalcohol, benzaldehyde, phenylacetaldehyde, isoeugenol, eugenol, 2-phenylethanol, benzyl alcohol, methyl benzoate, benzylacetate, ethyl benzoate, vanillin, phenylpropanoi d, benzyl benzoate, methyl salicylate, 2- phenethyl acetate, phenethyl benzoate, l-penten-3-one, trans-2-hexenol, trans-2-hexenal, linalool, a- terpineol, geraniol, limonene, cis-3-hexen-l-ol, nerol, l-penten-3-ol, 1 ,8-cineole, methyl butanoate, ethyl butanoate, methyl hexanoate, butyl butanoate, ethyl hexanoate, 3-methylbutyl butanoate, hexyl acetate, hexenyl acetate, methyl anthranilate, linalool, myrtenyl acetate; nerolidol, decalactone, undecalactone, benzaldehyde, undecanon, hexanoic acid, cis-2-hexen- 1 -ol, methyl butyrate, ethyl caproate, hexyl butyrate, cis-3-hexen-l-ol, ira«i-2-penetenal, /rara-2-heptenal, isovaleraldehyde, 3- methyl- l -butanol, methional, isovaleric acid, 2-butylacetate, cis-3-hexen-l -ol, citric acid, 3-methyl-l- butanol, 2-methylbutanal, l-octen-3-one, trans,trans-2,4-decadienal, geranial, 2-methylbutanal, 3- methyl-l -butanal, 2-isobutylthiazole, 6-methyl-5-hepten-2-one, β-ionone, geranylacetone, isobutyl acetate, cw-3-hexen-l -ol, l -nitro-2-phenylethane, 2-methylbutanal, hexyl alcohol, guaiacol, 1 -octen- 3-one, methyl sal icy late, 77" «s-2-hexenal, β-damascenone, 2-methyl- l -butanol, (S)-linalool, 8- hydroxylinalool, linalool glycoside, nerolidol, limonene, methylbenzoate, bl-nitro-2-phenylathane, 2- benzyl acetate, phenylethyl acetate, pseudoionene, geranylacetone, β-ionone, hexanol, (Z)-3-hexenol, trans-2,4-hexadienal, cz^'s-3-hexenol, 1-hexanol, hexanal, 6-methyl-5-hepten-2-one, 2-isobutylthiazole, c s-3-hexenal, /ra«s-2,4-hexadienal, 2-ethylhexanol, β-caryophyllene, cembrene, nerolidol, furanoid, c/s-linalool oxide, 4-methyl- l -pentanol, 6-methyl-hept-5-en-2-ol, hexenal, and hexenol.

29. A plant lighting system for altering the emission level of a volatile organic compound of interest from a flower or fruit, comprising:

a light source; and a controlling device configured to control the range of wavelength and/or bandwidth of the light emitted from the light source so that when the narrow-bandwidth light is applied to the flower or fruit, the emission level of a volatile organic compound of interest from the flower or fruit is altered.

30. The plant lighting system, according to claim 29, wherein the light source is a light- emitting diode (LED) or organic light-emitting diode (OLED).

31. The plant lighting system, according to claim 29, wherein the volatile organic compound of interest increases the intensity of floral fragrance of the flower.

32. The plant lighting system, according to claim 29, wherein the volatile organic compound of interest increases the intensity of aroma and/or flavor of the fruit.