WO2017217773A1 - Microneedle probe device for measuring sap flow rate of plant, and method for measuring sap flow rate of plant by using same - Google Patents

Abstract

According to one embodiment, a microneedle probe device for measuring the sap flow rate of a plant can comprise: a substrate of which at least a part is to be inserted into a plant and having a microscale thickness and width; a single metal wire provided on the substrate; a power source for heating the metal wire by applying a current to the metal wire for a predetermined time; and a processor for calculating the flow rate of sap through the movement, according to the flow of the sap within the plant, of the heat generated by the metal wire.

Description

Microneedle Probe Device for Measuring Sap Flow Rate of Plant and Sap Flow Rate Measurement Method of Plant Using the Same

The following description relates to a microneedle probe device for measuring the sap flow rate of the plant and a method of measuring the sap flow rate of the plant using the same.

Plant growth models have a direct impact on the yield and quality of plants. Plant bioinformatics that have a major impact on plant growth include temperature, Sap Flow and Electroconductivity (EC). Based on these plant bioinformation, water cycle scheduling, temperature and The plant growth model will be determined by controlling the quantity of light, the timing and amount of fertilizer supply.

Measurements for plant growth models have been limited to external environmental variables, such as temperature and humidity, and destructive or indirect measurements. Traditionally, methods of measuring soil conductivity, water consumption, and electrical conductivity from plant samples have been used. . This approach, however, provided indirect or detailed information and lacked clues in predicting plant responses.

In order to measure the flow of sap of a plant, for example, a technique of inserting a probe directly into the stem of a plant has been developed to measure the sap flow by inserting the probe into the stem of a plant, but an invasive needle ) Device was used.

As a method of measuring the sap flow, (i) using an invasive probe to give the plant a periodic heat pulse and to detect the heat pulse movement according to the sap flow of the plant with a separate temperature probe to calculate the flow rate Heat pulse (HP) technology, (ii) using invasive probes to continuously feed heat to the plant and to vary the temperature loss in the absence of sap flow at night and in the presence of sap flow Heat Dissipation (HD) technology measured and calculated; (iii) Invasive probes consisted of temperature measuring probes and heater probes. Heat field deformation (HFD) technology, which measures the degree of deformation due to temperature measurement probes to calculate the fluid flow rate, and (iv) installed outside the plant stem. Stem Heat Balance (SHB) technology using heat generated by the heated heater to generate a temperature difference between the upper and lower stems due to the sap flow.

However, since these techniques use invasive needles having a diameter of 1 to 5 mm, they are used only for tree types, and it is difficult to insert them into plants such as fruits and vegetables or tomatoes such as tomatoes and paprika. In addition, the size of the measuring device is large, expensive, and complicated, and it is difficult to apply it to various parts of one crop or to several crops at once. It was also disadvantageous in terms of securing.

However, after the Industrial Revolution, innovation is rapidly being made in agriculture due to the development of various science and technology. In particular, with the development of agriculture, ICT-based MEMS, and nanotechnology, technologies related to plant growth are also entering a new era.

It is necessary to develop a technology that can measure biometric information of various plants including trees using minimally invasive technology. To this end, the implementation of precision measurement technology based on micro electro mechanical systems (MEMS) technology This is necessary.

More specifically, the size of the sensor inserted into the plant should be small to a micro scale in order to satisfy the minimum invasion requirements. The microneedle probe may be manufactured using MEMS technology, which is a silicon process technology, but the shape and size of the microneedle probe may be used. It should be appropriate in relation to the organization of this plant.

The embodiments described herein can be applied to plants such as tomatoes and paprika and plants such as tomatoes and paprika by measuring the temperature and sap flow rate inside the plant, which are essential for determining the growth model of the plant, directly and minimally invasively from the plant. It is to provide the technology that can be.

In addition, by miniaturizing and compacting the measuring apparatus, it is intended to provide a technology that can be easily applied to various parts or multiple crops of a crop at the same time to secure measurement reliability.

Microneedle probe device for measuring the sap flow rate of a plant according to one embodiment, the substrate is at least a portion of which is inserted into the plant, the thickness and width of the microscale; A single metal wire provided on the substrate; A power source for heating the metal wire by applying a current to the metal wire for a predetermined time; And it may include a processor for calculating the flow rate of the sap through the movement according to the flow of the sap in the plant of the heat generated from the metal wire.

In addition, the metal wire may be provided in plurality, and the plurality of metal wires may be spaced apart from each other in the flow direction of the sap on the substrate so that the flow rate of the sap may be measured at a plurality of locations.

In addition, the metal wire may include a portion extending in a direction orthogonal to the flow direction of the sap.

In addition, the power source may periodically apply a current to the metal line to generate a heat pulse to the metal line.

In addition, the processor, the resistance measuring module for measuring the resistance of the metal wire and the change of the resistance; A temperature calculation module for calculating a change in temperature of the metal wire from the change in resistance of the metal wire; And it may include a flow rate calculation module for calculating the flow rate of the sap from the change of the temperature of the metal wire.

In addition, the substrate, one end is formed thinly inserted thin portion is inserted into the plant; And a thick part positioned on the opposite side of the thin part and having a thickness thicker than that of the thin part, and increasing as the width of one end portion of the thin part side increases away from the thin part.

According to an embodiment, a method of measuring a sap flow rate of a plant may include inserting a microneedle probe device into a plant, the substrate including a microscale substrate having a thickness and a width, and a single metal wire provided on the substrate; Heating the metal wire by applying a current to the metal wire for a predetermined time; And calculating a flow rate of the sap through the movement of the sap in the plant of the heat generated by the metal wire.

The method may further include causing a heat pulse to be generated in the metal line by periodically applying current to the metal line after the end of the predetermined time.

In addition, calculating the flow rate of the sap, measuring the change in the resistance of the metal wire; Calculating a change in temperature of the metal wire from the change in resistance of the metal wire; And calculating a flow rate of the sap from the change of the temperature of the metal wire.

According to the embodiments described herein, it is possible to reliably measure the sap flow rate and the temperature inside the plant through the microneedle probe that can be applied minimally invasive to the plant.

In addition, the types of plants capable of measuring the sap flow rate can be extended from trees to fruit crops, such as tomatoes and paprika, and to crops with small diameters of stems such as flowers.

In addition, not only can the sap flow rate be measured in several places in a crop, but also the sap flow rate can be measured in several crops at the same time, thereby increasing the reliability of the measured value.

1 is a schematic side cross-sectional view of a microneedle probe device for measuring the sap flow rate of a plant according to an embodiment.

FIG. 2 is a schematic plan view of the microneedle probe device for measuring the sap flow rate of the plant of FIG. 1.

3 is a flowchart illustrating a method of measuring a sap flow rate of a plant according to an embodiment.

Microneedle probe device for measuring the sap flow rate of a plant according to an embodiment, the substrate is at least a part inserted into the plant, the substrate is a microscale thickness and width; A single metal wire provided on the substrate; A power source for heating the metal wire by applying a current to the metal wire for a predetermined time; And it may include a processor for calculating the flow rate of the sap through the movement according to the flow of the sap in the plant of the heat generated from the metal wire.

In addition, the metal wire may be provided in plurality, and the plurality of metal wires may be spaced apart from each other in the flow direction of the sap on the substrate so that the flow rate of the sap may be measured at a plurality of locations.

In addition, the metal wire may include a portion extending in a direction orthogonal to the flow direction of the sap.

In addition, the power source may periodically apply a current to the metal line to generate a heat pulse to the metal line.

In addition, the processor, the resistance measuring module for measuring the resistance of the metal wire and the change of the resistance; A temperature calculation module for calculating a change in temperature of the metal wire from the change in resistance of the metal wire; And it may include a flow rate calculation module for calculating the flow rate of the sap from the change of the temperature of the metal wire.

In addition, the substrate, one end is formed thinly inserted thin portion is inserted into the plant; And a thick part positioned on the opposite side of the thin part and having a thickness thicker than that of the thin part, and increasing as the width of one end portion of the thin part side increases away from the thin part.

According to an embodiment, a method of measuring a sap flow rate of a plant may include inserting a microneedle probe device into a plant, the substrate including a microscale substrate having a thickness and a width, and a single metal wire provided on the substrate; Heating the metal wire by applying a current to the metal wire for a predetermined time; And calculating a flow rate of the sap through the movement of the sap in the plant of the heat generated by the metal wire.

The method may further include causing a heat pulse to be generated in the metal line by periodically applying current to the metal line after the end of the predetermined time.

In addition, calculating the flow rate of the sap, measuring the change in the resistance of the metal wire; Calculating a change in temperature of the metal wire from the change in resistance of the metal wire; And calculating a flow rate of the sap from the change of the temperature of the metal wire.

Hereinafter, specific embodiments will be described in detail with reference to the accompanying drawings. In addition, when it is determined that the detailed description of the related known configuration or known function may obscure the gist of the embodiments, the detailed description thereof will be omitted.

On the other hand, the singular expression includes the plural expression unless the context clearly indicates the singular. And when a particular part is said to "include" a particular configuration, this means that unless specifically stated otherwise said particular portion may further include said other configuration, not to exclude other configurations than said specific configuration.

1 and 2 are schematic cross-sectional side views and plan views, respectively, of a microneedle probe device 1 (hereinafter referred to as a “microneedle probe”) for measuring a sap flow rate of a plant according to one embodiment. The microneedle probe 1 according to the present embodiment may be manufactured through a silicon-based MEMS process, and the flow rate of the sap flowing into the throat of a plant (water tube part) and flowing in the throat may be measured in a minimally invasive manner. have.

The microneedle probe 1 may have a substrate 10. The substrate 10 may be made of silicon through a MEMS process as described above. The substrate 10 may include a thin portion 11 inserted into the plant and a thick portion 12 on the opposite side of the thin portion, wherein the thin portion 11 has a relatively thin thickness. The thick portion 12 may have a relatively thick thickness (see FIG. 1). Thus, since the thin portion 11 is formed thinner than the thick portion 12, the microneedle probe 1 can be easily inserted into the plant internal tissue, and the thick portion 12 is formed thicker than the thin portion 11 Therefore, the rigidity of the substrate 10 can be secured.

In addition, one end of the side inserted into the plant in the thin portion 11 is sharply formed at the atomic level so that the microneedle probe 1 can be easily inserted into the plant. The sharpness of the one end may be controlled by a semiconductor dry etching process or silicon doping and selective etching.

On the other hand, the width of the thick portion 12 may be larger than the width of the thin portion 11 (see Fig. 2). For example, one end of the thin portion 11 side of the thick portion 12 may have the same width as that of the thin portion 11 and increase toward the thick portion 12 side. As a result, a tapered inclined surface may be formed at one end of the thick portion 12. With this structure, it is possible to secure the rigidity to prevent the microneedle probe 1 from breaking when the microneedle probe 1 is inserted into the plant to measure the fluid flow rate.

Substrate 10 of the microneedle probe 1 according to the present embodiment is made of a small size of the micro-scale, it is possible to measure the fluid flow rate under the minimum invasive conditions. The substrate 10 may have a length l of 1 to 6 mm, a thickness t of 100 to 200 m, and a width d of 200 to 400 m.

Unlike conventional probes, which have a diameter of 1 to 5 mm and are applicable only to large and hard trees, the microneedle probe 1 according to the present embodiment can be inserted and maintained in the microstructure of a plant: bar, tomato, or paprika. It is also applicable to plants whose stems are thinner than trees such as fruits and vegetables.

The metal wire 20 for measuring the fluid flow rate may be provided on the substrate 10. The metal wire 20 may be, for example, a platinum material, and may be formed of a metal micro pattern. As will be described later, when a current is applied to the metal wire 20, the metal wire 20 may be heated, and heat generated from the metal wire 20 may move in the same direction as the sap by the flow of the sap. This may cause the metal wire 20 to lose heat to the sap. The temperature change of the metal wire 20 may be represented by a change in the resistance of the metal wire 20, and the change of the resistance may be read to calculate the temperature change, and further, the fluid flow rate may be calculated through the temperature change. .

In addition, the metal wire 20 may be disposed to extend in a direction orthogonal to the flow direction of the sap (see FIG. 2). For example, as shown in FIG. 2, the metal wire 20 may include a plurality of portions formed of a single wire but extending in a direction orthogonal to the flow direction of the sap. In this configuration, the heat generated from the metal wire 20 can be better dissipated by the sap flow, so that the measurement of the resistance change of the metal wire 20 and ultimately the accuracy of the fluid flow rate measurement can be improved. have.

On the other hand, as shown, a plurality of metal wires 20 may be provided, the plurality of metal wires 20 may be spaced apart from each other along the longitudinal direction of the substrate 10. In this case, since the flow rate of the sap can be measured at various places of the plant, the reliability of the measured value can be improved.

The power source (not shown) may be disposed on the substrate 10 or spaced apart from the substrate 10, and may apply a current to the metal line 20 through the BUS line 30 mounted on the substrate 10. have. The BUS line 30 may be a low resistance BUS line and may be connected to a power source through contact pads 40.

On the other hand, the power source may apply a current to the metal wire 20 only for a predetermined time, and furthermore, by periodically applying a current to the metal wire 20 to generate a heat pulse to the metal wire 20.

The processor (not shown) may include a resistance measuring module, a temperature calculating module and a flow rate calculating module. For example, the modules may have the form of a circuit. The resistance measuring module may measure a change in resistance of the metal wire 20 due to heating or cooling of the metal wire 20. The temperature calculation module may calculate a change in temperature of the metal wire 20 using the change in the resistance. In this case, the temperature change according to the resistance change may be calculated using the temperature coefficient of resistance. The flow rate calculation module may calculate the flow rate of the sap by using the change in temperature.

Meanwhile, the processor may be understood as a concept including a resistance measuring module, a temperature calculating module, and a flow rate calculating module, and is not necessarily limited to the form of a single physical chip. When the processor is mounted on the substrate 10, the resistance measuring module, the temperature calculating module, and the flow rate calculating module may be integrated on one chip or divided into two or more chips. Alternatively, at least one of the temperature calculating module and the flow rate calculating module may be spaced apart from the substrate 10 while the resistance measuring module is mounted on the substrate 10. In this case, the resistance and the resistance change value of the metal wire 20 measured by the resistance measurement module may be transmitted to the outside of the substrate 10 by a wired or wireless manner by a communication module (not shown).

A cover (not shown) may be provided on the substrate 10 to cover all or part of the above-described metal wire 20. The cover may be provided, for example, in the form of a thin film and may cover the metal wire 20 to protect the metal wire 20 mechanically, electrically, and chemically. And the cover may have insulation.

When the cover is provided in the form of a thin film, the material may be an inorganic material such as silicon oxide, silicon nitride, aluminum oxide, hafnium oxide, or the like, and polytetra It may be a water-repellent organic material such as fluoroethylene (PTFE), cyclic transparent optical polymer (CYTOP). The cover may include a plurality of inorganic material layers, a plurality of organic material layers, or a mixture of an inorganic material layer and an organic material layer in order to increase insulation performance.

For example, silicon nitride may be deposited on the metal line 20 by chemical vapor deposition (CVD). In addition, in order to minimize the effect of defects on the process, the silicon nitride layer and the silicon oxide layer may be alternately deposited. In this case, even if one layer is defective, the other layer can function as an insulating film. Alternatively, defects in the inorganic material layer may be compensated for by using atomic layer deposition. Atomic layer deposition can fill defects such as cracks or pin holes in silicon nitride thin films because of the high uniformity of the deposited thin films and can improve the quality of insulating thin films. As another example, a composite layer of an organic thin film and an inorganic thin film may be used to increase insulation performance. An organic material thin film layer such as PTFE, CYTOP, etc. may be formed on the inorganic material thin film layer by dip coating, spin coating, vapor deposition, or the like. The hydrophobic organic thin film prevents liquid from penetrating into the metal wire 20, thereby improving the performance of the insulating thin film. Hereinafter, the operation of the microneedle probe 1 according to the present embodiment will be described.

The power source may apply a current to the metal wire 20 for a predetermined time, and thus the metal wire 20 may be heated. In addition, as described above, the power supply may periodically apply current to the metal wire 20, and in this case, a heat pulse may be generated in the metal wire 20. For example, when the power source supplies 100 mW of power to the metal wire 20 for 30 seconds, the temperature of the metal wire 20 may increase with respect to the surroundings. Then, after a certain time, the heat generated from the metal wire 20 and the amount of heat dissipated to the surroundings are in equilibrium, so that the metal wire 20 may be maintained at a constant temperature (reaching the stagnation point of temperature). Then, when the power is cut off, the temperature of the metal wire 20 decreases again and may be equal to the ambient temperature after a predetermined time. When the sap flow is fast, since heat dissipation caused by convection is large, heat generated from the metal wire 20 and heat dissipated can be balanced at a low temperature. At this time, the time to equilibrium may be relatively short. If the fluid flow is slow or absent, the heat dissipation by convection is low and thermal equilibrium can be achieved at high temperatures. In this case, the time to equilibrium may be relatively long.

On the other hand, applying a voltage lower than 0 V to the metal wire 20 may be more advantageous in preventing the electrochemical oxidation of the metal wire 20. For example, if a voltage higher than 0 V (eg, 5 V) is applied to the metal wire 20, the metal tissue 20 may be exposed to plant tissues when the metal wire 20 is exposed in the absence or defect of the cover described above. The contact portion has a relatively high potential compared to the plant, which may accelerate the electrochemical oxidation and shorten the lifespan. On the other hand, if a voltage of less than 0 V is applied to the metal wire 20, the potential of the metal wire 20 exposed even under the absence of a cover or in a defect condition is lower than that of the plant, so that the oxidation occurring in the metal wire 20 can be suppressed. Can lead to increased lifespan.

In the case of this embodiment, the temperature change of the metal wire 20 as described above can be calculated from the resistance change of the metal wire 20. As described above, the resistance measurement module of the processor may measure the resistance of the metal wire 20 that changes according to the change in temperature, and the temperature calculation module may measure the resistance of the metal wire 20 using a resistance temperature coefficient or the like based on the resistance change value. The temperature change can be calculated.

For example, a Wheatstone bridge circuit can be used to measure the resistance of the metal wire 20. The metal wire 20 having a constant resistance value and three other resistance wires having a similar resistance value may form a rectangle. When the four resistance values are the same, the potential difference between the two midpoints of the Wheatstone bridge circuit is zero. When the resistance value of the metal wire 20 is changed by heating the metal wire 20 or the like, a potential difference is generated between the two intermediate points. And, by measuring the potential difference generated in this way, the resistance change can be inverted. For reference, amplifying the potential difference with a differential amplifier can measure more precise resistance changes.

Another example of measuring the resistance change of the metal wire 20 is a constant current circuit. By using a constant current regulator or the like to produce a circuit in which a constant current flows, the metal wire 20 can be connected thereto. Since a constant current flows irrespective of the resistance of the metal wire 20, when the voltage applied to the metal wire 20 is measured, the resistance value of the metal wire 20 may be inverted. Again, amplifying the voltage signal with an amplifier allows for more accurate measurements.

On the other hand, if the resistance change and the resistance temperature coefficient (TCR) of the metal wire 20 is known, the temperature change amount of the metal wire 20 can be known. For example, if the initial resistance 100 Ω of the metal wire 20 made of gold (Au) increases to 101 Ω by the temperature change of the metal wire 20, the temperature change amount of the metal wire 20 at that time is It can be obtained as shown in Equation 1.

[Equation 1]

Here, T1 and T2 respectively mean the initial temperature and the temperature after the change of the metal wire 20, R1 and R2 respectively mean the initial resistance and resistance after the change of the metal wire 20, α is the resistance of the metal wire 20 It may mean a temperature coefficient. When the resistance of the metal wire 20 increases from 100 Ω to 101 Ω, since the resistance temperature coefficient α of gold is known as 0.0034, the temperature change of the metal wire 20 may be about 2.94 degrees.

Subsequently, the flow rate calculation module may calculate the flow rate of the sap based on the temperature change value of the metal wire 20 as described above. The correlation between the fluid flow rate and the temperature change of the metal wire 20 is shown in Equation 2 below.

[Equation 2]

Here, u is the flow rate of the sap (m ³ / m ² s), ΔT is the temperature difference between when the power is applied to the metal wire 20 in the thermal equilibrium state and when not applied. ΔT _M is the temperature difference value (ie, the maximum value of ΔT) of the metal wire 20 when there is no sap flow. a and b are constants obtained experimentally. ΔT and ΔT _M can be obtained by turning on and off the power applied to the metal wire 20.

In the case of the microneedle probe 1 according to the present exemplary embodiment, the structure may be simple because it is a single wire system using a single metal wire 20 mounted on a single substrate 10. Simplification of this structure is a very important factor in the structure of the micro-scale can be advantageous in terms of ease of implementation.

In addition, unlike the prior art in which the heater probe and the temperature measuring probe are separately provided, heat generation and temperature measurement are possible using only a single metal wire 20 on the single substrate 10, which may also contribute to the simplification of the structure. .

Similarly, since the power supply probe and the temperature measurement probe are not provided separately, the temperature change of the metal wire 20 can be measured by adjusting the power supply using only a single substrate 10, so that the structure of the structure can be simplified. May be advantageous.

3 is a flowchart illustrating a method of measuring a sap flow rate of a plant according to an embodiment. Hereinafter, the sap flow rate measuring method will be described with reference to FIG. 3 in parallel with FIGS. 1 and 2.

In order to measure the sap flow rate of the plant, first, the microneedle probe 1 may be inserted into the plant (S10). As described above, the microneedle probe 1 may include a substrate 10 and a metal line 20 provided on the substrate 10. The substrate 10 may include a thin portion 11 and a thick portion 12, and at least a portion of the thin portion 11 may be inserted into the neck of the plant stem. One end of the thin portion 11 may be sharply formed to facilitate insertion. Meanwhile, the microneedle probe 1 may be inserted into the plant such that at least a portion of the metal wire 20 extends in a direction orthogonal to the flow of the sap.

Subsequently, the metal wire 20 may be heated by controlling a power supply to apply a current to the metal wire 20 for a predetermined time (S20). As described above, the power source may apply the current to the metal line 20 again after a predetermined time passes after the predetermined time is over. As such, a power pulse is periodically applied to the metal wire 20 to generate a heat pulse to the metal wire 20.

Next, ultimately, the speed of the sap can be calculated by detecting the movement of heat generated in the metal wire 20 (S30). Specifically, the heat moves in the flow direction of the sap by the flow of the sap, the temperature of the metal wire 20 is changed by the movement of this heat. The flow rate can be calculated by grasping the change in temperature, but the present embodiment will be described as grasping the change in temperature by grasping the change in resistance of the metal wire 20. In other words, no separate temperature probe is required. For example, the change in resistance of the metal wire 20 can be measured using the relationship between temperature and resistance (resistance temperature coefficient, etc.), and then the change in temperature of the metal wire 20 can be calculated based on the change in resistance. When the temperature change of the metal wire 20 is calculated, the flow rate of the sap can be calculated based on this.

The embodiments described above are merely illustrative of some examples of the technical idea, and the scope of the technical idea is not limited to the described embodiments, but within the scope of the technical idea by those skilled in the art. There may be various changes, modifications or substitutions in. For example, the components or features described together in a particular embodiment may be implemented in a distributed manner, and the components or features described in each of the different embodiments may be implemented in a combined form. Likewise, the elements or features described in each claim may be practiced in a distributed manner or in combination with one another. And all such implementations should be seen as belonging to the scope of the present invention.

Claims (9)

A substrate at least partially inserted into the plant, the substrate being microscale in thickness and width; A single metal wire provided on the substrate; A power source for heating the metal wire by applying a current to the metal wire for a predetermined time; And And a processor for calculating a flow rate of the sap through the movement of the sap in the plant of the heat generated by the metal wire. The method of claim 1, The plurality of metal wires are provided, the plurality of metal wires are disposed spaced apart from each other in the flow direction of the sap on the substrate so that the flow rate of the sap is a microneedle probe device for measuring the flow rate of the plant. The method of claim 1, The metal wire is a microneedle probe device for measuring the fluid flow rate of a plant comprising a portion extending in a direction orthogonal to the flow direction of the sap. The method of claim 1, The power source is a microneedle probe device for measuring the fluid flow rate of the plant to apply a current periodically to the metal wire to generate a heat pulse to the metal wire. The method of claim 1, The processor, A resistance measuring module measuring a resistance of the metal wire and a change in the resistance; A temperature calculation module for calculating a change in temperature of the metal wire from the change in resistance of the metal wire; And Microneedle probe device for measuring the sap flow rate of the plant comprising a flow rate calculation module for calculating the flow rate of the sap from the change of the temperature of the metal wire. The method of claim 1, The substrate, A thin portion having one end sharply inserted into the plant; And Microneedle probe device for measuring the fluid flow rate of a plant located on the opposite side of the thin portion, having a thicker thickness than the thin portion, and including a thick portion that increases as the width of one end portion of the thin portion increases away from the thin portion. . Inserting into the plant a microneedle probe device comprising a substrate having a thickness and width microscale and a single metal wire provided on the substrate; Heating the metal wire by applying a current to the metal wire for a predetermined time; And Comprising a step of calculating the flow rate of the sap through the movement of the sap flow in the plant of the heat generated in the metal wire sap flow rate measuring method. The method of claim 7, wherein After the end of the predetermined time, the method for measuring the sap flow rate of the plant further comprising the step of applying a current periodically to the metal wire to generate a heat pulse to the metal wire. The method of claim 7, wherein Calculating the flow rate of the sap, Measuring a change in resistance of the metal wire; Calculating a change in temperature of the metal wire from the change in resistance of the metal wire; And Comprising a step of calculating the flow rate of the sap from the change of the temperature of the metal wire sap flow rate measuring method of the plant.

Images