JP5309410B2 - Method and apparatus for monitoring pore opening - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and apparatus for monitoring a stomatal aperture, accurately grasping the water stress condition of a plant with an easy means. <P>SOLUTION: This method for monitoring a stomatal aperture includes arranging each a wet surface imitation leaf 1 getting wet in water and a dried imitation leaf 2 evaporating completely no water in the vicinity of a raw leaf 110 of a plant 100, measuring each leaf temperature of the raw leaf 110, the wet surface imitation leaf 1, and the dried imitation leaf 2, and obtaining a stomatal aperture of the raw leaf 110 using each of the measured leaf temperatures. Since each leaf temperature of the raw leaf, the wet surface imitation leaf, and the dried imitation leaf is measured, it is possible to exclude environmental factors based on the leaf temperatures, and accurately grasp the relative value of the stomatal aperture by an easy means. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method and an apparatus for monitoring pore opening required for management of plant water.

  Plant water management is very important because it directly affects the yield and quality of vegetables and fruits. If the amount of water supplied is too large, it will cause adverse effects such as root rot, and conversely, if water is insufficient, it will die or grow poorly. These phenomena are caused by plant water stress.When plants are subjected to water stress, prior to the above phenomenon, the plant reduces the stomatal opening of the leaves and increases the transpiration rate in order to retain the moisture in the body. Reduce. Therefore, the stomatal opening is important as an indicator of water stress in the plant body.

  In order for plants to grow normally, water management that avoids water stress is necessary. Therefore, proper management of water requires monitoring the presence and extent of water stress in plants.

  Patent Document 1 discloses a water vapor sensor for monitoring the transpiration rate. In Non-Patent Document 1, the dry simulating leaf is used to calculate the amount of corn solid transpiration from the dry simulated leaf and the leaf temperature and temperature of the fresh leaf.

JP 2006-214858 A

Imahisa et al., “Calculation of solid transpiration of corn using dry simulated leaves”, Agricultural Meteorology Vol. 64, No. 3, September 2008

  However, the water vapor sensor has a problem that it has aged deterioration, is inferior in reliability, and is expensive. In addition, calculation of solid transpiration using dry simulated leaves is simple, but it is difficult to calculate the exact transpiration rate due to the influence of environmental factors such as temperature and airflow.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method and an apparatus for monitoring the pore opening that can accurately grasp the transpiration rate at a low cost with a simple method.

  In order to achieve the above object, the method for monitoring stomatal opening according to the present invention includes a wet surface simulated leaf and a dry simulated leaf disposed in the vicinity of a raw leaf of the plant, respectively, and the raw leaf, the wet surface simulated leaf, and the dry simulation. It is characterized by measuring the leaf temperature of each leaf. By measuring the leaf temperature of fresh leaves, wet simulated leaves, and dry simulated leaves, it is possible to calculate only the relative value of the stomatal opening in the fresh leaves based on these leaf temperatures, eliminating environmental factors. Become.

  In addition, the method for monitoring stomatal opening of the present invention is based on the measured leaf temperature of the fresh leaf, the measured leaf temperature of the wet simulated leaf and the measured leaf temperature of the dried simulated leaf. It is characterized by calculating | requiring. The relative value of the determined pore opening is accurate with the environmental factors eliminated.

In addition, the method for monitoring stomatal opening according to the present invention includes a measured leaf temperature of T _L , measured wet surface simulated leaf temperature T _W , and measured dried simulated leaf leaf temperature T _D. When the following formula (1)
_{(T D -T L) / (} T D -T W) ··· (1)
From the above, a simple pore opening ratio is obtained. Equation (1) calculates the ratio of the leaf temperature difference between the dry simulated leaf and the fresh leaf and the leaf temperature difference between the dry simulated leaf and the wet surface simulated leaf. The proportional simple pore opening ratio can be easily obtained.

  It is preferable that the raw leaves, the wet surface simulated leaves, and the dry simulated leaves have the same shape and size. By making the shape and size of these fresh leaves, wet surface simulated leaves, and dry simulated leaves the same, it is possible to eliminate environmental factors.

  The stomatal opening monitoring device according to the present invention includes a wet surface simulated leaf disposed in the vicinity of a raw leaf of a plant, a dry simulated leaf disposed in the vicinity of the raw leaf, a leaf temperature of the raw leaf, and the wet surface simulation. It has a leaf temperature measuring means for detecting the leaf temperature of the leaf and the leaf temperature of the dry simulated leaf. The relative value of the stomatal opening degree of the raw leaf can be calculated using the three types of leaf temperature data detected by the leaf temperature measuring means.

  The monitoring device for stomatal opening according to the present invention comprises: storage means for storing leaf temperature data of the fresh leaves, leaf temperature data of the wet surface simulated leaves, and leaf temperature data of the dry simulated leaves; It is preferable to include a control unit that stores each leaf temperature data detected by the measurement unit in the storage unit. It is possible to calculate only the relative value of the stomatal opening in the fresh leaf, excluding environmental factors, based on the leaf temperature data of the fresh leaf, wet surface simulated leaf, and dry simulated leaf.

  Moreover, it is preferable that a means for obtaining a relative value of the stomatal opening degree of the fresh leaf using the leaf temperature data of the fresh leaf, the wet surface simulated leaf, and the dry simulated leaf is set in the control unit. The relative value of the determined transpiration rate is accurate with the environmental factors eliminated.

In addition, the pore opening monitoring device according to the present invention may be configured such that the controller controls the measured leaf temperature of the fresh leaf to T _L , the measured wet surface simulated leaf temperature to T _W , and the measured dry simulated leaf when the leaf temperature and _{T D,} the following formula (1)
_{(T D -T L) / (} T D -T W) ··· (1)
From the above, a means for obtaining a simple pore opening ratio is set. It is possible to easily obtain a simple pore opening ratio that is proportional to only the pore opening in the raw leaves by eliminating environmental factors.

  According to the method and apparatus for monitoring stomatal opening of the present invention, because it is configured to measure each leaf temperature of fresh leaves, wet surface simulated leaves and dry simulated leaves, environmental factors can be eliminated based on these leaf temperatures, It is possible to accurately grasp the relative value of the pore opening by a simple method.

It is a schematic diagram which shows an example of the arrangement | positioning method of the wet surface simulated leaf used for the monitoring method of the stomatal opening degree of the leaf of this invention, and a dry simulated leaf. It is a block diagram which shows schematic structure of the monitoring apparatus of the stomatal opening degree of the leaf of this invention. It is a graph which shows the correlation of the actual value of the transpiration rate of a tomato leaf, and a simple pore opening ratio.

  Hereinafter, although the embodiment of the method and apparatus for monitoring the pore opening degree of the present invention will be described, the present invention is not limited to the following embodiment.

  The plant absorbs normal water from the root hair, and the absorbed water ascends the plant through the xylem conduit or temporary conduit, evaporates from the pores of the leaves, and is released into the atmosphere as water vapor. Transpiration refers to a phenomenon in which water in a plant body is released outside the body in the form of water vapor. There are many pores on the back of the leaf, open and close, and in many plants, when exposed to light, the pores open for photosynthesis, carbon dioxide is taken into the plant, and water in the body is lost due to transpiration. When the amount of transpiration exceeds the amount of water absorption and the amount of water in the plant body decreases, the pores are closed and the opening of the pores is adjusted so that water is not lost.

  The pore opening monitoring method of the present invention indirectly measures the amount of water evaporated from the leaf pores. In FIG. 1, the conceptual diagram of the monitoring method of the pore opening degree of this invention is shown. First, a plant 100 to be measured for transpiration is selected. The plant may be either herbaceous or woody as long as it has leaves. Plants may exist indoors or outdoors where the environment is adjusted. One fresh leaf 110 representing the plant 100 is selected. In the present invention, the wet surface simulated leaf 1 and the dry simulated leaf 2 having the same shape and the same size as the selected fresh leaf 110 are prepared. The same shape and size do not need to be exact, but are generally sufficient.

  The wet surface simulated leaf 1 has substantially the same shape and size as the fresh leaf 110, and has a structure in which the entire surface on one side or the entire surface of both surfaces can be wetted with water and the water can be evaporated. The thickness of the wet surface simulated leaf 1 is preferably close to the fresh leaf 110. For example, a laminate in which a water-absorbing sheet such as filter paper, woven fabric, or non-woven fabric having the same shape as that of the substrate is attached to a fresh leaf-shaped substrate can be used. The substrate is used to keep the leaf shape and prevent water from evaporating from one side, and can be made of metal such as aluminum, copper, iron, wood, earthenware, plastic thin plate, sheet or film. . If the water-absorbing sheet itself can maintain the shape of the leaf, the substrate can be omitted, and for example, it can be configured with only filter paper. Alternatively, the wet surface simulated leaf 1 may be formed using a porous material such as unglazed baking. The wet surface simulated leaf 1 is connected to a water absorption unit 11 that sucks water from a water storage tank (not shown) that stores water, and water is always supplied from the water storage tank via the water supply unit 11. Water always evaporates from the entire surface.

  The color of the wet surface simulated leaf 1 is preferably black with an emissivity (emission rate) of 0.93 to 0.96 equivalent to that of the fresh leaf. In the case of a laminate of a substrate and a water absorbent sheet, the substrate is preferably colored, painted or surface-treated with a matte black, and the water absorbent sheet is also preferably black. Also, the heat capacity must be equivalent to that of fresh leaves. By making the wet surface simulated leaf 1 black, the short wave radiation (solar radiation) flux (solar radiation, absorbed radiation) absorbed by the raw leaf and absorbed and the short wave radiation flux absorbed by the simulated leaf are substantially reduced. Can be the same. As a result, it is possible to eliminate the influence of solar radiation in environmental factors.

  The dry simulated leaves 2 are preferably substantially the same shape and size as the fresh leaves 110, have a thickness close to that of the fresh leaves 110, and preferably have the same structure as the wet simulated leaves. If the wet surface simulated leaf 1 is a laminate of a substrate and a water-absorbent sheet, the dry simulated leaf 2 is preferably a laminate having the same structure. However, a structure different from the wet surface simulated leaf 1 may be used. For example, it can be formed of only a metal plate such as aluminum, copper, iron, a plastic sheet or a film. Moreover, it is preferable that the surface of the dry simulation leaf 2 is also colored, painted, or surface-treated with matte black. Similar to the wet surface simulated leaf 1, it is possible to eliminate the influence of the amount of solar radiation in the environmental factors by making the absorption rate of sunlight the same as that of the raw leaf. Water is not supplied to the dry simulated leaf 2 and used as a simulated leaf in which water does not evaporate.

  The wet simulated leaf 1 and the dry simulated leaf 2 are preferably arranged in the vicinity of the selected fresh leaf 110. Moreover, although the position to arrange | position is not limited, as shown in FIG. 1, it is preferable to arrange | position to the left and right of the fresh leaf 110, and to arrange | position with a fresh leaf, and to arrange | position at the same height. By setting it as such an arrangement | positioning, the influence of an airflow can be excluded.

  FIG. 2 shows a schematic configuration of the pore opening monitoring device of the present invention. The pore opening monitoring device 3 includes a leaf temperature measuring means 4 for measuring each leaf temperature of the wet surface simulated leaf 1, the fresh leaf 110, and the dry simulated leaf 2, temperature data measured by the leaf temperature measuring means 4, and the like. Or it has the memory | storage means 5 which memorize | stores a program, the control part 6 which controls the whole apparatus, and the display part 7 which displays each leaf temperature etc., These are connected by the bus | bath.

  As shown in FIG. 2, the leaf temperature measuring unit 4 includes thermocouples 41, 42, and 43, and a data acquisition unit 4 a that acquires each leaf temperature data obtained from the thermocouples 41, 42, and 43. Can be used. The temperature measuring points of the thermocouples 41, 42 and 43 are preferably near the center of the leaf. Further, since there are more pores on the back surface than on the leaf surface, and in order to avoid direct solar radiation to the thermocouple sensitive part, the thermocouples 41, 42, and 43 are preferably attached to the back surface of the leaf. As the leaf temperature measuring means 4, a radiation thermometer that measures the temperature of an object by measuring the intensity of infrared rays or visible rays emitted from the object can be used. The radiation thermometer is excellent in that it can simultaneously measure three leaf temperatures in a non-contact manner, but since it is expensive, it is preferable to use a thermocouple as shown in FIG.

  Each leaf temperature data measured by the leaf temperature measuring unit 4 is stored in the storage unit 5 from the data acquisition unit 4a to the storage unit 5 by a command of a program by the control unit 6 at regular intervals, for example, and each leaf temperature is displayed on the display unit 7. Display. Further, the control unit 6 calculates the relative value of the pore opening degree of the fresh leaf 110 from the leaf temperature data of the wet surface simulated leaf 1, the fresh leaf 110, and the dry simulated leaf 2, and causes the display unit 7 to display the result.

The heat balance in a single leaf maintaining a constant temperature is expressed by the following equation. The unit is W / m ² .

  [Short wave radiation (solar radiation) flux absorbed by entering the leaf] + [Long wave wavelength (thermal radiation) flux-Long wave radiation flux emitted from the leaf] = [Net absorbed radiation flux] = [Sensible heat (temperature) Thermal energy transported from the high temperature side to the low temperature side in proportion to the gradient) Flux] + [Latent heat (thermal energy consumed when water turns into water vapor during the transpiration process on the leaf surface) Flux]

  During sunshine, the net absorbed radiant flux is increased due to solar radiation. Since the latent heat flux of the dry simulated leaf 2 is zero, the leaf temperature increases most, and then the leaf temperature decreases in the order of the raw leaf 110 and the wet surface simulated leaf 21 in this order. At night, the short wave radiant flux is zero, so the leaf temperature of the dry simulated leaf 2 is almost the same as the temperature, or slightly lower when there is radiative cooling, and the leaf temperature of the fresh leaf 110 is lower than that of the dry simulated leaf 2, The leaf temperature of the wet simulated leaf 1 is lower than that of the fresh leaf 110.

  On the surface of the leaf, a layer of air called the foliar boundary layer is formed, and in leaves placed in an air stream, the thickness of the foliar boundary layer varies depending on the site of the foliage, resulting in sensible and latent heat. Since the transport flux is different, the leaf temperature is unevenly distributed on the leaf surface. By using the wet surface simulated leaf 1 that is affected by the same airflow as that of the fresh leaves, it is possible to eliminate the influence of uneven leaf temperature caused by the airflow.

  Increasing shortwave radiation flux (irradiation amount) increases leaf temperature, but if the simulated leaves 1 and 2 are black and the light absorptivity of the simulated leaves 1 and 2 is the same as that of fresh leaves, the amount of solar radiation varies. The influence of can be eliminated.

  In addition, since the transpiration rate from the leaf is proportional to the difference between the water vapor pressure (or absolute humidity) in the leaf and the water vapor pressure in the surrounding area, the leaf temperature of the fresh leaf 110 increases as the humidity increases even if the pore opening is the same. Since the temperature of the wet surface simulated leaf 1 similarly rises, the temperature difference between the raw leaf 110 and the wet surface simulated leaf 1 is substantially constant. Therefore, the temperature difference between the fresh leaf 110 and the wet simulated leaf 1 corresponds to a difference in water vapor conductance (an index of easiness of transpiration) that depends only on the pore opening, and the influence of fluctuations in water vapor pressure can be eliminated. it can. Further, since the sensible heat flux is proportional to the difference between the leaf temperature and the air temperature, even if the water vapor pressure (or absolute humidity) is the same, when the air temperature rises, the sensible heat flux in the leaf is decreased and the leaf temperature of the fresh leaf 110 is decreased. However, since the temperatures of the wet simulated leaf 1 and the dry simulated leaf 2 also increase, Equation (1) can eliminate the effect of temperature fluctuations by eliminating the sensible heat flux term.

  As a result, by measuring the leaf temperature of the wet simulated leaf 1, fresh leaf 110, and dry simulated leaf 2, only the water vapor conductance that affects the latent heat flux by eliminating environmental factors such as solar radiation, humidity, temperature, and airflow. Can be calculated. Therefore, the relative value of the pore opening can be calculated by obtaining the relative value of the water vapor conductance that depends only on the pore opening.

  The control unit 6 in the pore opening degree monitoring device 3 shown in FIG. 2 uses the computer program set in the control unit 6 to simulate the wet surface simulated leaf 1, the fresh leaf 110 and the dry simulated leaf stored in the storage unit 5. The relative value of the stomatal opening degree of the fresh leaf 110 is calculated based on each leaf temperature of 2 and the value is displayed on the display unit 7.

However, in irrigation management, the exact value of the transpiration rate is not necessary, and the relative value of the pore opening is sufficient. In this case, as a computer program set in the control unit 6, for example, when the leaf temperature of the fresh leaf is T _L , the leaf temperature of the wet surface simulated leaf is T _W , and the leaf temperature of the dry simulated leaf is T _D ,
_{(T D -T L) / (} T D -T W) ··· (1)
From this equation, a simple pore opening ratio can be obtained. For example, when T _D = 30 ° C., T _L = 23 ° C., and T _W = 20 ° C., the simple pore opening ratio is 0.7. When simple stomatal aperture ratio is _{0, (T D -T L) =} 0, i.e., the state where pores are fully closed when the simple stomatal aperture ratio is _1, when T L = _{T W} That is, the stomatal opening of the fresh leaves is 100%, and the transpiration rates of the fresh leaves 110 and the wet surface simulated leaves 1 are the same. For this reason, ideally, the transpiration rate of the wet surface simulated leaf 1 should be matched with the transpiration rate when the pore opening degree of the fresh leaf 110 is 100%.

The control unit 6 obtains a simple pore opening ratio from the leaf temperature T _{L of} the fresh leaves, the leaf temperature T _{W of} the wet surface simulated leaf, and the leaf temperature T _D of the dry simulated leaf, and displays the value on the display unit 7. Using the value of the simple pore opening ratio, it is possible to automatically adjust the irrigation system in real time so that a certain amount of irrigation is started when the relative value of the pore opening falls below a set value.

  In addition, the simple pore opening ratio may be divided into several stages, for example, five stages in the range of 0 to 1, and irrigation management may be performed depending on which classification the pore opening degree corresponds to.

(Experimental example)
An experiment was conducted to confirm the consistency between the transpiration rate of tomato leaves and the simple pore opening ratio. A plant from which other parts were removed while leaving a single leaf 110, stem and root was used. Wet surface simulated leaf 1 is a black filter paper cut into almost the same shape and size as the selected raw leaves to form a part corresponding to the blade, and a part of the filter paper is extended so as to correspond to the petiole to store water The water supply part 11 which sucks up water from the tank was formed. The dry simulated leaf 2 was formed by cutting an aluminum plate having a thickness of 0.35 mm into a shape and size substantially the same as the selected leaf and performing matte black coating.

A thermocouple contact was affixed to the center of the back surface of each selected leaf 110, wet surface simulated leaf 1, and dry simulated leaf 2. Each of the wet simulated leaf 1 and the dry simulated leaf 2 was arranged at the same height as the selected leaf in the same direction. Water was supplied from the water storage tank to the wet surface simulated leaf 1 through the water supply unit 11. These fresh leaves, wet surface simulated leaves, and dry simulated leaves were heated at a temperature of 23.5 to 34.2 ° C., a short wave radiation flux of 42 to 740 W / m ² , a relative humidity of 38 to 59%, and an air velocity of 0.1 to 0.3 m. / S environment. The leaf temperature data from these three thermocouples were acquired every predetermined time and stored in the storage means 5 shown in FIG. At the same time, the transpiration rate of tomato leaves was measured by a weighing method.

  FIG. 3 shows the correlation between the measured value of the transpiration rate of tomato leaves and the simple pore opening ratio. The correlation determination coefficient R2 was a high value of 0.93, and it was confirmed that the simple pore opening ratio is a highly accurate index of the transpiration rate.

  The stomatal opening monitoring method and apparatus of the present invention can be used for water management of cultivated plants.

1: wet surface simulated leaf 11: water supply unit 2: dry simulated leaf 3: stomatal opening monitoring device 4: leaf temperature measuring unit 5: storage unit 6: control unit 7: display unit 100: plant 110: fresh leaves

Claims (8)

  Stomatal opening monitoring characterized in that a wet surface simulated leaf and a dry simulated leaf are arranged in the vicinity of a raw leaf of a plant, and each leaf temperature of the raw leaf, the wet surface simulated leaf and the dry simulated leaf is measured. Method.   The stomatal opening of the said raw leaf is calculated | required using the measured leaf temperature of the said raw leaf, the measured leaf temperature of the said wet surface simulated leaf, and the measured leaf temperature of the said dry simulated leaf. How to monitor the opening. When the measured leaf temperature is T _L , the measured wet surface leaf temperature is T _W , and the measured dry simulated leaf temperature is T _D , the following formula (1)
_{(T D -T L) / (} T D -T W) ··· (1)
2. The method for monitoring the pore opening degree according to claim 1, wherein a simple pore opening ratio is obtained.   The method for monitoring pore opening according to any one of claims 1 to 3, wherein the raw leaves, the wet surface simulated leaves, and the dry simulated leaves have the same shape and size. Wet surface simulated leaves placed in the vicinity of the raw leaves of the plant,
A dry simulated leaf disposed in the vicinity of the fresh leaf;
A stomatal opening monitoring device comprising leaf temperature measuring means for detecting the leaf temperature of the fresh leaf, the leaf temperature of the wet surface simulated leaf, and the leaf temperature of the dry simulated leaf. Storage means for storing the leaf temperature data of the raw leaves, the leaf temperature data of the wet surface simulated leaves, and the leaf temperature data of the dry simulated leaves;
6. A device for monitoring a pore opening degree according to claim 5, further comprising a control unit for storing data of each leaf temperature detected by said leaf temperature measuring means in said storage means.   The said control part is set with the means to obtain | require the pore opening degree of the said raw leaf using each leaf temperature data of the said raw leaf, the said wet surface simulated leaf, and the said dry simulated leaf. 6. The device for monitoring pore opening according to 6. In the control unit,
When the measured leaf temperature is T _L , the measured wet surface leaf temperature is T _W , and the measured dry simulated leaf temperature is T _D , the following formula (1)
_{(T D -T L) / (} T D -T W) ··· (1)
7. A device for monitoring a pore opening according to claim 5 or 6, wherein means for obtaining a simple pore opening ratio is set.

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