Plant biosensor

A plant biosensor includes a solar radiation sensor that measures a solar radiation amount with which the plant is irradiated, a sap flow sensor that measures a flow rate of sap flowing in a body of the plant, and an absorbed nutrient sensor that measures a nutritional state of the plant.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. national stage of application No. PCT/JP2020/040639, filed on Oct. 29, 2020. Priority under 35 U.S.C. § 119(a) and 35 U.S.C. § 365(b) is claimed from Japanese Application No. 2019-200153, filed Nov. 1, 2019, the disclosure of which is also incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a plant biosensor capable of measuring environmental information and biological information of a plant.

BACKGROUND ART

Patent Document 1 discloses an environment control method for a greenhouse.

PRIOR ART DOCUMENTS

Patent Documents

Patent Document 1: JP H08-103173 A

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

With the environment control method, various devices for adjusting the environment in a greenhouse are controlled based on light intensity, temperature, and humidity, which are environmental information in the greenhouse. For this reason, there is a case of not being capable of providing an optimal environment for individual plants in the greenhouse.

An object of the present disclosure is to provide a plant biosensor capable of measuring environmental information and biological information of a plant.

Means for Solving the Problems

A plant biosensor of an example of the present disclosure isa plant biosensor that measures environmental information and biological information of a plant, the plant biosensor including:a solar radiation sensor that measures a solar radiation amount with which the plant is irradiated;a sap flow sensor that measures a flow rate of sap flowing in a body of the plant; andan absorbed nutrient sensor that measures a nutritional state of the plant.

Here, “environmental information” is information regarding the environment of a measurement object plant, and includes a solar radiation amount, a carbon dioxide amount, humidity, temperature, and a volatile organic compound amount. “Biological information” is information regarding biological information of a measurement object plant and includes a flow rate of sap and a nutritional state. “Nutritional state” is indicated by, for example, the ingredient amount of a predetermined substance in the body of a plant. The predetermined substance includes nitrate nitrogen, carbohydrates, proteins, minerals, antioxidants, and moisture.

Effects of the Invention

The plant biosensor includes the solar radiation sensor that measures the solar radiation amount with which the plant is irradiated, the sap flow sensor that measures the flow rate of sap flowing in the body of the plant, and the absorbed nutrient sensor that measures a nutritional state of the plant. Such configuration makes it possible to achieve a plant biosensor capable of measuring biological information of individual plants in a greenhouse, for example.

MODE FOR CARRYING OUT THE INVENTION

An example of the present disclosure will be described below with reference to the accompanying drawings. In the following description, terms indicating specific directions or positions (e.g., terms including “up”, “down”, “right”, and “left”) are used as necessary, but these terms are used for facilitating understanding of the present disclosure with reference to the drawings, and the technical scope of the present disclosure is not limited by the meanings of these terms. The following description is merely exemplary in nature, and is not intended to limit the present disclosure, its application, or its use. Furthermore, the drawings are schematic, and ratios of dimensions and the like do not necessarily match actual ones.

As shown inFIG.1, a plant biosensor1of one embodiment of the present disclosure includes a solar radiation sensor10, a sap flow sensor20, and an absorbed nutrient sensor30, and measures environmental information and biological information of a measurement object plant.

The plant biosensor1further includes a casing2(hereinafter referred to as a first casing2) as an example, and the solar radiation sensor10is accommodated inside the casing2. Specifically, a substrate (not illustrated) is provided inside the first casing2, and this substrate is mounted with the solar radiation sensor10, a communication device11, a first connection part12, a second connection part13, a carbon dioxide sensor14, a temperature and humidity sensor15, a VOC sensor16, and an arithmetic device17(an example of a calculation unit). The solar radiation sensor10and the communication device11are disposed at one end (e.g., the upper end shown inFIG.1) of the first casing2, and the first connection part12and the second connection part13are disposed at the other end (e.g., the lower end shown inFIG.1) opposing the one end of the first casing2.

The solar radiation sensor10measures a solar radiation amount with which a measurement object plant is irradiated. Specifically, the solar radiation sensor10measures a solar radiation amount with which the periphery of a measurement object plant is irradiated and measures this solar radiation amount as the solar radiation with which the plant is irradiated.

The communication device11receives information regarding a measurement result measured by sensors including the solar radiation sensor10, the sap flow sensor20, and the absorbed nutrient sensor30, and transmits the received information regarding a measurement result to an external device connected wirelessly or by wire. In a case where information regarding the received measurement result is wirelessly transmitted, any communication standard such as Wi-Fi (brand name) and Bluetooth (registered trademark) can be used.

The first connection part12is connected with the sap flow sensor20and receives information regarding a measurement result measured by the sap flow sensor20. The first connection part12and the sap flow sensor20are connected by, for example, an electrical cable41. The second connection part13is connected with the absorbed nutrient sensor30and receives information regarding a measurement result measured by the absorbed nutrient sensor30. The second connection part13and the absorbed nutrient sensor30are connected by, for example, an optical fiber42. The first connection part12and the sap flow sensor20may be connected by wireless communication of any communication standard.

The carbon dioxide sensor14measures a carbon dioxide amount in the air around a measurement object plant. The temperature and humidity sensor15measures a temperature and humidity around a measurement object plant. The VOC sensor16measures a volatile organic compound amount in the air around a measurement object plant.

The arithmetic device17includes a CPU that performs arithmetic operation, a ROM and a RAM that store information, and the like, and calculates a reproductive growth degree of the plant based on a photosynthesis amount of the plant measured by a flow rate measurement unit27described later and a vegetative growth degree of the plant measured by a growth degree measurement unit38described later. A photosynthesis amount of the plant measured by the flow rate measurement unit27is acquired from the sap flow sensor20via the first connection part12. A vegetative growth degree of the plant measured by the growth degree measurement unit38is acquired from the absorbed nutrient sensor30via the second connection part13.

“Vegetative growth degree” is a degree indicating the growth state of a trunk, a branch, a stem, a leaf, and the like. “Reproductive growth degree” is a degree indicating the growth state of a flower, a bud, a fruit, and the like.

As an example, the various sensors, the communication device11, and the arithmetic device17that constitute the plant biosensor1are electrically connected to a battery (not illustrated) accommodated inside the first casing2, and electric power is supplied from the battery.

As shown inFIG.2toFIG.5, the sap flow sensor20includes a casing21(hereinafter referred to as a second casing21) inside of which is provided with an accommodation part25, and a heater unit22and a temperature sensor unit23disposed inside the accommodation part25. In this sap flow sensor20, as an example, as shown inFIG.4andFIG.5, the heater unit22and the temperature sensor unit23are disposed so as to face each other across a main stem101in the radial direction (e.g., the Y direction shown inFIG.4andFIG.5) of the main stem101in a state where the second casing21is attached to the main stem101(an example of a first structure part through which sap flows).

As shown inFIG.2, the second casing21has a substantially rectangular parallelepiped box shape and is configured to be attachable about a direction (e.g., the X direction) in which the main stem101extends with respect to the main stem101of a measurement object plant. Specifically, as shown inFIG.3, the second casing21includes two members211rotatably connected via a hinge213. Each member211has an opening surface212, and the members211are connected with each other in a state where the opening surfaces212oppose each other. The hinge213extends in a long direction of the second casing21and is disposed on one side edge in a short direction of the opening surface212of each member211. As shown inFIG.1, the other side surface in the short direction at the opening surface212of the second casing21is provided with a connection mechanism29for snap-fitting each member211.

As shown inFIG.3, the surface (in other words, the inner surface of the second casing21) of the accommodation part25is provided with a heat insulation layer26. The heat insulation layer26includes a closed space (air or vacuum) or a material having a high heat insulation property (e.g., sponge). By providing the heat insulation layer26, it is possible to efficiently apply heat to the main stem101without releasing heat to the outside of the accommodation part25, and it is possible to secure heat insulation between the heater unit22and the temperature sensor unit23. As an example, the heat insulation layer26is provided on the entire surface of the accommodation part25except for the heater unit22, the temperature sensor unit23, and a pair of through holes214and215described later.

As shown inFIG.3, the second casing21includes the pair of through holes214and215(an example of a pair of first through holes) provided at both respective ends in a first direction (e.g., the X direction) in which the main stem101extends in the state where the second casing21is attached to the main stem101, and a pair of elastic members216and217(an example of a pair of first elastic members) provided in the through holes214and215, respectively.

Each of the through holes214and215has a substantially circular shape in which the main stem101can be disposed and penetrates the second casing21in the X direction. Each of the elastic members216and217is made of, for example, sponge, and is disposed on each member211constituting the second casing21. In other words, the elastic members216and217are each disposed so as to be able to hold the main stem101from a radial direction (in other words, a second direction intersecting the first direction) of the main stem101in the state where the second casing21is attached to the main stem101. The elastic members216and217prevent the sap flow sensor20from falling off a measurement object plant.

Both ends of the second casing21in the X direction are each provided with a band attachment part28for attaching a banding band110. By connecting the second casing21and the main stem101using the banding band110, it is possible to more reliably prevent the sap flow sensor20from falling off a measurement object plant.

As shown inFIG.3, the heater unit22is disposed inside the accommodation part25in such a manner to be able to heat the main stem101. Specifically, the heater unit22has a substantially V shape including a first surface and a second surface disposed to intersect the first surface. As shown inFIG.3, each of the first surface and the second surface is provided with a heat transfer sheet221. In other words, the heater unit22is configured such that each of the first surface and the second surface is in contact with the main stem101via the heat transfer sheet221.

As shown inFIG.3, the temperature sensor unit23is disposed inside the accommodation part25so as to be able to measure the temperature of the sap flowing through the main stem101on both sides with respect to the heater unit22in a direction (e.g., the X direction) where the main stem101extends in the state where the second casing21is attached to the main stem101. Specifically, the temperature sensor unit23includes a main body unit231having a rectangular plate shape in which the X direction is a long direction, and a pair of temperature sensors232provided on a surface of the main body unit231opposing the heater unit22. Each temperature sensor232has a substantially cylindrical shape protruding from the main body unit231toward the heater unit22and is disposed at an interval in the X direction. A tip of each temperature sensor232comes into contact with the main stem101and measures a temperature of the sap flowing through the main stem101.

As shown inFIG.3, the sap flow sensor20includes a position adjustment mechanism24. As shown inFIGS.4and5, the position adjustment mechanism24includes a screw hole218provided in the second casing21and a position adjustment member241.

The screw hole218has a shape that allows the position adjustment member241to be inserted, is disposed on a straight line L passing through the heater unit22and the temperature sensor unit23in the second casing21, and penetrates the second casing21in a direction (e.g., the Y direction) in which the straight line L extends. An inner periphery of the screw hole218is provided with a screw groove (not illustrated). The straight line L extends along the radial direction of the main stem101in the state where the second casing21is attached to the main stem101. An outer peripheral surface of the second casing21in the direction where the straight line L extends is provided with a boss part219. The screw hole218penetrates this boss part219in the direction where the straight line L extends.

As an example, the position adjustment member241, which has an elongated substantially cylindrical shape, extends from the outside of the accommodation part25to the inside of the accommodation part25via the screw hole218, and is connected to the main body unit231of the temperature sensor unit23. An outer periphery of the position adjustment member241is provided with a screw thread (not illustrated) to be fitted into the screw groove of the screw hole218. The position adjustment member241is configured to be movable in a direction where the straight line L extends by being rotated about the straight line L. In other words, by rotating the position adjustment member241about the straight line L, it is possible to move the temperature sensor unit23in the direction where the straight line L extends (seeFIG.4andFIG.5) to perform position adjustment. An end of the position adjustment member241on the outer side of the accommodation part25is provided with a substantially cylindrical operation unit242having a diameter larger than the screw hole218. This operation unit242facilitates rotation operation of the position adjustment member241.

As shown inFIG.1, the sap flow sensor20further includes the flow rate measurement unit27. The flow rate measurement unit27includes a CPU that performs arithmetic operation, a ROM and a RAM that store information, and a communication device that transmits information to the first connection part12and measures a flow rate of the sap flowing through inside the body of the main stem101based on a temperature of the sap flowing through inside the body of the main stem101measured by the temperature sensor unit23. The flow rate measurement unit27measures a photosynthesis amount performed by a plant from a measured flow rate of sap. That is, the flow rate measurement unit27is an example of a first measurement unit. Information regarding a result measured by the sap flow sensor20is transmitted to the first connection part12via the electrical cable41.

As an example, each of the heater unit22, the temperature sensor unit23, and the flow rate measurement unit27is electrically connected to a battery (not illustrated) accommodated inside the second casing21, and electric power is supplied from the battery.

As shown inFIG.6toFIG.9, the absorbed nutrient sensor30includes a casing31(hereinafter referred to as a third casing31), and a holding part32and a nutritional state sensor unit33that are provided inside the third casing31.

As shown inFIG.6, the third casing31is configured to be attachable about a direction (e.g., the Y direction) in which a petiole102(an example of a second structure part through which sap flows) extends with respect to the petiole102of the plant. As an example, the petiole102extends in a direction (e.g., the X direction) intersecting a direction in which the main stem101extends.

Specifically, the third casing31, as shown inFIG.6andFIG.7, has a substantially T shape as a whole, and, as shown inFIG.8andFIG.9, includes a first member311in which the holding part32is accommodated and a second member312in which the nutritional state sensor unit33is accommodated.

The first member311has a substantially rectangular plate shape, and the second member312is connected to one end of the first member311in the long direction. The other end of the first member311in the long direction is provided with a connection part34to which the optical fiber42is connected, and a substantially arc-shaped cable attachment part35to which a cable120(seeFIG.1) for hanging the absorbed nutrient sensor30is attached. The second member312has a substantially rectangular parallelepiped box shape and is disposed such that the short direction of the first member311becomes the long direction of the second member312. The second member312includes two members314rotatably connected via a hinge313. Each member314includes an opening surface315. The members are connected in a state where the opening surfaces315oppose each other. The hinge313extends in the long direction of the third casing31and is disposed on one side edge in the short direction of the opening surface315of each member314. As shown inFIG.6, the other side surface in the short direction at the opening surface315of the third casing31is provided with a connection mechanism36for snap-fitting each member314.

As shown inFIG.6andFIG.7, the second member312includes a pair of through holes316and317(an example of a pair of second through holes) provided at both ends in a direction (e.g., the Y direction) in which the petiole102extends in a state where the third casing31is attached to the petiole102, and a pair of elastic members318and319(an example of a pair of second elastic members) provided in the through holes316and317, respectively.

Each of the through holes316and317has a substantially circular shape in which the petiole102can be disposed and penetrates the third casing31in the Y direction. Each of the elastic members318and319is made of, for example, sponge, and is disposed on each member314constituting the second member312. In other words, the elastic members318and319are each disposed so as to be able to hold the petiole102from the radial direction of the petiole102in the state where the third casing31is attached to the petiole102. The elastic members318and319prevent the absorbed nutrient sensor30from falling off a measurement object plant.

As shown inFIG.6andFIG.7, the surface of the second member312to which the first member311is connected is provided with a band attachment part37for attaching the banding band110. By connecting the second member312and the main stem101using the banding band110, it is possible to more reliably prevent the absorbed nutrient sensor30from falling off a measurement object plant.

As shown inFIG.8andFIG.9, the holding part32includes a first holding member321, a second holding member322disposed so as to oppose the first holding member321, and a biasing member323that biases the first holding member321toward the second holding member322. The first holding member321is disposed to be movable in a radial direction (in other words, a fourth direction (e.g., the X direction) intersecting the third direction in which the petiole102extends in the state of being attached to the petiole102) of the petiole102in the state where the third casing31is attached to the petiole102. The second holding member322is disposed so as to oppose the first holding member321in the X direction and is fixed to the third casing31. The biasing member323include, for example, a coil spring, and is disposed between the first holding member321and the bottom surface of the third casing31on the second member312side in the X direction.

Each of the first holding member321and the second holding member322includes a recess324that is recessed in a direction away from each other and in which the petiole102is disposed. Each recess324is curved along the outer shape of the petiole102.

As an example, the nutritional state sensor unit33includes a light-projecting unit331that irradiates a measurement site of a plant with light and a light-receiving unit332that receives light from a measurement site of the plant. This nutritional state sensor unit33measures a nutritional state of the petiole102(an example of a measurement site) from light received by the light-receiving unit332. The light-projecting unit331includes, for example, a light-emitting diode (an example of a light-emitting element that generates light) having a small warm-up time and high time responsiveness, and a light-projecting fiber that guides light generated by the light-emitting diode to the petiole102. The light-projecting unit331can also include a plurality of light-emitting diodes having different wavelengths. The light-receiving unit332includes, for example, a spectrometer or a photodiode (an example of a light-receiving element) that receives reflected light emitted from the light-emitting diode to the petiole102and reflected, and a light-receiving fiber that guides the reflected light from the petiole102to the spectrometer or the photodiode. As an example, the light-projecting unit331and the light-receiving unit332are disposed on the same side (inFIG.8andFIG.9, above the petiole102) with respect to the petiole102in a state where the third casing31is attached in plan view including the third direction and the fourth direction (seeFIG.8andFIG.9). The light-projecting fiber and the light-receiving fiber are disposed in a V shape.

As shown inFIG.1, the absorbed nutrient sensor30further includes the growth degree measurement unit38as an example of a second measurement unit. The growth degree measurement unit38includes a CPU that performs arithmetic operation, a ROM and a RAM that store information, and a communication device that transmits information to the second connection part13and measures a vegetative growth degree of a measurement object plant based on a nutritional state of the petiole102measured by the nutritional state sensor unit33. Information regarding a result measured by the absorbed nutrient sensor30is transmitted to the second connection part13via the optical fiber42.

Each of the nutritional state sensor unit33and the growth degree measurement unit38is electrically connected to a battery (not illustrated) accommodated inside the third casing31, and electric power is supplied from the battery.

With reference toFIG.10andFIG.11, a usage example of environmental information and biological information of a plant measured by the plant biosensor1will be described. An image200shown inFIG.10includes a first display region210and a second display region220. An upper region of the first display region210displays CG of a greenhouse, and a lower region of the first display region210displays in real time environmental information and biological information of a plant measured by the plant biosensor1. The second display region220displays recommendation regarding cultivation management of a plant in chronological order from environmental information and biological information of a plant measured and accumulated by the plant biosensor1. An image300shown inFIG.11is an example of recommendation. An upper region310of the image300displays content of the recommendation, and a lower region320of the image300displays environmental information and biological information of a plant that are the basis for the displayed recommendation.

According to the plant biosensor1, the following advantageous effects can be achieved.

It includes the solar radiation sensor10that measures the solar radiation amount with which the plant is irradiated, the sap flow sensor20that measures the flow rate of sap flowing in a body of the plant, and the absorbed nutrient sensor30that measures a nutritional state of the plant. Such configuration makes it possible to achieve the plant biosensor1capable of measuring biological information of individual plants in a greenhouse, for example.

The solar radiation sensor10and the communication device11are disposed at one end of the first casing2, and the first connection part12and the second connection part13are disposed at the other end of the first casing2opposing the one end of the first casing2. Such configuration makes it possible to dispose the solar radiation sensor10and the communication device11at the upper end of the first casing2in the vertical direction at the time of use of the plant biosensor1, for example. In this case, it is possible to more reliably transmit the measured environmental information and biological information of a plant to the external device while more accurately measuring a solar radiation amount with which the measurement object plant is irradiated.

The carbon dioxide sensor14, the temperature and humidity sensor15, and the VOC sensor16are included. Such configuration makes it possible to achieve the plant biosensor1capable of measuring environmental information of more plants.

The sap flow sensor20includes the second casing21, the heater unit22, the temperature sensor unit23, and the flow rate measurement unit27. The second casing21internally includes the accommodation part25provided with the heat insulation layer26on the surface thereof and is configured to be attachable around the direction in which the main stem101extends with respect to the main stem101. The heater unit22is disposed inside the accommodation part25and configured to be able to heat the main stem101. The temperature sensor unit23is disposed inside the accommodation part25and is configured to be able to measure the temperature of the sap flowing through the main stem101on both sides with respect to the heater unit22in the direction where the main stem101extends in the state where the second casing21is attached to the main stem101. The flow rate measurement unit27measures a flow rate of the sap flowing through inside the body of the main stem101based on a temperature of the sap flowing through inside the body of the main stem101measured by the temperature sensor unit23. Such configuration makes it possible to more accurately measure a flow rate of sap flowing in a body of the plant.

The heater unit22and the temperature sensor unit23are disposed so as to face each other across the main stem101in the radial direction of the main stem101in the state where the second casing21is attached to the main stem101. With such configuration, the heat of the heater unit22is not directly transmitted to the temperature sensor unit23, the SN ratio of the sap flow sensor20can be increased. Space efficiency in the accommodation part25can be enhanced.

The sap flow sensor20includes the position adjustment member241. The position adjustment member241extends from the outside of the accommodation part25to the inside of the accommodation part25via the screw hole218, is connected to the temperature sensor unit23, is provided with the screw thread fitted into the screw groove on the outer periphery, and is configured to be movable in the direction where the straight line L extends by being rotated about the straight line L. Such configuration makes it possible to allow the sap flow sensor20to be attached to the main stem101without damaging the main stem101even when the measurement object plant grows and the main stem101becomes large.

The heater unit22includes the first surface that can come into contact with the main stem101and the second surface that is disposed so as to intersect the first surface and can come into contact with the main stem101. Each of the first surface and the second surface is provided with the heat transfer sheet221including elasticity, and each of the first surface and the second surface comes into contact with the main stem101via the heat transfer sheet221. Such configuration makes it possible to stably bring the heater unit22into contact with the main stem101, and therefore makes it possible to more accurately measure a flow rate of sap flowing in a body of the plant.

The second casing21includes a pair of first elastic members216and217provided in each of the pair of first through holes214and215and capable of holding the main stem101in the radial direction of the main stem101. Such configuration makes it possible to allow the sap flow sensor20to be attached to the main stem101without damaging the main stem101. The first elastic members216and217may be provided in only one of the pair of first through holes214and215.

The absorbed nutrient sensor30includes the third casing31, the holding part32, and the nutritional state sensor unit33. The third casing31is configured to be attachable around the direction in which the petiole102extends with respect to the petiole102of the plant. The holding part32is provided inside the third casing31and is configured to be able to hold the petiole102in the radial direction of the petiole102. The nutritional state sensor unit33is provided inside the third casing31and is configured to be able to measure a nutritional state of the petiole102. Such configuration makes it possible to more accurately measure a nutritional state of the plant.

The holding part32includes the first holding member321, the second holding member322, and the biasing member323. The first holding member321is disposed to be movable along the radial direction of the petiole102in the state where the third casing31is attached to the petiole102. The second holding member322is disposed so as to oppose the first holding member321in the radial direction of the petiole102in the state where the third casing31is attached to the petiole102and is fixed to the third casing31. The biasing member323is configured to be capable of biasing the first holding member321in a direction approaching the second holding member322. With such configuration, even when an external force is applied to the petiole102, the petiole102can be retained at a predetermined measurement position, and therefore a nutritional state of the plant can be more reliably measured.

Each of the first holding member321and the second holding member322has the recess324that is recessed in the direction away from each other and in which the petiole102is disposed. With such configuration, a position of the petiole102with respect to the holding part32can be determined more accurately, and therefore a nutritional state of the plant can be more reliably measured.

The third casing31includes a pair of second elastic members318and319provided in each of the pair of second through holes316and317and capable of holding the petiole102in the radial direction of the petiole102. Such configuration makes it possible to allow the absorbed nutrient sensor30to be attached to the petiole102without damaging the petiole102. The second elastic members318and319may be provided in only one of the pair of second through holes316and317.

The plant biosensor1further includes the first measurement unit (e.g., the flow rate measurement unit27), the second measurement unit (e.g., the growth degree measurement unit38), and the calculation unit (e.g., the arithmetic device17). The flow rate measurement unit27measures a photosynthesis amount performed by the plant from a flow rate of sap measured by the sap flow sensor20. The growth degree measurement unit38measures a vegetative growth degree of the plant from a nutritional state of the plant measured by the absorbed nutrient sensor30. The arithmetic device17calculates a reproductive growth degree of the plant based on a photosynthesis amount of the plant measured by the flow rate measurement unit27and a vegetative growth degree of the plant measured by the growth degree measurement unit38. With such configuration, a growth state of the plant can be grasped in real time.

The plant biosensor1can also be configured as follows.

The plant biosensor1needs to include the solar radiation sensor10, the sap flow sensor20, and the absorbed nutrient sensor30. A part or all of the first casing2, the communication device11, the carbon dioxide sensor14, the temperature and humidity sensor15, and the VOC sensor16may be omitted.

The sap flow sensor20is not limited to the configuration including the second casing21, the heater unit22, the temperature sensor unit23, and the flow rate measurement unit27, and may adopt another configuration capable of measuring the flow rate of sap flowing through the body of a plant. For example, in plan view including the first direction and the second direction (seeFIG.4andFIG.5), the heater unit22and the temperature sensor unit23may be disposed so as to be positioned on the same side with respect to the main stem101. This configuration makes it possible to simplify the structure of the sap flow sensor20. The temperature sensor unit23may also be configured to serve as the flow rate measurement unit27. The heater unit22is not limited to have a substantially V shape, and may have another shape (e.g., a substantially C shape formed by three or more surfaces) that can come into contact with the main stem101. The heat transfer sheet221may be omitted. The pair of first elastic members216and217may be omitted. The position adjustment mechanism24may include an elastic member such as a coil spring instead of the position adjustment member241. In this case, the elastic member may be disposed so as to bias the main body unit231of the temperature sensor unit23toward the main stem101.

The absorbed nutrient sensor30is not limited to the configuration including the third casing31, the holding part32, and the nutritional state sensor unit33, and may adopt another configuration capable of measuring the nutritional state of the plant. For example, the light-projecting unit331and the light-receiving unit332may be disposed to oppose each other with respect to the petiole102. The holding part32needs to be configured to be capable of holding the petiole102, and, instead of the biasing member323, a configuration capable of retaining the holding state of the petiole102by the first holding member321and the second holding member322may be adopted. The recess324may be omitted. The pair of second elastic members318and319may be omitted.

The second casing21and the third casing31may be casings having the same shape. The sap flow sensor20and the absorbed nutrient sensor30may be integrally provided, and the second casing21may also be configured to serve as the third casing31(or the third casing31also serves as the second casing21).

A place other than one end (e.g., the upper end ofFIG.1) of the first casing2may be provided with a display unit that displays a remaining battery level, a communication state, and the like, or a power switch.

The first measurement unit may be provided separately from the flow rate measurement unit27. The arithmetic device17may also serve as the first measurement unit and the second measurement unit, or the first measurement unit, the second measurement unit, and the calculation unit may be provided in an external device (e.g., a server).

Various embodiments of the present disclosure have been described above in detail with reference to the drawings, and finally, various aspects of the present disclosure will be described. In the following description, as an example, reference numerals are also added.

According to a first aspect of the present disclosure, there is provided a plant biosensor1that measures environmental information and biological information of a plant, the plant biosensor1including:a solar radiation sensor10that measures a solar radiation amount with which the plant is irradiated;a sap flow sensor20that measures a flow rate of sap flowing in a body of the plant; andan absorbed nutrient sensor30that measures a nutritional state of the plant.

The plant biosensor1of a second aspect of the present disclosure further includes:a communication device11that transmits information regarding the solar radiation amount measured by the solar radiation sensor10, a flow rate of the sap measured by the sap flow sensor20, and a nutritional state of the plant measured by the absorbed nutrient sensor30; anda first casing2that accommodates the solar radiation sensor10and the communication device11inside of first casing, whereinthe first casing2includesa first connection part12to which the sap flow sensor20is connected, anda second connection part13to which the absorbed nutrient sensor30is connected,the solar radiation sensor10and the communication device11are disposed at one end of the first casing2, andthe first connection part12and the second connection part13are disposed at an other end of the first casing2opposing the one end.

The plant biosensor1of a third aspect of the present disclosure further includesa carbon dioxide sensor14that measures a carbon dioxide amount in air around the plant, whereinthe carbon dioxide sensor14is accommodated in the first casing2and disposed in a middle of the one end and the other end of the first casing2.

The plant biosensor1of a fourth aspect of the present disclosure further includesa temperature and humidity sensor15that measures temperature and humidity around the plant, whereinthe temperature and humidity sensor15is accommodated in the first casing2and disposed in a middle of the one end and the other end of the first casing2.

The plant biosensor1of a fifth aspect of the present disclosure further includesa VOC sensor16that measures a volatile organic compound amount in air around the plant, whereinthe VOC sensor16is accommodated in the first casing2and disposed in a middle of the one end and the other end of the first casing2.

In the plant biosensor1of a sixth aspect of the present disclosure,the plant includes a first structure part101through which sap flows, andthe sap flow sensor20includesa second casing21that internally includes an accommodation part25provided with a heat insulation layer26on a surface, the second casing being attachable around a direction in which the first structure part101extends with respect to the first structure part101,a heater unit22that is disposed inside the accommodation part25and heats the first structure part101,a temperature sensor unit23that is disposed inside the accommodation part25and measures a temperature of sap flowing through the first structure part101on both sides with respect to the heater unit22in a first direction where the first structure part101extends in a state where the second casing21is attached to the first structure part101, anda flow rate measurement unit27that measures a flow rate of sap flowing through the first structure part101based on a temperature of sap flowing through the first structure part101measured by the temperature sensor unit23.

In the plant biosensor1of a seventh aspect of the present disclosure,the heater unit22and the temperature sensor unit23are disposed to face each other across the first structure part101in a second direction intersecting the second casing21in the first direction.

In the plant biosensor1of an eighth aspect of the present disclosure,the heater unit22and the temperature sensor unit23are disposed to be positioned on a same side with respect to the first structure part101in plan view including the first direction and a second direction intersecting the first direction.

In the plant biosensor1of a ninth aspect of the present disclosure,the second casing21includesa screw hole218that is disposed on a straight line L passing through the heater unit22and the temperature sensor unit23, penetrates the second casing21in a direction where the straight line L extends, and is provided with a screw groove on an inner periphery, andthe sap flow sensor20includesa position adjustment member241that extends from an outside of the accommodation part25to the inside of the accommodation part25via the screw hole218, is connected to the temperature sensor unit23, is provided with a screw thread fitted into the screw groove on an outer periphery, and is movable in a direction where the straight line L extends by being rotated about the straight line L.

In the plant biosensor1of a tenth aspect of the present disclosure,the heater unit22includesa first surface, anda second surface disposed to intersect the first surface, and

each of the first surface and the second surface is provided with a heat transfer sheet221including elasticity, and each of the first surface and the second surface comes into contact with the first structure part101via the heat transfer sheet221.

In the plant biosensor1of an eleventh aspect of the present disclosure,the second casing includesa pair of first through holes214and215that are provided at both respective ends in the first direction, penetrate the second casing21in the first direction, and are capable of disposing the first structure part101, anda pair of first elastic members216and217that are provided in at least any of the pair of first through holes214and215and capable of holding the first structure part101in a second direction intersecting the first direction.

In the plant biosensor1of a twelfth aspect of the present disclosure,the plant includes a second structure part102through which sap flows, andthe absorbed nutrient sensor30includesa third casing31that is attachable around a direction in which the second structure part102extends with respect to the second structure part102,a holding part32that is provided inside the third casing31and capable of holding the second structure part102in a direction intersecting a direction in which the second structure part102extends, anda nutritional state sensor unit33that is provided inside the third casing31and capable of measuring a nutritional state of the second structure part102.

In the plant biosensor1of a thirteenth aspect of the present disclosure,the holding part32includesa first holding member321that is disposed to be movable along a fourth direction intersecting a third direction in which the second structure part102extends in a state where the third casing31is attached to the second structure part102,a second holding member322that is disposed to cause the third casing31to oppose the first holding member321in the fourth direction, and is fixed to the third casing31, anda biasing member323that biases the first holding member321in the fourth direction and in a direction approaching the second holding member322.

In the plant biosensor1of a fourteenth aspect of the present disclosure,each of the first holding member321and the second holding member322includes a recess324that is recessed in a direction away from each other and in which the second structure part102is disposed.

In the plant biosensor1of a fifteenth aspect of the present disclosure,the absorbed nutrient sensor30includesa light-projecting unit331that irradiates, with light, the second structure part102in a state of being attached with the third casing31, anda light-receiving unit332that receives light from the second structure part102.

In the plant biosensor1of a sixteenth aspect of the present disclosure,the light-projecting unit331includesa light-emitting element that generates light, anda light-projecting fiber that guides light generated by the light-emitting element to the second structure part102, andthe light-receiving unit332includesa light-receiving element that receives light, anda light-receiving fiber that guides light from the second structure part102to the light-receiving element332.

In the plant biosensor1of a seventeenth aspect of the present disclosure,the light-projecting unit331and the light-receiving unit332are disposed on a same side with respect to the second structure part102in a state where the third casing31is attached to the second structure part102in plan view including a third direction in which the second structure part102extends in a state where the third casing31is attached to the second structure part102and a fourth direction intersecting the third direction, and the light-projecting fiber and the light-receiving fiber are disposed to have a V shape.

In the plant biosensor1of a eighteenth aspect of the present disclosure,the light-projecting unit331and the light-receiving unit332are disposed to oppose each other with respect to the second structure part102in a state where the third casing31is attached to the second structure part102.

In the plant biosensor1of a nineteenth aspect of the present disclosure,the third casing31includesa pair of second through holes316and317that are provided at both respective ends in a third direction where the second structure part102extends in a state where the third casing31is attached to the second structure part102, penetrate the third casing31, and are capable of disposing the second structure part102, anda pair of second elastic members318and319that are provided in at least any of the pair of second through holes316and317and capable of holding the second structure part102in a fourth direction intersecting the third direction.

In the plant biosensor1of a twentieth aspect of the present disclosure,a first measurement unit27that measures a photosynthesis amount performed in the plant from a flow rate of sap measured by the sap flow sensor20;a second measurement unit38that measures a vegetative growth degree of the plant from a nutritional state of the plant measured by the absorbed nutrient sensor30; anda calculation unit17that calculates a reproductive growth degree of the plant based on the photosynthesis amount of the plant measured by the first measurement unit27and the vegetative growth degree of the plant measured by the second measurement unit38.

By appropriately combining any embodiments or modifications among the various embodiments or modifications, it is possible to achieve respective effects they have. Combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features in different embodiments or examples are also possible.

Although the present disclosure has been fully described in connection with preferred embodiments with reference to the accompanying drawings, various modifications and corrections will be obvious to those skilled in the art. Such modifications and corrections are to be understood as being included within the scope of the present disclosure as long as they do not depart from the appended claims.

INDUSTRIAL APPLICABILITY

The plant biosensor of the present disclosure can be applied to a plant cultivated in a greenhouse, for example.

DESCRIPTION OF REFERENCE CHARACTERS