JP7097543B2 - Rice production method - Google Patents

Description

The technical field of the present specification relates to a method for producing rice.

Plasma technology is applied in the fields of electricity, chemistry, and materials. Inside the plasma, ultraviolet rays and radicals are generated in addition to charged particles such as electrons and ions. It has been found that these have various effects on living tissues, including sterilization of living tissues.

For example, Patent Document 1 discloses a technique for sterilizing microorganisms in water by irradiating water with plasma. Further, the plasma device of Patent Document 1 can irradiate plasma into water without passing an electric current through the water.

Japanese Unexamined Patent Publication No. 2009-183867 Japanese Unexamined Patent Publication No. 2014-195450

According to Patent Document 2, the viable yeast count decreases when the yeast is irradiated with a large amount of atmospheric pressure plasma, but the viable yeast count increases when the yeast is irradiated with a small amount of atmospheric pressure plasma. Is described. Thus, the possibility of activating and killing yeast by irradiating with plasma has been studied. However, the effects of plasma on other organisms are not always clear.

By the way, rice is mainly consumed as edible rice in Japan. In addition, rice suitable for sake brewing (sake rice) represented by Yamada Nishiki is used for sake brewing. In addition, while domestic rice consumption is declining, rice exports are on the rise. On the other hand, in Japan, where the birthrate is declining and the population is aging rapidly, the number of producers is steadily decreasing, and maintaining productivity has become a problem. Under such circumstances, it is desired to increase the production amount and improve the quality of rice.

The technique described in the present specification has been made to solve the problems of the above-mentioned conventional technique. In other words, the challenge is to provide a rice production method that aims to increase the yield of rice and improve the quality of rice.

The method for producing rice in the first aspect is an aqueous solution preparation step of preparing an aqueous solution containing L-sodium lactate, a plasma irradiation step of irradiating the aqueous solution with atmospheric pressure plasma to obtain a plasma-activated aqueous solution, and rice growth. It has an aqueous solution supply step of supplying a plasma-activated aqueous solution to a point, and in the aqueous solution supply step, the growth point is exposed by surrounding the rice with a tubular member and pumping water inside the tubular member. It is a feature.
Further, in the rice production method according to the second aspect, the rice growth point is exposed by surrounding the rice with a tubular member and pumping water inside the tubular member to direct the exposed rice growth point. Directly irradiate the atmospheric pressure plasma.

This method of producing rice increases the yield of brown rice. It also reduces the proportion of immature rice in the harvested brown rice. Then, for rice suitable for sake brewing, the proportion of white rice, which is important for sake brewing, is increased. That is, the quality of rice suitable for sake brewing is improved.

In the present specification, a rice production method for increasing the yield of rice and improving the quality of rice is provided.

It is a conceptual diagram for demonstrating the structure of the robot arm which scans the gas outlet of the plasma generator of 1st Embodiment. Figure 2. A is a cross-sectional view showing the configuration of the first plasma generator, and FIG. 2. B is a diagram showing the shape of the electrode. Figure 3. A is a cross-sectional view showing the configuration of the second plasma generator, and FIG. B is a partial cross-sectional view in a cross section perpendicular to the longitudinal direction of the plasma region. It is a figure which shows the schematic structure of the 3rd plasma generator in 1st Embodiment. It is a schematic block diagram which shows the superstructure of the 3rd plasma generator in 1st Embodiment. It is a schematic block diagram which shows the substructure of the 3rd plasma generator in 1st Embodiment. It is a figure for demonstrating the case where the 3rd plasma generator irradiates plasma in 1st Embodiment. It is a figure for demonstrating the aqueous solution supply process in 1st Embodiment. It is a figure for demonstrating the plasma irradiation process in 2nd Embodiment. It is a graph which shows the yield of brown rice in Experiment A. It is a graph which shows the ratio of the perfect grain in the harvested brown rice in Experiment A. It is a graph which shows the ratio of each rice to the number of grains of the harvested brown rice in Experiment A. It is a graph which shows the weight (yield amount) of the brown rice harvested from one strain in Experiment B. It is a graph which shows the ratio of the immature rice and the cracked rice in the harvested brown rice in Experiment B. It is a graph which shows the ratio of the belly white rice and the heart white rice in the harvested brown rice in Experiment B.

Hereinafter, a specific embodiment will be described with reference to the drawings, taking as an example a rice production method. The dimensions and the like of the plasma generator are examples, and numerical values other than the illustrated numerical range may be used.

(First Embodiment)
The first embodiment will be described. In the rice production method of the first embodiment, the plasma-activated aqueous solution is supplied toward the rice growth point. This plasma-activated aqueous solution is obtained by irradiating an aqueous solution containing sodium lactate with plasma. Therefore, first, a plasma generator that irradiates plasma will be described.

1. 1. Plasma activated aqueous solution production equipment 1-1. Configuration of Plasma Activated Aqueous Solution Manufacturing Device The plasma activated aqueous solution manufacturing device PM of the present embodiment includes a plasma irradiation device P1 and an arm robot M1 as shown in FIG. The plasma irradiation device P1 is for generating plasma and irradiating the plasma toward a solution.

As shown in FIG. 1, the arm robot M1 can move the position of the plasma irradiation device P1 in each of the x-axis, y-axis, and z-axis directions. For convenience of explanation, the direction of irradiating the plasma is the −z axis direction. Thereby, the distance between the liquid level of the solution and the plasma irradiation device P1 can be adjusted. Further, the plasma activation aqueous solution manufacturing apparatus PM can irradiate plasma only for that time by setting the plasma irradiation time in advance.

As will be described later, the plasma irradiation device P1 has three types of methods (first plasma generator P10, second plasma generator P20, and third plasma generator P30). And any method may be used. The third plasma generator P30 does not have the robot arm M1 and the like shown in FIG.

1-2. First plasma generator Figure 2. A is a cross-sectional view showing a schematic configuration of a plasma generator P10. Here, the plasma generator P10 is a first plasma generator that ejects plasma in dots. Figure 2. B is shown in FIG. It is a figure which shows the detail of the shape of the electrode 2a, 2b of the plasma generator P10 of A.

The plasma generator P10 has a housing portion 10, electrodes 2a and 2b, and a voltage applying portion 3. The housing portion 10 is made of a sintered body made of alumina (Al ₂ O ₃ ) as a raw material. The shape of the housing portion 10 is a tubular shape. The inner diameter of the housing portion 10 is 2 mm or more and 3 mm or less. The thickness of the housing portion 10 is 0.2 mm or more and 0.3 mm or less. The length of the housing portion 10 is 10 cm or more and 30 cm or less. A gas introduction port 10i and a gas outlet 10o are formed at both ends of the housing portion 10. The gas introduction port 10i is for introducing a gas for generating plasma. The gas outlet 10o is an irradiation unit for irradiating the outside of the housing portion 10 with plasma. The direction in which the gas moves is the direction of the arrow in the figure.

The electrodes 2a and 2b are a pair of counter electrodes arranged so as to face each other. The length of the electrodes 2a and 2b in the facing surface direction is smaller than the inner diameter of the housing portion 10. For example, it is about 1 mm. The electrodes 2a and 2b are shown in FIG. As shown in B, a large number of recesses (hollows) H are formed on each of the facing surfaces. Therefore, the facing surfaces of the electrodes 2a and 2b have a fine uneven shape. The depth of the recess H is about 0.5 mm.

The electrode 2a is arranged inside the housing portion 10 and in the vicinity of the gas introduction port 10i. The electrode 2b is arranged inside the housing portion 10 and in the vicinity of the gas ejection port 10o. Therefore, in the plasma generator P10, the gas is introduced from the opposite side of the facing surface of the electrode 2a, and the gas is ejected to the opposite side of the facing surface of the electrode 2b. The distance between the electrodes 2a and 2b is, for example, 24 cm. The distance between the electrodes 2a and 2b may be smaller than this.

The voltage application unit 3 is for applying an AC voltage between the electrodes 2a and 2b. The voltage application unit 3 boosts the voltage to 9 kV using 60 Hz and 100 V, which are commercial AC voltages, and applies a voltage between the electrodes 2a and 2b.

When argon is introduced from the gas introduction port 10i and a voltage is applied between the electrodes 2a and 2b by the voltage applying portion 3, plasma is generated inside the housing portion 10. Figure 2. As shown by the diagonal line A, the region where plasma is generated is referred to as the plasma generation region P. The plasma generation region P is covered with the housing portion 10.

1-3. Second plasma generator Figure 3. A is a cross-sectional view showing a schematic configuration of a plasma generator P20. Here, the plasma generator P20 is a second plasma generator that ejects plasma linearly. Figure 3. B is shown in FIG. It is a partial cross-sectional view in the cross section perpendicular to the longitudinal direction of the plasma generation region P of the plasma generation apparatus P20 of A.

The plasma generator P20 includes a housing portion 11, electrodes 2a and 2b, and a voltage applying portion 3. The housing portion 11 is made of a sintered body made of alumina (Al ₂ O ₃ ) as a raw material. A gas introduction port 11i and a large number of gas outlets 11o are formed at both ends of the housing portion 11. The gas inlet 11i is shown in FIG. It has a slit shape with the left-right direction of A as the longitudinal direction. The slit width (width in the left-right direction in FIG. 3.B) from the gas introduction port 11i to directly above the plasma generation region P is, for example, 1 mm.

The gas outlet 11o is an irradiation unit for irradiating the outside of the housing portion 11 with plasma. The gas outlet 11o has a cylindrical shape or a slit shape. The gas outlet 11o in the case of a cylindrical shape is formed in a straight line along the longitudinal direction of the plasma region. The inner diameter of the gas outlet 11o is within the range of 1 mm or more and 2 mm or less. Further, in the case of a slit shape, it is preferable that the slit width of the gas outlet 11o is 1 mm or less. As a result, a stable plasma is formed. Further, the gas introduction port 11i is adapted to introduce gas in a direction intersecting the line connecting the electrodes 2a and 2b.

The electrodes 2a and 2b and the voltage application unit 3 are the same as those of the plasma generator P10 shown in FIG. Then, similarly, a commercial AC voltage is used to apply a voltage between the electrodes 2a and 2b. As a result, the plasma can be ejected in a straight line.

Further, the plasma generator P20 that ejects plasma in a straight line is shown in FIG. By arranging them in a row in the left-right direction of B, plasma can be ejected in a plane over a certain rectangular region.

1-4. The third plasma generator FIG. 4 is a conceptual diagram showing a schematic configuration of the third plasma generator P30. The plasma generator P30 is for irradiating the contained solution with plasma.

As shown in FIG. 4, the plasma generator P30 includes a first electrode 110, a second electrode 210, a first potential applying unit 120, a second potential applying unit 220, and a first lead wire 130. , The second lead wire 230, the gas supply unit 140, the gas pipe coupling connector 150, the gas pipe 160, the first electrode protection member 170, the second electrode protection member 240, and the first electrode support member 180. It has a sealing member 191, a connecting member 192, a container 250, a sealing member 260, and a gantry 270.

1-4-1. Schematic configuration of electrodes The first electrode 110 has a tubular shape portion 110a. Then, plasma gas can be supplied to the inside of the tubular portion 110a. That is, the inside of the first electrode 110 communicates with the gas supply unit 140. The first electrode 110 blows gas from the tubular portion 110a toward the second electrode 210. The tip of the first electrode 110 has an injection needle shape. That is, the tip of the first electrode 110 has an inclined surface that is inclined with respect to the direction perpendicular to the axial direction of the first electrode 110. A microhollow is formed at the tip of the first electrode 110.

The second electrode 210 is an electrode facing the first electrode 110. The second electrode 210 is a rod-shaped electrode. The second electrode 210 has a cylindrical shape. Alternatively, it may have a polygonal prism shape. Alternatively, it may have a needle shape with a sharp tip. Here, the second electrode 210 has a tip portion 211. The tip portion 211 of the second electrode 210 is made of an iridium alloy containing iridium. For example, an alloy of iridium and platinum. Alternatively, it is an alloy of iridium, platinum, and osmium. The iridium alloy has high hardness and excellent heat resistance. Therefore, the iridium alloy is suitable for the tip portion 211 of the second electrode 210. Further, platinum may be used instead of iridium. Alternatively, it may be palladium. Alternatively, it may be a metal or alloy containing at least one of iridium, platinum and palladium. Further, the tip portion 211 of the second electrode 210 may be gold. Further, at the time of discharge, the second electrode 210 is immersed in the solution contained in the container 250.

The first potential applying unit 120 is for applying a potential that changes periodically to the first electrode 110. The second potential applying unit 220 is for applying a potential that changes periodically to the second electrode 210. Here, either one of the first potential applying unit 120 and the second potential applying unit 220 may be grounded. The first lead wire 130 is for electrically connecting the first electrode 110 and the first potential applying portion 120. The first lead wire 130 may be made of nickel alloy or stainless steel. The second lead wire 230 is for electrically connecting the second electrode 210 and the second potential applying portion 220. The second lead wire 230 may be made of nickel alloy or stainless steel. As a result, a high frequency voltage is applied between the first electrode 110 and the second electrode 210. That is, the first potential applying unit 120 and the second potential applying unit 220 are voltage applying units for applying a voltage between the first electrode 110 and the second electrode 210.

1-4-2. Gas supply path The plasma generator P30 has a gas supply unit 140, a gas pipe coupling connector 150, and a gas pipe 160, as described above. Therefore, the gas supply unit 140 supplies plasma gas to the inside of the tubular portion of the first electrode 110 via the gas pipe 160 and the gas pipe coupling connector 150. Here, the gas supply unit 160 supplies, for example, Ar gas. Alternatively, other rare gas may be supplied. Alternatively, it may contain a small amount of other gas such as oxygen gas. Therefore, the plasma gas is blown from the first electrode 110 toward the solution contained in the solution 250.

1-4-3. Configuration of the superstructure FIG. 5 is a diagram showing the superstructure of the plasma generator P30. As shown in FIG. 5, the first electrode 110 has a tip portion 111. As shown in FIG. 4, the tip portion 111 is arranged at a position facing the second electrode 210. The tip portion 111 of the first electrode 110 has an inclined surface 111a. The inclined surface 111a is a surface inclined with respect to a surface perpendicular to the axial direction of the first electrode 110. Further, a microhollow 111b is formed at the tip portion 111. The micro hollow 111b is a minute recess having a length of 0.5 mm or more and 1 mm or less and a width of 0.3 mm or more and 0.5 mm or less.

Further, as described above, the plasma generator P30 has a sealing member 191 and a coupling member 192. The sealing member 191 is attached to the container 250 shown in FIG. 4 and is for sealing the inside of the container 250. The coupling member 192 is a member for connecting the first electrode 110 and the gas pipe coupling connector 150 via the sealing member 191 and the like.

1-4-4. Configuration of the lower structure FIG. 6 is a diagram showing the lower structure of the plasma generator P30. As described above, the plasma generator P30 has a container 250, a sealing member 260, and a gantry 270. The container 250 can contain the solution inside. Here, the solution also includes an aqueous solution and an organic solvent. Further, the container 250 houses the first electrode 110 and the second electrode 210 inside. Further, the container 250 may have a scale. This is to measure the amount of the solution contained in the container 250.

The sealing member 260 is for closing the gap between the second electrode protecting member 240 and the container 250. Examples of the sealing member 260 include O-ring. Other members may be applied as long as the airtightness of the container 250 is ensured and the solution is prevented from leaking to the bottom of the container 250. The gantry 270 is for supporting the container 250 and other members.

2. 2. Plasma generated by the plasma generator 2-1. The plasma generated by the first plasma generator and the second plasma generators P10 and P20 is a non-equilibrium atmospheric pressure plasma. Here, the atmospheric pressure plasma means a plasma having a pressure in the range of 0.5 atm or more and 2.0 atm or less.

In this embodiment, Ar gas is mainly used as the plasma generating gas. Of course, electrons and Ar ions are generated inside the plasma generated by the plasma generators P10 and P20. And Ar ion generates ultraviolet rays. Moreover, since this plasma is released into the atmosphere, it generates oxygen radicals, nitrogen radicals, and the like.

The plasma density of this plasma is in the range of 1 × 10 ¹⁴ cm ^-3 or more and 1 × 10 ¹⁷ cm ^-3 or less. The plasma density in the plasma generated by the dielectric barrier discharge is about 1 × 10 ¹¹ cm ^-3 or more and 1 × 10 ¹³ cm ^-3 or less. Therefore, the plasma density of the plasma generated by the plasma generators P10 and P20 is about three orders of magnitude higher than the plasma density of the plasma generated by the dielectric barrier discharge. Therefore, more Ar ions are generated inside this plasma. Therefore, a large amount of radicals and ultraviolet rays are generated. The plasma density is almost equal to the electron density inside the plasma.

The plasma temperature at the time of plasma generation is in the range of about 1000 K or more and 2500 K or less. Further, the electron temperature in this plasma is higher than the temperature of the gas. Moreover, although the electron density is in the range of 1 × 10 ¹⁴ cm ^-3 or more and 1 × 10 ¹⁷ cm ^-3 or less, the gas temperature is in the range of about 1000 K or more and 2500 K or less. The temperature of this plasma is the temperature in the plasma generation region P where the plasma is generated. Therefore, by setting the plasma conditions and the distance from the gas ejection port to the water surface to different conditions, the plasma temperature at the position of the liquid surface can be set to about room temperature.

2-2. The third plasma generator FIG. 7 is a diagram schematically showing how the plasma generator P30 is generating plasma. The plasma generated by the plasma generator P30 is a non-equilibrium atmospheric pressure plasma.

As shown in FIG. 7, the plasma gas supplied from the gas supply unit 140 is discharged from the first electrode 110 in the direction of arrow K1. Then, when a high frequency voltage is applied between the first electrode 110 and the second electrode 210, a plasma generation region PG1 is formed between the first electrode 110 and the second electrode 210. The plasma generation region PG1 in FIG. 7 is conceptually drawn.

When the first potential applying unit 120 and the second potential applying unit 220 apply a voltage to apply a voltage between the first electrode 110 and the second electrode 210, the second electrode 210 is arranged inside the liquid. ing. As described above, between the first electrode 110 and the second electrode 210, there is a liquid and an atmosphere contained in the container 250. Then, the line connecting the first electrode and the second electrode intersects the liquid level LL1 of the liquid.

Therefore, plasma is generated between the liquid level LL1 and the first electrode 110. At this time, the liquid level LL1 of the liquid is recessed toward the liquid side by receiving the wind pressure of the plasma gas discharged from the first electrode 110 in the direction of the arrow K1. Then, inside the liquid, the solution is partially electrolyzed and vaporized. Plasma is also generated inside the vaporized gas. Further, the plasma generation region PG1 is in contact with the liquid level LL1 of the liquid.

As a result, radicals derived from the atmosphere or water are generated. Then, the solution is irradiated with radicals. This causes the radical to react with the water molecule or the solute in the solution.

3. 3. Method for Producing Plasma Activated Aqueous Solution 3-1. Aqueous solution preparation step First, the first aqueous solution is prepared. The first aqueous solution means an aqueous solution before irradiation with plasma. The first aqueous solution contains L-sodium lactate, sodium chloride, potassium chloride, and calcium chloride.

3-2. Plasma irradiation step Next, the first aqueous solution is irradiated with the atmospheric pressure plasma generated in the plasma generation region by the plasma activation aqueous solution manufacturing apparatus PM. The distance between the liquid level and the plasma ejection port when irradiating plasma is, for example, 3 mm. Further, this distance may be changed, for example, within the range of 0.1 cm or more and 3 cm or less. The plasma density in the plasma generation region is in the range of 1 × 10 ¹⁴ cm ^-3 or more and 1 × 10 ¹⁷ cm ^-3 or less. The plasma temperature in this plasma is in the range of about 1000 K or more and 2500 K or less. However, this plasma temperature can be lowered to about room temperature (about 300K) at the liquid level. These plasma conditions are shown in Table 1. These conditions are just examples.

[Table 1]
Condition Numerical range Liquid level-spout distance 0.1 cm or more 3 cm or less Plasma density 1 x 10 ¹⁴ cm ^-3 or more 1 x 10 ¹⁷ cm ^-3 or less Plasma temperature 1000 K or more 2500 K or less

By irradiating the first aqueous solution with atmospheric pressure plasma in this way, the first aqueous solution becomes the second aqueous solution. The second aqueous solution is a plasma activated aqueous solution. It is considered that the components of the first aqueous solution react with the radicals derived from the plasma by the irradiation of the atmospheric pressure plasma. In addition, nitrite ions and nitrate ions increase in the aqueous solution. It is considered that the components of the first aqueous solution also react with these ions and the like.

The plasma density of the atmospheric pressure plasma is, for example, 2 × 10 ¹⁶ cm ^-3 . The irradiation time of the atmospheric pressure plasma is, for example, 30 seconds or more and 300 seconds or less. The volume of the first aqueous solution when irradiating with atmospheric pressure plasma is, for example, 10 ml or more and 1000 ml or less.

In this case, the plasma density time product per unit volume in the plasma-activated aqueous solution is 6 × 10 ¹⁴ sec · cm ^-3 · ml ^-1 or more and 6 × 10 ¹⁵ sec · cm ^-3 · ml ^-1 or less. .. Here, the plasma density time product per unit volume is (plasma density) × (irradiation time) / (volume of the first aqueous solution). That is, the plasma density time product per unit volume is the amount of plasma product irradiated to the first aqueous solution per unit volume.

4. Effect of Plasma Activated Aqueous Solution The plasma activated aqueous solution of the present embodiment is obtained by irradiating an aqueous solution containing L-sodium lactate with plasma. More specifically, a first aqueous solution containing L-sodium lactate, sodium chloride, potassium chloride, and calcium chloride is irradiated with atmospheric pressure plasma. This plasma-activated aqueous solution has the effect of increasing the yield of rice. It also has the effect of increasing the whiteness of sake rice. Therefore, the plasma-activated aqueous solution is suitable for the production of sake rice.

5. Rice production method using plasma-activated aqueous solution The rice production method of this embodiment includes an aqueous solution preparation step of preparing an aqueous solution containing L-sodium lactate and a plasma-activated aqueous solution by irradiating the aqueous solution with atmospheric pressure plasma. It has a plasma irradiation step and an aqueous solution supply step of supplying a plasma activation aqueous solution to the growth point of rice.

5-1. Aqueous solution preparation step As described above, in the aqueous solution preparation step, a first aqueous solution containing L-sodium lactate, sodium chloride, potassium chloride, and calcium chloride is prepared.

5-2. Plasma irradiation step Next, a plasma irradiation step is carried out. As described above, in this step, the first aqueous solution is irradiated with atmospheric pressure plasma to obtain a second aqueous solution. As described above, the second aqueous solution is a plasma activated aqueous solution.

5-3. Aqueous solution supply step As shown in FIG. 8, the aqueous solution supply step is carried out. In this step, the plasma-activated aqueous solution is supplied to the rice growth point GP1. The growth point of a plant is that there is a population of cells (meristem) with high division ability. The growth point is generally at the tip of the stem or root. As shown in FIG. 8, the rice growth point GP1 exists near the root of the stem. The position of the rice growth point GP1 is not so far from the position where the rice seeds were.

Immerse the rice growth point GP1 in the paddy field in a plasma-activated aqueous solution. Specifically, as shown in FIG. 8, the rice is surrounded by a cylindrical member, and the cylindrical member is sunk into the soil of the paddy field. Then, the water inside the cylindrical member is pumped up by a pump or the like. As a result, the rice growth point GP1 is exposed. Next, a plasma-activated aqueous solution is supplied around the rice. Since the rice is in the region surrounded by the cylindrical member, there is almost no possibility that the plasma-activated aqueous solution will flow out from the upper part of the cylindrical member. In this way, the plasma activation aqueous solution may be left immersed in the rice growth point GP1. In addition to this, the supplied plasma active aqueous solution will permeate into the soil over time and then be absorbed from the roots.

The frequency of carrying out the aqueous solution supply step is, for example, once or more and five times or less per week. The period for carrying out the aqueous solution supply process is the period from planting of rice to heading.

5-4. Cultivation process After that, rice can be cultivated in paddy fields.

6. Modification 6-1. Method of Aqueous Solution Supply Step In the present embodiment, the plasma-activated aqueous solution is supplied to the rice growth point GP1 after exposing the rice growth point GP1. However, the plasma activating aqueous solution may be simply added to the paddy field without exposing the rice growth point GP1.

6-2. Implementation time of the aqueous solution supply step It is advisable to carry out the aqueous solution supply step during the period from the planting of rice to the formation of young ears. This is because, as will be described later, the effect of increasing the yield of brown rice is high.

6-3. Cylindrical member In the aqueous solution supply process, the rice is surrounded by a cylindrical member. However, it does not have to be a cylindrical member, but may be a cylindrical member. For example, the tubular member has a hexagonal cylindrical shape. Of course, it may be another polygonal tubular shape.

6-4. Third plasma generator The plasma generator P30 may be used in producing the plasma activating aqueous solution. Therefore, the first aqueous solution is irradiated with the atmospheric pressure plasma generated in the plasma generation region by the plasma generator P30. The first electrode 110 is placed outside the first aqueous solution, and the second electrode 210 is placed inside the first aqueous solution. Then, the gas is irradiated from the tubular portion 110a of the first electrode 110 toward the first aqueous solution. Then, in that state, a voltage is applied between the first electrode 110 and the second electrode 210.

6-5. First electrode of the third plasma generator In the plasma generator P30 of the present embodiment, the tubular portion 110a of the first electrode 110 has a cylindrical shape. However, it is not limited to the cylindrical shape. If it has a tubular shape, it may have a polygonal shape.

6-6. Miniaturized plasma generator The plasma generators P10, P20 and the like may be further miniaturized. By making it sufficiently small, a pen-type plasma generator can be manufactured. Even in that case, a plasma density equivalent to that of the plasma generators P10 and P20 can be obtained.

6-7. Combination An example of modification of the first embodiment may be combined as appropriate.

(Second embodiment)
The second embodiment will be described. In the second embodiment, the plasma-activated aqueous solution of the first embodiment is not used. Instead, in the second embodiment, the atmospheric pressure plasma is directly applied to the growth point of the rice. As the atmospheric pressure plasma device, the plasma generators P10 and P20 of the first embodiment can be used. Therefore, the points different from the first embodiment will be described.

1. 1. Rice production method In this embodiment, instead of supplying the plasma-activated aqueous solution to the rice growth point GP1, the non-equilibrium atmospheric pressure plasma is directly irradiated to the rice growth point GP1.

1-1. Plasma irradiation step As shown in FIG. 9, non-equilibrium atmospheric pressure plasma is directly irradiated toward the rice growth point GP1. As shown in FIG. 9, the rice is surrounded by a cylindrical member, and the cylindrical member is sunk into the soil of the paddy field. Then, the water inside the cylindrical member is pumped up by a pump or the like. As a result, the rice growth point GP1 is exposed. Next, using a plasma generator P20 or the like, atmospheric pressure plasma is directly irradiated toward the rice growth point GP1. After the plasma irradiation is finished, the cylindrical member may be removed.

The plasma density is the same as in the first embodiment. The time for irradiating the plasma is, for example, 30 seconds or more and 600 seconds or less. For example, assuming that the plasma density of atmospheric pressure plasma is 2 × 10 ¹⁶ cm ^-3 , the plasma density time product, which is the product of the plasma density of atmospheric pressure plasma and the irradiation time, is 6 × 10 ¹⁷ sec · cm ^-3 or more 1 .2 x 10 ¹⁹ sec · cm ^-3 or less.

The frequency of irradiating the plasma is, for example, once or more and five times or less per week. The period of plasma irradiation is from rice planting to heading. In other words, it is the period from planting of rice to heading.

1-2. Cultivation process After that, rice can be cultivated in paddy fields.

2. 2. Effect of directly irradiating the growth point of rice with plasma By irradiating the atmospheric pressure plasma toward the growth point GP1 of rice, atoms / molecules, ions, radicals, etc. derived from nitrogen atom or oxygen atom become the growth point GP1 of rice. Is supplied to. This will increase the yield of rice. It also has the effect of increasing the whiteness of sake rice. Therefore, the plasma-activated aqueous solution is suitable for the production of sake rice.

3. 3. Modification 3-1. Implementation time of the plasma irradiation process It is advisable to irradiate the growth point with plasma during the period from the planting of rice to the formation of young ears. This is because, as will be described later, the effect of increasing the yield of brown rice is high.

3-2. Other Modified Examples The first embodiment and its modified examples and the second embodiment and its modified examples may be combined.

1. 1. Experiment A (direct irradiation of plasma)
1-1. Rice In this experiment, we cultivated Aichi no Kaori (rice variety), which is the main food rice.

1-2. Direct irradiation of plasma As shown in FIG. 9, atmospheric pressure plasma was directly irradiated to the growth point GP1 of rice after rice planting. At that time, the plasma generator P20 was used. The plasma density in the plasma generator P20 was 2 × 10 ¹⁶ cm ^-3 . The plasma gas was argon gas.

The plasma irradiation time was 30 seconds or 5 minutes. The frequency of plasma irradiation was twice a week. As the period for irradiating plasma, the first half and the second half were set. The first half is the period (about 1 to 2 months) from the planting of rice to the formation of young ears. The latter stage is the period from the formation of young ears to the heading (about 1 month). The group of rice that was irradiated with plasma for 30 seconds each time in the first half, the group of rice that was irradiated with plasma for 5 minutes each time in the first half, and the group of rice that was irradiated with plasma for 5 minutes each time in the first half and the second half. And cultivated. In addition, rice in the control group not irradiated with plasma was set separately.

1-3. Experimental Results FIG. 10 is a graph showing the yield of brown rice. In the early stage of rice growth (the period from planting to the formation of young ears), the yield of brown rice per plant when the plasma irradiation time is 30 seconds is the amount of brown rice per plant when the plasma is not irradiated. It was 12% more than the yield. In the early stage of rice growth (the period from planting to the formation of young ears), the yield of brown rice per plant when the plasma irradiation time is 5 minutes is the amount of brown rice per plant when plasma irradiation is not performed. It was 15% more than the yield.

However, in the early stage (the period from planting to the formation of young ears) and the late stage (the period from the formation of the young ears to the heading) of rice growth, when the plasma irradiation time is 5 minutes, the brown rice per plant The yield was less than the yield of brown rice per strain without plasma irradiation.

FIG. 11 is a graph showing the proportion of perfect grains in the harvested brown rice. The ratio of complete grains was about 80% regardless of the presence or absence of plasma irradiation.

FIG. 12 is a graph showing the ratio of each rice to the number of grains of harvested brown rice. Belly white rice is a type of incomplete rice. Heart-polished rice is a type of incomplete rice. However, Shinshiro rice is preferably used for sake brewing. By irradiating with plasma, the proportion of white rice in the belly is decreasing, but the proportion of white rice in the heart is increasing.

From this experimental result, it is expected that the desired effect can be obtained by irradiating the rice suitable for sake brewing (sake rice) with atmospheric pressure plasma.

2. 2. Experiment B (Comparison between sake rice and main food rice)
2-1. Rice In this experiment, Kaori Aichi (rice variety), which is the main food rice, and Yamada Nishiki (rice variety), which is suitable for sake brewing, were cultivated.

2-2. Plasma-activated aqueous solution The plasma-activated aqueous solution in this experiment is a solution (PAL: Plasma Activated Lactec (Lactec is a registered trademark)) in which an aqueous solution having the same components as LACTEC (registered trademark) is irradiated with plasma. Lactec (registered trademark) is a Lactated Ringer's solution containing sodium chloride, potassium chloride, calcium chloride, and L-sodium lactate. The concentration of sodium chloride is 6.0 g / L. The concentration of potassium chloride is 0.3 g / L. The concentration of calcium chloride hydrate is 0.2 g / L. The concentration of L-sodium lactate is 3.1 g / L.

As a plasma device, a plasma generator P20 was used. The irradiation time of plasma to Lactec (registered trademark) was 5 minutes. Argon gas was used as the type of gas. The distance between the plasma irradiation port and the first aqueous solution in the plasma generator P20 was 3 mm. The plasma density in the plasma generator P20 was 2 × 10 ¹⁶ cm ^-3 .

Then, as shown in FIG. 8, PAL was supplied to the growth point GP1 of rice. The supply method is the same as the above-mentioned aqueous solution supply step.

2-3. Direct irradiation of plasma As in Experiment A, the plasma generator P20 was used to directly irradiate the growth point of rice with atmospheric pressure plasma. The plasma irradiation time was 30 seconds.

2-4. Experimental Results FIG. 13 is a graph showing the weight (yield amount) of brown rice harvested from one strain. In FIG. 13, the term “distilled water” indicates that the rice was provided with distilled water corresponding to the amount of PAL. Further, the notation of "x100" of PAL indicates that PAL is diluted 100 times. Similarly, the notation of "x25" indicates that PAL is diluted 25 times.

Regarding the fragrance of Aichi, the main food rice, the yield of brown rice did not change so much even if it was directly irradiated with plasma. When PAL was supplied to the growth point of rice, the yield of brown rice was increased by about 30% as compared with the case where distilled water was supplied to the growth point of rice.

For Yamada Nishiki of sake rice, the yield of brown rice increased by about 10% by directly irradiating it with plasma. When PAL was supplied to the growth point of rice, the yield of brown rice was similar to that when distilled water was supplied to the growth point of rice.

FIG. 14 is a graph showing the ratio of immature rice and cracked rice in the harvested brown rice. As shown in FIG. 14, when PAL diluted 100 times is supplied to the rice growth point in the main edible rice, immature rice is compared with the case where distilled water is supplied to the rice growth point. The ratio of rice decreased from about 10% to about 3%. The percentage of cracked rice was about 5% regardless of the presence or absence of PAL.

On the other hand, for Yamada Nishiki of sake rice, the amount of immature rice decreased from about 10% to about 6% by directly irradiating with plasma. About cracked rice, it was about 15% regardless of the presence or absence of plasma irradiation.

FIG. 15 is a graph showing the ratio of belly-polished rice and heart-polished rice in the harvested brown rice. As shown in FIG. 15, the ratios of belly-polished rice and heart-polished rice did not change significantly depending on the presence or absence of PAL with respect to the aroma of the main food rice.

On the other hand, for Yamada Nishiki of sake rice, the ratio of white rice increased from about 45% to about 50% by directly irradiating it with plasma.

3. 3. Summary of experiment 3-1. Increase in yield As shown in FIG. 10, the yield of brown rice increased by using direct irradiation of plasma. Further, from the viewpoint of yield, it is preferable to use PAL for the main food rice. It is preferable to directly irradiate sake rice with plasma.

3-2. Quality In addition, as shown in FIG. 14, the proportion of immature rice was reduced by using plasma.

As shown in FIG. 15, the proportion of white rice in Yamada Nishiki increased by using direct plasma irradiation. Therefore, it can be said that the quality of Yamada Nishiki rice suitable for sake brewing is further improved by using plasma.

(Additional note)
The method for producing rice in the first aspect is an aqueous solution preparation step of preparing an aqueous solution containing L-sodium lactate, a plasma irradiation step of irradiating the aqueous solution with atmospheric pressure plasma to obtain a plasma-activated aqueous solution, and rice growth. It has an aqueous solution supply step of supplying a plasma activated aqueous solution to a point.

In the rice production method according to the second aspect, the aqueous solution supply step is carried out during the period from the planting of rice to the formation of young ears.

In the rice production method according to the third aspect, in the aqueous solution supply step, the growth point is exposed by surrounding the rice with a tubular member and pumping water inside the tubular member.

In the rice production method according to the fourth aspect, the atmospheric pressure plasma is directly irradiated toward the rice growth point.

In the rice production method according to the fifth aspect, the irradiation of the growth point with plasma is carried out during the period from the planting of rice to the formation of young ears.

In the rice production method according to the sixth aspect, when the growth point is irradiated with plasma, the growth point is exposed by surrounding the rice with a tubular member and pumping water inside the tubular member.

P1 ... Plasma irradiation device M1 ... Robot arm PM ... Plasma activation aqueous solution production device P10, P20, P30 ... Plasma generators 10, 11 ... Housing parts 10i, 11i ... Gas inlets 10o, 11o ... Gas outlets 2a, 2b ... Electrode P ... Plasma region H ... Recessed (hollow)
110 ... First electrode 120 ... First potential applying unit 130 ... First lead wire 140 ... Gas supply unit 150 ... Gas tube coupling connector 160 ... Gas tube 170 ... First electrode protection member 210 ... Second electrode 220 ... Second electrode 2 potential applying portion 230 ... 2nd lead wire 240 ... 2nd electrode protection member 250 ... Container 260 ... Sealing member 270 ... Mount GP1 ... Growth point

Claims (4)

An aqueous solution preparation step for preparing an aqueous solution containing L-sodium lactate,
A plasma irradiation step of irradiating the aqueous solution with atmospheric pressure plasma to obtain a plasma-activated aqueous solution,
An aqueous solution supply step of supplying the plasma-activated aqueous solution to the growth point of rice, and
Have,
In the aqueous solution supply step, the growth point is exposed by surrounding the rice with a tubular member and pumping water inside the tubular member.
A rice production method characterized by. In the rice production method according to claim 1,
A method for producing rice, wherein the aqueous solution supply step is carried out during the period from the planting of the rice to the formation of young ears. The growth point of rice is exposed by surrounding the rice with a tubular member and pumping water inside the tubular member.
Directly irradiating the atmospheric pressure plasma toward the growth point of the exposed rice.
A rice production method characterized by. In the rice production method according to claim 3 ,
A method for producing rice, which comprises irradiating the growth point with plasma during the period from the planting of the rice to the formation of young ears.

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