JP2012034649A - Plant cultivation system and plant cultivation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plant cultivation system by which plants efficiently and stably absorb a sufficient amount of gas such as carbon dioxide or hydrogen from the roots of the plants without causing oxygen deficiency in their roots leading to root rot and the like so as to remarkably and continuously promote growth of the plant over a long period of time.SOLUTION: The plant cultivation system includes: an imperforate hydrophilic film for cultivating the plants thereon; gas-dissolved water obtained by dissolving at least one kind of gas which promotes the growth of the plants, and put in a position so as to come in contact with the undersurface of the imperforate hydrophilic film; and a gas-dissolved water-holding means for holding the gas-dissolving water under the imperforate hydrophilic film.

Description

  The present invention relates to a plant cultivation system and a plant cultivation method. More specifically, a nonporous hydrophilic film for cultivating a plant thereon, gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, A gas-dissolved water disposed so as to be in contact with the lower surface of the hydrophilic hydrophilic film, and a gas-dissolved water retaining means for retaining the gas-dissolved water under the nonporous hydrophilic film. The present invention relates to a plant cultivation system and a plant cultivation method using such a plant cultivation system. When the system of the present invention is used to cultivate a plant by supplying gas-dissolved water obtained by dissolving at least one gas that promotes the growth of the plant such as carbon dioxide and hydrogen from the root of the plant, the above gas Can be effectively and efficiently utilized to promote plant growth without causing plant growth inhibition due to lack of oxygen.

Plants take in gas such as carbon dioxide in the atmosphere from the leaves and take water from the roots to carry out photosynthesis. By photosynthesis, plants synthesize carbohydrates from carbon dioxide and grow. As one method for promoting the growth of plants such as vegetables, a method for supplying carbon dioxide is known. Specifically, a technique for promoting plant growth by supplying carbonated water in which carbon dioxide is dissolved at a high concentration (see Patent Document 1), and supplying carbonated water to planted seedlings to reduce environmental stress. A technique that enables planting in severe areas (see Patent Document 2) and a technique that avoids excessive acidification of the carbon dioxide solution by adding carbonate or bicarbonate are disclosed (see Patent Document 3). Yes. As related techniques, a method for producing a carbon dioxide solution for growing plants and a supply device for the carbon dioxide solution for growing plants (see Patent Documents 4 and 5) have been developed. Moreover, instead of using carbonated water, a technique and cutting method (see Patent Document 6) that promotes plant growth by exposing carbon dioxide to the entire constant space and giving the plant a high concentration of carbon dioxide (see Patent Document 6). It has been put to practical use as “ ₂ fertilization”.

  Furthermore, a plant cultivation technique is also known in which a plant root is immersed in a culture solution containing a fertilizer component, and the plant is grown while air with a carbon dioxide concentration of 500 ppm or more is continuously blown into the culture solution during the cultivation period of the plant. (See Patent Document 7). This document discloses the use of carbon dioxide in so-called hydroponic cultivation (generally often referred to as “hydroponic cultivation”) in which plants are cultivated using facilities in greenhouses that have attracted attention in recent years. is doing. This document intends to supply oxygen to the roots of a plant and supply carbon dioxide to the leaves of a plant by supplying bubbles containing carbon dioxide from directly under the plant. Further, in this document, it is described that carbon dioxide gas makes the culture solution weakly acidic, and combined with the stirring action of bubbles, has the effect of preventing the decay of microorganisms and fine organic substances in the culture solution.

However, the techniques described in Patent Documents 1 to 7 have the following problems. Since the rate of carbon fixation (photosynthesis, etc.) required for plant growth is governed by the concentration of carbon dioxide and bicarbonate ions dissolved in the water in the plant body, the active supply of carbon dioxide is It is effective in increasing the photosynthesis of and promoting the growth of plants. However, since the amount of gas dissolved in water or air is proportional to the partial pressure of the gas, if the partial pressure of carbon dioxide in atmospheric pressure is increased, the partial pressure of other gases such as oxygen is reduced accordingly. As a result, the oxygen concentration in the water or in the air is lowered, and a failure due to lack of oxygen (for example, rooted) occurs. In addition, when a plant grows in a gas environment containing a high concentration of carbon dioxide, the growth proceeds rapidly at an early stage, but eventually the nitrogen concentration in the plant body decreases, and the photosynthetic rate and growth rate may decrease. Are known. In order to continue growing in a high-concentration CO ₂ environment, it is necessary to supply various nutrient salts such as nitrogen and phosphorus, potassium, etc., and take measures to alleviate the acidification of water in the plant body. It is difficult to disseminate the effects by economically matching them. Furthermore, when water or nutrient solution in which carbon dioxide is dissolved is used, carbon dioxide is easily dissipated in the air, so that effective and efficient use of carbon dioxide is very difficult. In this regard, in Patent Document 7 described above, plants are cultivated by hydroponics by continuously blowing air having a carbon dioxide concentration of 500 ppm or more into the culture solution. In addition to the need for large-scale equipment, a large amount of energy is required, which is problematic in terms of economy. In addition, in order to continue supplying carbon dioxide, it is necessary to generate carbon dioxide at the site, but most of the carbon dioxide that is continuously supplied is released into the atmosphere without being used by plants. Therefore, there was an environmental problem.

Japanese Patent Laid-Open No. 2003-111521 JP2003-325063 JP 2005-333854 A Japanese Patent No. 2847372 Japanese Patent No. 2847373 JP 2001-186814 A JP-A-11-66

  As another method for promoting the growth of plants, a method of supplying hydrogen gas is also known. When plant photosynthesis is suppressed by strong light such as in summer, low temperature, dryness, and poor nutrition, excess active oxygen is generated, which damages and destroys chloroplasts. Therefore, excessive active oxygen adversely affects plant growth and leads to plant death. In recent years, FSD2 and FSD3, two FeSOD genes essential for chloroplast development, have been identified from analysis using Arabidopsis mutants, and plants that strongly expressed two FeSOD genes It has been analyzed that it has a function of suppressing a decrease in photosynthesis in the presence of a drug to be generated. And it has been suggested that by strongly expressing these genes, it is possible to cultivate plants in which active oxygen is removed and reduction in photosynthesis is suppressed (Non-patent Document 1).

  However, since this method performs genetic manipulation, when it is applied to cultivation of plants such as vegetables and fruits, there is a problem in safety whether the harvested vegetables can be handled as food. Moreover, since genetic manipulation according to the type of plant is required, there is a problem that the cost is increased.

Fumiaki Akaga discovers two enzyme genes essential for removal of active oxygen in chloroplasts-elucidation of new functions of superoxide dismutase that eliminates active oxygen harmful to plants-[online], 2008 12 May 2, RIKEN, [Search March 8, 2010], Internet (URL: http://www.riken.go.jp/r-world/research/results/2008/081202/ index.html)

Moreover, the hydroponic cultivation apparatus using the nutrient solution which melt | dissolved hydrogen oxygen mixed gas is also disclosed (patent document 8). In this device, when only oxygen is dissolved in the nutrient solution to prevent rooting that occurs during hydroponics, active oxygen is generated, so by dissolving the hydrogen-oxygen mixed gas in the nutrient solution, Oxygen is supplied to the plant while suppressing the generation of active oxygen. In this invention, hydrogen gas is used to achieve an effective supply of oxygen. Naturally, if the amount of oxygen decreases, the roots of the plant fall into oxygen deficiency, so that the concentration of hydrogen gas is sufficient. There was a problem that it could not be raised. Furthermore, in the technology of this patent document, the hydrogen-oxygen hybrid gas supplied into water is easily dissipated in the air, as in the case of the technology using carbon dioxide, and thus the effect of the hydrogen-oxygen hybrid gas. The current situation is that efficient and efficient use is very difficult. In the examples of this patent document, a hydrogen-oxygen hybrid gas produced by a very special device called a hydrogen-oxygen hybrid gas (SHG) generator is used, and this gas is dissolved in 0.4 m ³ of water. In addition, it is very cumbersome and time-consuming to repeatedly supply gas intermittently by repeating the supply of 120 liters over 1 hour and the supply stop for 1 hour, but plant cultivation on a commercial scale. It is not realistic to employ a technique that involves such work.

JP 2009-22211 A

In addition, hydroponics as employed in Patent Document 7 and Patent Document 8 has no continuous cropping obstacles, is less affected by natural conditions, and is relatively easy to adjust the cultivation environment, compared to soil cultivation. It is known that there are certain advantages. However, it has been considered that it is not appropriate or practical to use water or nutrient solution in which carbon dioxide or hydrogen is dissolved as described above as a culture solution in nutrient solution cultivation. The specific reason is as follows. Although it is necessary to always supply oxygen to the root of the plant, the root of the plant is always immersed in the nutrient solution in the hydroponics, so the nutrient solution is the only oxygen source for the root. For this reason, in hydroponics, it was particularly difficult to dissolve a sufficient amount of carbon dioxide and hydrogen in the nutrient solution without leaving the roots deficient. Furthermore, even if carbon dioxide or hydrogen is dissolved in a large amount of water or nutrient solution in the aquarium, most of it is quickly absorbed from the surface of the nutrient solution in the aquarium to the atmosphere without being absorbed from the roots. Therefore, there is a problem that it is extremely inefficient compared with the case of procuring a necessary amount of water or nutrient solution in which carbon dioxide or hydrogen is dissolved and spraying on leaves or irrigating soil. It was. Although the use of water or nutrient solution in which carbon dioxide or hydrogen is dissolved is disclosed in Patent Document 7 and Patent Document 8, as described above, it is practical from the viewpoints of economy and environment. Although it is not a technology, the current situation is that there is no technology that can withstand practical use for nutrient solution cultivation using water or nutrient solution in which carbon dioxide or hydrogen is dissolved as a culture solution. Also, especially in the case of carbon dioxide, it is known that it is mainly absorbed from the leaves and used for photosynthesis. Therefore, by dissolving carbon dioxide in the nutrient solution for hydroponics and absorbing it from the roots, The fact that it was not recognized that there was a merit is also considered to be one of the reasons that no practical proposal was made regarding the application of water in which carbon dioxide was dissolved or nutrient solution to the nutrient solution cultivation method. . (The above Patent Document 7 also introduces carbon dioxide into the nutrient solution with the intention of supplying carbon dioxide to the leaves of the plant.) In addition, regarding conventional hydroponics, plant roots and nutrient solutions However, the present inventors have the following problems: the adjustment of nutrient solution is delicate, the management range is very narrow, and the capital investment is expensive. In order to overcome the problems of simple hydroponic cultivation, research on hydroponic cultivation using film has been repeated, and the following plant cultivation system and cultivation method have been disclosed: non-porous hydrophilicity in contact with nutrient solution Plant cultivation tool and plant cultivation method for cultivating a plant by integrating the film and plant root on the film (Patent Document 9), Plant cultivation instrument and plant cultivation method for irrigating the upper part of the film (Patent Document 9) Reference 10), the above-mentioned fill Plant cultivation instrument and plant cultivation method (Patent Document 11), plant cultivation system (Patent Document 12) in which the film continuously moves on nutrient solution, the film and the upper part thereof The plant cultivation system (patent document 13) which provides an air layer between the evaporation suppression members arrange | positioned in a plant, and the plant cultivation system (patent document 14) using the means to supply a nutrient solution continuously to the lower surface side of the said film are disclosed. is doing. However, basically, the application of water or nutrient solution in which carbon dioxide or hydrogen is dissolved is considered to have no merit from the viewpoints of economy and environment for the above reasons. Regarding the systems as described in Patent Documents 9 to 14, the use of water or nutrient solution in which carbon dioxide or hydrogen is dissolved has not been proposed.
No. 2004-64499 Japanese Patent No. 4425244 JP 2008-61503 A JP 2008-182909 JP 2008-193980 A Japanese Patent No. 4142725

  In order to promote the growth of plants, it is necessary to expose carbon dioxide to a whole space to give plants high concentrations of carbon dioxide, or to supply plants with water or nutrient solutions in which carbon dioxide or hydrogen is forcibly dissolved. Although effective, on the other hand, in order to increase the concentration of carbon dioxide or hydrogen in water and air, the oxygen concentration in water and air necessary for plant respiration is reduced, and the effect of promoting plant growth is sufficient. There was a problem that could not be demonstrated. Conversely, in order to avoid plant roots from being deficient due to oxygen deficiency, it is necessary to increase the oxygen concentration in the water and air in contact with the plant roots. There was a problem that the concentration of carbon dioxide and hydrogen in the liquid could not be increased sufficiently. Further, excessive supply of oxygen is accompanied by problems such as plant dysfunction due to generation of active oxygen. Furthermore, since gas such as carbon dioxide and hydrogen dissolved in water and nutrient solution is easily dissipated in the air, it is very difficult to use the gas effectively and efficiently. was there.

  In order to solve the above-mentioned problems, the present inventors have conducted intensive research. As a result, surprisingly, the nonporous hydrophilic film for cultivating the plants thereon, the growth of plants such as carbon dioxide and hydrogen, etc. A gas-dissolved water obtained by dissolving a gas to be promoted in water, the gas-dissolved water disposed so as to be in contact with the lower surface of the nonporous hydrophilic film, and the gas-dissolved water. Using the plant cultivation system, the gas-dissolved water is made non-porous from the bottom surface of the non-porous hydrophilic film, characterized by comprising gas-dissolved water retaining means for retaining under the hydrophilic film. When supplying a plant grown on a hydrophilic hydrophilic film, a sufficient amount of gas such as carbon dioxide and hydrogen can be efficiently and stably supplied without causing an oxygen-deficient state of the root that causes rooting. Can be absorbed from the roots of the Heading persistently that it is possible to significantly accelerate the growth of plants over a long period of time by, the present invention has been completed.

  When a plant is cultivated using the plant cultivation system of the present invention, a sufficient amount of carbon dioxide, hydrogen, etc. can be efficiently and stably produced without causing an oxygen-deficient state of the root that causes rooting. The gas can be absorbed from the roots of the plant, which makes it possible to significantly promote the growth of the plant continuously over a long period of time.

According to one aspect of the invention,
Nonporous hydrophilic film for cultivating plants on it,
Gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film, and the gas There is provided a system for plant cultivation characterized by comprising gas dissolved water retaining means for retaining dissolved water under the nonporous hydrophilic film.

According to another aspect of the invention,
(1) a nonporous hydrophilic film for cultivating plants thereon,
Gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film, and the gas Providing a system for plant cultivation characterized by comprising gas-dissolved water retaining means for retaining dissolved water under the nonporous hydrophilic film;
(2) placing the plant on a non-porous hydrophilic film in the system; and (3) contacting the plant with the gas-dissolved water through the non-porous hydrophilic film. A plant cultivation method is provided that includes cultivating a plant on a non-porous hydrophilic film.

  Next, in order to facilitate understanding of the present invention, basic features and preferred embodiments of the present invention are listed.

1. Nonporous hydrophilic film for cultivating plants on it,
Gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film, and the gas A system for plant cultivation, comprising gas dissolved water holding means for holding dissolved water under the nonporous hydrophilic film.

2. The gas is at least one selected from the group consisting of carbon dioxide and hydrogen, and when carbon dioxide is dissolved in water, the amount of carbon dioxide dissolved in the gas-dissolved water is 50 ppm or more, and hydrogen The plant cultivation system according to item 1, wherein the amount of hydrogen dissolved in the gas-dissolved water is 0.002 ppm or more when dissolved in water.
3. 3. The plant cultivation system according to item 1 or 2, wherein the gas-dissolved water further contains a fertilizer component.
4). 4. The plant cultivation system according to any one of items 1 to 3, wherein the pH of the gas-dissolved water is in the range of 4 to 8.
5. When the nonporous hydrophilic film is cultivated on the nonporous hydrophilic film of the plant cultivation system for 35 days, the nonporous hydrophilic film peels off from the root of the plant where the nonporous hydrophilic film is grown. The plant cultivation system according to any one of the preceding items 1 to 4, wherein the film has a peel strength of 10 g or more.

6). The gas-dissolved water holding means is a hydroponics aquarium, and the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film is accommodated in the hydroponics aquarium. The system for plant cultivation according to any one of 1 to 5 above.
7). The gas-dissolved water holding means has a water-impermeable surface, and the non-porous hydrophilic film is laid thereon, and the gas is interposed between the non-porous hydrophilic film and the gas-dissolved water holding means. 7. The plant cultivation system according to any one of the preceding items 1 to 6, further comprising gas dissolved water supply means for supplying the dissolved water continuously or intermittently.
8). 8. The plant cultivation system according to item 7, wherein the gas-dissolved water supply means is a drip irrigation tube installed between the non-porous hydrophilic film and the gas-dissolved water holding means.

9. (1) a nonporous hydrophilic film for cultivating plants thereon,
Gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film, and the gas Providing a system for plant cultivation characterized by comprising gas-dissolved water retaining means for retaining dissolved water under the nonporous hydrophilic film;
(2) placing the plant on a non-porous hydrophilic film in the system; and (3) contacting the plant with the gas-dissolved water through the non-porous hydrophilic film. A plant cultivation method comprising cultivating a plant on a nonporous hydrophilic film.

10. The gas is at least one selected from the group consisting of carbon dioxide and hydrogen, and when carbon dioxide is dissolved in water, the amount of carbon dioxide dissolved in the gas-dissolved water is 50 ppm or more, and hydrogen 10. The plant cultivation method according to item 9, wherein the amount of hydrogen dissolved in the gas-dissolved water is 0.002 ppm or more when dissolved in water.
11. As the gas-dissolved water, gas-dissolved water further containing a fertilizer component is used, whereby in the step (3), the plant roots are grown on the film and integrated with the film. 11. The plant cultivation method according to item 9 or 10 above.
12 The plant cultivation method according to any one of items 9 to 11, wherein the pH of the gas-dissolved water is in the range of 4 to 8.

The present invention will be described below.
The present invention is a system for cultivating a plant using gas-dissolved water obtained by dissolving in water at least one gas that promotes the growth of the plant.

  In the present invention, the at least one gas that promotes plant growth is a gas other than oxygen that exerts some action to promote plant growth, and is at least one selected from the group consisting of carbon dioxide and hydrogen. It is preferable that any of them can be used alone or in combination. Next, gas dissolved water obtained by dissolving carbon dioxide in water and gas dissolved water obtained by dissolving hydrogen gas in water will be described in detail.

<Gas dissolved water obtained by dissolving carbon dioxide in water>
In the present invention, carbon dioxide (carbon dioxide gas) can be used as a gas. The solubility of carbon dioxide in water depends on the carbon dioxide partial pressure in the gas phase. At atmospheric partial pressure of carbon dioxide (350 ppm), about 0.5 mg of carbon dioxide per liter of water dissolves in water. Therefore, the carbon dioxide content of the gas dissolved water used in the present invention must be 50 ppm or more. Further, the saturation solubility of carbon dioxide at 1 atm with respect to water at 5 ° C. is about 2,800 ppm, and the gas-dissolved water containing carbon dioxide in an amount exceeding this value is uneconomical because excess carbon dioxide tends to escape. Accordingly, the carbon dioxide content of the dissolved gas used in the present invention is 50 to 2,800 ppm, preferably 100 to 2,000 ppm, more preferably 200 to 1.500 ppm. The concentration of carbon dioxide dissolved in water can be confirmed with a commercially available carbon dioxide concentration meter. For example, a portable carbon dioxide concentration meter CGP-1 manufactured by Toa DKK Corporation of Japan can be used, and measurement can be performed by the method described in the instruction manual for this concentration meter.

A maximum of 1,491 mg of carbon dioxide per liter of water can be dissolved under 1 atm of carbon dioxide at 25 ° C., and a maximum of 2,815 mg of carbon dioxide can be dissolved at 5 ° C. Carbon dioxide in contact with water dissolves very slowly and exists as carbonic acid in the liquid. Carbonic acid in the liquid is ionized into hydrogen ions and bicarbonate ions to reach an equilibrium state. One liter of water at this time contains 10 ^−3.91 mol of hydrogen ions and 0.12 mM / L bicarbonate ions, and its pH is 3.91. In addition, under a carbon dioxide partial pressure (0.035 atm) in the atmosphere at 25 ° C., a maximum of 0.52 mg of carbon dioxide can be dissolved per liter of water. At this time, 1 liter of water is 10 ^−5.64 mol. Of hydrogen ion and about 2 μM / L bicarbonate ion, and its pH is 5.64.

  In gas-dissolved water in which carbon dioxide is dissolved (hereinafter often referred to as “carbon dioxide water” or “carbonated water”), the pH at a carbon dioxide concentration of 50 ppm is about 4.7. The bicarbonate ion content of carbonated water is only about 0.02 mM / L (20 μM / L). However, by dissolving bicarbonate in this carbonated water and forcibly increasing the amount of bicarbonate ions to 2.0 mM / L, the pH can be temporarily raised to about 6.6.

  Generally, it is desirable that the pH of water or nutrient solution used for plant cultivation is in the range of 4-8. The pH of the carbon dioxide water can be adjusted by increasing the amount of bicarbonate ions using an alkaline substance. Any alkaline substance can be used, but carbonate or bicarbonate is used as the alkaline substance in the present invention for the purpose of supplying carbon dioxide to a plant. When an alkaline substance other than this is added to carbonated water, dissolved carbonic acid is dissociated (ionized) and lost, and therefore, use of carbonate or bicarbonate is preferred. As the carbonate or bicarbonate, an alkali metal salt or an ammonium salt is suitable, and a preferable alkali metal salt is a potassium salt or a sodium salt, and a potassium salt is more preferable.

  The following method (1) and method (2) are mentioned as a method for obtaining carbonated water whose pH is adjusted using bicarbonate. The carbon dioxide dissolution concentration and bicarbonate ion concentration in the present invention mean the carbon dioxide dissolution amount and bicarbonate ion concentration in an aqueous solution having a liquid temperature of 25 ° C. unless otherwise specified.

  Method (1): When bicarbonate is added to water, the pH is gradually increased. When the amount of bicarbonate added is 1 mM / L, the pH becomes 8.27, and when 2 mM / L. , The pH is 8.57. When this aqueous bicarbonate solution is used as raw water and carbon dioxide is dissolved to a saturated concentration at 1 atm, the pH of carbonated water containing 1 mM / L of bicarbonate is lowered to 4.82, and the bicarbonate is dissolved. The pH of 2 mM / L carbonated water drops to 5.11.

  Method (2): When carbon dioxide is dissolved in water to a saturated concentration under 1 atm, the pH becomes 3.91 (bicarbonate ion concentration 0.12 mM / L). When bicarbonate is added to the carbonated water, the pH thereof is gradually increased to 4.82 at an addition amount of 1 mM / L and 5.11 at an addition amount of 2 mM / L.

  In the case of the above method (1), carbonate can be used instead of bicarbonate. However, the use of bicarbonate is preferred because the addition of carbonate raises the pH abruptly compared to the addition of bicarbonate. Also in the case of method (2), the amount of bicarbonate ion in the liquid is increased to 0.12 mM / L or more by using carbonate instead of bicarbonate and adding it to carbonated water. Can do. However, the use of bicarbonate is preferred because carbonate increases the pH significantly with small additions.

  In the present invention, the method (1) and the method (2) described above are combined, and the dissolution of carbon dioxide and the addition of bicarbonate are allowed to proceed simultaneously. Alternatively, by adding the solution, carbonated water containing 50 ppm or more of carbon dioxide and adjusted to a desired pH value can be obtained. In any case, when supplying carbonated water containing 50 ppm or more of carbon dioxide to the plant, the carbonated water is forcibly made to contain 0.12 to 2.0 mM / L of bicarbonate ions, What is necessary is just to adjust the pH in the range of 4-8.

In the present invention, the effect of “gas-dissolved water in which 50 ppm or more of carbon dioxide is dissolved and the pH is adjusted to a range of 4 to 8” on the growth of plants and the rooting of cuttings is described as follows. be able to.
It is the concentration of carbon dioxide and bicarbonate ions dissolved in the water in the plant that dominates the rate-limiting step of carbon fixation (photosynthesis, etc.) required for plant growth. Under the partial pressure of carbon dioxide in the environment where plants are grown, water in the plant body cannot dissolve carbon dioxide above the saturation concentration at that partial pressure. On the other hand, carbon dioxide dissolved in water according to the pH of the water in the plant body is ionized into bicarbonate ions to reach an equilibrium state. Furthermore, carbon dioxide may be quickly converted into bicarbonate ions due to the high molecular activity of carbonic anhydrase (carbonic acid dehydratase) widely present in plants. In particular, since the pH of the chloroplast is around 8, it can be said that this reaction is actively carried out.

  From the above, the concentration of carbon dioxide dissolved in the water in the plant is determined by the partial pressure of carbon dioxide, the pH of the water in the plant, and the action of carbonic anhydrase. It is not necessarily a sufficient condition for realizing rooting. According to the present invention, it is considered that the concentration of carbon dioxide and bicarbonate ions dissolved in water in a plant grown in the atmosphere can be increased more than that in a state in which plants are normally grown. Enzymatic reactions such as ribulose bisphosphate carboxylase and phosphoenolpyruvate carboxylase involved in carbonic acid fixation can be activated. As a result, it is considered that the growth of plants and the rooting of cuttings are promoted.

In addition, when carbonated water is used in the present invention, the carbonated water exhibits an effect of improving the environmental stress resistance of plants. This point will be specifically described below.
First, carbonated water can relieve carbon dioxide deficiency stress. If the plant is not sufficiently supplied with carbon dioxide, the final electron acceptor of the photosynthetic reaction, the photosynthetic reaction stops and the cells are stressed. Excess light energy received by chlorophyll cannot be consumed in the carbonic acid fixation reaction, and part of it is released as fluorescence or heat, but the remaining energy reduces oxygen molecules to produce active oxygen, which causes photochemical systems, etc. Cell components are damaged.

  According to the present invention, it is considered that the concentration of carbon dioxide and bicarbonate ions dissolved in the water in the body of a plant grown in the atmosphere can be increased more than that in a state where the plant is normally grown. By doing so, even in C3 plants subjected to environmental stress conditions such as strong light, dryness, and excessive salt content, C4 plants for actively incorporating and concentrating inorganic carbon (carbon dioxide or bicarbonate ions) into the living body. It is considered that the tolerance to environmental stress is increased by avoiding a carbon dioxide deficient stress state, similarly to the mechanism of aquatic photosynthetic organisms.

  Second, by using carbonated water, the amount of transpiration due to pore closure induced by high-concentration carbon dioxide can be suppressed. It is well known that pores are closed when the partial pressure of carbon dioxide in the plant is increased. According to the present invention, this action is considered to reduce or avoid water loss caused by drying, high salt concentration, etc., and increase resistance to environmental stress.

There is no limitation in particular in the manufacturing method of the carbon dioxide water used by this invention, Carbonated water marketed can also be used. Any known method can be employed to produce carbonated water by dissolving carbon dioxide in water. For example, a method of blowing combustion gas such as fossil fuel or carbon dioxide filled in a gas cylinder, a method of electrolyzing water using an electrode made of a carbon material, a method of bringing dry ice into contact with water, a method of filling carbon dioxide A method of introducing water into a tank, a method of dissolving a soluble carbonate or bicarbonate in water and then allowing an acid to act, a hollow fiber membrane comprising a microporous porous membrane or a nonporous gas permeable membrane A method of dissolving carbon dioxide in water on the opposite side of the membrane by using a membrane module such as the above can be adopted. Among these methods, a method of using a plant growth apparatus (see Patent Document 1) equipped with a membrane module is preferable in that a necessary amount of carbonated water can be easily prepared in a necessary amount.
In the plant cultivation system of the present invention, the gas dissolved water prepared in advance can be stored or supplied in the gas dissolved water holding means, or the gas can be dissolved in the water stored in the gas dissolved water holding means. .

  In order to make bicarbonate ions present in carbonated water for pH adjustment, soluble carbonate or bicarbonate is added directly to carbonated water, or an aqueous solution of carbonate or bicarbonate is prepared in advance. A method of adding to carbonated water can be employed. Alternatively, a method of adding carbonate or bicarbonate (or an aqueous solution thereof) to water and then using carbonated water is also included. In addition, any method can be employed such as water to which a strong basic compound such as sodium hydroxide is added or ammonia water is used as carbonated water.

In the present invention, it is important that the gas-dissolved water whose final carbon dioxide concentration is in the range of 50 to 2,800 ppm and whose pH is suitably adjusted as described above can be easily and quickly procured. For this purpose, it is preferable to use a device that links a carbon dioxide supply device or a pump for feeding a basic compound solution such as bicarbonate with a carbon dioxide concentration meter or pH meter.

<Gas dissolved water obtained by dissolving hydrogen gas in water>
In the present invention, hydrogen gas can be used as a gas. In gas dissolved water obtained by dissolving hydrogen gas in water (hereinafter often referred to as “hydrogen water”), the concentration of dissolved hydrogen gas (hereinafter simply referred to as “hydrogen concentration”) is 0.002 to 3 0.000 ppm, more preferably 0.0442 to 1.62 ppm. According to the study by the present inventors, when a photosynthesis photon flux density is set to 362 to 420 μmol / s · m ² , and a solanaceous plant is cultivated for 24 hours, the hydrogen concentration is 2 μg / L (0.002 ppm) or less. In the aqueous solution, the chlorophyll in the leaves of the plant body decreased and physiological disorder (chlorosis) occurred. In addition, when hydrogen water having a hydrogen concentration of 44.2 μg / L (0.0442 ppm) is supplied to a plant under the same conditions as described above, the chlorophyll of the plant body is not substantially reduced and chlorosis occurs. I didn't.

  In the present invention, the action of hydrogen water having a hydrogen concentration of 0.002 ppm or more on the growth of plants can be explained as follows. Plants take in gas such as carbon dioxide in the atmosphere from leaves into the body of the plant and take water from the roots for photosynthesis. In photosynthesis, active oxygen is generated in cells, but when photosynthesis is suppressed such as intense light in summer, low temperature, drying, and poor nutrition, excessive active oxygen is generated. Active oxygen has a very strong oxidizing power, and excessive generation of active oxygen damages and destroys chloroplasts. When the chloroplast is destroyed, the photosynthetic efficiency decreases, the growth of the plant is inhibited, and it eventually withers. However, when gas dissolved water in which 0.002 ppm or more of hydrogen gas is dissolved is given to the plant, the hydrogen gas that exists as stable fine bubbles in the aqueous solution is absorbed from the root of the plant and goes around the plant as it is to the leaves. Go and remove active oxygen. It is considered that the removal of active oxygen suppresses the destruction of chloroplasts and promotes plant growth.

  The hydrogen gas concentration of the dissolved gas used in the present invention can be adjusted as appropriate. When cultivating a plant by irradiating particularly strong light, an aqueous solution having a higher hydrogen concentration may be used. When a plant is irradiated with strong light, active oxygen is generated in excess. For this reason, in order to remove excess active oxygen, it is necessary to take in more hydrogen gas in a plant body. For this reason, according to the light quantity to irradiate, it is good to supply and grow to the plant the aqueous solution which raised hydrogen concentration suitably within said range.

There is no limitation in particular in the manufacturing method of the hydrogen water used by this invention, Commercially available hydrogen water can also be used. Any conventionally known method can be employed to produce hydrogen water in which hydrogen gas is dissolved in water. For example, there is a method in which hydrogen gas filled in a hydrogen gas cylinder or hydrogen gas generated by electrolyzing distilled water is dissolved in water. As a method for dissolving hydrogen gas in water, an air diffuser (diffuser) in which a large number of fine vent holes are perforated is placed in a container containing water, hydrogen gas is supplied through the pipe, Examples include a method of diffusing water as fine bubbles and a method of entraining hydrogen gas using a pump for circulating water. For a specific method for producing hydrogen water, reference can be made to, for example, JP 2010-51963 A.
In the plant cultivation system of the present invention, the gas dissolved water prepared in advance can be stored or supplied in the gas dissolved water holding means, or the gas can be dissolved in the water stored in the gas dissolved water holding means. .

  When hydrogen water is used in the present invention, the hydrogen concentration can be measured by a known method. For example, it can be measured by using a commercially available measuring device such as a dissolved hydrogen meter (hydrogen concentration measuring device) KM2100DH (manufactured by Kyoei Electronics Research Laboratories, Japan). It can also be quantified by a titration method using an aqueous methylene blue solution.

  Further, the gas-dissolved water of the present invention may further contain the above gas as “microbubbles” and / or “nanobubbles” as long as a gas such as carbon dioxide or hydrogen gas is dissolved in the above amount. Good. “Microbubble” refers to a fine bubble having a diameter of 50 μm or less, and “nanobubble” refers to a finer bubble having a diameter of 1 μm or less. The advantage that water containing gas as microbubbles and / or nanobubbles can contain more gas stably than water that simply dissolves gas without containing microbubbles or nanobubbles There is. Microbubbles and nanobubbles cannot pass through a nonporous hydrophilic film as they are, but are known to dissolve gas in water while gradually shrinking. It can be used as a supply source. Nanobubbles are usually generated by instantaneous crushing of microbubbles in water containing electrolyte ions. In the present invention, when the gas-dissolved water is a nutrient solution containing fertilizer components, nanobubbles are stably generated. In the present invention, nanobubbles can be particularly preferably used because they contain electrolyte ions that are suitable for the production. Regarding microbubbles and nanobubbles, for example, JP-A-2004-121962, JP-A-2005-245817, JP-A-2005-246294 and JP-A-2008-206448 can be referred to. When the gas is contained as microbubbles and / or nanobubbles, the amount of microbubbles and / or nanobubbles is 100,000 / ml or more, more preferably 15,000,000 / ml or more.

In the present invention, when carbon dioxide and hydrogen gas are used at the same time, it is important that the gas-dissolved water in which the two gases are forcibly dissolved satisfies the above-described conditions relating to the carbon dioxide water and hydrogen water. Accordingly, the carbon dioxide concentration of such gas-dissolved water must be 50 ppm or more and the hydrogen concentration must be 0.002 ppm or more. As mentioned above, carbon dioxide promotes carbon fixation by plants, and hydrogen gas protects chloroplasts by removing active oxygen. Therefore, combined use of carbon dioxide and hydrogen gas further promotes plant growth. The When carbon dioxide and hydrogen gas are used in combination, there is no particular limitation on the method for dissolving these gases in water, a method for dissolving a mixed gas of carbon dioxide and hydrogen gas in water, and carbon dioxide and hydrogen gas in water sequentially. Any of a method of dissolving, a method of mixing carbon dioxide water and hydrogen water prepared in advance may be used.
The gas-dissolved water contains other gases that are normally dissolved in water and nutrient solution under normal temperature and pressure as long as the amount of carbon dioxide or hydrogen necessary for obtaining the effects of the present invention is dissolved. It does not matter. For example, carbonated water obtained by forcibly dissolving carbon dioxide gas in tap water may contain oxygen or nitrogen dissolved in tap water under normal temperature and pressure in addition to carbon dioxide.

  The gas-dissolved water used in the present invention may further contain a fertilizer component. The fertilizer to be used is not particularly limited, and any fertilizer that has been used in conventional soil culture, hydroponics, or hydroponics can be used. In general, inorganic components are indispensable for plant growth, but the main components are: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S ), Trace components: iron (Fe), manganese (Mn), boron (B), copper (Cu), zinc (Zn), molybdenum (Mo). In addition, silicon (Si), chlorine (Cl), aluminum (Al), sodium (Na) and the like can be cited as subcomponents. If necessary, other physiologically active substances can be added as long as the effects of the present invention are not substantially inhibited. Furthermore, sugars such as glucose (glucose), amino acids and the like can be added.

  Furthermore, the pH of the gas-dissolved water used in the present invention is preferably in the range of 4-8. Plants have different pH values for optimal growth depending on the type, but in many plants, the passive change in intracellular pH caused by the difference in pH between the inside and outside the cell is suppressed, and the intracellular pH is maintained within a suitable range. However, it is important for advancing biochemical processes, and it is preferable that the difference in pH between the inside and outside of the cell is small because energy consumption for transporting hydrogen ions is reduced. Since the optimum pH at which plants usually grow is said to be in the range of 4-7, in the present invention, the more preferred pH of the gas-dissolved water is in the range of 4-7, more preferably 4-6. .6 range.

When the gas-dissolved water is carbon dioxide water, the pH of the carbon dioxide water can be adjusted to an arbitrary value by adjusting the amount of bicarbonate ions dissolved in the carbonated water as described above. Moreover, although pH of hydrogen water is normally neutral, it can also be adjusted in consideration of the fertilizer component etc. which are contained. The pH of the gas-dissolved water can be easily confirmed using a commercially available pH meter or the like.

<Plant cultivation system>
Next, a basic configuration of the plant cultivation system of the present invention for cultivating a plant using gas-dissolved water will be described.
As a component of the plant cultivation system of the present invention, a nonporous hydrophilic film is essential, but it can be roughly divided into two types depending on the difference in gas dissolved water holding means. In the first type, the gas-dissolved water holding means is a hydroponics tank, and gas-dissolved water arranged so as to be in contact with the lower surface of the nonporous hydrophilic film is accommodated in the hydroponics tank. This is a system for plant cultivation. Patent Document 9 can be referred to for a system having such a structure. In the second type, the gas-dissolved water holding means has a water-impermeable surface, and a non-porous hydrophilic film is laid on the surface. A system for plant cultivation characterized by further comprising a gas-dissolved water supply means for supplying gas-dissolved water continuously or intermittently between them. A typical gas-dissolved water supply means is nonporous hydrophilic It is the drip irrigation tube installed between the film and the gas dissolved water holding means. That is, this second type cultivation system is a system having a multilayer structure in which a gas-dissolved water holding means is used as a base material layer and a nonporous hydrophilic film is laminated directly or indirectly thereon. . Hereinafter, the gas dissolved water holding means in this cultivation system is often referred to as a “gas holding layer”. Patent Document 14 can be referred to for a system having such a structure.

  FIG. 1 is a schematic cross-sectional view showing a basic aspect of a second type of plant cultivation system. Gas dissolved water (3) obtained by dissolving gas in water by blowing gas (carbon dioxide and / or hydrogen gas) (2) into the fertilizer nutrient solution, feed pump (4) and supply pipe (9) Is supplied so as to be in contact with the lower surface of the nonporous hydrophilic film (1). In the example of FIG. 1, a water absorbing material (5) such as a nonwoven fabric is installed between the nonporous hydrophilic film (1) and the water-impermeable surface (11), and a fertilizer component is added to the water absorbing material (5). The gas-dissolved water (3) containing is absorbed. The gas-dissolved water (3) containing the fertilizer component absorbed by the water-absorbing material (5) is absorbed by the nonporous hydrophilic film (1), and the root (7) of the plant (6) is nonporous hydrophilic. It adheres to the upper surface of the film (1) and absorbs water, gas (carbon dioxide and / or hydrogen gas), and fertilizer components contained in the nonporous hydrophilic film (1). In addition, the water absorbing material (5) such as a nonwoven fabric is used arbitrarily, and by using this, the gas-dissolved water (3) containing a fertilizer component is uniformly spread to lower the nonporous hydrophilic film (1). Can be supplied to. However, of course, the gas-dissolved water (3) may be supplied directly between the nonporous hydrophilic film (1) and the water-impermeable surface (11) without using the water absorbing material (5). .

  If necessary, a plant cultivation support (8) such as soil and / or a water-permeable or low-permeability evaporation suppressing member (not shown) on the nonporous hydrophilic film (1). ) (For example, a mulching material to be described later). When the support for plant cultivation (8) is disposed on the nonporous hydrophilic film (1), an effect of protecting the root of the plant body can be obtained. Moreover, when the water vapor evaporated from the nonporous hydrophilic film (1) to the atmosphere is condensed in the surface of the evaporation suppression member or the support for plant cultivation (8) by arranging the evaporation suppression member, the condensed water vapor is Plants can be used as water. However, when using the evaporation suppression member, if the plant root is blocked from the outside air by this, the plant root may be deficient in oxygen, so several ventilation openings are provided to avoid this. It is desirable to devise such as.

  According to the plant cultivation system of the present invention, water, gas (carbon dioxide and / or hydrogen gas), and gas-dissolved water (3) containing fertilizer components are supplied to the plant via the nonporous hydrophilic film (1). The Since the gas-dissolved water (3) is separated from the air layer by the nonporous hydrophilic film (1), the gas component in the gas-dissolved water is prevented from being dissipated in the air, and the gas dissolved in the water (Carbon dioxide and / or hydrogen gas) is maintained at a high concentration. On the other hand, in the conventional hydroponic cultivation method in which the root of the plant is immersed in water (or nutrient solution), the surface of water or nutrient solution is in contact with the air layer, so that a gas such as carbon dioxide or hydrogen is present. Even if it is dissolved, it is easily dissipated in the air.

  In addition, in the conventional hydroponics method in which the root of the plant is immersed in water (or nutrient solution), the root absorbs oxygen dissolved in water, so the amount of dissolved oxygen in water used for cultivation exceeds a certain level. There was a need to keep. Since the amount of gas dissolved in water is proportional to the gas partial pressure, if the gas is forcibly dissolved in water at atmospheric pressure, the oxygen concentration that was originally dissolved decreases, and the cultivated plant falls into oxygen deficiency. There was a thing. There was also a limit to the amount of gas that could be dissolved in water. On the other hand, in the plant cultivation system of the present invention, the root of the plant is in the air layer on the nonporous hydrophilic film (1), so that oxygen can be absorbed from the air. And since gas can be dissolved in water as much as necessary without worrying about problems such as rooting due to a decrease in dissolved oxygen amount of water due to forcibly dissolving gas, gas (carbon dioxide and carbon dioxide) The effect of promoting the growth of (or hydrogen gas) can be sufficiently exerted.

  Furthermore, if necessary, means (10) for fine mist spraying (for example, a valve) can be arranged on the upper part of the film (1), and water, nutrient solution or agrochemical dilution can be sprayed intermittently. By disposing such means for spraying fine mist (10), cooling in the summer especially by intermittent spraying of water, cooling of the environment by spraying of nutrient solution and supply of fertilizer components by foliar spraying, blending of agricultural chemicals It is possible to obtain an advantage that automation of spraying of agricultural chemicals by spraying of the water or nutrient solution that has been performed is possible. However, when it is intended to reduce a specific component of the plant (eg, nitrate nitrogen), basically, from the top of the nonporous hydrophilic film (1) (to avoid nutrient accumulation) It is preferable to supply only water.

  In order to promote the “integration” of the film and the root, it is preferable to supply a nutrient solution from below the film (1). The present inventors use a polyvinyl alcohol (PVA) film having a thickness of 40 μm as a non-porous hydrophilic film, and investigate the effect of fertilizer concentration supplied from under the film on the integration phenomenon between the root and the film. It was. Specifically, about 300 ml of vermiculite or rock fiber is placed as soil on a non-porous hydrophilic film (PVA) of about 20 cm × 20 cm, and in this soil, a seedling of Sunny lettuce (slightly more than one true leaf) is placed. 2) were planted. As a nutrient solution supplied from the bottom of the film, a total of six types of systems were prepared using Hyponex 100-fold diluted solution, 1000-fold diluted solution, and water (tap water, ie, no fertilizer). The amount of nutrient solution was 300 ml each, and the thickness of the soil on the film (PVA) was about 2 cm. The experiment was performed in a house, using natural light, under conditions of an air temperature of 15 to 25 ° C. and a humidity of 50 to 90% RH. After 13 days and 35 days after the start of cultivation, the peel strength was measured in the same manner as the integration test described later. The results are shown in Table 1.

  As is apparent from Table 1, not only the growth of the plant but also the adhesive strength between the root and the film was remarkably improved by using the nutrient solution as compared with the case where only water was supplied from the lower surface of the film. This indicates that the plant absorbs not only water but also fertilizer components through the film. Furthermore, in order to efficiently absorb water and fertilizer components through the film, it is essential that the roots adhere strongly to the film surface, and as a result, the roots and the film are considered to be integrated. .

  If water is added excessively from above the film before the “integration” of the nonporous hydrophilic film (1) and the root is completed, the plant absorbs easy moisture on the film, The need to remove moisture is reduced, and as a result, the roots tend to become less integrated with the film. Therefore, it is not preferable to add excessive moisture from above the film until the roots are integrated with the film. On the other hand, if the roots are integrated with the nonporous hydrophilic film, moisture / nutrient may be appropriately given from above the film. At this time, the water or nutrient solution supplied from above the nonporous hydrophilic film (1) is obtained by dissolving at least one gas (carbon dioxide, hydrogen gas) that promotes plant growth in water. Gas-dissolved water may be used.

<Configuration of system for plant cultivation>
Hereinafter, the structure of each part in the plant cultivation system of this invention is demonstrated in detail. Regarding such a configuration (or function), “detailed description of the invention”, “examples”, and the like in the documents (Patent Documents 9 to 14) by the present inventor can be referred to as necessary.

(Nonporous hydrophilic film)
In the plant cultivation system of the present invention, a nonporous hydrophilic film for cultivating a plant thereon is essential. The nonporous hydrophilic film used in the present invention preferably satisfies all the various physical properties described below.

(Integration test)
It is important that the nonporous hydrophilic film is a film that can be “substantially integrated with the roots of the plant” that is being cultivated. A film that can be substantially integrated with the roots of a plant is a nonporous hydrophilic film when a plant is grown for 35 days on the nonporous hydrophilic film of the plant cultivation system of the present invention. It is a film having a peel strength of 10 g or more for peeling from the roots of cultivated plants. The “integration test” for measuring the integration of the root and the film can be performed as follows.

  Using the "Zaru Bowl Set", put the film to be tested (200 x 200mm) on the sieve, place 150g of vermiculite (water content 73%, dry weight 40g) on it, and seedlings of sunny lettuce (one real leaf) 2) are planted. This rice cake is placed in a bowl filled with 240 to 300 g of nutrient solution, and the film is brought into contact with the nutrient solution to grow seedlings. Cultivation is carried out in a house, using natural light, temperature is 0-25 ° C., humidity is 50-90% RH for 35 days. Next, the stems and leaves are cut at the roots of the cultivated plants, and the film is cut into a width of 5 cm (length: about 20 cm) so that the stems of the film with which the roots are closely attached are centered to form a test piece.

  A commercially available clip is attached to the spring-type hand balance, and one of the test pieces obtained above is fixed with the clip, and the weight indicated by the spring-type hand balance (corresponding to the weight of the test piece = A gram) is recorded. Next, the stalk at the center of the test piece is held by hand and gently pulled downward, and the weight (load = B grams) when the root and the film are separated (or cut) is read from the scale of the spring-type hand balance. The (B-A) gram obtained by subtracting the initial weight from this value is defined as a 5 cm wide peel load, and this peel load is defined as the peel strength.

  The peel strength of the nonporous hydrophilic film used in the present invention is preferably 10 g or more, more preferably 30 g or more, and most preferably 100 g or more.

(Ion permeability test)
Furthermore, in the present invention, as one of the indicators for judging whether or not the nonporous hydrophilic film can be “substantially integrated with the root of the plant”, there is a balance of ion permeability.
When a plant is grown using the plant cultivation system of the present invention, the plant absorbs the fertilizer as ions through the film. Therefore, the salt (ion) permeability of the film used affects the amount of fertilizer component given to the plant. In the present invention, electrical conductivity measured at the cultivation temperature of water and salt water when water and 0.5% by mass salt water are opposed to each other for 4 days (96 hours) through a nonporous hydrophilic film. A film having a difference in degree (EC) of 4.5 dS / m or less is preferable. The difference in electrical conductivity between water and salt water is more preferably 3.5 dS / m or less, and most preferably 2.0 dS / m or less. When such a film is used, it becomes easy to supply a suitable water or fertilizer solution to the roots and promote integration of the film and the roots.

Electrical conductivity (EC, EC) is an index of the amount of salts (or ions) dissolved in the liquid, and is also referred to as specific conductivity. As EC, the value of electrical conductivity when ^two electrodes having a cross-sectional area of 1 cm ² are separated by a distance of 1 cm is used, and the unit is Siemens (S), which is expressed by S / cm. However, since the EC of the nutrient solution is small, mS / cm, which is a unit of 1/1000, is used (in the international unit system, dS / m (d is deci)).

The ion permeability of the film can be measured as follows.
10 g of commercially available salt is dissolved in 2000 ml of water to make 0.5% salt water (EC: about 9 dS / m). Using the “Zaru Bowl Set”, place the film to be tested (size: 200-260 × 200-260 mm) on the sieve and add 150 g of water on the film. On the other hand, 150 g of the above-mentioned salt water is added to the bowl side, and the entire system obtained is wrapped with a food wrap (polyvinylidene chloride film, trade name: Saran Wrap, manufactured by Asahi Kasei Co., Ltd.) to prevent moisture evaporation. In this state, it is allowed to stand at room temperature, and ECs on the water side and salt water side are measured every 24 hours. Specifically, a small amount of a sample (that is, a solution on the water side or the salt water side) is placed on the measurement site (sensor unit) of the electric conductivity meter using a dropper, and the conductivity is measured.

(Water permeability / glucose solution permeability test)
In the present invention, the nonporous hydrophilic film preferably exhibits a predetermined glucose permeability from the viewpoint of facilitating nutrient absorption (organic matter) of plant roots via the nonporous hydrophilic film. This film with excellent glucose permeability is obtained at the cultivation temperature of water and glucose solution when water and 5% glucose aqueous solution are opposed to each other for 3 days (72 hours) through a nonporous hydrophilic film. It is a film having a difference in measured density (Brix%) of 4 or less, more preferably 3 or less, more preferably 2 or less, and most preferably 1.5 or less.

The glucose permeability of the film can be measured as follows.
A 5% glucose solution is prepared using commercially available glucose (glucose). Using the same “Zel Bowl Set” as in the ion permeability test above, place a nonporous hydrophilic film (size: 200 to 260 × 200 to 260 mm) to be tested on the filter and add 150 g of water onto the film. . On the other hand, 150 g of the above glucose solution is added to the bowl side, and the entire system obtained is wrapped in food wrap (polyvinylidene chloride film, trade name: Saran Wrap, manufactured by Asahi Kasei Co., Ltd.) to prevent moisture evaporation. In this state, the sample is left at room temperature, and the sugar content (Brix%) on the water side and glucose solution side is measured with a saccharimeter every 24 hrs.

(Water pressure resistance)
Furthermore, in this invention, it is preferable that a nonporous hydrophilic film has a water impermeability of 10 cm or more as a water pressure resistance. When such a nonporous hydrophilic film is used, the integration of the root and the film can be promoted. Moreover, it becomes easy to prevent contamination with pathogenic bacteria through a suitable oxygen supply to the roots and the nonporous hydrophilic film.

  The water pressure resistance can be measured by a method according to JIS L1092 (Method B). The water pressure resistance of the nonporous hydrophilic film used in the present invention is preferably 10 cm or more, more preferably 20 cm or more, still more preferably 30 cm or more, and particularly preferably 200 cm or more.

(Material)
The material of the nonporous hydrophilic film used in the present invention is not particularly limited, and can be appropriately selected from known hydrophilic materials that can be used usually in the form of a film or a membrane. Specific examples include hydrophilic materials such as polyvinyl alcohol (PVA), cellophane, cellulose acetate, cellulose nitrate, ethyl cellulose, and polyester. The thickness of the nonporous hydrophilic film is not particularly limited, but is usually 300 μm or less, preferably 5 to 200 μm, more preferably 20 to 100 μm.

  The nonporous hydrophilic film used in the present invention preferably satisfies all the above-described physical properties (ion permeability, glucose permeability and water pressure resistance). The present inventors evaluated the physical properties of various nonporous hydrophilic films and a comparative porous hydrophobic film by the method described above. Specifically, ion permeability was tested for six types of PVA, biaxially stretched PVA (boblon), hydrophilic polyester, cellophane, PH-35, and ultrafine fiber nonwoven fabric (Charelia), and PVA, biaxially stretched PVA, Glucose permeability was tested for five types of cellophane, penetrating cellophane, and PH-35, and water resistance was tested for five types of PVA, biaxially stretched PVA, cellophane, hydrophilic polyester, and ultrafine fiber nonwoven fabric. The results are shown in Tables 2 to 4 below.

As is clear from Table 2, the films having a large ion permeability were ultrafine fiber nonwoven fabric (Charelia), PVA, hydrophilic polyester and cellophane. On the contrary, the one having a small ion permeability was bobron, and the one having no ion permeability was a microporous polypropylene film (PH-35). Therefore, it can be seen that the microporous polypropylene film (PH-35) is unsuitable from the viewpoint of ionic salt permeability.

  As is apparent from Table 3, among the five films tested, PVA, cellophane and osmotic cellophane had good glucose permeability, but almost no glucose permeability was observed with bobron. Further, no permeability was observed with PH-35. From the viewpoint of glucose permeability, it can be seen that films that can be suitably used in the present invention are PVA and cellophane.

  As is apparent from Table 4, from the viewpoint of the water pressure resistance of the film, a porous film cannot be used in the present invention as in the case of an ultrafine fiber nonwoven fabric.

As is clear from the data shown in Tables 2 to 4, the film satisfying all of the ion permeability, glucose permeability and water resistance is a nonporous hydrophilic film such as PVA, cellophane, hydrophilic polyester and the like. It is. Accordingly, a nonporous hydrophilic film is used in the present invention.

<Support for plant cultivation>
In the plant cultivation system of this invention, in order to protect the root of a plant body, the support body for plant cultivation, such as soil, can be arrange | positioned on a nonporous hydrophilic film. There is no limitation in particular in the support body for plant cultivation used, The soil thru | or culture medium normally used can be used. Examples of such soil or medium include soil used for soil cultivation and medium used for hydroponics.
Examples of inorganic supports for plant cultivation include natural sand, rubble, and pumice sand, and processed products (high temperature firing etc.) include rock wool, vermiculite, perlite, ceramic, rice husk charcoal, etc. Examples of the support for cultivation include natural peat moss, coconut fiber, bark culture medium, rice husk, neat and sotan, and synthetic granular phenol resins. These may be used alone or in combination as appropriate. You can also. Synthetic fiber cloth or non-woven fabric can also be used as a plant cultivation support.

Minimal fertilizer and trace elements may be added to the plant cultivation support. According to the knowledge of the present inventors, until the roots of the plant extend to the extent that water or nutrients can be absorbed from the water / nutrient solution that is contacted via the nonporous hydrophilic film, in other words, the roots and the film 1 are Until integration, it is desirable to add nutrients to the plant cultivation support on the non-porous hydrophilic film as “minimum fertilizer and trace elements” as used herein.

<Gas dissolved water retention means>
The plant cultivation system of the present invention includes gas-dissolved water retaining means for retaining gas-dissolved water under the nonporous hydrophilic film. In the plant cultivation system of the present invention, either a container-like gas-dissolved water holding means for storing gas-dissolved water or a gas-dissolved water-holding layer functioning as a base material layer having a water-impermeable surface can be used. is there.
The container-like gas-dissolved water holding means for storing the gas-dissolved water is not particularly limited as long as it is a container capable of holding a necessary amount of gas-dissolved water, and the material thereof is light weight and easy moldability. From the viewpoint of cost reduction, general-purpose plastics such as polypropylene, polyvinyl chloride, and polyethylene can be preferably used. For example, a conventionally used hydroponics tank can be used.

The water-impermeable surface of the gas-dissolved water holding layer is not particularly limited as long as it is made of a material that does not allow water to pass through, and examples thereof include synthetic resin, wood, metal, and ceramic. The shape of the gas-dissolved water holding layer is not particularly limited, and examples thereof include a film shape, a sheet shape, a plate shape, and a box shape.
The gas-dissolved water supply means is not particularly limited as long as it is a means conventionally used for continuous or intermittent supply of water or nutrient solution. In the present invention, it is preferable to use a drip irrigation tube (also referred to as “drip tube”) capable of supplying gas-dissolved water little by little. By drip irrigation using a drip irrigation tube, it is possible to supply as little water and fertilizer as necessary for crop growth.

  Furthermore, in the aspect including the gas-dissolved water holding layer and the gas-dissolved water supply means, in order to assist the supply of the gas-dissolved water to the non-porous hydrophilic film, the water-absorbing material is further replaced with the non-porous hydrophilic film. And a water impermeable surface. The water-absorbing material is basically not particularly limited as long as it is a material that absorbs and holds water. Examples include sponges and non-woven fabrics made from synthetic resins, fabrics made from woven fabrics, plant fibers, chips, powders, or materials commonly used as plant supports such as peat moss and moss. Can also be used.

  The plant that can be cultivated using the plant cultivation system of the present invention is not particularly limited, and all plants that are normally grown in the fields of agriculture, forestry, and horticulture can be targeted.

  Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1
(Nutrient solution used for cultivation experiment)
Nutrient solution A: In distilled water, potassium sulfate 4 mM / L, ammonium nitrate 2 mM / L, potassium dihydrogen phosphate 0.4 mM / L, magnesium nitrate 0.2 mM / L, calcium chloride 0.8 mM / L, Fe (III) -EDTA 0.02 mM / L, boric acid 9.7 · M / L, manganese sulfate 8.3 · M / L, zinc sulfate 1.4 · M / L, potassium iodide 0.9 · M / L, molybdic acid An aqueous solution obtained by dissolving disodium 0.2 · M / L, copper sulfate 0.02 · M / L, and cobalt chloride 0.02 · M / L.

Nutrient solution B: An aqueous solution obtained in the same manner as the above nutrient solution A except that 0.5 mM / L of potassium bicarbonate was added and potassium sulfate was changed from 4 mM / L to 3.75 mM / L.

(experimental method)
The schematic diagram of the system used for the cultivation experiment is shown in FIG. 2A. A granular activated carbon is formed on the nonporous hydrophilic film of each of the two culture apparatuses using a 65 μm-thick polyvinyl alcohol film (manufactured by Aicero Chemical Co., Ltd., Japan) as the nonporous hydrophilic film. The seeds of Komatsuna (“Torsai Komatsuna” manufactured by Tohoku Tanae Co., Ltd., Japan) were sown at an equal interval of about 5 mm, and the activated carbon was moistened by spraying. Connect a tube (outer diameter 6 mm, inner diameter 4 mm, made of polyurethane) to the two holes at the bottom of the culture apparatus, put it in a plastic tank (5 L) containing culture medium A (20) or culture medium B (21), and A unimol pump (18) (manufactured by Nitto Kohki, Japan) was passed through the tube. With the unimol pump (18), the culture solution A (20) or the culture solution A (20) or the space surrounded by the nonporous hydrophilic film of the culture device and the acrylic frame is transferred from the plastic tank containing the culture solution A (20) or the culture solution B (21). The culture solution B (21) was filled and returned to the plastic tank from the other hole at the bottom of the culture apparatus, and the culture solution was circulated. Two culture devices inoculated with komatsuna were installed in a closed container (48 x 64 x 17 cm), humidity 90%, temperature 25 ° C, photosynthetic photon flux density (PPFD) 250 µmol m ^-2 s ^-1 Under 12-hour illumination, the carbon dioxide concentration was kept at atmospheric concentration (720 ppm) and the seedlings were grown for 17 days, and the roots were entrapped in a nonporous hydrophilic film.

  After 18 days after sowing, the culture medium A was circulated without dissolving the carbon dioxide (the control group), and carbon dioxide was blown into the culture tank at a rate of 50 ml / min from the carbon dioxide cylinder (19). A section (carbonated water section) for circulating and culturing the culture solution B (21) in which carbon dioxide was dissolved was provided. The carbon dioxide concentration in the culture solution in the carbonated water section was about 1000 ppm as measured using a portable carbon dioxide concentration meter CGP-1 manufactured by Toa DKK Corporation. In order to remove carbon dioxide in the air in the sealed container, the air in the container is taken out by an air pump (16), and the carbon dioxide is removed by ventilating the column (15) filled with soda lime outside the sealed container. Air was again circulated into the container. In carbonated water, the culture device is covered with a plastic bag to prevent carbon dioxide in the culture solution from being diffused directly into the air through the nonporous hydrophilic film and used for photosynthesis. A gap with a width of 5 mm was made at the hypocotyl part of the body. Insert a tube with a hole in the bottom of the plastic bag, suck the air inside the plastic bag with a pump, vent it through a column filled with soda lime outside the sealed container, remove carbon dioxide, and recontain the air in the container It was fed in and circulated. The air in the sealed container is sucked from the gap between the plastic bags below the hypocotyl of Komatsuna in the carbonated section, and the air from which carbon dioxide has been removed is sent into the sealed container. Since carbon dioxide in the culture medium diffuses directly into the air through the nonporous hydrophilic film and is sucked at the same time, the diffusion of carbon dioxide into the air can be substantially prevented. In addition, a small electric fan is operated inside the sealed container so that the blower does not directly hit the plant body, the carbon dioxide concentration in the container is made uniform, and the carbon dioxide concentration in the container is almost 0 ppm (USA KANOMAX, Inc.) KANOMAX INDOOR GAS MONITOR MODEL2331 manufactured). Five days after the start of carbon dioxide treatment, the plant height and the fresh weight of the above-ground part were investigated.

  FIG. 2B shows a more specific structure of the culture apparatus used in the system shown in FIG. 2A. Hereinafter, the culture apparatus will be described. An acrylic plate having a thickness of 8 mm is cut into a rectangular shape having a length of 5 cm and a width of 23 cm, and a rectangular shape having a length of 3 cm and a width of 19 cm, which is 1 to 1.5 cm inside, is cut from the outer periphery. Cut an acrylic plate with a thickness of 8 mm into a rectangle with a length of 5 cm and a width of 25 cm, carve a groove (28) for embedding the O-ring (27) at a distance of 5 mm from the outer periphery, and culture medium near both ends of the inner part of the groove The bottom member B (25) is formed with two holes for taking in and out. A non-porous hydrophilic film (1) is sandwiched between the frame member A (24) and the bottom member B (25), and is bolted to the outer periphery every 2 cm, and the culture solution (gas dissolved water (3)) Sealed to prevent leakage. Using a unimol pump (manufactured by Nitto Kohki, Japan) from the tank containing the culture solution, the culture solution (3) is placed in the gap between the bottom member B (25) and the nonporous hydrophilic film (1). The culture medium (3) was circulated in the culture device by filling the bottom member B from one hole (22) opened, discharging from the other hole (23) and returning to the culture medium tank.

(Description of experimental results)
The experimental results are shown in FIGS.

  Two days after the start of low carbon dioxide treatment, in the control plot, the cotyledon died and the true leaf was also partially greened, and the plant body was wilted and laid down (B in FIG. 3). Furthermore, as a result of conducting a growth survey 5 days after the low carbon dioxide treatment, the carbonated water area exceeded the control area in both plant height and fresh weight (FIGS. 4A and 4B). In the carbonated water area, some cotyledons and wilt were observed in the cotyledons, but no degreasing, wilt and rooting were observed in the main leaves (A in FIG. 3).

  In this experiment, carbon dioxide deficiency was artificially generated, photooxidation damage was generated, and it was investigated whether carbon dioxide dissolved in the culture medium could be used for photosynthesis. If carbon dioxide in the culture medium can be used for photosynthesis, the occurrence of photooxidation damage should be reduced. After the experiment was completed, the carbon dioxide concentration was measured at a plurality of locations in the sealed container. From this, it is considered that photooxidation damage occurs due to carbon dioxide deficiency during light irradiation. In the control plot, photooxidation damage occurred, such as the cotyledon withered and the true leaf also turned green two days after the carbon dioxide deficiency treatment. In the carbonated water area, some cotyledon photooxidation damage occurred in the cotyledons, but almost no photooxidation damage occurred in the main leaves. It is considered that carbon dioxide dissolved in the culture broth permeated through the nonporous hydrophilic film and absorbed from the roots, and was used for photosynthesis, causing almost no photooxidation damage. Furthermore, in the carbonated water area, the plant height and fresh weight of the plant body exceeded that of the control area. From this, it is considered that the carbon dioxide dissolved in the culture broth permeates through the nonporous hydrophilic film and is absorbed from the roots and used for photosynthesis, thereby restoring the growth of the plant body. It was also proved that plant roots can be avoided from becoming deficient in oxygen deficiency even when cultured in a culture solution in which carbon dioxide is dissolved.

Example 2
In order to evaluate the difference in the rate of dissipation of carbon dioxide from carbonated water in the plant cultivation system of the present invention using a nonporous hydrophilic film and the conventional open hydroponic cultivation system in which plant roots are immersed in nutrient solution The experiment was conducted as follows.

  The experiment was performed in a culture chamber maintained at 25 ° C. As the nutrient solution, carbonated water obtained by dissolving carbon dioxide in the nutrient solution B used in Example 1 in the same manner as in Example 1 was used. This carbonated water was put in two containers each having a length of 20 cm, a width of 30 cm, and a depth of 6 cm so that the water depth was 4 cm. A nonporous hydrophilic film similar to that used in Example 1 was placed on the surface of one nutrient solution in two containers to obtain the system of the present invention (the other nonporous hydrophilic film). A container that does not use is equivalent to a conventional open hydroponics system.) Both containers were stirred at 180 rpm per minute using a 4 cm stirrer chip. After 1 hour, a portable carbon dioxide concentration meter CGP-1 manufactured by Toa DKK Corporation of Japan was used, and the carbon dioxide concentration in the nutrient solution was measured by the method described in the instruction manual for this concentration meter. The results are shown in Table 5.

  As is apparent from the above table, about 90% of the dissolved carbon dioxide is dissipated in one hour in the conventional open hydroponics system, whereas about 25% is dissipated in the system of the present invention. It can be seen that

  When a plant is cultivated using the plant cultivation system of the present invention, a sufficient amount of carbon dioxide, hydrogen, etc. can be efficiently and stably without causing an oxygen-deficient state of the root that causes rooting. Gas can be absorbed from the roots of the plant, thereby making it possible to significantly promote the growth of the plant continuously over a long period of time. Therefore, the plant cultivation system and the plant cultivation method using the same according to the present invention can be widely applied to agriculture, forestry, and horticulture in general, and crops such as cereals and vegetables, florets, fruit trees, and afforestation.・ Exhibits excellent effects in increasing yield, quality improvement, and large-scale clonal propagation by cuttings for tree planting.

The saddle type sectional view showing an example of the basic mode of the plant cultivation system of the present invention. 1 is a schematic diagram showing the entire experimental system employed in Example 1. FIG. 1 is a schematic diagram of a cultivation device included in an experimental system employed in Example 1. FIG. In Example 1, the photograph which shows the growth condition of the komatsuna 2 days after a low carbon dioxide process start. A is carbonated water zone, B is a control zone. In Example 1, the graph which shows the average value (n = 7) of the plant height of the komatsuna 5 days after a low carbon dioxide process start. (Error bars indicate standard deviation.) In Example 1, the graph which shows the average value (n = 7) of the raw weight of the above-ground part of a komatsuna 5 days after a low carbon dioxide process start. (Error bars indicate standard deviation.)

DESCRIPTION OF SYMBOLS 1 Nonporous hydrophilic film 2 Gas 3 Gas dissolved water 4 Feed pump 5 Water absorption material 6 which absorbs gas dissolved water 6 Plant 7 Root 8 Support for plant cultivation (soil)
9 Gas-dissolved water supply pipe 10 Fine spraying means 11 Water impermeable surface
12 Air discharge 13 Air flow 14 Air suction 15 Carbon dioxide removal column 16 Air pump 17 Fluorescent lamp 18 Pump 19 Carbon dioxide cylinder 20 Solution A
21 Solution B
22 Culture solution inlet hole 23 Culture solution outlet hole 24 Member A
25 Member B
26 Groove for root 27 O-ring 28 O-ring integrated with non-porous hydrophilic film

Claims (12)

Nonporous hydrophilic film for cultivating plants on it,
Gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film, and the gas A system for plant cultivation, comprising gas dissolved water holding means for holding dissolved water under the nonporous hydrophilic film.   The gas is at least one selected from the group consisting of carbon dioxide and hydrogen, and when carbon dioxide is dissolved in water, the amount of carbon dioxide dissolved in the gas-dissolved water is 50 ppm or more, and hydrogen The plant cultivation system according to claim 1, wherein when water is dissolved in water, the amount of hydrogen dissolved in the gas-dissolved water is 0.002 ppm or more.   The system for plant cultivation according to claim 1 or 2, wherein the gas-dissolved water further contains a fertilizer component.   The plant cultivation system according to any one of claims 1 to 3, wherein the pH of the gas-dissolved water is in the range of 4 to 8.   When the nonporous hydrophilic film is cultivated on the nonporous hydrophilic film of the plant cultivation system for 35 days, the nonporous hydrophilic film peels off from the root of the plant where the nonporous hydrophilic film is grown. The plant cultivation system according to claim 1, wherein the film has a peel strength of 10 g or more.   The gas-dissolved water holding means is a hydroponics aquarium, and the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film is accommodated in the hydroponics aquarium. The system for plant cultivation according to any one of claims 1 to 5.   The gas-dissolved water holding means has a water-impermeable surface, and the non-porous hydrophilic film is laid thereon, and the gas is interposed between the non-porous hydrophilic film and the gas-dissolved water holding means. The plant cultivation system according to any one of claims 1 to 5, further comprising gas dissolved water supply means for supplying the dissolved water continuously or intermittently.   The plant cultivation system according to claim 7, wherein the gas-dissolved water supply means is a drip irrigation tube installed between the nonporous hydrophilic film and the gas-dissolved water holding means. (1) a nonporous hydrophilic film for cultivating plants thereon,
Gas-dissolved water obtained by dissolving at least one gas that promotes plant growth in water, the gas-dissolved water disposed so as to contact the lower surface of the nonporous hydrophilic film, and the gas Providing a system for plant cultivation characterized by comprising gas-dissolved water retaining means for retaining dissolved water under the nonporous hydrophilic film;
(2) placing the plant on a non-porous hydrophilic film in the system; and (3) contacting the plant with the gas-dissolved water through the non-porous hydrophilic film. A plant cultivation method comprising cultivating a plant on a nonporous hydrophilic film.   The gas is at least one selected from the group consisting of carbon dioxide and hydrogen, and when carbon dioxide is dissolved in water, the amount of carbon dioxide dissolved in the gas-dissolved water is 50 ppm or more, and hydrogen The plant cultivation method according to claim 9, wherein when water is dissolved in water, the amount of hydrogen dissolved in the gas-dissolved water is 0.002 ppm or more.   As the gas-dissolved water, gas-dissolved water further containing a fertilizer component is used, whereby in the step (3), the plant roots are grown on the film and integrated with the film. The plant cultivation method according to claim 9 or 10.   The plant cultivation method according to any one of claims 9 to 11, wherein the pH of the gas-dissolved water is within a range of 4 to 8.

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