JP4456410B2 - Plant growth method - Google Patents

Description

  The present invention relates to a method for growing plants, and more specifically, it can promote the growth of plants while enhancing resistance to environmental stress, and can also promote the rooting of plant cuttings. It relates to a plant growing method.

The present inventors have already provided a plant with carbonated water in which carbon dioxide is dissolved at a high concentration to promote plant growth (see Patent Document 1), and the carbonated water is supplied to planted seedlings for environmental protection. A technique that enables planting in areas with severe stress (see Patent Document 2), and at least one type of dissolved water selected from the group consisting of carbonated water, bicarbonate ionized water, and carbonated ionized water for cuttings of plants A technology for supplying and promoting rooting of cuttings (see Patent Document 3) has been developed.
As a similar technique, a method for producing a carbon dioxide solution for plant growth and a device for supplying a carbon dioxide solution for plant growth (see Patent Documents 4 and 5) have been developed.

Carbonic acid (H ₂ CO ₃ ) produced by dissolving carbon dioxide in water exists only as an aqueous solution. The solubility of carbon dioxide in water depends on the partial pressure of carbon dioxide in the gas phase, and 0.52 ppm of carbon dioxide dissolves in water at atmospheric pressure. Carbonic acid in the aqueous solution is partly ionized to generate hydrogen ions and bicarbonate ions, and some of the bicarbonate ions generated here are further ionized into hydrogen ions and carbonate ions. Some carbonated water is typically acidic. The degree of acidity depends on the amount of dissolved carbon dioxide, and the hydrogen ion exponent (pH) of carbonated water decreases as the amount of dissolved carbon dioxide increases. By the way, when carbon dioxide is dissolved in 1 liter of pure water to a saturation concentration at 1 atm, the aqueous solution contains a maximum of 10 ^−3.91 mol hydrogen ions and 0.12 mM bicarbonate ions, and the pH is 3.91. It becomes.

Giving carbonated water obtained by forcibly dissolving carbon dioxide in water to plants is extremely effective in promoting plant growth, but as described above, carbon dioxide was dissolved at a high concentration. Since carbonated water inevitably has a low pH value, it is not preferable to give such carbonated water to a plant because it results in leaching of cations (NH ₄ ⁺ _, K ⁺ etc.) from the plant body.

On the other hand, in actual production situations such as agriculture and forestry, it is extremely rare to use pure water or ion-exchanged water as plant supply water. Usually, river water from the nearest river or tap water that has processed the river water is used. It is almost to use. The concentration of bicarbonate ions in rivers in each region is 51.7 mg / l (approximately 0.85 mM / L) in the world average, but in Japan it is generally excluding Okinawa on coral reefs. The national average is 31 mg / l (about 0.51 mM / L). When such water is used as raw water, and carbon dioxide is dissolved therein to form carbonated water, the pH of the carbonated water at the beginning of dissolution is not lowered to the extent that it adversely affects plants.
However, according to a recent study by the present inventors, the equilibrium relationship in which the carbonic acid in the liquid is ionized into hydrogen ions and bicarbonate ions proceeds in the reverse direction, and the neutralization reaction between hydrogen ions and bicarbonate ions causes This molecule is eventually released as carbon dioxide into the atmosphere. For this reason, if carbonated water is prepared in a closed tank and carbonated water is continuously prepared without adding (supplementing) fresh raw water, bicarbonate ions are consumed and the pH of the carbonated water gradually decreases. It has been found that when applied continuously, the plant is adversely affected.

Instead of using the carbonated water, carbon dioxide and exposed to a whole constant space, techniques and cuttings methods to promote the growth of plants by providing carbon dioxide concentrations high plant (see Patent Document 6) is "CO ₂ fertilization It has been put to practical use. It is known that when a plant is grown under such a gas environment, the growth proceeds rapidly at an early stage, but eventually the nitrogen concentration in the plant body decreases and the photosynthetic rate and the growth rate decrease. This phenomenon can also be explained by the acidification of the water in the plant body as described above. 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.
Japanese Patent Laid-Open No. 2003-111521 JP2003-325063 JP2003-339227 Japanese Patent No. 2847372 Japanese Patent No. 2847373 JP 2001-186814 A

Promoting plant growth, increasing plant tolerance to the environment, and promoting rooting of cuttings directly lead to industrial benefits, so plant growth is based on various growth environments. The development of a simple CO ₂ fertilization technique that promotes stable and sustainable at a very high level and further enables rooting from cuttings to be stably carried out with high efficiency is awaited. Provide a method for efficiently producing eucalyptus and acacia clonal seedlings planted in large areas, particularly for the purpose of promoting a stable supply of papermaking raw materials and large-scale fixation of carbon dioxide in the atmosphere. This is an issue.
The present invention has been made in view of the above circumstances, and is a technique that promotes the growth of plants more efficiently and stably than conventional techniques, a technique that enhances the resistance of plants to the environment, and an efficient and stable technique. A cutting technique that promotes rooting from cuttings is provided.

In order to solve the above problems, the present invention adopts the following configuration.
That is, the plant growing method according to the present invention is a plant growing method for supplying carbonated water obtained by forcibly dissolving carbon dioxide in water to the plant. Carbon dioxide content of carbonated water supplied to the plant The pH of the carbonated water is maintained in the range of 4 to 6.6 by adding bicarbonate or carbonate together with the content of 50 ppm or more.
The amount of carbonate or bicarbonate added to the carbonated water is selected such that the amount of bicarbonate ions in the carbonated water is in the range of 0.12-2.0 mM / L.
Plants cultivated by the method of the present invention include Eucalyptus spp. And Acacia spp., And for plant growth in the present invention, rooting of cuttings is used. Is included.

  According to the plant growing method of the present invention, compared to general agriculture and forestry using tap water, and a plant growing method and cutting method that give carbonated water in which carbon dioxide dissolved in a high concentration is disclosed to the plant. Thus, it is possible to further promote plant growth, increase the tolerance of the plant to the environment, and promote rooting of the cuttings.

Hereinafter, the best mode for carrying out the present invention will be described.
The present invention uses carbonated water in which carbon dioxide is dissolved at a high concentration. Here, carbonated water means water in which more than 0.52 mg of carbon dioxide per liter of water is dissolved at a partial pressure of carbon dioxide (350 ppm) in the atmosphere and a water temperature of 25 ° C. The carbon dioxide content of carbonated water used in the present invention is not particularly limited as long as it is 50 ppm or more, but carbon dioxide containing about 2800 ppm or more of carbon dioxide, which is the saturated solubility of carbon dioxide at 1 atm. The preferred carbon dioxide content is in the range of 50-2800 ppm because water is not economical because excess carbon dioxide escapes easily.

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.
The pH of carbonated water in which 50 ppm of carbon dioxide is dissolved is about 4.7, but the bicarbonate ion content of this 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.

In order to adjust the pH of carbonated water, any alkaline substance can be used. In the present invention, which aims to supply carbon dioxide to a plant, carbonate or bicarbonate is used as the alkaline substance. When an alkaline substance other than this is added to carbonated water, the dissolved carbonic acid is dissociated (ionized) and lost, so use of carbonate or bicarbonate is preferred. As the carbonate or bicarbonate, alkali metal salts or ammonium salts are suitable.
Methods (1) and (2) for obtaining carbonated water adjusted to pH using bicarbonate will be described below with numerical examples. Unless otherwise specified, the dissolved concentration of carbon dioxide referred to in the present invention The bicarbonate ion concentration means the amount of carbon dioxide dissolved in the aqueous solution having a liquid temperature of 25 ° C. and the bicarbonate ion concentration.

(1) When bicarbonate is added to water existing in the atmosphere, the pH gradually increases. When the amount of bicarbonate added is 1 mM / L, the pH becomes 8.27 and 2 mM. At / L, the pH is 8.57. When this water is used as raw water and carbon dioxide is dissolved to a saturated concentration under 1 atm, the pH drops to 4.82 and 5.11, respectively.
(2) When carbon dioxide is dissolved in water present in the atmosphere to a saturated concentration at 1 atm, the pH is 3.91 (bicarbonate ion concentration 0.12 mM / L). As bicarbonate is added to the pH, the pH will increase successively, reaching 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 method (1), carbonate can be used instead of bicarbonate, but the addition of carbonate increases the pH sharply compared to the addition of bicarbonate. Use is preferred. In the case of method (2), carbonate is used in place of bicarbonate, and this is added to carbonated water to increase the amount of bicarbonate ions in the liquid to 0.12 mM / L or more. However, the use of bicarbonate is preferred because carbonate increases the pH significantly with small additions.

In the present invention, the above-described method (1) and method (2) are combined, and the dissolution of carbon dioxide and the addition of bicarbonate are simultaneously advanced to dissolve the carbon dioxide in the raw water. 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 4-6.6.
Plants have different pH values for optimal growth depending on the type of the plant, but according to the present invention, carbonated water containing carbon dioxide at a high concentration can be supplied to the plant at a pH optimum for the plant to be grown. It is possible to maximize the effects of promoting plant growth and rooting promotion of cuttings. By the way, in many plants, it is important to suppress the passive change in intracellular pH caused by the difference in pH between inside and outside the cell, and to maintain the intracellular pH within a suitable range in order to advance the biochemical process. In addition, it is preferable that the difference in pH between the inside and outside of the cell is small because energy consumption required for transporting hydrogen ions is reduced. Usually, the optimal pH for plants to grow is said to be in the range of 4-7, and the optimal value differs for each plant, but in the present invention, by adjusting the amount of bicarbonate ions dissolved in carbonated water, The pH of the carbonated water can be arbitrarily adjusted within the range of 4 to 6.6.

In the present invention, "the carbonated water in which 50 ppm or more of carbon dioxide is dissolved and the pH is adjusted to a range of 4 to 6.6" has an effect on plant growth and cutting rooting as follows. Can be explained.
That is, it is the concentration of carbon dioxide and bicarbonate ions dissolved in water in the plant that controls the rate-limiting step of carbon dioxide fixation (photosynthesis, etc.) necessary for plant growth. Under the partial pressure of carbon dioxide at which 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 body is determined by the partial pressure of carbon dioxide, the pH of the water in the plant body, 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 the water in the plant grown in the atmosphere can be higher than that in a state where the plant is normally grown, Enzymatic reactions such as ribulose bisphosphate carboxylase and phosphoenolpyruvate carboxylase involved in carbon fixation can be activated. As a result, it is considered that plant growth promotion and rooting promotion are achieved.

Moreover, the environmental stress tolerance improvement effect | action of the plant which the above-mentioned carbonated water of this invention fulfills can be demonstrated as follows.
The first is mitigation of 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 plant grown in the atmosphere can be higher than that in a state where the plant is normally grown, even in environmental stress conditions such as strong light, drying, salinity excessive, for the same reason as the mechanism to actively uptake concentrated into a living body to inorganic carbon (carbon dioxide or bicarbonate ions) with the C ₄ plants and aquatic photosynthetic organisms, It is thought that the tolerance to environmental stress is increased by avoiding the carbon dioxide deficiency stress state.
Secondly, suppression of transpiration due to pore closure induced by high-concentration carbon dioxide can be mentioned. It is well known that when the partial pressure of carbon dioxide in the plant is increased, the pores are closed, but according to the present invention, this action reduces or avoids water loss caused by drying, high salt concentration, etc. Resistance to environmental stress is considered to increase.

Next, the manufacturing method of carbonated water is illustrated below. Any conventionally known method can be employed to dissolve 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, and filling carbon dioxide A method of introducing water into a tank, a method in which a soluble carbonate or bicarbonate is dissolved in water and then an acid is acted on, a hollow fiber comprising a microporous membrane or a nonporous gas permeable membrane By using a membrane module such as a membrane and supplying carbon dioxide, a method of dissolving in water on the opposite side of the membrane can be adopted.
Among these methods, a method of using a plant growing apparatus (see Patent Document 1) equipped with a membrane module is preferable in that a necessary amount of carbonated water having a desired concentration can be easily prepared.
In order to contain bicarbonate ions in water or carbonated water, a soluble carbonate or bicarbonate is added directly to water or carbonated water, or an aqueous solution of carbonate or bicarbonate is prepared in advance. The method of adding to water or carbonated water can be employed. Alternatively, any method can be employed, for example, water to which a strong basic compound such as sodium hydroxide is added or ammonia water is used as carbonated water.
Finally, the concentration of bicarbonate ions is in the range of 0.12-2.0 mM / L, the concentration of carbon dioxide is in the range of 50-2,815 ppm, and the pH is suitably adjusted as described above. It is important in the present invention that can be procured easily and quickly. For this purpose, it is preferable to link a carbon dioxide supply device or a feed pump for a basic compound solution such as bicarbonate with a carbon dioxide concentration meter or a pH meter.
In the carbonated water adjusted in pH used in the present invention, elements such as nitrogen, phosphoric acid, potassium, magnesium, calcium, and iron can be dissolved at a desired concentration as required.

A method of supplying the carbonated water of the present invention to a plant or a plant cutting head will be described.
As a first example, there is a method of spraying intermittently on the above-ground part of the plant body or the cutting head of the plant. Since the frequency of spraying differs depending on the type of plant and its growing environment, it cannot be specified unconditionally. For example, when the spraying time is about 15 seconds to 1 minute, the spraying frequency is 1/10 minutes to 1 You can choose from times / two days. As a second example, there is a method of irrigating the underground part of the plant body or the cutting head of the plant. The frequency of irrigation varies depending on the type of plant and its growing environment and cannot be specified unconditionally. For example, it can be selected within a range of several times a day to once a week.

In the present invention, the plants to be grown are not particularly limited, and all plants that are normally grown in the fields of agriculture, forestry, and horticulture can be targeted. Eucalyptus plants and Acacia plants, which have recently been encouraged to plant trees, are typical plants for breeding.
By the way, as Eucalyptus plants, tree species for papermaking (pulp), Eucalyptus camaldulensis (Eucalyptus camaldulensis), Eucalyptus grandis (E. grandis), Eucalyptus globulus (E. globulus), Eucalyptus night ten (E nitens), Eucalyptus tereticornis, Eucalyptus europhylla, etc., and hybrids with these as one parent, subspecies / variants, and landscaping / greening / decorative tree species Eucalyptus Gunnii, Eucalyptus Viminalis, etc. are included.

  In addition, as an Acacia genus plant, Acacia auriculiformis (Acacia auriculiformis), Acacia mangium (A. mangium), A. mearnsii (A. mearnsii), Acacia classical carpa (A. crassicarpa) , A. aulacocarpa, etc., and hybrids with these as one parent, subspecies / variant, and landscaping / greening / decorative tree species, A. baileyana, A. dealbata ) Etc. are included.

Experimental example 1
The following seven types of hydroponics A to G were prepared.
Hydroponic solution A : Tap water containing 38 mg / L (about 0.62 mM / L) of bicarbonate ion (pH measured value: 7.70) is used as raw water, and 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 μM / L, manganese sulfate 8 .3 μM / L, zinc sulfate 1.4 μM / L, potassium iodide 0.9 μM / L, disodium molybdate 0.2 μM / L, copper sulfate 0.02 μM / L, cobalt chloride 0.02 μM / L A hydroponic solution A was obtained. The pH of the hydroponics A was 7.32.
Hydroponic solution B : An aqueous solution in which 1000 ppm of carbon dioxide was dissolved once every two days with respect to the hydroponic solution A was designated as hydroponic solution B. The pH of the hydroponics B immediately after dissolving the carbon dioxide dropped to 4.72.
Hydroponic solution C : Instead of potassium sulfate 4 mM / L of hydroponic solution A, 0.25 mM / L of potassium bicarbonate and 3.875 mM / L of potassium sulfate were used. Aqueous solution C was dissolved in 1000 ppm.
Hydroponic solution D : Instead of potassium sulfate 4 mM / L in hydroponic solution A, 0.5 mM / L potassium bicarbonate and 3.75 mM potassium sulfate are used, and carbon dioxide is emitted once every two days. An aqueous solution in which 1000 ppm was dissolved was designated as hydroponic solution D.
Hydroponic liquid E : Instead of 4 mM / L of potassium sulfate in hydroponic liquid A, 1.0 mM / L of potassium bicarbonate and 3.5 mM / L of potassium sulfate are used, and carbon dioxide is emitted once every two days. 1000 ppm was dissolved and the aqueous solution was designated as hydroponic solution E.
Hydroponic fluid F : Instead of potassium sulfate 4 mM / L in hydroponic fluid A, use potassium bicarbonate 2.0 mM / L and potassium sulfate 3.0 mM / L, and carbon dioxide once every two days. 1000 ppm was dissolved, and the aqueous solution was designated as hydroponic solution F.
Hydroponic solution G : Instead of 4 mM / L of potassium sulfate in hydroponic solution A, 4.0 mM / L of potassium bicarbonate and 2.0 mM / L of potassium sulfate are used, and carbon dioxide is emitted once every two days. 1000 ppm was dissolved and the aqueous solution was used as hydroponic solution G.

Using the experimental system outlined in FIG. 1, using each of the above-mentioned hydroponic fluids A to G as circulating experimental water, and selecting Eucalyptus globulus cuttings as experimental plants and growing them for 7 weeks . The hydroponic solution was put in a container and circulated while constantly ventilating with an air pump. Hydroponic liquids A to G were each replaced after the first week, and thereafter replaced with freshly prepared hydroponic liquids A to G before becoming pH 4 or lower.
The pH of each hydroponic solution before dissolving carbon dioxide, the pH of each hydroponic solution after dissolution, and the pH and bicarbonate ion concentration of each hydroponic solution after growing the experimental plant for one week were measured. The results are shown in Table 1.

When 1000 ppm of carbon dioxide was dissolved in raw water (pH 7.32 to 8.35) containing 0.62 to 4.62 mM / L bicarbonate ion, the pH of the water became 4.72 to 5.59, which is an experimental plant. The pH of the water after 1 week of cultivation was 3.98-8.29. At that time, the bicarbonate ion concentration contained in the water was 0.08 mM / L or less in the hydroponics B, and the pH was 4 or less, making it unsuitable for growing experimental plants. However, hydroponic liquids C to F to which potassium bicarbonate is added so that the concentration of bicarbonate ions in the liquid is in the range of 0.87 to 2.62 mM / L are liquid even after one week of growth. The bicarbonate ion concentration in the solution was 0.19 to 1.00 mM / L, and the pH was within the range of 4 to 6.6, maintaining conditions suitable for growing experimental plants.
Even in the case of hydroponic solution B, conditions suitable for growing experimental plants can be maintained by replacing with freshly prepared hydroponic solution B within one week when bicarbonate ions are 0.12 mM / L or less. . In the case of hydroponic solution G, some of the leaves of the experimental plant turned yellow after one week of growth. This is because the pH of the hydroponics G after one week of cultivation is too high, such as 8 or higher, but even in such hydroponics, the bicarbonate ion is 2.0 mM / L or less and the pH is 4 to 6.6. If high-concentration carbon dioxide is dissolved so as to be in the range, a hydroponic solution suitable for growing experimental plants can be obtained.

Experimental example 2
Seed height, leaf size (vertical x horizontal), SPAD value, and 7 weeks after growth of experimental plants (4 clone seedlings each) grown for 4 weeks using each of the above-mentioned hydroponics A to G The dry weight of the experimental plants was measured. The results are shown in Table 2. The numbers in parentheses in the table are the data at the beginning of the experiment.

The total dry weight of experimental plants grown in hydroponic broth B to G after 7 weeks was in the range of 7.38 to 8.39 g / plant, and was grown in hydroponic broth A in which carbon dioxide was not dissolved It can be seen that the growth is promoted compared to 7.14 g / plant, which is the total dry weight of the plant after 7 weeks. In particular, the root weight increase was remarkable.
However, the total dry weight after 7 weeks of the experimental plant grown in hydroponic solution B (which is equivalent to carbonated water of the prior art because carbon dioxide is dissolved once every two days) There was no significant difference from the total dry weight of hydroponic solution A in which carbon dioxide was not dissolved, and the dry weight of stem was rather small. The seedling height, leaf size, and SPAD value are all smaller than those of hydroponics solution A, and the carbonated water in which carbon dioxide is dissolved at a high concentration according to the conventional technology does not necessarily promote the growth of plants in all parts. It turns out that it does not become the result.
In contrast, when grown in hydroponic solution C to G to which potassium bicarbonate was added so that the concentration of bicarbonate ions was 0.87 mM / L or more, the dry matter 7 weeks after the experimental plant All the weight is much higher than that of hydroponic liquid A. However, the seedling height does not change so much, and the leaf size / SPAD value is smaller than that of the hydroponic liquid A. In particular, in the experimental plants grown with hydroponic solution G, some of the leaves turned yellow, and the SPAD value, which is an index value of the chlorophyll concentration in the leaves, was also extremely small. From this, when the bicarbonate ion concentration continues to be 2.0 mM / L or more, the pH value increases excessively except when carbon dioxide is dissolved at a high concentration, and trace elements such as iron ions It became clear that deficiency became severe and became unsuitable for plant growth.

Experimental example 3
Photosynthetic rate of experimental plants (three clone seedlings each) grown for 6 weeks using each of the above-mentioned hydroponics A, B, D, F, transpiration rate after dark adaptation (dark treatment for 30-40 minutes), The transpiration rate and conductance after light saturation (350 ppm carbon dioxide, 1,500 μmol photon m ⁻² s ⁻¹ ) were measured. Moreover, in order to investigate the influence when an experimental plant receives environmental stress (light inhibition), after being adapted for 12-14 hours under weak light while immersing the root of the plant in a 200 mM / L solution of sodium chloride, The measurement was carried out in the same manner as above by leaving it to stand for 6 hours under light irradiation of 400 μmol photon m ² s ⁻¹ . The results are shown in Table 3.

  The transpiration rate and conductance of the experimental plants that were grown for 6 weeks in hydroponic broth B, D, and F in which carbon dioxide was dissolved once every two days and were not subjected to environmental stress (before light inhibition) Smaller than that of the experimental plant grown in the cultivation liquid A. This tendency was the same after applying environmental stress (after light inhibition). In particular, the photosynthetic rate of the experimental plants grown in hydroponic fluid D was reduced and avoided by the experimental plants, and resistance to environmental stress was improved.

The cutting target adjusted from the Eucalyptus globulus harvesting mother tree was inserted into red jade soil as a growing target, and the growing target plant was housed in the greenhouse of the experimental system schematically shown in FIG. Then, the following water spray was sprayed from the ceiling of the greenhouse so that the irrigation amount per day was 1 to ² mm / cm ² .
Water sprinkling liquid a : Carbon dioxide was dissolved in tap water containing 0.62 mM / L of bicarbonate ions and a membrane module was installed to form carbonated water, which was stored in a treated water tank. Moreover, about 30 ml of ammonium bicarbonate solution (concentration 100 mM / L) per 6 L of carbonated water supplied to the treatment tank was sent from the chemical solution tank to the treatment water tank and added to the carbonated water. Further, the circulation pump was operated for 2 minutes every hour to circulate the liquid in the treated water tank to the carbon dioxide inhaler, and carbon dioxide was infused into the liquid. As a result, carbon dioxide was dissolved above the saturation concentration under atmospheric pressure (1500 ppm), and a water spray a containing bicarbonate ions in the range of 0.5 to 1.2 mM / L could be prepared. .
Watering solution b: Except for not adding ammonium bicarbonate solution (concentration 100 mM / L), and the watering solution a similar carbonated water and watering solution b. Since the water spray b does not contain bicarbonate, it corresponds to carbonated water of the prior art.
Water spray c : Tap water itself containing bicarbonate ion of 0.62 mM / L was used as water spray c.

  Each of the above-mentioned water sprays a to c was sprinkled on a growing object under different watering conditions to grow it, and the rooting rate after 8 weeks was investigated. The results are shown in Table 4. The rooting rate indicates the number of cuttings rooted per 12 cuttings of each experiment as a percentage.

  When the above-mentioned cuttings are grown using watering solution a in which carbon dioxide is dissolved to a saturated concentration or higher under atmospheric pressure where a plant is grown and further contains bicarbonate ions, the rooting rate is 58%. On the other hand, the rooting rate when using ordinary tap water (water spray c) in which carbon dioxide is not dissolved at a saturation concentration or higher under atmospheric pressure is only 8 to 25%. Moreover, the rooting rate at the time of using the carbonated water (sprinkling liquid b) of a prior art is 33 to 42%. From this, it can be seen that for the growth of plants including the rooting of cuttings, carbon dioxide dissolved at a high concentration and containing an appropriate amount of bicarbonate ions is effective.

  The present invention can be widely applied to agriculture, forestry, and horticulture in general. Yield increase, quality improvement, mass cutting by cuttings, crops such as cereals and vegetables, flowering plants, fruit trees, tree planting and tree planting. Excellent effect on clonal propagation.

Schematic diagram of the experimental system adopted in the experimental example. The schematic diagram of the experimental system employ | adopted in the Example.

Claims (2)

  In the plant growth method for supplying carbonated water obtained by forcibly dissolving carbon dioxide to a plant, the carbon dioxide content of the carbonated water supplied to the plant is 50 ppm or more, and bicarbonate ions in the liquid A plant growth method comprising adjusting the pH of the carbonated water to a range of 4 to 6.6 by adding bicarbonate so that the concentration is 0.87 to 2.62 mM / L.   The method according to claim 1, wherein the plant to be grown is a plant selected from the group consisting of Eucalyptus spp. And Acacia spp.

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