Growth activation liquid for plant seedling cultivation

Abstract

To provide plant growth activating liquid usable in plant seedling cultivation and eliminating the need of use of an agent such as an antiseptic due to ion liquid which is applicable instead of an antiseptic required in plant seedling rearing, and is mixed with a silver ion at a concentration in a concentration range of not completely eliminating nursery bed microorganisms and microorganisms endosymbiotic with plants, at which sound growth promotion of plant seedlings becomes possible.SOLUTION: Sound growth of seedlings is accelerated, and resistance force against plant pathogenic microorganisms bringing disease damages to plant young seedlings is imparted by providing as growth activating liquid to be used in plant seedling rearing cultivation, an aqueous solution which contains a silver ion at concentration of 0.0005 mg / L or more and 0.025 mg / L or less as concentration of a silver ion not completely eliminating symbiotic microorganisms, a free halogen and a combined residual halogen compound at concentration of 4.0 μmol / L or less, and a halide ion at concentration of 3.0 mmol / L or less.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a solution-like plant growth environment improving agent for supplying a cultivated plant body and / or a soil and / or a hydroponic solution with silver ions at a concentration that only incompletely eliminates plant-growing soil microorganisms, plant-growing nutrient solution microorganisms, and attached symbiotic microorganisms or endosymbiotic microorganisms of plants. [Background technology]

[0002] Silver ions are used as antibacterial agents, disinfectants, and sanitizers for pathogenic microorganisms such as viruses and bacteria, and have been effectively applied to products and methods that have the desired effects. Therefore, silver ions have been used as a material to prevent and inhibit the occurrence of microbial diseases mainly in the fields of health and hygiene, medicine, and the food industry.

[0003] The present applicant and the present inventor discovered that an aqueous solution containing a low concentration of silver ions, which can only partially eliminate plant cultivation soil microorganisms, plant cultivation nutrient solution microorganisms, and attached symbiotic microorganisms and / or endosymbiotic microorganisms of plants, has a remarkable effect in improving the plant cultivation environment, and thus arrived at the present invention.

[0004] Plants grown in soil or hydroponic culture cannot live in a completely sterile environment (microorganism-free) except in very special environments, and in many cases they grow in symbiosis with microorganisms such as bacteria, archaea, and fungi. In some cases, the symbiosis between these microorganisms and plants is simply a shared habitat, but in many cases, a commensal or mutualistic symbiotic relationship is formed. In commensal relationships, microorganisms may be pathogenic to plants, but while commensal and mutualistic relationships that are not like this are commonly seen, commensal cases in which pathogenicity is observed are very rare. Therefore, many microorganisms that live in soil and water environments are harmless to plant growth, or rather play a role in promoting plant growth.

[0005] Antibacterial agents and disinfectants for pathogenic microorganisms such as viruses and bacteria that contain a certain concentration or more are effectively used to prevent the occurrence of microbial infections by eliminating microorganisms, and have come to form important application technical fields of silver ions in the fields of health and hygiene, medicine, the food industry, etc. However, in industrial fields such as agriculture, forestry, and horticulture where the cultivation of plants is essential, it is necessary to maintain the symbiotic relationship between the aforementioned microorganisms and plants, and therefore the bacteriostatic and disinfectant properties of high concentrations of silver ions above a certain concentration that eliminate almost all microorganisms often have the opposite effect.

[0006] The product and its application technology of the present invention were discovered through the results of a study conducted to determine the minimum concentration of silver ions effective as an antibacterial and disinfectant agent. When the test bacteria were exposed to a solution with a silver ion (Ag+) concentration of 0.060 mg / L or more diluted with dechlorinated water for 30 minutes and then applied to an NB agar plate medium to measure the number of surviving bacteria, all of the test bacteria of the genus Pseudomonas, Escherichia, and Bacillus lost their growth activity, and the silver ion water of this concentration showed a complete disinfecting effect. The test bacteria exposed to a solution with a silver ion (Ag+) concentration of 0.030 mg / L to 0.050 mg / L diluted with dechlorinated water for 30 minutes lost their growth activity in almost proportion to the silver ion concentration in this range, although this differed depending on the three types of test bacteria used, and the average inactivation rate was 47 to 69%. Next, the silver ion concentration was reduced to below 0.025 mg / L and the samples were exposed to the same solution to examine the disinfection effect. The average inactivation rate of all three types of test bacteria was 22% or less (survival rate of 78% or more).

[0007] Furthermore, Komatsuna was sown on agar medium for germination prepared using water containing 0.025mg / L or less of silver ions, and germination and rooting tests were carried out with varying silver ion concentrations. The germination and rooting tests were carried out in an artificial climate chamber set at 22℃, with one cycle of 12 hours of 2500lx white fluorescent light (light condition) and 12 hours of no fluorescent light (dark condition). The average stalk length 5 days after sowing when the silver ion concentration added to the agar medium was 0.025mg / L was 1.18 times and 1.13 times, respectively, compared to when the silver ion concentration was 0.040mg / L and 0.030mg / L. On the other hand, when the root length of seedlings in agar culture medium was compared under the same conditions, the average root length of seedlings 5 ​​days after sowing when the silver ion concentration was 0.025mg / L was 1.52 times and 1.32 times, respectively, compared to when the silver ion concentration was 0.040mg / L and 0.030mg / L, indicating that the root elongation rate of seedlings is particularly rapid when the silver ion concentration is 0.025mg / L or less. No significant differences were observed in the germination rate of Komatsuna among the three levels of added silver ion concentrations.

[0008] The promotion effect of a low concentration of silver ions of 0.025 mg / L on the growth of Komatsuna seedlings was observed to be almost the same even when the silver ion concentration of the agar culture medium was further reduced under the same temperature and light irradiation conditions, down to a silver ion concentration of 0.0002 mg / L. However, the average stalk length and average root length of seedlings 5 ​​days after sowing when the silver ion concentration was 0.0001 mg / L were 1.0 times and 1.06 times, respectively, compared to the average stalk length and average root length of seedlings when the silver ion concentration was 0.030 mg / L, and there was no significant difference. Furthermore, when the silver ion concentration was reduced to 0.00005 mg / L by dilution with dechlorinated water, the average stalk length and average root length of seedlings 5 ​​days after sowing were not significantly different from the average stalk length and average root length of seedlings when the silver ion concentration was 0.030 mg / L.

[0009] However, this silver ion below 0.025mg / L is difficult to store at a constant concentration for more than 4 months.Therefore, in the present invention, in order to store silver ion water for a long period of time at a stable concentration, the silver ion storage stock solution is prepared as a high-concentration aqueous solution with a silver ion concentration of 8mg / L or more, and this is diluted with dehalogenated water just before being used as a plant growth environment improving agent, and the low-concentration silver ion water below 0.025mg / L or above 0.0002mg / L is used as the growth activation solution for plants with roots, thus solving this problem.

[0010] The agar medium used in the germination and rooting test of Komatsuna was prepared using purified water, but when the agar medium for germination was prepared using tap water after chlorine disinfection treatment containing chloramine, which is 5.0 μmol / L of residual combined chlorine, or a silver ion aqueous solution containing 5.0 mmol / L of sodium chloride or sodium bromide, and the growth test of Komatsuna was performed under the same artificial weather machine conditions, the plant growth promotion effect of silver ions was not observed when the concentration of silver ions was 0.010 mg / L, unlike the results using the silver ion-added agar medium prepared with purified water. From this result, it was presumed that the free chlorine and residual combined chlorine and halide ions such as chlorine and bromine contained in the tap water inhibited the expression of the plant growth promotion effect of low concentration silver ions. In order to eliminate this inhibition, sodium thiosulfate was added to the halogen-containing agar culture medium preparation water, and agar culture medium was prepared using tap water (chloride ion concentration 15 mg / L) after dehalogenation treatment, and a komatsuna germination and root formation test was performed.

[0011] In this dehalogenation operation, the concentration of sodium thiosulfate was changed, and the concentration of the remaining halogen ions and halogen compounds was measured each time. Then, an agar culture medium for the germination and rooting test of Komatsuna was prepared and the germination and rooting test was performed. The test results showed that by performing dehalogenation so that the concentration of the remaining chloramine was 4.0 μmol / L or less, the halogen inhibition of the growth promotion of Komatsuna caused by the low concentration silver ions of 0.010 mg / L or less can be eliminated.

[0012] Next, a low-concentration silver ion solution of 0.010 mg / L was prepared using tap water that had been dehalogenated so that the concentration of free halogen and combined residual halogen compounds was 1.0 μmol / L or less, and sodium chloride or bromide ions were added so that the chloride ion concentration was 17.7 mg / L to 249 mg / L, and this was used to prepare an agar culture medium for the germination and rooting test of Japanese mustard spinach, and a germination and rooting test was performed. From the test results, it was found that by using a silver ion solution with a chloride ion or bromide ion concentration of 3.0 mmol / L or less, the halogen inhibition of the low-concentration silver ion of 0.010 mg / L or less against the growth promotion of Japanese mustard spinach could be eliminated.

[0013] It is known that in the use of silver ions (Ag+) in the environment, the silver ions can no longer maintain their ionic state when they come into contact with reducing compounds or when they form insoluble salts. In the present invention, it is predicted that the silver ions will lose their growth-promoting effect on plants when they come into contact with reducing compounds present in the soil for plant cultivation or the plant cultivation solution, changing from an ionic state to a non-ionic state. In order to prevent such loss of the growth-promoting effect of silver ions, it is necessary to re-oxidize silver that has lost its cationic character by reduction and return it to silver ions (Ag+). Therefore, in the present invention, a photooxidation catalyst was added to a low-concentration silver ion aqueous solution with a concentration of 0.010 mg / L or less at a concentration 8 times the silver ion concentration by weight, and a test was conducted to see if the growth-promoting effect of silver ions could be restored.

[0014] First, the solution was diluted with dechlorinated water that had been aerated with argon gas to a low silver ion concentration of 0.010 mg / L, and dithiothreitol was added to the solution to a concentration of 0.10 mg / L. The solution was then sealed with a butyl rubber stopper and reacted for 30 minutes to reduce the silver ions. The resulting solution was then used to prepare an agar medium for germination. Komatsuna was then seeded on the agar medium, and germination and rooting tests were carried out in an artificial climate chamber set at 22°C under a cycle of 13 hours of 2500 lx white fluorescent light irradiation (light condition) and 11 hours of no fluorescent light irradiation (dark condition). As a result, there was almost no change in the germination rate compared to the results of the control test in which dithiothreitol was not added, but the average seedling stem length on the 3rd and 5th days after sowing was 1.03 times and 0.98 times, respectively. Regarding seedling root length, the average seedling root length on the 3rd and 5th days after sowing was 0.99 and 1.02 times, respectively, compared to the results of the control test in which dithiothreitol was not added. When 0.10 mg / L dithiothreitol was added, no effect of the low concentration of silver ions (0.010 mg / L) on promoting root elongation of komatsuna seedlings was observed.

[0015] Next, agar medium for germination was prepared by adding 0.20mg / L titanium dioxide nanoparticles with an average primary particle size of 25 nm as a photooxidation catalyst to a reaction solution of 0.025mg / L silver ions and 0.25mg / L dithiothreitol, which was prepared using deoxygenated water and dechlorinated water. Using this medium, germination and rooting tests of Komatsuna were carried out under conditions of 13 hours of fluorescent light irradiation and 11 hours of non-fluorescent light irradiation in an artificial weather chamber set at 22℃ with 2400lx white fluorescent light irradiation. As a result, almost no change in germination rate was observed compared to the results of the control test without adding 0.20mg / L titanium dioxide, but the average seedling stem length 5 days after sowing was 1.39 times that of the control test without adding titanium dioxide. The average seedling root length 5 days after sowing was 1.54 times that of the control test without adding titanium dioxide, and the high growth promotion effect of 0.025mg / L silver ions was confirmed to be restored. These results suggest that titanium dioxide nanoparticles functioned as a photooxidation catalyst, oxidizing metallic silver produced by reduction with dithiothreitol under light irradiation conditions, thereby regenerating silver ions (Ag+) and restoring the growth-promoting effect of low-concentration silver ions on plants.

[0016] In the above test, the amount of titanium dioxide nanoparticles added was changed and the germination and rooting test of Komatsuna was performed without changing other conditions. When titanium dioxide was added at a concentration below 0.001 mg / L, the growth promotion effect of Komatsuna by adding 0.025 mg / L of silver ions was almost not observed. In order to oxidize the reducing compound dithiothreitol and silver to regenerate silver ions (Ag+), it was thought that the amount of titanium dioxide added must be at least 0.001 mg / L. In order to achieve the effect of regenerating silver ions by titanium dioxide, it was thought that the amount of titanium dioxide added must be at least 0.001 mg / L. On the other hand, when titanium dioxide exceeding 20 mg / L was added, the growth promotion effect of silver ions on Komatsuna was reduced, and it was known that adding titanium dioxide at a concentration exceeding 20 mg / L has a negative effect on the growth of Komatsuna seedlings due to excessive progress of photooxidation reactions.

[0017] Next, instead of titanium dioxide nanoparticles, tungsten trioxide-palladium alloy nanoparticles and tungsten trioxide-copper alloy nanoparticles with an average primary particle size of 400 nm or less were used to carry out germination and rooting tests of Komatsuna plants under exactly the same conditions as those for titanium dioxide, with 13 hours of 2500 lx white fluorescent light irradiation (light condition) and 11 hours of fluorescent light non-irradiation (dark condition) and at 22°C. Almost the same results were obtained for the growth promotion effect of Komatsuna plants. Furthermore, the concentration range in which these alloy nanoparticles have a growth promotion effect was the same as that of titanium dioxide. From these results, it was considered that tungsten trioxide-palladium alloy particles and tungsten trioxide-copper alloy particles act as photooxidation catalysts in the same manner as titanium dioxide when added at the same concentration, and can function as oxidation catalysts for the reionization of reduced silver. Therefore, it was considered that tungsten trioxide-palladium alloy nanoparticles or tungsten trioxide-copper alloy nanoparticles having a photocatalytic function could be used as an alternative material to titanium dioxide nanoparticles for promoting plant growth using silver ions according to the present invention. [Prior art documents] [Patent documents]

[0018] [Patent Document 1] Patent Publication No. 63-060904 [Patent Document 2] Patent Publication No. 63-060905 [Patent Document 3] Patent Publication No. 2001-010913 [Patent Document 4] Patent Publication No. 2006-141252 Summary of the Invention [Problem to be solved by the invention]

[0019] The problem to be solved by the present invention is to enable the reduction of the amount of disinfectant used, which has been necessary so far, to prevent the occurrence of plant diseases in plant cultivation, or to enable the elimination of the use of disinfectants. In addition, the problem to be solved is to enable the prevention of the new emergence of disinfectant-resistant plant pathogenic microorganisms caused by the continued use of disinfectants. Furthermore, the problem to be solved is to convert industries based on plant cultivation, such as agriculture, forestry, horticulture, and green space development, into more environmentally friendly industries by reducing or eliminating the use of insecticides in plant cultivation. [Means for solving the problem]

[0020] In order to solve the above problems, the present invention does not rely entirely on the use of pest control agents such as disinfectants and insecticides in plant cultivation, but instead aims to reduce or eliminate the use of disinfectants and insecticides in plant cultivation by enhancing the resistance and immunity that plants naturally possess against pathogenic microorganisms and feeding damage by insects, etc. In order to realize this basic means, it is considered important to maximize the nutrient intake and growth abilities of plants. The expression of these abilities is considered to activate healthy growth in cultivated plants, which in turn gives them immunity and resistance to plant pathogenic microorganisms and resistance to feeding damage by insects, etc.

[0021] In order to maximize a plant's inherent ability to take up nutrients and grow, it is necessary to promote vigorous and healthy growth during the seedling stage after germination and rooting, and during the growth stage of the plant root (roots and rhizomes) and shoot (stems and leaves, etc.). During the seedling stage, the plant roots in particular need to take in nutrients and absorb water, so vigorous growth of the plant root is important for acquiring resistance to plant diseases. The present inventors have invented a plant growth activation liquid containing a low concentration of silver ions, an actual use concentration of 0.025 mg / L or less, which can only partially eliminate attached symbiotic microorganisms and / or endosymbiotic microorganisms of plants, as described in claim 1 of the invention.

[0022] According to the prior art, the effect of silver ions on the elongation of plant roots has been considered ineffective at low concentrations of 0.03 mg / L (= 30 ppb) or less. However, in the present invention, it has been found that the phenomenon of loss of the effect of silver ions on root elongation at such low concentrations is due to the interfering effect of halogen compounds and / or halide ions present in the cultivation soil or cultivation water. As a result, it has been found that such interference with the effect of silver ions on the elongation of plant roots can be solved by using water that has been dehalogenated so that the concentration of free halogen and combined residual halogen compounds in the water used to prepare the silver ion solution is 4.0 μmol / L or less, and the concentration of halide ions such as chloride ions and bromide ions is 3.0 mmol / L or less.

[0023] In the conventional method, it was technically difficult to store a silver ion aqueous solution at a stable concentration for more than one week when the silver ion concentration was 0.03 mg / L or less. However, in the present invention, it was known that the silver ion concentration can be stably maintained for a long period of time by preparing a silver ion preservation solution with a silver ion concentration of 8 mg / L or more, so a method was adopted in which the preservation solution is diluted just before practical use to make a low-concentration silver ion water of 0.025 mg / L or less, and used for revitalizing plant growth.

[0024] Low-concentration silver ions of 0.025 mg / L or less are thought to promote the growth of plant roots, thereby enabling cultivated plants to absorb more nutrients from the cultivation soil or nutrient solution, resulting in vigorous growth of the above-ground parts of cultivated plants, as well as increasing resistance to infection by pathogenic microorganisms and damage caused by insects, etc. In addition, such low-concentration silver ions do not suppress or eliminate microorganisms living inside plants (endophytes), and therefore do not disrupt the favorable symbiotic relationship between plants and microorganisms. Effect of the Invention

[0025] As a plant growth activator for cultivating plant seedlings, water that does not contain free halogen molecules, halogen acid compounds, halo acid compounds, hypohalous acid compounds, chloramines, bromoamines, and other halogen compounds at a concentration of more than 4.0 μmol / L, and water that does not contain halide ions such as chloride ions and bromide ions at a concentration of 3.0 mmol / L or more, and a low concentration of silver ions of 0.0005 mg / L to 0.025 mg / L are dissolved and used to promote the elongation of the seedling stem and root after germination and rooting of the plant. In particular, since the vigorous elongation of the plant root part, which is the effect of the present invention, can be induced, there is an advantage that the intake of nutrients and absorption of water by the plant seedling can be vigorous. As a result, the effect of enhancing the immunity to plant diseases and the resistance of the plant itself to feeding damage by insects and the like is created.

[0026] In addition to promoting the growth of plant roots and shoots with low-concentration silver ions of 0.0005 mg / L to 0.025 mg / L, the use of a plant growth activation solution containing zinc ions at a practical use concentration of 0.0001 mg / L to 2.0 mg / L can enhance the growth activity of endosymbiotic microorganisms in plants. This is because low-concentration silver ions of 0.0005 mg / L to 0.025 mg / L have almost no effect on the growth activity of soil microorganisms, nutrient solution microorganisms, and endosymbiotic microorganisms in plants, and the effect of promoting the growth activity of microorganisms, particularly endosymbiotic microorganisms in plants, with zinc ions of 0.0001 mg / L to 2.0 mg / L can be fully exerted, independent of the presence of silver ions. The increased growth of endosymbiotic microorganisms has the advantage of further activating the growth of plant seedlings.

[0027] Similarly, the addition of magnesium ions at a practical concentration of 0.005 mg / L to 5.0 mg / L to an aqueous solution containing a low concentration of silver ions at 0.0001 mg / L to 2.0 mg / L also has a significant effect on promoting the proliferation activity of plant endosymbiotic microorganisms, just like the addition of zinc ions. The difference with the addition of zinc ions is that magnesium ions at a practical concentration of 0.005 mg / L to 5.0 mg / L not only promote the proliferation activity of plant endosymbiotic microorganisms, but also promote the root elongation of plant seedlings, although not as much as silver ions. Due to this feature, magnesium ions have the advantage of being able to directly exert a synergistic effect on plant growth activation when used in combination with silver ions.

[0028] It has been known that low concentrations of silver ions of 0.0005 mg / L or more and 0.025 mg / L or less are effective in elongating plant roots and shoots, but in environments where there are many reducing substances in the soil or nutrient solution where plants grow, the effect of the low concentrations of silver ions gradually disappears. In order to solve this problem, by adding fine titanium dioxide, tungsten trioxide-palladium alloy particles, or tungsten trioxide-copper alloy particles with an average primary particle size of 400 nm or less, which is a photooxidation catalyst, at a practical concentration of 0.001 mg / L or more and 20 mg / L or less to a low concentration silver ion aqueous solution of 0.0005 mg / L or more and 0.025 mg / L or less, it is possible to continuously obtain the effect of the added silver ions by regenerating the silver ions reduced by reacting with the reducing substances back to silver ions.

[0029] As described above, by providing plants with low concentrations of silver ions between 0.0005 mg / L and 0.025 mg / L, healthy plant growth is possible. This brings out the plants' inherent immunity against pathogenic microorganisms and resistance against damage caused by insects, and has the advantage of making plant cultivation safer and more secure, and even more environmentally friendly, without the use of pesticides such as disinfectants and insecticides that were previously necessary to prevent disease and damage to cultivated plants, or by minimizing the use of such pesticides. As a result, it enables the sustainable development of industries that are based on plant cultivation, such as agriculture, forestry, horticulture, and green space development.

[0030] In the present invention, a solution containing low-concentration silver ions at a concentration of 0.0005 mg / L or more and 0.025 mg / L or less and not containing halide ions at 3.0 mmol / L or more is mixed with titanium dioxide particles, tungsten trioxide-palladium alloy particles, or tungsten trioxide-copper alloy particles having an average primary particle size of 400 nm or less as a photooxidation catalyst at an actual use concentration of 0.001 mg / L or more and 20 mg / L or less, as necessary, for practical use. However, storing such a low-concentration silver ion solution for practical use after preparation is not only difficult because it is difficult to stably contain low-concentration silver ions for a long period of time, but also requires containers for preparing and storing a large amount of solution on the scale of several tons, as shown in the examples, as well as transportation costs to the storage site and the use site.

[0031] In order to avoid these needs, in the present invention, the concentration of each of these metal ions and the concentration of the photooxidation catalyst are prepared and stored as a dilution stock solution containing a concentration 100 to 10,000 times higher than the actual use concentration. When using after preparation and storage, it is advantageous to dilute them 100 to 10,000 times with agricultural water such as tap water and / or river water and / or groundwater that can be obtained at the site of use, adjust the concentration of each ion and the photooxidation catalyst to the actual use concentration, and use it as a plant growth environment improvement agent in farmland, forest land, green space (lawn, etc.), bonsai, etc. as soon as possible without storing it. Note that, when the dilution water contains free halogen molecules at a concentration exceeding 4.0 μmol / L, it is important to use the dilution water as a solution dehalogenated with a dehalogenating agent such as thiosulfate in order to activate plant growth. Also, when the dilution water contains halide ions such as chloride ions and bromide ions exceeding 3.0 mmol / L, it is important not to use it. [Brief description of the drawings]

[0032] [Figure 1] Survival rate of test bacteria (Pseudomonas putida, Escherichia coli, Bacillus subtilis) after 30 minutes of exposure to solutions of various silver ion concentrations [Diagram 2] The relationship between the silver ion concentration immediately after preparation of the stock solution of silver ion aqueous solution and the residual percentage of silver ions remaining in the stock solution after storing it sealed in a polyethylene bottle at room temperature for 120 days. [Diagram 3] The relationship between the stalk and root length of Komatsuna seedlings and the chloramine concentration 5 days after sowing, when a germination and rooting test was conducted using agar medium containing 0.010 mg / L silver ion and 1.0 μmol / L to 7.0 μmol / L of chloramine, a halogen compound, as combined residual chlorine. [Figure 4] The relationship between the stem length and root length of Komatsuna seedlings and the chloride ion concentration 5 days after sowing, when germination and rooting tests were conducted using agar culture medium to which 0.010 mg / L of silver ion and 0.5 mmol / L to 7.0 mmol / L of chloride ion, a halide ion, had been added. [Diagram 5] Relationship between the silver ion concentration of water used to prepare agar medium for germination tests and the average stem and root lengths of Komatsuna seedlings 5 ​​days after sowing [Figure 6] When a germination and rooting test was conducted using agar medium prepared in water containing 0.010 mg / L silver ions and 0.10 mg / L dithiothreitol, the average shoot and root lengths of Komatsuna seedlings 3 and 5 days after sowing were compared with those of agar medium containing no dithiothreitol. [Figure 7] Agar medium for germination was prepared using a solution in which titanium dioxide nanoparticles with an average diameter of 100 nm were added as a photooxidation catalyst at concentrations between 0.001mg / L and 30mg / L to a reaction solution with a silver ion concentration of 0.025mg / L and a dithiothreitol concentration of 0.25mg / L. In an artificial climate chamber set at 22℃ and irradiated with white fluorescent light at 2500lx, the germination and rooting tests of Komatsuna were carried out under conditions of 13 hours of fluorescent light irradiation and 11 hours of no fluorescent light irradiation. The relationship between the concentration of added titanium dioxide nanoparticles and the average stem and root length of Komatsuna seedlings 5 ​​days after sowing was examined. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] Hereinafter, embodiments of the present invention will be illustrated by Examples 1 to 7. EXAMPLES

[0034] <Example 1> A growth activation solution with a silver ion concentration of 8 mg / L was prepared by adding 200 ml of the solution per 0.04 square meters of seedbed material to the seedlings, using tap water containing 0.40 mmol / L or less of chloride and bromide ions, and dehalogenated water with sodium sulfite added so that the concentrations of free halogen compounds and combined residual halogen compounds in the tap water are 4.0 μmol / L or less, so that the silver ion concentration is 0.016 mg / L. 32 g of rice seeds were then sown and raised. (b) The average seedling height (stalk length) and average root length per 30 rice seeds 12 days after sowing were increased by 1.06 times and 1.55 times, respectively, compared to the average seedling height (stalk length) and average root length per 30 rice seeds 12 days after sowing when 32 g of rice seeds were sown in a bed material diluted 1 / 500 with dehalogenated water without added silver ions and added evenly to the bed material at 200 mL per 0.04 square meters. This means that the growth of rice seedlings (especially the growth of the seedling roots) was greatly promoted by the silver ion activation solution with a concentration of 0.016 mg / L.

[0035] <Example 2> Example for growing tomato seedlings: Tap water containing less than 0.40 mmol / L of chloride ions was further dehalogenated by adding sodium sulfite so that the concentrations of free halogens and combined residual halogen compounds were less than 2.0 μmol / L. The silver ion solution was diluted to a silver ion concentration of 0.016 mg / L, and the resulting silver ion solution was added evenly at 200 ml per 0.04 square meters of seedbed material. Thereafter, 50 tomato seeds were sown in the seedbed, allowed to germinate and take root, and then grown as seedlings. The average seedling height (stem length) and average root length per 40 plants that had germinated and taken root 16 days after sowing were 1.08 times and 1.64 times greater, respectively, than the average seedling height (stem length) and average root length per 37 plants that had germinated and taken root 16 days after sowing when 50 tomato seeds were sown in a seedbed material containing the same dehalogenated tap water but without the addition of silver ions. This demonstrated that silver ions at a concentration of 0.016 mg / L promote the growth of tomato seedlings (especially the growth of the roots).

[0036] <Example 3> Example for raising eggplant seedlings: Tap water containing less than 0.40 mmol / L of chloride ions was further dehalogenated by adding sodium sulfite so that the concentrations of free halogens and combined residual halogen compounds were less than 2.0 μmol / L. The silver ion solution was diluted to a silver ion concentration of 0.016 mg / L and added evenly at 200 ml per 0.04 square meters of seedbed material. Thereafter, 50 eggplant seeds were sown in the seedbed, allowed to germinate and take root, and then grown as seedlings. The average seedling height (stem length) and average root length per 41 seedlings that germinated and took root 16 days after sowing were 1.10 times and 1.58 times, respectively, compared to the average seedling height (stem length) and average root length per 39 seedlings that germinated and took root 16 days after sowing when 50 tomato seeds were sown in the same seedbed material using the same dehalogenated tap water but without the addition of silver ions. This demonstrated that silver ions at a concentration of 0.016 mg / L promote the growth of eggplant seedlings (especially the growth of the roots).

[0037] <Example 4> Example for raising cucumber seedlings: Tap water containing less than 0.40 mmol / L of chloride ions was further dehalogenated by adding sodium sulfite so that the concentrations of free halogens and combined residual halogen compounds were less than 2.0 μmol / L. The silver ion solution was diluted to a silver ion concentration of 0.016 mg / L and added evenly at 200 ml per 0.04 square meters of seedbed material. Thereafter, 50 cucumber seeds were sown in the seedbed, allowed to germinate and take root, and then grown as seedlings. The average seedling height (stem length) and average root length per 44 plants that germinated and took root 14 days after sowing were 1.12 times and 1.60 times greater than the average seedling height (stem length) and average root length per 42 plants that germinated and took root 14 days after sowing when 50 cucumber seeds were sown in a seedbed material containing the same dehalogenated tap water but without the addition of silver ions. This demonstrated that silver ions at a concentration of 0.016 mg / L promote the growth of cucumber seedlings (especially the growth of the roots).

[0038] <Example 5> Example for growing pea seedlings: Tap water containing less than 0.50 mmol / L of chloride ions was dehalogenated by adding sodium sulfite so that the concentrations of free halogens and combined residual halogen compounds were less than 2.0 μmol / L. The silver ion solution was diluted to a silver ion concentration of 0.016 mg / L and added evenly at 200 ml per 0.04 square meters of seedbed material. Thereafter, 50 pea seeds were sown in the seedbed, allowed to germinate and take root, and then grown as seedlings. The average seedling height (stem length) and average root length per 47 seedlings that germinated and took root 15 days after sowing were 1.30 times and 1.68 times greater than the average seedling height (stem length) and average root length per 48 seedlings that germinated and took root 14 days after sowing when 50 pea seeds were sown in a seedbed material containing the same dehalogenated tap water but without the addition of silver ions. This demonstrated that silver ions at a concentration of 0.016 mg / L promote the growth of pea seedlings (especially the growth of the seedling roots).

[0039] <Example 6> Example for growing pepper seedlings: Tap water containing less than 0.50 mmol / L of chloride ions was dehalogenated by adding sodium sulfite so that the concentrations of free halogens and combined residual halogen compounds were less than 2.0 μmol / L. The silver ion solution was diluted to a silver ion concentration of 0.016 mg / L and added evenly at 200 ml per 0.04 square meters of seedbed material. Thereafter, 50 bell pepper seeds were sown in the seedbed, allowed to germinate and take root, and then grown as seedlings. The average seedling height (stem length) and average root length per 43 plants that germinated and took root 14 days after sowing were 1.12 times and 1.60 times greater than the average seedling height (stem length) and average root length per 41 plants that germinated and took root 14 days after sowing when 50 bell pepper seeds were sown in a seedbed material containing the same dehalogenated tap water but without the addition of silver ions. This demonstrated that silver ions at a concentration of 0.016 mg / L promote the growth of bell pepper seedlings (especially the growth of the roots).

[0040] <Example 7> In addition to the above examples, seedlings of 40 kinds of plants, including corn, radish, Chinese cabbage, cabbage, lettuce, bok choy, lettuce, carrots, burdock, soybeans, green onions, shishito peppers, paprika, okra, melons, watermelons, pumpkins, grapes, blueberries, pears, apples, plums, peaches, persimmons, mandarin oranges, oranges, olives, cedars, cypresses, sumac trees, maples, nandinas, ginkgo trees, white oaks, Japanese sycamore trees, camellias, sasanquas, American dogwoods, mountain dogwoods, and rose of Sharon, were cultivated by a nursery company. When seedlings were irrigated with a plant activation solution containing 0.010 mg / L of silver ions, which was made by adding sodium sulfite to tap water containing 1.0 mmol / L or less of chloride ions so that the concentrations of free halogens and combined residual halogen compounds were 4.0 μmol / L or less, the cultivation period (number of days) from the sowing date to the time when the seedlings could be shipped was shortened by more than 15% for all plant seedlings, compared to when the seedlings were irrigated with tap water that did not contain silver ions. For bok choy and Japanese cedar, which had the shortest cultivation periods, the number of days until they could be shipped was shortened by 2 / 3. [Industrial Applicability]

[0041] Instead of the disinfection that has been required so far to prevent plant disease during the cultivation of plant seedlings, a low concentration silver ion solution of 0.0005 mg / L or more and 0.025 mg / L or less can be applied to plants in the elongation stage, thereby reducing or eliminating the use of pesticides such as disinfectants and insecticides. This can be used to convert industries based on plant cultivation, such as agriculture, forestry, horticulture, and green space development, into safer and more secure industries, and can also be used to transform them into environmentally friendly and sustainable industries. In addition, reducing or eliminating the use of pesticides in this way can reduce the cost of cultivating plant seedlings, thereby increasing the profitability of industries related to plant cultivation, such as agriculture, forestry, horticulture, and green space development, and can contribute to reducing the labor force of these industries by saving labor such as spraying pesticides. Furthermore, using a liquid containing a low concentration of silver ions of 0.0005 mg / L or more and 0.025 mg / L or less as a growth activation liquid for cultivating plant seedlings is also effective in preventing the new emergence of pesticide-resistant plant pathogenic microorganisms and feeding-damaging insects, which have been repeatedly caused by the use of pesticides as described above. [Explanation of symbols]

[0042] PCR: Abbreviation for polymerase chain reaction. (An enzyme reaction that uses DNA polymerase to amplify all or part of a DNA molecule contained in an organism in vitro.)

[0043] 16S rRNA: A type of ribosomal RNA found in prokaryotes such as bacteria and archaea, and the 16S rRNA gene that serves as the template is encoded on chromosomal DNA.

Claims

[Claim 1] A growth activation liquid in the form of a solution intended to be used to activate the growth of plant seedlings having roots, the growth activation liquid for cultivating plant seedlings having roots containing silver ions at a concentration of not less than 0.0005 mg / L and not more than 0.025 mg / L, and not containing free residual chlorine and combined residual chlorine with concentrations exceeding 4.0 μmol / L, and not containing chloride ions and bromide ions exceeding 3.0 mmol / L.

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