Agent for improving heat tolerance or salt tolerance of plants

Abstract

The present invention provides a plant heat or salt tolerance improving agent containing acetic acid or a salt thereof, or a solvate thereof.

Description

Technical Field

[0001] This invention relates to agents that improve the heat or salt tolerance of plants. Background Technology

[0002] Currently, with the population experiencing explosive growth, producing sufficient quantities of plants for food has become a global challenge. Furthermore, land desertification caused by the reduction of green spaces has become a problem. In addition, rising surface temperatures due to global warming are also a concern. Therefore, environmental problems related to plant growth are constantly increasing.

[0003] In other words, excessive stress caused by Earth's environmental factors often becomes a problem in plant growth.

[0004] One example of stress on plants is desiccation stress.

[0005] For drought stress, attempts were made to create recombinant plants by modifying drought stress-responsive genes, and to apply chemical or biological regulators that improve drought stress tolerance.

[0006] Patent document 1 discloses a method for improving the drought stress tolerance of plants, which includes the step of applying more than 10 mM acetic acid to the roots of plants by irrigation and causing the plants to grow under drought stress conditions.

[0007] In addition, Non-Patent Literature 1 discloses a drying response network in which a dynamic shift in metabolic flux from glycolysis to acetic acid synthesis is triggered by stimulating the jasmonic acid signaling pathway, thereby enabling plants to acquire drying tolerance.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: U.S. Patent No. 9,258,954

[0011] Non-patent literature

[0012] Non-patent literature 1: Kim, JM et al., Nature Plants, Vol.3, 17097 (2017). Invention Overview

[0014] The problem that the invention aims to solve

[0015] In plant growth, there are other stresses besides drought stress.

[0016] Therefore, this study investigated whether the stress on plants in high-temperature and saline environments could be used as an indicator to assess plant tolerance.

[0017] The problem to be solved by the present invention is to provide a means to confer heat resistance or salt resistance to plants.

[0018] Methods for solving problems

[0019] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that acetic acid and other substances help plants resist heat stress or salt stress and grow well, thus completing the present invention.

[0020] That is, the present invention is as follows. (1)

[0022] Plant heat or salt tolerance enhancers containing acetic acid or its salts, or their solvates. (2)

[0024] (1) The heat resistance or salt resistance improving agent further contains at least one solvent, including water. (3)

[0026] (2) The heat resistance or salt resistance improving agent has a pH range of 3 to 9. (4)

[0028] The heat resistance or salt resistance improver described in (2) or (3) contains 0.01 to 0.5% by volume of acetic acid or its salt. (5)

[0030] Compositions for improving the heat or salt tolerance of plants contain acetic acid or its salts, or their solvates. (6)

[0032] (5) The composition further contains at least one solvent, including water. (7)

[0034] (6) The composition thereof has a pH range of 3 to 9. (8)

[0036] The composition of (6) or (7) contains 0.01 to 0.5% by volume of acetic acid or a salt thereof. (9)

[0038] Methods for improving the heat or salt tolerance of plants include applying acetic acid or its salts, or solvates thereof, to the plants, the material used for application to the plants, or the soil, culture medium, or nutrient solution in which the plants grow. (10)

[0040] Methods for managing plant growth include:

[0041] Obtain one or more pieces of information related to plant growth; and

[0042] Based on one or more pieces of information obtained, determine the conditions for applying the heat resistance or salt resistance enhancer of any one of (1) to (4) or the composition of any one of (5) to (8) to plants, materials for application to plants, or soil, culture medium or nutrient solution in which plants grow.

[0043] Invention Effects

[0044] This invention provides a means to impart heat resistance or salt resistance to plants. Attached Figures

[0045] Figure 1 : Figure 1 The figure illustrates the results of heat resistance test 1 using leaf lettuce (Sanchu) in the examples. The left side shows the symmetrical water supply group, and the right side shows the 0.1 vol% acetic acid aqueous solution supply group.

[0046] Figure 2: Figure 2 is a graph showing the results of heat resistance test 2 using leaf lettuce in the embodiment. Figure 2A and Figure 2B The left side is a symmetrical water supply group, and the right side is a 0.06% acetic acid aqueous solution supply group. Figure 2A This shows leaf lettuce before it is grown at a temperature of 42°C. Figure 2B Leaf lettuce grown at 42°C is shown. Figure 2C A graph showing survival rates is provided.

[0047] Figure 3: Figure 3 is a graph showing the results of heat resistance test 3 using tomatoes in the embodiment. Figure 3A and Figure 3B The left side is a symmetrical water supply group, and the right side is a 0.06% acetic acid aqueous solution supply group. Figure 3A This shows tomatoes before they are grown at 42°C. Figure 3B The image shows tomatoes grown at 42°C.

[0048] Figure 4 : Figure 4 The diagram illustrates the results of salt tolerance tests using leaf lettuce in the examples. The left side shows the symmetrical water supply group, the middle side shows the 0.1 vol% acetic acid aqueous solution supply group, and the right side shows the 0.2 vol% acetic acid aqueous solution supply group. Detailed Implementation

[0049] The following describes in detail the embodiments of the present invention, but the present invention is not limited to the following embodiments and can be implemented in various ways.

[0050] This invention relates to a plant heat or salt tolerance enhancer, which contains acetic acid or its salts, or their solvates (hereinafter, in this specification, sometimes referred to as "acetic acid, etc.").

[0051] In this invention, the heat resistance and / or salt tolerance of plants can be improved by applying a plant heat resistance or salt tolerance enhancer to the plants. The plant heat resistance or salt tolerance enhancer of this invention can be a heat resistance enhancer, a salt tolerance enhancer, or a heat resistance enhancer and a salt tolerance enhancer in combination.

[0052] The plant heat resistance or salt resistance enhancer of the present invention can be used as a pesticide or agricultural chemical agent.

[0053] In this invention, by applying heat or salt tolerance enhancers to plants, plant tolerance can be imparted to plants in response to stresses that adversely affect plant growth, such as high temperatures or saline soils. In this specification, imparting tolerance to stresses during plant growth does not imply complete tolerance.

[0054] In this invention, the heat resistance or salt resistance enhancer for plants contains acetic acid, etc.

[0055] In this article, there are no special restrictions on acetic acid, etc., as long as they play the role of improving the heat resistance or salt resistance of plants. Plant heat resistance or salt resistance improvers contain acetic acid, etc. as active ingredients.

[0056] The active ingredient refers to components such as acetic acid that function as enhancers of heat or salt tolerance in plants.

[0057] The acetic acid or the like used in this invention can be industrial acetic acid or food acetic acid.

[0058] As acetic acid, safe and inexpensive acetic acid such as wood vinegar, which is also used in agriculture, and brewed vinegar, which is produced through fermentation, can be used.

[0059] Using the aforementioned acetic acid or the like as heat or salt tolerance enhancers for the plants of this invention is suitable because it is safe and low in cost.

[0060] The acetic acid or the like used in this invention can be not only acetic acid itself, but also a salt of acetic acid.

[0061] There are no particular limitations on what constitutes a salt of acetic acid, as long as it can provide acetate ions. Examples of salts that form with cations include sodium acetate, potassium acetate, calcium acetate, magnesium acetate, zinc acetate ions, and ammonium acetate.

[0062] In the case of ammonium acetate, it can also be an acetate formed by replacing ammonium ions with substituted or unsubstituted ammonium.

[0063] Potassium acetate, sodium acetate, ammonium acetate, magnesium acetate, and calcium acetate are preferably used as salts of acetic acid. Alternatively, liquid fertilizer obtained by dissolving eggshells in vinegar can also be used as acetic acid.

[0064] In this invention, acetic acid and acetate can be used as a mixture. The mixture of acetic acid and acetate can be a mixture obtained by mixing acetic acid itself with acetate, or it can be a mixture of acetic acid and acetate produced by adding a cation source that forms a salt with acetate ions to acetic acid, for example, a mixture of acetic acid and acetate generated by a neutralization reaction in aqueous solution. In this case, acetic acid can be completely neutralized, or a cation source can be added in an amount sufficient to neutralize a portion of the acetic acid.

[0065] Examples of aqueous solutions containing acetate include, for example, acetate buffer solution.

[0066] The acetic acid or the like used in this invention can be a solvate of acetic acid or a solvate of an acetate salt.

[0067] Solvents that can form solvates of acetic acid or its salts are not particularly limited, and examples include water, as well as organic solvents such as alcohols, dimethyl sulfoxide (DMSO), ethanolamine, and ethyl acetate.

[0068] As an alcohol, it can be either a lower alcohol or a higher alcohol. There is no particular limitation on the type of lower alcohol; examples include methanol, ethanol, or 2-propanol (isopropanol), which are straight-chain or branched alkanols with 1 to 6 carbon atoms, and are either saturated or unsaturated. There is no particular limitation on the type of higher alcohol; examples include 1-heptanol or 1-octanol, which are straight-chain or branched alkanols with 7 or more carbon atoms, and are either saturated or unsaturated.

[0069] The solvent used to form the solvate can be a single solvent or two or more solvents.

[0070] For solvates, for example, when used in the form of an aqueous solution of the solvate, the form of acetic acid or the like in the aqueous solution is not particularly limited, and it may not be solvated.

[0071] In this invention, "heat resistance enhancer" and "enhanced heat resistance" mean that by applying the heat resistance enhancer of the plant of this invention to a plant population, heat stress, which is an adverse effect on plant growth, can be substantially reduced, such effects include failure to grow (death), poor growth (e.g., whitening or yellowing of the whole plant or parts thereof (e.g., leaves or flowers), reduced root length or leaf number, or lodging), decreased growth rate, or reduced plant weight or crop yield.

[0072] For the confirmation of "heat resistance enhancer" and "enhanced heat resistance", it can be confirmed by comparison with a control plant group of heat resistance enhancers for plants that have not applied the present invention. In addition, it can be confirmed based on the survival rate increase being generally 30% or more, preferably 50% or more, 60% or more, 70% or more, more preferably 80% or more, further preferably 85% or more, and particularly preferably 90% or more.

[0073] In this specification, "thermal stress" means being placed in an environment with a temperature below 60 degrees Celsius, which can be an environment with a temperature below 50 degrees Celsius or an environment with a temperature below 45 degrees Celsius.

[0074] In addition, a constant temperature is generally considered to be around 25°C, preferably above 30°C, and even more preferably above 35°C.

[0075] In this manual, "thermal stress" can refer to being placed in an environment with a temperature range of 30 to 60°C, and an upper and lower limit can be set within this temperature range.

[0076] In this invention, there are no particular limitations on the confirmation of "heat resistance improver" and "improved heat resistance". It can be evaluated by the following means, and more specifically, by the methods listed in the examples.

[0077] For example, the evaluation can be conducted by growing the plant under normal growth conditions (i.e., non-stress conditions) in a certain amount of test solution (containing water and, depending on the situation, the usual nutrients). After a certain period of growth, a heat tolerance enhancer is applied, and then the plant is grown under heat stress conditions. Subsequently, it is grown under normal growth conditions (i.e., non-stress conditions), and the survival rate of the plant is calculated.

[0078] As a thermal stress condition, any condition that allows the body to stand for more than 30 minutes under the aforementioned "thermal stress" temperature conditions is acceptable, and the standing time can be set according to the temperature conditions.

[0079] In thermal stress conditions, the preferred conditions are constant humidity and the condition of standing without water supply.

[0080] In this invention, "salt tolerance enhancer" and "enhanced salt tolerance" mean that salt stress (specifically, high concentrations of salt stress) that is an adverse effect on plant growth can be substantially reduced by applying the salt tolerance enhancer of the plant of this invention to a plant population. Such effects include failure to grow (death), poor growth (e.g., whitening or yellowing of the whole plant or parts thereof (e.g., leaves or flowers), reduced root length or leaf number, or lodging), decreased growth rate, or reduced plant weight or crop yield.

[0081] For the confirmation of "salt tolerance enhancer" and "enhanced salt tolerance", it can be confirmed by comparison with a control plant group of salt tolerance enhancers for which the present invention has not been applied. In addition, it can be confirmed based on the survival rate increase being generally 30% or more, preferably 50% or more, 60% or more, 70% or more, more preferably 80% or more, further preferably 85% or more, and particularly preferably 90% or more.

[0082] In this specification, "salt stress" means being placed in an environment with a high concentration of salt.

[0083] The concentration of salts is not specifically defined; it can refer to the concentration of salts in soils classified as saline soils.

[0084] There are no particular limitations on the salts that can cause salt stress; they can be salts that can be observed in saline soils, such as phosphates, nitrates, and hydrochlorides.

[0085] As salts, specific examples include alkali metal salts, alkaline earth metal salts, and ammonium salts of phosphoric acid, nitric acid, and hydrochloric acid, such as sodium chloride and magnesium chloride.

[0086] In this invention, there are no particular limitations on the confirmation of "salt tolerance improver" and "improved salt tolerance". It can be evaluated by the following means, and more specifically by the methods listed in the examples.

[0087] For example, the evaluation can be conducted by: The plant being evaluated is placed in a test solution (containing water and, depending on the circumstances, the usual nutrients) under normal growth conditions (i.e., non-salt stress conditions). After a certain period of growth, a salt tolerance enhancer is applied, and the plant is then placed under salt stress conditions. Subsequently, it is placed under normal growth conditions (i.e., non-salt stress conditions), and the survival rate of the plant is calculated.

[0088] As a salt stress condition, it is sufficient to let the salt stand for more than 30 minutes under the temperature conditions described above. The standing time can be set according to the type and concentration of salt.

[0089] Salt stress conditions can be conditions with constant humidity, with water supplied while the plant remains still, or conditions with no water supply and the plant remains still.

[0090] In this invention, the plant heat resistance or salt resistance enhancer can be a plant heat resistance enhancer, a plant salt resistance enhancer, or both.

[0091] In this invention, the heat resistance or salt tolerance enhancer of plants can be a composition containing acetic acid or the like that enhances the heat resistance or salt tolerance of plants.

[0092] That is, in this specification, "plant heat resistance or salt resistance improver" can be understood to have the same meaning as "composition to improve plant heat resistance or salt resistance".

[0093] In various embodiments of the present invention, the effects of the plant heat or salt tolerance enhancer may include effects on the plant's own growth, such as growth-promoting effects like the extension of stems, leaves, or roots, an increase in the number of leaves, promotion of flowering or fruiting, an increase in the number of flowers or fruits, an increase in plant weight or crop yield, greening, or promotion of tillering.

[0094] In this invention, by applying acetic acid or the like to plants, heat resistance or salt resistance can be improved in response to heat stress or salt stress.

[0095] The heat or salt tolerance enhancers and compositions for enhancing the heat or salt tolerance of plants in this invention can be used as agricultural chemical agents or pesticides to promote plant growth.

[0096] In this invention, the plant heat resistance or salt resistance enhancer can be in any form, such as a solid (e.g., powder or granules), a liquid (e.g., solution or suspension), or a gas.

[0097] In this invention, the heat resistance or salt resistance enhancer for plants is preferably in liquid form such as a solution or suspension.

[0098] In this invention, when the plant heat resistance or salt resistance enhancer is used as a solution, it can be in liquid form or it can be used as a liquid prepared for use during application.

[0099] In the heat resistance or salt resistance enhancer of plants of the present invention, acetic acid or the like can preferably be used alone as an active ingredient, or it can be used in combination with one or more agriculturally acceptable ingredients.

[0100] The plant heat resistance or salt resistance enhancer of the present invention can be formulated into various formulations commonly used in this technical field, as a pesticide or even an agricultural chemical agent, according to the desired application method.

[0101] The heat resistance or salt tolerance enhancer for plants of the present invention may contain one or more agriculturally acceptable ingredients in addition to acetic acid.

[0102] Examples of agriculturally acceptable ingredients include solvents or carriers, excipients, binders, cosolvents, stabilizers, thickeners, swelling agents, lubricants, surfactants, oily liquids, buffers, fungicides, antifreeze agents, defoamers, colorants, antioxidants, additives, fertilizers, and other agents.

[0103] As an agriculturally acceptable solvent or carrier, it is preferably an agriculturally acceptable solvent or liquid carrier such as water, mineral oil components such as kerosene or diesel, oils derived from plants or animals, cyclic or aromatic hydrocarbons (e.g., paraffin, tetrahydronaphthalene, alkyl naphthalenes or their derivatives, or alkyl benzenes or their derivatives), alcohols (e.g., methanol, ethanol, propanol, butanol, ethylene glycol, glycerol or cyclohexanol), ketones (e.g., cyclohexanone), or amines (e.g., N-methylpyrrolidone), or mixtures thereof, more preferably including at least one solvent, such as water.

[0104] As fertilizers, organic fertilizers such as oilseed meal or cow manure, or inorganic fertilizers such as ammonium sulfate, sulfur dioxide, calcium cyanamide, or molten phosphorus are preferred.

[0105] When the plant heat resistance or salt resistance improver of the present invention further contains at least one solvent including water, the pH of the solution of the plant heat resistance or salt resistance improver of the present invention is preferably in the range of 3 to 9. Within this range, the lower limit of pH can be 4 or more, 5 or more, or 6 or more, and the upper limit of pH can be 8.5 or less, 8 or less, 7.5 or less, or 7 or less.

[0106] The pH range is more preferably 4 to 8, further preferably 5 to 7.5, and even more preferably 5 to 7. The pH range can be 5 to 6 or 6 to 7.

[0107] The pH of the plant heat tolerance or salt tolerance enhancer is preferably within the above-mentioned range when it is applied to the target plant.

[0108] The pH of the plant heat resistance or salt resistance improver of the present invention can be adjusted by acid or alkali. For example, it can be adjusted by acid, alkali or buffer such as hydrochloric acid, nitric acid, sulfuric acid, sodium hydroxide, potassium hydroxide, ammonia or ammonium acetate.

[0109] In the heat resistance or salt resistance enhancer of plants of the present invention, it is preferable that the pH is within the above-mentioned range when applied to the target plant. However, it is also possible that even if the application time to the target plant is not within the above-mentioned range, the pH can be adjusted to the above-mentioned range by utilizing the pH buffering effect of the applied soil, culture medium or culture solution.

[0110] When the plant heat resistance or salt resistance improver of the present invention further contains at least one solvent including water, the proportion of acetic acid or the like in the plant heat resistance or salt resistance improver of the present invention relative to the total volume is preferably in the range of 0.01 to 0.5 vol%. Within this range, the lower limit of the proportion can be 0.05 vol% or more, 0.075 vol% or more, 0.09 vol% or more, or 0.1 vol% or more, and the upper limit of the proportion can be 0.25 vol% or less or 0.2 vol% or less.

[0111] The proportion of acetic acid, etc., is more preferably in the range of 0.05 to 0.5 vol%, more preferably in the range of 0.075 to 0.25 vol%, even more preferably in the range of 0.09 to 0.2 vol%, and particularly preferably in the range of 0.1 to 0.2 vol%.

[0112] When the heat resistance or salt tolerance enhancer of plants of the present invention further contains at least one solvent including water, the concentration of acetic acid or the like in the heat resistance or salt tolerance enhancer of plants of the present invention is preferably in the range of 1 to 100 mM. Within this range, the lower limit of the concentration can be 2 mM or more, 5 mM or more, 7.5 mM or more, 9 mM or more, or 10 mM or more, and the upper limit of the concentration can be 50 mM or less or 40 mM or less.

[0113] The proportion of acetic acid, etc., is more preferably in the range of 1 to 50 mM, further preferably in the range of 7.5 to 50 mM, even more preferably in the range of 9 to 40 mM, and particularly preferably in the range of 10 to 40 mM.

[0114] When the plant heat resistance or salt resistance improver of the present invention further contains at least one solvent including water, it is preferable that the pH is within the above-mentioned range and the concentration of acetic acid or the like is within the above-mentioned range.

[0115] pH and concentration can be appropriately selected within the above range, either simultaneously or independently.

[0116] The heat resistance or salt tolerance enhancer of plants of the present invention may contain one or more other agents.

[0117] There are no particular limitations on the agent used; examples include auxins, gibberellins, cytokinins, 2-chloroethylphosphonic acid (trade name: Esrel (registered trademark)), carbide, benzyladenine, brassinosteroid, strigolactone, and jasmonic acid. Alternatively, the agent can be plant hormones, phytochemical regulators, and pesticides commonly used in this field.

[0118] In this invention, the plant being targeted is not particularly limited; for example, it may be selected from angiosperms and gymnosperms.

[0119] There are no particular limitations on the plants that can be included. For example, plants of the Asteraceae family such as chrysanthemum and privet can be listed; plants of the Solanaceae family such as potato, tomato and eggplant can be listed; plants of the Brassicaceae family such as rapeseed and rapeseed flowers can be listed; plants of the Poaceae family such as rice, corn, wheat, sugarcane and barley can be listed; plants of the Leguminosae family such as soybean can be listed; plants of the Convolvulaceae family such as morning glory can be listed; plants of the Salicaceae family such as poplar can be listed; plants of the Euphorbiaceae family such as castor bean, cassava and jatropha can be listed; plants of the Convolvulaceae family such as sweet potato can be listed; plants of the Rutaceae family such as orange and lemon can be listed; plants of the Rosaceae family such as cherry blossom and rose can be listed; plants of the Orchidaceae family such as Phalaenopsis can be listed; plants of the Gentianaceae family such as lisianthus can be listed; plants of the Primulaceae family such as cyclamen can be listed; plants of the Violaceae family such as pansy can be listed; plants of the Liliaceae family such as lily can be listed; plants of the Amaranthaceae family such as beet can be listed; plants of the Vitaceae family such as grape can be listed; plants of the Cupressaceae family such as cedar and cypress can be listed; plants of the Oleaceae family such as olive and osmanthus can be listed; and plants of the Pinaceae family such as red pine can be listed.

[0120] The plants to which this invention is intended as heat or salt tolerance enhancers possess a common mechanism involving acetic acid metabolism, including acetic acid synthesis. Therefore, it is believed that heat or salt tolerance derived from acetic acid, etc., is commonly exercised in plants through the action of functional gene groups universally retained across plant species.

[0121] The plant that is the object of study can be not only the whole plant (i.e., the complete plant body), but also parts of the plant such as tissues or organs (e.g., cut flowers, or vegetative reproductive organs such as rhizomes, tubers, bulbs or runners), cultured cells and / or callus tissue.

[0122] The heat or salt tolerance enhancer of the plant of the present invention can be applied to the whole or part of a plant at any growth stage, including before or after germination (e.g., the whole or part of a seed, seedling, or mature plant).

[0123] The heat or salt tolerance enhancer of the plant of the present invention can be applied not only to the plant itself, but also to the material used to apply it to the plant, or to the soil, culture medium or nutrient solution in which the plant grows.

[0124] This invention relates to a method for improving the heat or salt tolerance of plants, comprising applying acetic acid, preferably an agriculturally effective amount of acetic acid, to the plant, the material used for application to the plant, or the soil, culture medium, or nutrient solution in which the plant grows.

[0125] In the method of the present invention, the acetic acid and other substances applied are the same as those described in this specification for plant heat or salt tolerance enhancers.

[0126] There are no particular limitations on the materials used for application to plants; for example, various materials commonly used in this field, such as water and fertilizer, can be cited.

[0127] The formulation of the plant heat resistance or salt resistance improver of the present invention is not particularly limited, and can be a commonly used formulation in this technical field, such as emulsion, hydration agent, liquid preparation, water solvent, powder, paste or granule.

[0128] In various embodiments of the present invention, acetic acid or the like is contained or applied in an agriculturally effective amount. In various embodiments of the present invention, the agriculturally effective amount of acetic acid or the like is, for example, in the range of 0.01 to 0.5% by mass relative to the total mass at application, typically in the range of 0.05 to 0.5% by mass relative to the total mass at application, typically in the range of 0.075 to 0.25% by mass relative to the total mass at application, more typically in the range of 0.09 to 0.2% by mass relative to the total mass at application, and particularly in the range of 0.1 to 0.2% by mass relative to the total mass at application. For example, when the plant heat resistance or salt resistance enhancer of the present invention is in liquid form, the amount of acetic acid or the like that is agriculturally effective is, for example, in the range of 0.01 to 0.5 vol% relative to the total volume at application, typically in the range of 0.05 to 0.5 vol%, typically in the range of 0.075 to 0.25 vol%, more typically in the range of 0.09 to 0.2 vol%, and particularly in the range of 0.1 to 0.2 vol%.

[0129] In plant cultivation, by appropriately setting the conditions for applying the heat resistance or salt tolerance enhancer of the present invention to the plant, the material used for application to the plant, or the soil, culture medium, or nutrient solution in which the plant grows, based on the plant's growth status, it is possible to stably manage plant growth while improving the plant's heat resistance or salt tolerance.

[0130] This invention relates to a method for managing plant growth, comprising:

[0131] Obtain one or more pieces of information related to plant growth (hereinafter also referred to as "information acquisition steps"); and

[0132] Based on one or more pieces of information obtained, the conditions for applying the heat resistance or salt resistance enhancer of the present invention to the plant, the material used for application to the plant, or the soil, culture medium or nutrient solution in which the plant grows are determined (hereinafter also referred to as the "application condition determination step").

[0133] As one or more pieces of information related to plant growth obtained in the information acquisition step, there is no particular limitation. For example, various information related to growth-promoting effects such as the extension of stems, leaves or roots, the increase in the number of leaves, the promotion of flowering or fruiting, the increase in the number of flowers or fruits, the increase in plant weight or crop yield, greening, or the promotion of tillering under heat or salt stress conditions can be cited, as well as various information related to adverse effects on plant growth such as failure to grow (death), poor growth (e.g., whitening or yellowing of the whole plant or parts of it (e.g., leaves or flowers), reduced root length or number of leaves, or lodging), decreased growth rate, or reduced plant weight or crop yield.

[0134] The growth status of a plant can be evaluated by obtaining more than one piece of information from the examples above.

[0135] The conditions determined in the application condition determination step for applying the heat resistance or salt tolerance enhancer of the plant according to the present invention can be appropriately set in a way that can improve the heat resistance or salt tolerance of the plant by performing this application. The conditions determined in this step are not particularly limited; for example, one or more conditions selected from the group consisting of the composition, pH, application amount and application time of the heat resistance or salt tolerance enhancer of the plant according to the present invention, and the content of acetic acid, etc., contained as an active ingredient, can be cited.

[0136] The specific values ​​for these conditions can be appropriately set based on the ranges exemplified in this specification.

[0137] In this invention, the number and order of the information acquisition step and the application condition determination step in the method for managing plant growth are not particularly limited. For example, the information acquisition step and the application condition determination step can each be performed once in this order, or they can be performed in the order of information acquisition step, application condition determination step, and then another information acquisition step, or the combination of the information acquisition step and the application condition determination step can be repeated multiple times in a manner such as first information acquisition step, first application condition determination step, second information acquisition step, and second application condition determination step.

[0138] Example

[0139] The present invention will be further illustrated below with examples. However, the scope of the present invention is not limited to these examples.

[0140] <Heat Resistance Test 1>

[0141] In a simply constructed incubator, leaf lettuce (Sanchu, *Lactuca sativa* L., family Asteraceae) was germinated in vinyl pots and cultivated for two weeks at 22°C and 40–50% humidity. During cultivation, water was supplied using a watering tray, with the bottom of the vinyl pot submerged in water.

[0142] Then, excess water from the bottom surface is removed by natural dripping onto the dried water supply tray.

[0143] Use water or a 0.1% (v / v) aqueous solution of acetic acid to provide bottom watering for 24 hours via a watering tray. This bottom watering treatment allows water or an aqueous solution of acetic acid to be supplied to the leaf lettuce from the bottom of the ethylene pot.

[0144] Then, the ethylene bowl was moved to another tray, the water supply was stopped, and it was placed in an incubator for 4 days under continuous light and a temperature of 35°C.

[0145] After standing for 4 days, the ethylene pot was removed from the incubator and watered from the bottom at 22℃. The condition of the leaf lettuce was observed after 24 hours.

[0146] The results are shown in Figure 1 middle.

[0147] It should be noted that in the following experiments, leaf lettuce and tomatoes were grown under continuous light, with the illuminance in the incubator at a temperature of 42°C set at approximately 3300 lux, and otherwise set at approximately 5000 lux.

[0148] <Heat Resistance Test 2>

[0149] For leaf lettuce grown in the same manner as in heat resistance test 1, 50 mL of water or a 0.1% (v / v) acetic acid aqueous solution was injected into the roots of each plant and allowed to stand for 24 hours. This injection treatment allows water or an acetic acid aqueous solution to be supplied to the leaf lettuce from the soil surface within the ethylene pot.

[0150] Afterwards, the water supply was stopped, and the container was left to stand in the incubator for 3 days under continuous light and a temperature of 42°C.

[0151] After standing for 3 days, the ethylene pot was removed from the incubator and watered at 22℃. The survival rate of the leaf lettuce was then calculated after 2 days.

[0152] The results are shown in Figure 2.

[0153] <Heat Resistance Test 3>

[0154] In a simply constructed incubator, using ethylene pots, tomatoes (variety: Momotaro, Solanaceae family, Solanum genus) were germinated and cultivated for 3 weeks at a temperature of 22°C and a humidity of 40-50%. During cultivation, water was supplied using a watering tray, with the bottom of the ethylene pot submerged in water.

[0155] Then, excess water from the bottom surface is removed by natural dripping onto the dried water supply tray.

[0156] Irrigate each plant with 50 mL of water or a 0.06% (v / v) acetic acid solution and let it stand for 24 hours. This irrigation treatment allows water or acetic acid solution to be supplied to the tomato plants from the soil surface inside the ethylene pot.

[0157] Afterwards, the water supply was stopped, and the container was left to stand in the incubator for 3 days under continuous light and a temperature of 42°C.

[0158] After standing for 3 days, the ethylene pots were removed from the incubator and watered from the bottom at 22°C. The survival rate of the tomatoes was then calculated after 2 days. The survival rate of tomatoes in the acetic acid solution group was 100%, while the survival rate of tomatoes in the water supply group was 0%.

[0159] The results are shown in Figure 3.

[0160] <Salt Tolerance Test>

[0161] For leaf lettuce grown in the same manner as in heat resistance test 1, each plant was irrigated with 100 mL of water and either a 0.1% vol% acetic acid aqueous solution or a 0.2% vol% acetic acid aqueous solution, and allowed to stand for 24 hours. This irrigation treatment allows water or acetic acid aqueous solution to be supplied to the leaf lettuce from the soil surface within the ethylene pot.

[0162] Irrigate the roots of each plant with 100 mL of a 3.5% sodium chloride solution and let it stand for 3 days. Then, irrigate the roots with another 100 mL of the 3.5% sodium chloride solution.

[0163] The condition of leaf lettuce was observed 7 days after the initial infusion of sodium chloride solution.

[0164] The results are shown in Figure 4 middle.

Claims

1. Use of acetic acid or its salts, or their solvates, in the manufacture of heat-resistant agents for plants.

2. The use as described in claim 1, wherein, The heat resistance improver contains at least one solvent, including water.

3. The use as described in claim 2, wherein, The pH of the heat resistance enhancer is in the range of 3 to 9.

4. The use as described in claim 2 or 3, wherein, The heat resistance improver contains 0.01 to 0.5% by volume of acetic acid or its salt.

5. Use of acetic acid or its salts, or their solvates, in the manufacture of compositions for improving the heat resistance of plants.

6. The use as described in claim 5, wherein, The composition also contains at least one solvent, including water.

7. The use as described in claim 6, wherein, The pH of the composition is in the range of 3 to 9.

8. The use as described in claim 6 or 7, wherein, The composition contains 0.01 to 0.5% by volume of acetic acid or a salt thereof.

9. A method for improving the heat resistance of plants, comprising applying acetic acid or its salts or solvates thereof to plants, materials for application to plants, or soil, culture medium or nutrient solution in which plants grow.

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