Temperature stress tolerance improving agent for plant propagules

Abstract

Provided is a novel technical means capable of improving temperature stress tolerance of plant propagules.　This temperature stress tolerance improving agent for plant propagules contains a compound represented by formula (I) or a tautomer thereof, or an agriculturally acceptable salt of the compound or the tautomer. (In the formula (I), R1 and R2 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R3, R4, and R5 each independently represent an alkyl group having 1 to 4 carbon atoms.)

Description

Temperature stress tolerance enhancer for plant propagates

[0001] This patent application is made with a claim of priority based on Japanese Patent Application No. 2025-053349, filed on 27 March 2025, and the entire disclosures in the said prior patent application are incorporated herein by reference.

[0002] This invention relates to an agent for improving temperature stress tolerance.

[0003] Plant reproductive bodies (e.g., seeds) generally enter a dormant state and become capable of germination when placed in a suitable environment. Therefore, various methods are being investigated to improve germination rates and / or promote post-germination growth (including increases in seed yield, number of flower buds, number of fruits, and fruit yield).

[0004] On the other hand, it is known that plant reproductive cells have a significantly reduced germination rate if they are placed in unsuitable environments during the period leading up to germination. It is believed that in order for plant reproductive cells to germinate, they need to be placed in an environment that meets the appropriate conditions for germination, such as moisture, temperature, and / or light. Among these, temperature is considered one of the important conditions for plant reproductive cell germination.

[0005] The optimal temperature for plant germination varies depending on the plant species. It is known that when plant germination is subjected to temperature stress (for example, under a temperature environment different from the temperature range suitable for germination), metabolic activity within the plant germination decreases, thereby suppressing germination.

[0006] For example, Patent Document 1 discloses a technique for improving the germination rate of seeds when they are subjected to low-temperature stress (for example, under temperature conditions below the optimal germination temperature range) by using a compound having a specific structure.

[0007] Japanese Patent Publication No. 2023-33235

[0008] Patent Document 1 does not disclose a case where seeds are exposed to high-temperature stress (for example, under temperature conditions exceeding the optimal germination temperature range). It has been suggested that seeds exposed to high-temperature stress exhibit a mechanism different from that under low-temperature stress, for example, enhanced metabolism occurs, contrary to the case where seeds are exposed to low-temperature stress, resulting in a decrease in germination rate.

[0009] Along with recent climate change, extreme weather events have increased, and the risk that plant propagules after sowing are exposed to temperature stress has increased. Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a new technical means capable of improving temperature stress tolerance of plant propagules.

[0010] According to the present invention, the following is provided. [1] A temperature stress tolerance improving agent for plant propagules, comprising a compound represented by the following formula (I), a tautomer thereof, or an agriculturally acceptable salt thereof. (In formula (I), R １ and R ２ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ３ , R ４ and R ５ each independently represent an alkyl group having 1 to 4 carbon atoms) [2] In the above formula (I), R １ and R ２ are hydrogen atoms, and R ３ , R ４ and R ５A temperature stress tolerance improving agent according to [1], wherein is a methyl group. [3] A temperature stress tolerance improving agent according to [1] or [2], comprising a microbial extract. [4] A temperature stress tolerance improving agent according to any one of [1] to [3], further comprising a liquid carrier. [5] A temperature stress tolerance improving agent according to any one of [1] to [4], wherein the application rate of the compound represented by formula (I) above, its tautomer, or an agriculturally acceptable salt thereof is 0.5 g or more and 1000 g or less per 100 kg of the plant reproductive body. [6] A temperature stress tolerance improving agent according to any one of [1] to [5], wherein the application rate of the compound represented by formula (I) above, its tautomer, or an agriculturally acceptable salt thereof is 1 g or more and 500 g or less per 100 kg of the plant reproductive body. [7] A temperature stress tolerance improving agent according to any one of [1] to [6], wherein the plant reproductive body is exposed to temperature stress for all or part of the period before germination. [8] The temperature stress tolerance improving agent according to any one of [1] to [7], wherein the plant reproductive body is exposed to a temperature environment different from the optimal germination temperature range for all or part of the period until germination. [9] The temperature stress tolerance improving agent according to any one of [1] to [8], wherein the plant reproductive body is a seed.

[10] The temperature stress improving agent according to any one of [1] to [9], wherein the temperature stress is caused by the plant reproductive body being exposed to a temperature environment exceeding the optimal germination temperature range for all or part of the period before germination.

[11] The temperature stress tolerance improving agent according to any one of [1] to

[10] , wherein the temperature stress tolerance improving agent is an agent for improving reduced germination caused by temperature stress.

[12] The temperature stress tolerance improving agent according to any one of [1] to

[10] , wherein the temperature stress tolerance improving agent is an agent for improving delayed germination caused by temperature stress.

[13] A method for producing plant reproductive bodies with improved temperature stress tolerance, comprising the steps of: exposing the plant reproductive bodies to temperature stress for all or part of the period before germination; and applying a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof to the plant reproductive bodies to obtain plant reproductive bodies with improved temperature stress tolerance, wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (wherein it independently represents an alkyl group having 1 to 4 carbon atoms) A method for producing germinated plants, comprising the step of germinating plant reproductives produced by the method described in

[14] and

[13] to obtain germinated plants.

[15] A method for producing a plant population including germinated plants, comprising the steps of exposing plant reproductives to temperature stress for all or part of the period before germination, germinating plant reproductives to obtain germinated plants, applying a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof to a section in which plant reproductives are germinated, and obtaining a plant population including germinated plants from the section, wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (represents an alkyl group having 1 to 4 carbon atoms independently)

[16] In the above formula (I), R １ and R ２ is a hydrogen atom, R ３ , R ４ and R ５The method according to any one of

[13] to

[15] , wherein is a methyl group.

[17] The method according to any one of

[13] to

[16] , wherein the plant reproductive body is a seed.

[18] The method according to any one of

[13] to

[17] , wherein the temperature stress is caused by the plant reproductive body being exposed to a temperature environment exceeding the optimal germination temperature range for all or part of the period before germination.

[19] A method for improving temperature stress tolerance in a plant reproductive body, comprising the steps of: exposing the plant reproductive body to temperature stress for all or part of the period before germination; and applying to the plant reproductive body a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof, wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (represents an alkyl group having 1 to 4 carbon atoms independently)

[20] The method for improving temperature stress tolerance is the method for improving germination delay caused by temperature stress, according to

[19] .

[21] In the above formula (I), R １ and R ２ is a hydrogen atom, R ３ , R ４ and R ５ The method according to

[19] or

[20] , wherein is a methyl group.

[22] The method according to any one of

[19] to

[21] , wherein the plant reproductive body is a seed.

[23] The method according to any one of

[19] to

[22] , wherein the temperature stress is caused by the plant reproductive body being exposed to a temperature environment exceeding the optimal germination temperature range for all or part of the period before germination.

[24] The use of a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof in the manufacture of a temperature stress tolerance improver for plant reproductive bodies. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R４ and R ５ (represents an alkyl group having 1 to 4 carbon atoms independently)

[25] Use of a compound represented by the following formula (I) or its tautomer or an agrochemically acceptable salt thereof in improving the temperature stress tolerance of plant reproductive bodies. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (represents an alkyl group having 1 to 4 carbon atoms independently)

[26] In the above formula (I), R １ and R ２ is a hydrogen atom, R ３ , R ４ and R ５ The use according to

[24] or

[25] , wherein is a methyl group.

[27] The use according to any one of

[24] to

[26] , wherein the plant reproductive body is a seed.

[28] The use according to any one of

[24] to

[27] , wherein the temperature stress is caused by the plant reproductive body being exposed to a temperature environment exceeding the optimal germination temperature range for all or part of the period before germination.

[0011] According to one embodiment of the present invention, it becomes possible to improve the temperature stress tolerance of plant reproductive bodies.

[0012] [Temperature Stress Tolerance Improving Agent] According to one embodiment of the present invention, a temperature stress tolerance improving agent for plant reproductive bodies comprises a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.)

[0013] The above-mentioned temperature stress tolerance improving agent is advantageous in that it can suppress the decrease in the germination rate of plant reproductive bodies caused by temperature stress and / or the delay in germination of plant reproductive bodies caused by temperature stress. Furthermore, since the above-mentioned temperature stress tolerance improving agent can suppress the decrease in the germination rate of plant reproductive bodies caused by temperature stress and / or the delay in germination, it is also advantageous in that it can contribute to the growth of roots, leaves, and stems of the germinated plant reproductive bodies (i.e., post-germination plants), and to an increase in the number of flowers, seeds, and yield, and the number and yield of fruits of the post-germination plants. In addition, when it is desired to manage a uniform population of post-germination plants in a certain area, the ability to suppress the decrease in the germination rate of plant reproductive bodies and / or the delay in germination reduces the amount of work required for thinning, and / or makes it possible to sow plant reproductive bodies without the need for thinning, thus reducing the number of plant reproductive bodies used. The temperature stress tolerance improving agent of the present invention will be described in detail below.

[0014] (Compound of the present invention) According to one embodiment of the present invention, the temperature stress tolerance improving agent comprises the compound represented by formula (I) above, or a tautomer thereof, or an agriculturally acceptable salt thereof (hereinafter also referred to as "the compound of the present invention").

[0015] R １ ~R ５ The alkyl group that can be formed may be linear or branched. １ ~R ５ Examples of alkyl groups that can be formed include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, and tert-butyl groups.

[0016] According to one embodiment of the present invention, R １ and R ２ Preferably, at least one of them is a hydrogen atom, and more preferably, both are hydrogen atoms. According to one embodiment of the present invention, R １ and R ２If it is an alkyl group, it is preferably a methyl group, an ethyl group, or a propyl group, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.

[0017] According to one embodiment of the present invention, R ３ , R ４ and R ５ R is preferably independently a methyl group, an ethyl group, or a propyl group, more preferably independently a methyl group or an ethyl group, and even more preferably a methyl group. According to one embodiment of the present invention, R ３ , R ４ and R ５ Preferably, at least one of the groups is a methyl group, more preferably at least two are methyl groups, and even more preferably all are methyl groups.

[0018] Furthermore, the compound represented by formula (I) is R １ and R ２ When at least one of them is a hydrogen atom, it has tautomers. More specifically, the compound represented by formula (I) is R ２ When is a hydrogen atom, it has a tautomer compound represented by the following formula (II). Also, the compound represented by formula (I) is R １ When is a hydrogen atom, the compound has a tautomer represented by the following formula (III). In this specification, when simply referred to as "tautomer," it means that both the compound represented by formula (II) and the compound represented by formula (III) are included.

[0019] In equations (II) and (III), R １ ~R ５ R in equation (I) １ ~R ５ It is identical to [the other one].

[0020] Normally, in solution, the compound represented by formula (I) and the compound represented by formula (II) or formula (III) can exist in equilibrium. The ratio of the compound represented by formula (I) to the compound represented by formula (II) or formula (III) can vary depending on the solvent, temperature, pH, etc.

[0021] According to one embodiment of the present invention, R １ and R ２ is a hydrogen atom, and R ３ , R ４ and R ５ This is a methyl group.

[0022] According to one embodiment of the present invention, the compound represented by formula (I) is preferably ergothioneine, and more preferably L-ergothioneine((2S)-3-(2-sulfanylidene-2,3-dihydro-1H-imidazole-4-yl)-2-(trimethylazanyl)propanoate).

[0023] The compounds of the present invention may be commercially available, or they may be synthesized by techniques well known to those skilled in the art, such as those described in Japanese Patent Publication No. 2013-506706 and Japanese Patent Application Publication No. 2006-160748. Furthermore, the compounds of the present invention, including ergothioneine, can be produced by bacteria and fungi. Examples of production methods using such microorganisms include those described in Japanese Patent Application Publication No. 2012-105618, Japanese Patent Application Publication No. 2014-223051, International Publication No. 2016 / 104437, International Publication No. 2016 / 121285, International Publication No. 2015 / 168112, International Publication No. 2017 / 150304 and Japanese Patent Application Publication No. 2021-141826. The compounds of the present invention may be obtained by concentrating or purifying a culture of the microorganism that produces them, or they may be included in a temperature stress tolerance improving agent in the form of an extract or culture of the microorganism. According to one embodiment of the present invention, the temperature stress tolerance improving agent comprises an extract of a microorganism. According to one embodiment of the present invention, the temperature stress tolerance improving agent comprises an extract of a microorganism that produces the compound of the present invention.

[0024] The above-mentioned microorganisms may, for example, be known microorganisms that produce ergothioneine, but are not limited to these. Furthermore, the above-mentioned microorganisms may be isolated from the natural environment or may be microorganisms that have been treated by mutation or genetic modification. The above-mentioned microorganisms are preferably eukaryotes, more preferably belonging to the Fungal Kingdom, even more preferably yeasts, and particularly preferably belonging to the Basidiomycota phylum.

[0025] "Agriculturally acceptable" means that it is safe, non-toxic, and not undesirable in any biological or other sense, and is acceptable for agricultural use, particularly as an agricultural material to improve the temperature stress tolerance of plant reproductive organs.

[0026] The term "agriculturally acceptable salt" of the compound represented by formula (I) or its tautomer means an agriculturally acceptable salt as defined above, which provides the action and effects of the compound represented by formula (I) or its tautomer. Here, the compounds of the present invention also include hydrates and solvates of the compound represented by formula (I) or its tautomer or its agriculturally acceptable salt. Specific examples of the above agriculturally acceptable salts include acid addition salts, salts formed by the substitution of an acidic proton (proton acid) present in the compound represented by formula (I) or its tautomer with a metal ion, and salts formed by the coordination of the above acidic proton with an organic or inorganic base.

[0027] Acid addition salts may be formed with inorganic acids or organic acids. Examples of inorganic acids include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, and phosphoric acid. Examples of organic acids include acetic acid, benzenesulfonic acid, benzoic acid, camphorsulfonic acid, citric acid, ethanesulfonic acid, fumaric acid, glucoheptonic acid, gluconic acid, glutamic acid, glycolic acid, hydroxynaphthoic acid, 2-hydroxyethanesulfonic acid, lactic acid, maleic acid, malic acid, mandelic acid, methanesulfonic acid, muconic acid, 2-naphthalenesulfonic acid, propionic acid, salicylic acid, succinic acid, dibenzoyl-L-tartaric acid, tartaric acid, p-toluenesulfonic acid, trimethylacetic acid, and trifluoroacetic acid.

[0028] Examples of metal ions that can substitute for acidic protons in the compound represented by formula (I) or its tautomers include alkali metal ions, alkaline earth metal ions, and aluminum ions.

[0029] Examples of organic bases that can coordinate with acidic protons present in the compound represented by formula (I) or its tautomers include diethanolamine, ethanolamine, N-methylglucamine, triethanolamine, and tromethamine. Examples of inorganic bases that can coordinate with acidic protons present in the compound represented by formula (I) include aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, and sodium hydroxide.

[0030] The content of the compound of the present invention in the temperature stress tolerance improving agent can be arbitrarily determined depending on the dosage form, treatment conditions on the plant reproductive body, etc. For example, the content of the compound of the present invention in the temperature stress tolerance improving agent can be 0.00001 to 99% by mass relative to the total mass of the temperature stress tolerance improving agent, but it is preferably 0.01 to 90% by mass, and more preferably 0.1 to 50% by weight. Herein, in this specification, "~" means a range including the lower limit and upper limit.

[0031] Furthermore, the temperature stress tolerance improving agent may be used as is, or its concentration may be adjusted by adding solvents, diluents, and bulking agents as appropriate before use. The concentration of the compound of the present invention in the temperature stress tolerance improving agent is preferably in the range of 0.01 to 100,000 mg / L. More specifically, the lower limit may be any of 0.01 mg / L, 0.1 mg / L, 1 mg / L, 2 mg / L, 10 mg / L, 40 mg / L, 100 mg / L, 250 mg / L, 1,000 mg / L, or 10,000 mg / L, and the upper limit may be any of 100,000 mg / L, 10,000 mg / L, 1,000 mg / L, 200 mg / L, 100 mg / L, 20 mg / L, 10 mg / L, 1 mg / L, or 0.1 mg / L, and the concentration may be within any combination of these lower and upper limits, but is not limited to these. The range of the concentration can be more preferably 0.1 mg / L to 10,000 mg / L, even more preferably 1 mg / L to 1,000 mg / L, particularly preferably 0.1 mg / L to 500 mg / L, and most preferably 0.2 mg / L to 250 mg / L.

[0032] (Auxiliary agents / other active ingredients) The temperature stress tolerance improving agent may contain only one compound of the present invention as an active ingredient, or it may contain other active ingredients in addition to the compound of the present invention. The compound of the present invention may be used as is as a temperature stress tolerance improving agent for treating plant propagates, or it may be mixed with an auxiliary agent and / or other active ingredient to form a composition which may be used as a temperature stress tolerance improving agent for treating plant propagates. Furthermore, when using the compound of the present invention in combination with other active ingredients, as described above, the compound of the present invention and the other active ingredients may be mixed and used as a single agent, but the formulation containing the compound of the present invention and the formulation containing the other active ingredients may be applied separately to plant propagates, and such embodiments are also included in the present invention.

[0033] The auxiliary agents and other active ingredients in the temperature stress tolerance improving agent are not particularly limited, and known ingredients can be used. Examples of auxiliary agents include carriers, surfactants, and other auxiliary agents. Carriers can improve the solubility, water retention, water compatibility, oil absorption, and duration of effect on plant reproductive tissue of the compound and formulation of the present invention, thereby increasing the utilization efficiency of the compound and formulation of the present invention, as well as improving handling properties such as stability and storage. Surfactants can improve the solubility, stability, dispersibility, emulsification, wettability, dilution, drift reduction, adhesion to and penetration of plant reproductive tissue, absorption, and spreadability of the compound and formulation of the present invention, thereby increasing the effect and utilization efficiency of the compound on plant reproductive tissue. Examples of other active ingredients include biostimulants other than the compound of the present invention, plant growth regulators other than the compound of the present invention, fungicides, insecticides, acaricides, nematicides, and herbicides.

[0034] The following describes more specific examples of auxiliary agents used in temperature stress tolerance improving agents.

[0035] Examples of carriers used as auxiliary agents include solid carriers and liquid carriers. Including a liquid carrier in the temperature stress tolerance improving agent is advantageous from the viewpoint that the compound of the present invention may be more easily absorbed by the plant reproductive bodies to which it is applied. According to one embodiment of the present invention, the temperature stress tolerance improving agent further includes a liquid carrier.

[0036] As solid carriers, they can be used as powder carriers and granular carriers, and examples include minerals, synthetic organic substances, inorganic salts, synthetic inorganic substances, plant-based carriers, and various polymer carriers. Specifically, substances described in International Publication No. 2024 / 071089 can be used.

[0037] Examples of liquid carriers include: aliphatic solvents such as paraffins (normal paraffin, isoparaffin, naphthene); aromatic solvents such as xylene, alkylbenzene, alkylnaphthalene, and solvent naphtha; mixed solvents such as kerosene; machine oils such as refined high-boiling-point aliphatic hydrocarbons; alcohols such as methanol, ethanol, isopropanol, butanol, and cyclohexanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, polyethylene glycol, and polypropylene glycol; polyhydric alcohol derivatives such as propylene glycol ethers; acetone, acetophenone, cyanoacrylate Examples include ketones such as chlorohexanone, methylcyclohexanone, and γ-butyrolactone; esters such as fatty acid methyl esters (coconut oil fatty acid methyl ester), ethylhexyl lactate, propylene carbonate, and dibasic acid methyl esters (dimethyl succinate, dimethyl glutamate, dimethyl adipate); nitrogen-containing solvents such as N-alkylpyrrolidones and acetonitrile; sulfur-containing solvents such as dimethyl sulfoxide; oils and fats such as coconut oil, soybean oil, and rapeseed oil; amide solvents such as dimethylformamide, N,N-dimethyloctanamide, N,N-dimethyldecanamide, methyl 5-(dimethylamino)-2-methyl-5-oxovalerate, and N-acylmorpholine solvents (CAS No. 887947-29-7, etc.); and water.

[0038] Examples of surfactants used as auxiliary agents include nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, silicone-based surfactants, fluorinated surfactants, and biosurfactants. Specifically, substances described in International Publication No. 2024 / 071089 can be used.

[0039] Other auxiliary agents include pH adjusters, thickeners, disintegrating dispersants, preservatives, supplements, colorants, defoamers, antioxidants, UV absorbers, drying agents, spreading agents, and phytotoxicity mitigating agents.

[0040] Furthermore, more specific examples of other active ingredients besides the compound of the present invention in temperature stress tolerance improving agents are described below.

[0041] Suitable active ingredients for biostimulant applications include, for example, seaweed extracts, corn extracts, microalgae, mycorrhizal fungi, humic acid, fulvic acid, oxidized glutathione, L-proline, glycine betaine, 5-aminolevulinic acid, 2-hexenal, trehalose, silicic acid, nicotinic acid, acetic acid, and ethanol.

[0042] Suitable active ingredients for plant growth regulator applications include, for example, aminoethoxyvinylglycine, chlormecoat, chlorprofam, cyclanilide, dikeglac, daminozite, etephon, flurprimidol, flumetraline, forchlorfenuron, gibberellin, maleate hydrazide, mepicote chloride, methylcyclopropene, benzylaminopurine, paclobutrazol, prohexadione, tidiazuron, tributylphosphoritrithioate, trinexapac-ethyl, uniconazole, and 1-naphthaleneacetate sodium. Examples include 1-naphthylacetamide, 1-methylcyclopropene, 4-CPA (4-chlorophenoxyacetic acid), MCPB (2-methyl-4-chlorophenoxybutyrate ethyl), isoprothiolane, itaconic acid, indolebutyrate, etichlozate, calcium formate, chlormecoat, choline, cyanamide, dichlorprop, gibberellin, daminozide, decyl alcohol, sorbitan trioleate, nicosulfuron, pyraflufen ethyl, butruarin, prohydrojasmon, anisifruprine, and pendimethalin.

[0043] Suitable effective ingredients for fungicide applications include, for example, nucleic acid synthesis and metabolism inhibitors, fungicides acting on the cytoskeleton and motor proteins, respiratory inhibitors, amino acid and protein biosynthesis inhibitors, signal transduction inhibitors, lipid biosynthesis or transport / cell membrane structure or function inhibitors, cell membrane sterol biosynthesis inhibitors, cell wall biosynthesis inhibitors, melanin biosynthesis inhibitors, host plant resistance inducers, multi-point fungicides, and biopesticides / biologically derived pesticides with multiple mechanisms of action. Specifically, these include substances described in International Publication No. 2024 / 071089.

[0044] Suitable active ingredients for insecticide, acaricide, and nematicide applications include, for example, acetylcholinesterase (AChE) inhibitors, GABAergic chloride ion channel blockers, sodium channel modulators, nicotinic acetylcholine receptor (nAChR) competitive modulators, nicotinic acetylcholine receptor (nAChR) allosteric modulators, glutamate-gated chloride ion channel (GluCl) allosteric modulators, juvenile hormone analogs, other nonspecific (multisite) inhibitors, choroidal organ TRPV channel modulators, mite growth inhibitors acting on CHS1, microbial insect midgut endothelial disruptors, mitochondrial ATP synthase inhibitors, and oxidative phosphorylation deactivators that disrupt the proton gradient. Examples include conjugates, nicotinic acetylcholine receptor (nAChR) channel blockers, CHS1-acting chitin biosynthesis inhibitors, chitin biosynthesis inhibitors (type 1), molting inhibitors (in flies), molting hormone (ecdysone) receptor agonists, octopamine receptor agonists, mitochondrial electron transport chain complex III inhibitors, mitochondrial electron transport chain complex I inhibitors (METI), voltage-gated sodium channel blockers, acetyl-CoA carboxylase inhibitors, mitochondrial electron transport chain complex IV inhibitors, mitochondrial electron transport chain complex II inhibitors, ryanodine receptor modulators, chordosal organ modulators, GABAergic chloride ion channel allosteric modulators, and baculoviruses. Specifically, examples include substances described in International Publication No. 2024 / 071089.

[0045] Suitable effective ingredients for herbicidal applications include, for example, acetolactate synthesis (ALS) inhibitors, amino acid compounds, cyclohexanedione compounds, acetamide compounds, bipyridilium compounds, allyloxyphenoxypropionic acid compounds, carbamate compounds, pyridine compounds, urea compounds, dinitroaniline compounds, protoporphyrinogen oxidase (PPO) inhibitors, phenoxyacetic acid compounds, hydroxyphenylpyruvate dioxygenase enzyme (HPPD) inhibitors, and triazine compounds. Specifically, examples include substances described in International Publication No. 2024 / 071089.

[0046] Furthermore, the above components may be stored and transported in a mixed state, or some components may be contained in the first container and other components in the second container, and stored and transported separately and independently. Alternatively, the first container containing the above components and the second container containing the other components may be packaged (kit-formed) into a product.

[0047] Furthermore, temperature stress tolerance improving agents can be marketed as formulations in various dosage forms. The dosage form is not particularly limited and can be arbitrarily determined according to the treatment conditions for plant reproductive bodies, etc. Examples include powders, granules, powder-granules, wettable powders, water-soluble powders, emulsions, liquids, oils, aerosols, microencapsulated formulations, pastes, coatings, fumigants, fumigants, and trace sprays.

[0048] (Temperature Stress) In this specification, "temperature stress" refers to environmental factors that can impair the physiological functions of plant reproductive bodies as a result of exposure to temperatures outside the optimal temperature range, exceeding the upper or lower limits of the optimal temperature range, for all or part of the period leading up to germination. Temperature stress includes high-temperature stress, which occurs when the temperature exceeds the upper limit of the optimal temperature range, and low-temperature stress, which occurs when the temperature exceeds the lower limit of the optimal temperature range. The optimal temperature range may vary depending on the plant species and the type of plant reproductive body. The optimal temperature range for the period leading up to germination of plant reproductive bodies may be determined by referring to publicly available information such as literature, or a person skilled in the art may determine the optimal temperature range for the plant reproductive body in advance through preliminary tests using indicators such as germination rate and germination speed. According to one embodiment of the present invention, when comparing the germination rate and / or germination speed in plant reproductive bodies of the same species under identical conditions other than temperature during the period until germination, the temperature range in which the germination rate and / or germination speed decreases compared to the optimal temperature can be defined as temperature stress, and when this temperature range is higher than the optimal temperature, it can be defined as high temperature stress, and when it is lower than this temperature range, it can be defined as low temperature stress.

[0049] In this specification, "the period before germination" includes the storage period of the plant reproductive organism (for example, the storage period before the plant reproductive organism is sown in the soil, etc.), the growth period of the plant reproductive organism, etc. The above-mentioned period before germination may consist only of the storage period, only of the growth period, or both.

[0050] According to one embodiment of the present invention, temperature stress occurs when the plant is grown in a temperature environment that exceeds the optimal germination temperature range or in a temperature environment that falls below the optimal germination temperature range. In this specification, "optimal germination temperature range" means the optimal temperature range for the germination of the target plant reproductive organism. The optimal germination temperature range may differ depending on the target plant reproductive organism. The optimal germination temperature range for a plant reproductive organism may be a value from literature, or a temperature range determined in advance by preliminary tests, etc. According to one embodiment of the present invention, temperature stress occurs when the plant reproductive organism is grown in a temperature environment that exceeds the optimal germination temperature range or in a temperature environment that falls below the optimal germination temperature range.

[0051] According to one embodiment of the present invention, high-temperature stress is a temperature environment exceeding the optimal germination temperature range. According to one embodiment of the present invention, high-temperature stress is a temperature environment exceeding the optimal germination temperature range by 1°C or more (preferably 3°C or more, more preferably 10°C or more). According to one embodiment of the present invention, low-temperature stress is a temperature environment below the optimal germination temperature range. According to one embodiment of the present invention, low-temperature stress is a temperature environment below the optimal germination temperature range by 1°C or more (preferably 3°C or more, more preferably 10°C or more).

[0052] According to one embodiment of the present invention, temperature stress is temperatures below 20°C and above 30°C, preferably above -10°C and below 20°C (for example, above 0°C and below 20°C, above -5°C and below 15°C, and above -10°C and below 10°C) and above 30°C and below 60°C (for example, above 30°C and below 45°C, above 35°C and below 50°C, and above 40°C and below 55°C), and can vary depending on the plant species, type of plant propagator, temperature environment for sowing, etc. According to one embodiment of the present invention, high temperature stress is temperatures above 30°C, preferably above 30°C and below 60°C (for example, above 30°C and below 45°C, above 35°C and below 50°C, and above 40°C and below 55°C), and can vary depending on the plant species, type of plant propagator, temperature environment for sowing, etc. According to one embodiment of the present invention, low-temperature stress is a temperature below 20°C, preferably -10°C or higher and below 20°C (for example, 0°C or higher and below 20°C, -5°C or higher and below 15°C, -10°C or higher and below 10°C), and can vary depending on the plant species, the type of plant propagator, the temperature environment in which sowing takes place, etc.

[0053] The temperature stress tolerance improving agent of the present invention can improve resistance to the above-mentioned temperature stress. The improvement of temperature stress resistance as described herein also includes prevention of temperature stress.

[0054] (Plant Reproductive Organs) In this specification, "plant reproductive organs" means those capable of producing plant bodies after germination, before the emergence of buds and / or radicles. Therefore, plant reproductive organs refer to those before germination and do not include those after germination. Plant reproductive organs may be derived from sexual reproduction (e.g., seeds) or from asexual reproduction (e.g., vegetative reproductive organs). Examples of plant reproductive organs, though not limited to these, include seeds of seed-producing plants, spores of spore-producing plants, and vegetative reproductive organs of vegetative-producing plants (e.g., bulbs, tubers, bulbils), and these may be used individually or in any combination of two or more.

[0055] According to one embodiment of the present invention, the plant reproductive organ is a seed.

[0056] In this specification, "post-germination plant body" means an individual plant after the plant reproductive body has germinated. A post-germination plant body usually has at least one of the following: buds (including young shoots), stems, roots (including radicles), and leaves. Examples of post-germination plant bodies, though not limited to these, include, for example, seedlings, young shoots, sprouts, seedlings (e.g., young seedlings, mature seedlings, transplanted seedlings), mature plants, and adults, and these may be individually or in any combination of two or more types.

[0057] In this specification, “germination” means that the tip of the young shoot and / or young radicle breaks through the outer membrane or outer layer (e.g., seed coat) of the plant reproductive body. Therefore, in this specification, germination is encompassed by rooting. Germination can be confirmed, for example, by visual inspection or by microscopy. According to one embodiment of the present invention, germination is evaluated by the method described in the examples of this specification.

[0058] According to one embodiment of the present invention, the plant propagates are exposed to temperature stress (e.g., high temperature stress, low temperature stress) for all or part of the period leading up to germination. According to one embodiment of the present invention, the plant propagates are exposed to a temperature environment different from the optimal germination temperature range (e.g., a temperature environment exceeding the optimal germination temperature range, a temperature environment below the optimal germination temperature range) for all or part of the period leading up to germination. According to one embodiment of the present invention, the plant propagates are grown (preferably germinated) under temperature stress (e.g., high temperature stress, low temperature stress). According to one embodiment of the present invention, the plant propagates are grown (preferably germinated) under a temperature environment different from the optimal germination temperature range (e.g., a temperature environment exceeding the optimal germination temperature range, a temperature environment below the optimal germination temperature range).

[0059] According to one embodiment of the present invention, the plant reproductive body will be subjected to temperature stress (e.g., high temperature stress, low temperature stress) for all or part of the period leading up to germination. According to one embodiment of the present invention, the plant reproductive body will be exposed to a temperature environment different from the optimal germination temperature range (e.g., a temperature environment exceeding the optimal germination temperature range, a temperature environment below the optimal germination temperature range) for all or part of the period leading up to germination.

[0060] The temperature stress tolerance improving agent of the present invention may be applied to the plant reproductive bodies of any plant, but examples of plant reproductive bodies to which it can be applied include the plant reproductive bodies of the following plants: Grasses such as rice, wheat, barley, rye, oats, rye grass (trichoose), corn, sorghum, sugarcane, turfgrass, bentgrass, Bermuda grass, fescue, ryegrass; legumes such as soybeans, peanuts, kidney beans, peas, adzuki beans, alfalfa; morning glory family such as sweet potato; nightshade family such as chili peppers, bell peppers, tomatoes, eggplants, potatoes, tobacco; buckwheat family such as buckwheat; daisy family such as lettuce, sunflowers; amaranth family such as spinach; ginseng family such as ginseng; brassica family such as rapeseed, Chinese cabbage, turnip, cabbage, radish, Arabidopsis thaliana, broccoli; amaranth family such as sugar beet; mallow family such as cotton; rusaceae family such as coffee plant; cocoa The following are examples of plants: plants from the Greek family, plants from the Camellia family such as tea, plants from the Cucurbitaceae family such as watermelon, melon, cucumber, pumpkin, onion, leek, garlic, etc., plants from the Rosaceae family such as strawberry, apple, almond, apricot, plum, cherry, Japanese apricot, peach, pear, etc., plants from the Apiaceae family such as carrot, plants from the Araceae family such as taro, plants from the Anacardiaceae family such as mango, plants from the Bromeliaceae family such as pineapple, plants from the Papayaceae family such as papaya, plants from the Ebenaceae family such as persimmon, plants from the Ericaceae family such as blueberry, plants from the Juglandaceae family such as pecan, plants from the Musaceae family such as banana, plants from the Oleaceae family such as olive, plants from the Arecaceae family such as coconut palm, date palm, plants from the Rutaceae family such as mandarin orange, orange, grapefruit, lemon, etc., plants from the Vitaceae family such as grape, plants from the Cannabaceae family such as hemp, hops, hackberry, and Chinese hackberry, plants from the Iridaceae family such as saffron, and herbaceous plants (Flowers) This includes trees other than fruit trees, plants used as raw materials for traditional Chinese medicine, and other ornamental plants.

[0061] Furthermore, the plant propagates may be wild plants, plant cultivars, plants and plant cultivars obtained by conventional biological breeding methods such as crossbreeding or plasmofusion, and plant propagates of genetically modified plants and plant cultivars obtained by genetic manipulation. Examples of genetically modified plants and plant cultivars include herbicide-resistant crops, pest-resistant crops incorporating genes that produce insecticidal proteins, disease-resistant crops incorporating genes that produce disease-resistant substances, crops with improved taste, crops with increased yield, crops with improved shelf life, and crops with increased yield. Examples of genetically modified plant cultivars approved in various countries include those stored in the database of the International Service for Agri-Biotechnology (ISAA). Specifically: AgriSure, AgriSure 3000GT, AgriSure 3122 EZ Refuge, AgriSure 3122 Refuge Renew, AgriSure Artesian 3030A, AgriSure Artesian 3011A, AgriSure Duracade, AgriSure Duracade 5222 EZ Refuge, AgriSure GT, AgriSure GT / CB / LL, AgriSure RW, AgriSure Viptera 3110, AgriSure Viptera 3111, AgriSure Viptera 3220 EZ Refuge, AgriSure Viptera 3220 Refuge Renew, BiteGard, Bollgard, Bollgard II, Bollgard II / Roundup Ready, Bollgard 3 XtendFlex Cotton, Bollgard Cotton, Bollgard / Roundup Ready Cotton, Bt, Bt / BXN Cotton, Bt Maize, BtXtra, BXN, BXN Canola, BXN Cotton, Clearfield, DroughtGard, Enlist, Enlist Cotton, Enlist WideStrike 3 Cotton, Genuity, Genuity Bollgard II XtendFlex, Genuity Intacta RR2 Pro, GenuitySmartStax、Genuity SmartStax RIB Complete、Genuity VT Double Pro、Genuity VT Double Pro RIB Complete、Genuity VT Triple Pro、Genuity VT Triple Pro RIB Complete、GlyTol、GlyTol Cotton、Herculex、Herculex 1、Herculex RW、Herculex XTRA、IMI、IMI Canola、InVigor、KnockOut、Liberty Link、Liberty Link Canola、Liberty Link cotton、NatureGard、Newleaf、Nucotn、Optimum、Optimum AcreMax、Optimum AcreMax I、Optimum AcreMax-R、Optimum AcreMax RW、Optimum AcreMax RW-R、Optimum AcreMax Xtra-R、Optimum AcreMax Xtreme-R、Optimum AcreMax Xtreme、Optimum Intrasect、Optimum Intrasect Xtra、Optimum Intrasect Xtreme、Optimum Leptra、Optimum TRIsect、Poast Compatible、Powercore、Powercore Corn、Powercore Corn Refuge Advanced、Protecta、Roundup Ready、Roundup Ready 2、Roundup Ready Canola、Roundup Ready Cotton、Roundup Ready Xtend、Roundup Ready / YieldGard、RR Flex / Bollgard II、SCS、SmartStax、SmartStax Refuge Advanced、StarLink、Twinlink、VipCot、VipCot Cotton、WideStrike、WideStrike 3、YieldGard、YieldGard Corn Borner、YieldGard Rootworm、YieldGard Plus、およびYieldGardExamples include those that include registered trademarks such as VT Triple.

[0062] According to one embodiment of the present invention, the plant propagator is at least one plant propagator selected from the group consisting of grasses (preferably rice), amaranths (preferably spinach), daisies (preferably lettuce), carrots (preferably carrots), legumes (preferably soybeans), and brassicas (preferably rapeseed or broccoli). In particular, the growth (preferably germination) of plant propagators of grasses (preferably rice) and brassicas (preferably rapeseed) under low temperature stress has been investigated. Furthermore, the growth (preferably germination) of plant propagators of legumes (preferably soybeans) and brassicas (preferably rapeseed or broccoli) under high temperature stress has been investigated. Therefore, the temperature stress tolerance improving agent of the present invention can be advantageously used against low-temperature stress on at least one plant propagule selected from the group consisting of grasses (preferably rice) and brassicas (preferably rapeseed), and against high-temperature stress on at least one plant propagule selected from the group consisting of legumes (preferably soybeans) and brassicas (preferably rapeseed or broccoli).

[0063] (Manufacturing Method) The temperature stress tolerance improving agent can be manufactured by conventional methods using the compound of the present invention, and optionally the above-mentioned auxiliary agents and / or other active ingredients. For example, a formulation having a predetermined dosage form may be prepared using the compound of the present invention and an auxiliary agent such as a solid carrier or a liquid carrier.

[0064] (Method of application) The method of applying the temperature stress tolerance improving agent or the compound of the present invention to plant propagates is not particularly limited and includes, for example, direct treatment to the plant propagates, mixing with irrigation water, spraying on soil, and injection into the subsoil using an injection machine. For example, when spraying the temperature stress tolerance improving agent or the compound of the present invention on soil, the plant propagates may be sown in the soil beforehand and then the temperature stress tolerance improving agent or the compound of the present invention may be sprayed on the soil beforehand and then the plant propagates may be sown on the soil, or both may be done.

[0065] The amount of the temperature stress tolerance improving agent or the compound of the present invention applied is not particularly limited as long as it is an amount that can achieve the objective of the present invention, and a person skilled in the art can adjust it as appropriate, taking into consideration the type of plant propagator, the degree of temperature stress, the method of application of the temperature stress tolerance improving agent, etc.

[0066] When mixing with irrigation water, for example, the temperature stress tolerance improving agent or the compound of the present invention can be applied to the water used for irrigating plant propagates or to the surface water of paddy fields. For example, the concentration of the compound of the present invention in the water used for irrigating or soaking plants can be 0.01 mg / L or more and 500,000 mg / L or less, and preferably 0.1 mg / L or more and 100,000 mg / L or less. When applying to paddy field water, the application rate of the temperature stress tolerance improving agent or the compound of the present invention can be, for example, 0.1 g or more and 10,000 g or less per 10 ares of paddy field, and preferably 1 g or more and 1,000 g or less.

[0067] When treating the soil, for example, the temperature stress tolerance improving agent or the compound of the present invention may be applied to the planting hole or its surroundings when sowing plant reproductive bodies, or the soil surrounding the plant reproductive bodies may be treated with the temperature stress tolerance improving agent or the compound of the present invention. Furthermore, after treating the soil, the soil and the temperature stress tolerance improving agent or the compound of the present invention may be mixed and stirred. Examples of areas to be treated include land (e.g., plots) where plant reproductive bodies exist, such as fields, paddies, orchards, and greenhouses. The application rate of the temperature stress tolerance improving agent or the compound of the present invention per hectare of land to be sprayed on the plant reproductive bodies is preferably 1 g to 2,000 g, more preferably 10 g to 500 g. Also, when treating the soil, the application rate of the temperature stress tolerance improving agent or the compound of the present invention per 1 m² of land area where plant reproductive bodies exist is, for example, per 1 m² of land area. ２ The amount per unit can be between 0.001 g and 10,000 g, and is preferably between 0.01 g and 1,000 g.

[0068] Furthermore, when direct treatment of plant reproductive bodies is performed (for example, seed treatment if the plant reproductive bodies are seeds), the temperature stress tolerance improving agent or the compound of the present invention may be mixed with the plant reproductive bodies and stirred, or the plant reproductive bodies may be immersed in a diluted temperature stress tolerance improving agent or the compound of the present invention (wettable powder, etc.). Alternatively, the temperature stress tolerance improving agent or the compound of the present invention may be coated onto the plant reproductive bodies. According to one embodiment of the present invention, the temperature stress tolerance improving agent is for direct treatment of plant reproductive bodies (preferably seed treatment).

[0069] When directly treating plant reproductive bodies, the amount of temperature stress tolerance improving agent or compound of the present invention applied can be, for example, 0.5 g to 1000 g per 100 kg of plant reproductive bodies, preferably 1 g to 500 g, more preferably 3 g to 450 g, and particularly preferably 5 g to 400 g.

[0070] When directly treating plant reproductive bodies, the treatment temperature (for example, the temperature of the temperature stress tolerance improving agent or the compound of the present invention) can be appropriately adjusted by those skilled in the art, taking into account the treatment time, etc. For example, it may be 0°C to 80°C, preferably 10°C to 50°C, and more preferably room temperature.

[0071] When directly treating plant reproductive bodies, the treatment time (for example, the contact time between the temperature stress tolerance improving agent or the compound of the present invention and the plant reproductive bodies) can be appropriately adjusted by those skilled in the art, taking into account the treatment temperature, etc., but may be, for example, 0.01 hours or more and 48 hours or less, preferably 0.03 hours or more and 36 hours or less, and more preferably 0.1 hours or more and 12 hours or less.

[0072] When directly treating plant reproductive bodies, the treated reproductive bodies may be dried or otherwise processed.

[0073] The temperature stress tolerance improving agent of the present invention can be advantageously used to improve the reduced germination rate of plant propagates caused by temperature stress, and / or to improve delayed germination caused by temperature stress. According to one embodiment of the present invention, the temperature stress tolerance improving agent is an agent for improving reduced germination rate caused by temperature stress (preferably low temperature stress and / or high temperature stress). According to one embodiment of the present invention, the temperature stress tolerance improving agent is an agent for improving delayed germination caused by temperature stress (preferably low temperature stress and / or high temperature stress). Germination rate refers to the germination rate and / or germination speed.

[0074] [Method for Producing Plant Propagants with Improved Temperature Stress Tolerance] According to one embodiment of the present invention, a method for producing plant propagants (preferably seeds) with improved temperature stress tolerance comprises: a step of exposing the plant propagants to temperature stress for all or part of the period before germination (hereinafter also referred to as the "temperature stress exposure step"), and a step of applying a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof (i.e., the compound of the present invention) to the plant propagants (preferably seeds) to obtain plant propagants (preferably seeds) with improved temperature stress tolerance (hereinafter also referred to as the "plant propagant acquisition step"), wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ A (which independently represents an alkyl group having 1 to 4 carbon atoms) is provided.

[0075] (Temperature Stress Exposure Step) According to one embodiment of the present invention, a method for producing plant propagules with improved temperature stress tolerance is characterized in that a temperature stress exposure step is performed. The period during which the plant propagules are exposed to temperature stress in the above temperature stress exposure step is not particularly limited and can be appropriately adjusted by those skilled in the art depending on the type of plant propagule, the type of temperature stress (e.g., high temperature stress, low temperature stress), the degree of temperature stress, etc.

[0076] According to one embodiment of the present invention, the temperature stress exposure step includes a step of growing plant reproductives under temperature stress. When the temperature stress exposure step includes a step of growing plant reproductives under temperature stress, the growth period and the like are not particularly limited and can be appropriately adjusted by those skilled in the art depending on the type of plant reproductives, the type of temperature stress (e.g., high temperature stress, low temperature stress), the degree of temperature stress, etc.

[0077] (Plant Propagation Acquisition Process) According to one embodiment of the present invention, a method for producing plant propagates with improved temperature stress tolerance is characterized in that a plant propagation acquisition process is carried out. Furthermore, according to one embodiment of the present invention, the above application is carried out before germination (preferably, the above application is carried out before germination and before exposure to temperature stress).

[0078] In this specification, the application being carried out before germination is not particularly limited to cases where the application is carried out before the plant reproductive body germinates. The application may be carried out before the plant reproductive body is exposed to temperature stress, while it is being subjected to temperature stress, or both. Specific embodiments of the application being carried out before germination include, for example, the application being carried out before sowing the plant reproductive body in a desired plot of land (for example, carrying out direct treatment of the plant reproductive body such as seed treatment), and the application being carried out on the land after sowing the plant reproductive body in a desired plot of land (for example, sowing the plant reproductive body in a desired plot of land and then spraying the land with the compound of the present invention). The land may already be exposed to temperature stress before sowing the plant reproductive body, may be exposed to temperature stress when sowing the plant reproductive body, or may be exposed to temperature stress after sowing the plant reproductive body.

[0079] Furthermore, in this specification, the phrase "the application is carried out before germination and before exposure to temperature stress" is not particularly limited to any application carried out before the plant reproductive body germinates and before exposure to temperature stress. Therefore, the embodiment of the application being carried out before germination and before exposure to temperature stress also includes an embodiment in which the application is started before exposure to temperature stress (for example, an embodiment in which the application is carried out before the plant reproductive body is exposed to temperature stress, and then, if necessary, the application is carried out again after the plant reproductive body has been exposed to temperature stress). According to one embodiment of the present invention, the application is carried out before germination and started before exposure to temperature stress. Specific embodiments of the above application being carried out before germination and before exposure to temperature stress include, for example, an embodiment in which the above application is carried out before sowing plant reproductive bodies (preferably plant reproductive bodies not exposed to temperature stress) in a desired plot of land (for example, an embodiment in which direct treatment of plant reproductive bodies such as seed treatment is carried out); an embodiment in which the above application is carried out in land not exposed to temperature stress and plant reproductive bodies (preferably plant reproductive bodies not exposed to temperature stress) are sown in land not exposed to temperature stress and the above application is carried out in said land not exposed to temperature stress (for example, an embodiment in which plant reproductive bodies are sown in land not exposed to temperature stress and then the compound of the present invention is sprayed on said land not exposed to temperature stress).

[0080] The method and amount of application of the compound of the present invention in the plant propagation process described above may be the same as those described above for the temperature stress tolerance improving agent.

[0081] According to one embodiment of the present invention, the plant propagation step includes applying the compound of the present invention (preferably an effective amount of the compound of the present invention) to a plant propagation that requires improvement in temperature stress tolerance.

[0082] According to one embodiment of the present invention, the amount of compound of the present invention applied in the plant propagation acquisition step may be 0.5 g or more and 1000 g or less per 100 kg of plant propagation (preferably 1 g or more and 500 g or less, more preferably 3 g or more and 450 g or less, and particularly preferably 5 g or more and 400 g or less).

[0083] According to one embodiment of the present invention, the plant reproductive body acquisition step includes contacting the plant reproductive body with the compound of the present invention (preferably directly treating the plant reproductive body with the compound of the present invention).

[0084] A method for producing plant propagules with improved temperature stress tolerance may include, as necessary, other steps in addition to those described above. Such other steps may be performed at any time before, during, or after each of the above steps.

[0085] Furthermore, preferred embodiments of the method for producing plant reproductive bodies with improved temperature stress tolerance may be the same as those described above for the temperature stress tolerance improving agent.

[0086] Plant reproductive bodies with improved temperature stress tolerance produced by the above method may contain the compound of the present invention. The amount of the compound of the present invention contained in the plant reproductive bodies with improved temperature stress tolerance can be, for example, 0.05 μg to 100 mg per gram of plant reproductive body, and preferably 0.5 μg to 10 mg. The amount of the compound of the present invention contained in the plant reproductive bodies with improved temperature stress tolerance can be determined, for example, by extracting the compound of the present invention from the plant reproductive bodies with a solvent and analyzing it using high-performance liquid chromatography and mass spectrometry. The above extraction and analysis methods can be appropriately adjusted by those skilled in the art, taking into consideration publicly known information, etc.

[0087] According to one embodiment of the present invention, the plant reproductive body with improved temperature stress tolerance produced by the above method contains the compound of the present invention inside the plant reproductive body and / or has the compound of the present invention attached to its surface.

[0088] According to another embodiment of the present invention, the application described above (preferably in the plant propagation acquisition step) in a method for producing plant propagules with improved temperature stress tolerance may be carried out during the temperature stress exposure step.

[0089] [Plant Reproduction with Improved Temperature Stress Tolerance] According to one embodiment of the present invention, plant reproduction (preferably seeds) with improved temperature stress tolerance is provided, produced by the above method. The above plant reproduction is advantageous in that, because of its improved temperature stress tolerance, a decrease in germination rate and / or delayed germination can be suppressed even when exposed to temperature stress.

[0090] [Method for producing a plant after germination] According to one embodiment of the present invention, a method for producing a plant after germination is provided, comprising the step of germinating a plant reproductive body (preferably seeds) produced by the above method to obtain a plant after germination. According to one embodiment of the present invention, a method for producing a plant after germination is provided, comprising the step of exposing a plant reproductive body (preferably seeds) produced by the above method to temperature stress for all or part of the period before germination (this step may be the same as the temperature stress exposure step), and the step of germinating the plant reproductive body to obtain a plant after germination. The conditions before germination (temperature, period, etc.) in the step of obtaining the plant after germination are not particularly limited and can be appropriately adjusted by those skilled in the art depending on the type of plant reproductive body, the desired plant after germination, etc.

[0091] The above method for producing the germinated plant may include other steps as needed, in addition to the steps described above. Such other steps may be carried out at any time before, during, or after the above steps.

[0092] A preferred embodiment of the method for producing the plant body after germination described above may be the same as that described above for producing a temperature stress tolerance improving agent and / or a plant propagule with improved temperature stress tolerance.

[0093] According to one embodiment of the present invention, the plant body after germination is a seedling.

[0094] [Post-germination Plant] According to one embodiment of the present invention, there is provided a post-germination plant (preferably a seedling) produced by the above method.

[0095] [Method for Producing Plant Population] According to one embodiment of the present invention, there is provided a method for producing a plant population including post-germination plants, the method comprising: a step of exposing a plant propagule (preferably a seed) to temperature stress for all or part of the period before germination (that is, the aforementioned temperature stress exposure step); a step of germinating a plant propagule (preferably a seed) to obtain a post-germination plant (also referred to as the "plant obtaining step" herein); a step of applying a compound represented by the following formula (I), a tautomer thereof, or an agriculturally acceptable salt thereof (that is, the compound of the present invention) to a section where plant propagules (preferably seeds) are germinated (also referred to as the "application step" herein); and a step of obtaining a plant population including post-germination plants from the aforementioned section (also referred to as the "plant population obtaining step" herein), wherein the aforementioned application is carried out before the aforementioned germination. (In formula (I), R １ and R ２ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ３ , R ４ and R ５ each independently represent an alkyl group having 1 to 4 carbon atoms). According to one embodiment of the present invention, pre-application of the compound of the present invention to a section where plant propagules are germinated suppresses germination delay of plant propagules caused by temperature stress, and increases the proportion of post-germination plants (that is, germinated plant propagules) included in the plant population recovered from the section. As a result, this is advantageous from the viewpoint that it can reduce the man-hours required for thinning out individuals with poor germination included in the plant population or individuals with slow growth after germination, and / or thinning out to adjust the plant population to an appropriate planting density even when the post-germination growth is normal, and / or can reduce the number of plant propagules to be sown.

[0096] In this specification, "plant population" means a group of plants that includes, at least a portion, plant bodies after germination. A plant population may include plant reproductive bodies. A plant population may include only one species of plant, or any combination of two or more species of plants.

[0097] (Plant Acquisition Process) According to one embodiment of the present invention, the method for producing the above-mentioned plant population is characterized in that a plant acquisition process is carried out. According to one embodiment of the present invention, the plant acquisition process includes a process of growing plant reproductive bodies. The growth conditions in the plant acquisition process may be the same as the growth conditions described for the method of producing the above-mentioned plant reproductive bodies. According to one embodiment of the present invention, the plant acquisition process includes growing and germinating the plant reproductive bodies under temperature stress.

[0098] (Application Process) According to one embodiment of the present invention, the method for producing the above-mentioned plant population is characterized in that an application process is carried out. Furthermore, according to one embodiment of the present invention, the application in the method for producing the plant population is characterized in that it is carried out before germination (preferably, the application is carried out before germination and before exposure to temperature stress).

[0099] The application conditions in the application step of the method for producing the above-mentioned plant population may be the same as the application conditions (application method, application amount, etc.) mentioned for the plant reproductive body acquisition step in the method for producing the above-mentioned plant reproductive body.

[0100] The area in which plant reproductive bodies are germinated is not particularly limited, and a person skilled in the art can adjust it as appropriate depending on the type of plant reproductive body and / or the type of plant after germination, the desired plant population, etc. Examples of such areas include soil and paddy fields.

[0101] According to one embodiment of the present invention, the application step includes applying the compound of the present invention (preferably an effective amount of the compound of the present invention) to a plot where plant propagates requiring improved temperature stress tolerance are germinating.

[0102] (Plant population acquisition process) According to one embodiment of the present invention, a method for producing a plant population is characterized in that a plant population acquisition process is carried out. The method for acquiring the plant population in the plant population acquisition process is not particularly limited, and may be, for example, by hand-picking the plant population from the above-mentioned area, or by recovering the plant population from the above-mentioned area using equipment or the like.

[0103] The method for producing the above-mentioned plant population may include other steps as needed, in addition to the steps described above. Such other steps may be performed at any time before, during, or after each of the above-mentioned steps.

[0104] Preferred embodiments of the method for producing the above-mentioned plant population may be the same as those described above for a temperature stress tolerance improving agent, a method for producing plant reproductive bodies with improved temperature stress tolerance, and / or a method for producing plants after germination.

[0105] According to another embodiment of the present invention, the application (preferably the application step) in the method for producing a plant population may be carried out during the temperature stress exposure step.

[0106] [Plant Population] According to one embodiment of the present invention, a plant population produced by the above method is provided. The plant population produced by the above method is advantageous in that it can reduce the amount of work required for thinning out individuals that have poor germination or slow growth after germination, or for thinning out individuals that have grown properly after germination to achieve an appropriate planting density.

[0107] [Method for improving temperature stress tolerance] According to one embodiment of the present invention, a method for improving temperature stress tolerance in plant propagates (preferably seeds) comprises the steps of: exposing plant propagates (preferably seeds) to temperature stress for all or part of the period before germination (i.e., the above temperature stress exposure step); and applying to plant propagates (preferably seeds) a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof (i.e., the compound of the present invention), wherein the application is carried out before germination. (In formula (I), R １ and R ２ each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ３ , R ４ and R ５ each independently represent an alkyl group having 1 to 4 carbon atoms) is provided.

[0108] (Temperature Stress Exposure Step) According to one embodiment of the present invention, in the method for improving temperature stress tolerance in plant propagative materials, a temperature stress exposure step is characterized to be carried out. The temperature stress exposure step described above is the same as the temperature stress exposure step in the method for producing the plant propagative material described above.

[0109] (Application Step) According to one embodiment of the present invention, in the method for improving temperature stress tolerance in plant propagative materials, the method is characterized in that a step of applying the compound of the present invention to a plant propagative material is carried out. Further, according to one embodiment of the present invention, the application in the method for improving temperature stress tolerance is characterized in that it is carried out before the germination (preferably carried out before the germination and also carried out before exposure to temperature stress).

[0110] The application step in the method for improving the temperature stress tolerance described above may be the same as the plant propagative material obtaining step in the method for producing the plant propagative material described above. According to one embodiment of the present invention, the application step comprises applying the compound of the present invention (preferably an effective amount of the compound of the present invention) to a plant propagative material in need of improvement of temperature stress tolerance.

[0111] The method for improving temperature stress tolerance may include other steps as necessary in addition to the steps described above. Such other steps may be carried out at any timing before, during or after each of the above steps.

[0112] In addition, preferred embodiments of the method for improving temperature stress tolerance may be the same as those described above for the temperature stress tolerance improving agent.

[0113] According to one embodiment of the present invention, a method for improving temperature stress tolerance is a method for improving reduced germination caused by temperature stress. According to one embodiment of the present invention, a method for improving temperature stress tolerance is a method for improving delayed germination caused by temperature stress.

[0114] According to another embodiment of the present invention, the application in the method for improving temperature stress tolerance may be carried out during the temperature stress exposure step.

[0115] [Other Embodiments] According to one embodiment of the present invention, a compound or a temperature stress tolerance improving agent of the present invention is provided for improving the temperature stress tolerance of plant reproductive bodies (preferably seeds).

[0116] According to one embodiment of the present invention, the use of the compound or temperature stress tolerance improving agent of the present invention is provided for improving the temperature stress tolerance of plant reproductive bodies (preferably seeds).

[0117] According to one embodiment of the present invention, the use of the compound of the present invention in the production of a temperature stress tolerance improver for plant reproductive bodies (preferably seeds) is provided.

[0118] According to one embodiment of the present invention, a composition comprising the compound of the present invention is provided for use as a temperature stress tolerance improving agent for plant reproductive bodies.

[0119] It should be noted that the embodiments described above are exemplary embodiments of the present invention, and it goes without saying that the present invention may include embodiments other than those described above within the scope of its core technical concept.

[0120] The present invention will be described in detail based on examples, but the present invention is not limited to these examples. Unless otherwise specified, the measurement methods and units described herein shall conform to those of the Japanese Industrial Standards (JIS).

[0121] [Example 1: Germination Evaluation under Low Temperature Stress 1 (Rapeseed)] A temperature stress tolerance improver was obtained by mixing commercially available L-(+)-ergothioneine (molecular weight: 229.3, also referred to as "EGT" in this specification) with pure water. 0.1 g of rapeseed (Norin No. 16, country of origin: Japan) seeds were placed in a tube, 5 μL of the above temperature stress tolerance improver was added, and the mixture was inverted and mixed. The seeds were then air-dried. 10 mL of water was added to a 9 cm petri dish lined with filter paper, and the air-dried seeds (30 seeds) were sown. The amount of EGT applied per unit weight of seeds is as shown in Table 1. The seeds were subjected to low temperature stress by storing the petri dish at 4°C for 48 hours after sowing. The petri dish was then stored in an artificial climate chamber set to 22°C, illuminance 5000 lx, light period 16 hours, and dark period 8 hours, and the germination rate was evaluated over time. Germination was determined when a sprout or radicle was visually confirmed. The germination rate was calculated as the ratio of the number of germinated seeds to the number of seeds provided (number of germinated seeds / number of seeds provided × 100). The same method was followed for the group without cold stress, except that the above petri dishes containing seeds without added temperature stress tolerance enhancers were not stored at 4°C. The Germination Rate Index (GRI) was calculated using the following formula based on the germination rate evaluated over time (germination rate from sowing to day 7). For the calculation of the GRI, the final day was defined as the day on which there was no difference in germination rate from the previous day for all groups, including the untreated group and the EGT-treated group (10g / dt seed, 100g / dt seed) (i.e., in Example 1, there was no difference in germination rate between day 6 and day 7 for all groups, including the untreated group and the EGT-treated group, so day 7 was defined as the final day). GRI is an indicator of germination rate; a higher value indicates a faster germination rate. The results are shown in Table 1.

[0122]

[0123]

[0124] [Example 2: Germination Evaluation under Low Temperature Stress 2 (Rice)] A temperature stress tolerance improver was obtained by mixing commercially available EGT with pure water so that the application rate of EGT was as shown in Table 2 below. 10 mL of the temperature stress tolerance improver obtained above was added to a 9 cm petri dish lined with filter paper, and rice (Koshihikari, country of origin: Japan) seeds (30 seeds) were sown. The amount of EGT applied per seed weight is as shown in Table 2. After sowing, the petri dish was stored in an incubator set to 15°C (low temperature stress), and the germination rate was evaluated over time in the same manner as in Example 1. The group without low temperature stress was stored in an incubator set to 28°C without the temperature stress tolerance improver added. In addition, the GRI was calculated in the same manner as in Example 1 based on the germination rate evaluated over time (germination rate from sowing to day 14). The results are shown in Table 2.

[0125]

[0126] [Example 3: Germination Evaluation under High Temperature Stress 1 (Soybean)] Commercially available EGT or glycine betaine (hereinafter also referred to as "GB") was mixed with pure water to obtain each temperature stress tolerance improving agent. 0.1 g of soybean (Enrei, country of origin: Japan) seeds were placed in a tube, 1 μL of the above temperature stress tolerance improving agent was added, and the mixture was inverted and mixed. The seeds were then air-dried. 10 mL of water was added to a 9 cm petri dish lined with filter paper, and the air-dried seeds (30 seeds) were sown. The amount of EGT and GB applied per unit weight of seeds is as shown in Table 3. After sowing, the petri dish was stored in an artificial climate chamber set to 35°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours, and the germination rate on the 5th day was evaluated using the same method as in Example 1. The group without high-temperature stress was stored in a petri dish containing seeds without any added temperature stress tolerance enhancer in an artificial climate chamber set to 22°C, 5000 lx illumination, 16 hours of light, and 8 hours of darkness. The results are shown in Table 3.

[0127]

[0128] [Example 4: Germination Evaluation under High Temperature Stress 2 (Rapeseed)] Commercially available EGT or GB was mixed with pure water to obtain each temperature stress tolerance improving agent. 0.1 g of rapeseed (Norin No. 16, country of origin: Japan) seeds were placed in a tube, 5 μL of the above temperature stress tolerance improving agent was added, and the mixture was inverted and mixed. The seeds were then air-dried. 10 mL of water was added to a 9 cm petri dish lined with filter paper, and the air-dried seeds (30 seeds) were sown. The amount of EGT and GB applied per unit weight of seeds is shown in Table 4. After sowing, the seeds were stored in an artificial climate chamber set to 40°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours, and the germination rate on the 10th day was evaluated using the same method as in Example 1. The group without high-temperature stress was stored in a petri dish containing seeds without any added temperature stress tolerance enhancer in an artificial climate chamber set to 22°C, 5000 lx illumination, 16 hours of light, and 8 hours of darkness. The results are shown in Table 4.

[0129]

[0130] [Example 5: Germination Evaluation under High Temperature Stress 3 (Broccoli)] Commercially available EGT or GB was mixed with pure water to obtain each temperature stress tolerance improving agent. 0.1 g of broccoli (Ryokuseki, country of origin: Japan) seeds were placed in a tube, 10 μL of the above temperature stress tolerance improving agent was added, and the mixture was inverted and mixed. The seeds were then air-dried. 10 mL of water was added to a 9 cm petri dish lined with filter paper, and the air-dried seeds (30 seeds) were sown. The amount of EGT and GB applied per unit weight of seeds is shown in Table 5. After sowing, the seeds were stored in an artificial climate chamber set to 35°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours, and the germination rate on the 6th day was evaluated using the same method as in Example 1. The group without high-temperature stress was stored in a petri dish containing seeds without any added temperature stress tolerance enhancer in an artificial climate chamber set to 22°C, illuminance of 5000 lx, 16 hours of light, and 8 hours of darkness. The results are shown in Table 5.

[0131]

[0132] [Example 6: Germination Evaluation under High Temperature Stress 4 (Spinach)] Commercially available EGT (Combi-Blocks) or EGT extract prepared by the method described in Japanese Patent Publication No. 2021-141826 was adjusted to a predetermined concentration with pure water to obtain each temperature stress tolerance improving agent. 10 mL of each temperature stress tolerance improving agent was added to a 9 cm diameter petri dish (Nipro Corporation) containing filter paper. If EGT was not applied, only pure water was used. Two petri dishes were prepared for each experimental group. 20 seeds of spinach (Justice, country of origin: Japan) (Sakata Seed Corporation) were sown in each petri dish. The EGT concentration and the amount of EGT applied per unit weight of seeds are as shown in Table 6. After sowing, the plants were stored in an artificial climate chamber set to 33°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours. The group without high-temperature stress was stored in an artificial climate chamber set to 15°C, 5000 lx illumination, 16 hours of light, and 8 hours of darkness. Germination was observed 14 days after sowing, and the germination rate and the percentage increase in germination rate compared to the unstressed and untreated groups were calculated. Germination was defined as the point at which the bud or radicle broke through the seed coat and was visually confirmed. The results are shown in Table 6.

[0133]

[0134] [Example 7: Germination Evaluation under High Temperature Stress 5 (Lettuce)] Commercially available EGT (Combi-Blocks) or EGT extract prepared by the method described in Japanese Patent Publication No. 2021-141826 was adjusted to a predetermined concentration with pure water to obtain each temperature stress tolerance improving agent. 10 mL of each temperature stress tolerance improving agent was added to a 9 cm diameter petri dish (Nipro Corporation) containing filter paper. If EGT was not applied, only pure water was used. Two petri dishes were prepared for each experimental group. 20 lettuce seeds (King Crown, country of origin: Japan) (Sakata Seed Corporation) were sown in each petri dish. The EGT concentration and the amount of EGT applied per seed weight are as shown in Table 7. After sowing, the plants were stored in an artificial climate chamber set to 33°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours. The group without high-temperature stress was stored in an artificial climate chamber set to 15°C, 5000 lx illumination, 16 hours of light, and 8 hours of darkness. Germination was observed 7 days after sowing, and the germination rate and the percentage increase in germination rate compared to the unstressed and untreated groups were calculated. Germination was defined as the point at which the bud or radicle broke through the seed coat and was visually confirmed. The results are shown in Table 7.

[0135]

[0136] [Example 8: Germination Evaluation under High Temperature Stress 6 (Broccoli)] Commercially available EGT (Combi-Blocks) or EGT extract prepared by the method described in Japanese Patent Publication No. 2021-141826 was adjusted to a predetermined concentration with pure water to obtain each temperature stress tolerance improving agent. Broccoli (Ohayo, Country of Origin: Japan) seeds (Sakata Seed Corporation) were placed in a 1.5 mL tube, the above temperature stress tolerance improving agents were added, and the mixture was inverted and mixed. The seeds were then air-dried. 10 mL of water was added to a 9 cm diameter petri dish (Nipro Corporation) with filter paper inside, and the air-dried seeds (50 seeds) were sown. The amount of EGT applied per unit weight of seeds is as shown in Table 7. After sowing, the seeds were stored in an artificial climate chamber set to 33°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours. The group without high-temperature stress was stored in an artificial climate chamber set to 15°C, 5000 lx illumination, 16 hours of light, and 8 hours of darkness. Germination was observed 14 days after sowing, and the germination rate and the percentage increase in germination rate compared to the unstressed and untreated groups were calculated. Germination was defined as the point at which the bud or radicle broke through the seed coat and was visually confirmed. The results are shown in Table 8.

[0137]

[0138] [Example 9: Germination Evaluation under High Temperature Stress 7 (Carrot)] Commercially available EGT (Combi-Blocks) or EGT extract prepared by the method described in Japanese Patent Publication No. 2021-141826 was adjusted to a predetermined concentration with pure water to obtain each temperature stress tolerance improving agent. 10 mL of each temperature stress tolerance improving agent was added to a 9 cm diameter petri dish (Nipro Corporation) containing filter paper. If EGT was not applied, only pure water was used. Two petri dishes were prepared for each experimental group. 20 carrot seeds (Kin'yo Gosun No. 2, country of origin: Japan) (Sakata Seed Corporation) were sown in each petri dish. The EGT concentration and the amount of EGT applied per seed weight are as shown in Table 9. After sowing, the plants were stored in an artificial climate chamber set to 33°C (high temperature stress), illuminance 5000 lx, light period 16 hours, and dark period 8 hours. The group without high-temperature stress was stored in an artificial climate chamber set to 15°C, 5000 lx illumination, 16 hours of light, and 8 hours of darkness. Germination was observed 7 days after sowing, and the germination rate and the percentage increase in germination rate compared to the unstressed and untreated groups were calculated. Germination was defined as the point at which the bud or radicle broke through the seed coat and was visually confirmed. The results are shown in Table 9.

[0139]

[0140] As is clear from the results of Examples 1 to 9, it is believed that applying the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof (preferably ergothioneine or its tautomer or an agriculturally acceptable salt thereof, more preferably L-(+)-ergothioneine or an agriculturally acceptable salt thereof) to plant reproductive bodies (preferably seeds) suppresses the decrease in germination rate of the plant reproductive bodies (preferably seeds) caused by temperature stress. The compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof according to the present invention is advantageous compared to glycine betaine, a known growth promoter, in terms of being able to more effectively suppress the decrease in germination rate of the plant reproductive bodies (preferably seeds) caused by temperature stress (Tables 3 to 5).

[0141] Furthermore, as is clear from the results of Examples 1 and 2, the GRI value increased when the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof (preferably ergothioneine or its tautomer or an agriculturally acceptable salt thereof, more preferably L-(+)-ergothioneine or an agriculturally acceptable salt thereof) was applied to plant reproductive bodies (preferably seeds). This suggests that the delayed germination of the plant reproductive bodies (preferably seeds) caused by temperature stress is suppressed.

[0142] Furthermore, as is clear from the results of Examples 6 and 9, applying an extract of a microorganism that produces the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof (preferably ergothioneine or its tautomer or an agriculturally acceptable salt thereof, more preferably L-(+)-ergothioneine or an agriculturally acceptable salt thereof) to plant reproductive bodies (preferably seeds) is advantageous in that it can more effectively suppress the decrease in germination rate of the plant reproductive bodies (preferably seeds) caused by temperature stress, compared to applying the compound alone. Although not bound by theory, it is thought that when applying the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof to plant reproductive bodies (preferably seeds), the addition of an extract of a microorganism that produces the compound (microbial components other than the compound) can more effectively suppress the decrease in germination rate of the plant reproductive bodies (preferably seeds) caused by temperature stress, compared to experimental groups using the same amount (concentration) of the compound.

[0143] While not bound by theory, a decrease in germination rate is thought to lead to a decrease in the yield of plants after germination and the products derived from those plants (fruits, seeds, etc.). Furthermore, if the germination of plant reproductive bodies is delayed, the germination timing of each plant reproductive body will tend to vary, leading to differences in the growth of each resulting plant after germination. As a result, the yield of plants after germination and the products derived from those plants (fruits, seeds, etc.) is thought to decrease (for example, early-germinating plants may cover late-germinating plants, delaying the growth of late-germinating plants). Therefore, in such cases, it is thought that disadvantages may arise, such as the need to sow extra plant reproductive bodies or perform thinning work to secure the required yield of plants and products derived from those plants, resulting in economic disadvantages. On the other hand, according to one embodiment of the present invention, it is possible to suppress the germination delay of plant reproductive bodies that have been subjected to temperature stress, are under temperature stress, and / or will be subjected to temperature stress in the future. Therefore, it is considered particularly advantageous from the viewpoint that the amount of plant reproductive bodies to be sown can be reduced and / or the amount of labor required for thinning and other tasks can be reduced.

[0144] Furthermore, in Examples 1, 3-5, when ergothioneine was applied to plant propagules (rapeseed seeds, soybean seeds, broccoli seeds) in the same manner as in the untreated group, except that temperature stress was not applied, there was almost no difference in germination rate or GRI compared to the untreated group, as revealed by the inventors' further investigations. Nevertheless, the fact that applying the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof to plant propagules prevents or improves the decrease in germination rate caused by temperature stress, and / or prevents or improves delayed germination, is a completely unexpected result.

[0145] International Publication No. 2024 / 071089 discloses that applying ergothioneine to germinated plants can suppress the mortality rate and leaf wilting rate of those germinated plants when subjected to temperature stress. However, the growth mechanism in germinated plants and the germination mechanism in plant reproductive bodies are considered to be completely different. Therefore, the fact that applying the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof to plant reproductive bodies can improve their temperature stress tolerance is a surprising effect that could not be predicted at all from International Publication No. 2024 / 071089.

[0146] Under modern climate change, both low-temperature stress and high-temperature stress are considered challenges in agriculture. According to one embodiment of the present invention, the compound of the present invention is particularly advantageous in that it can improve both low-temperature stress tolerance and high-temperature stress tolerance (i.e., it can improve both low-temperature stress tolerance and high-temperature stress tolerance without necessarily requiring temperature stress improving agents other than the compound of the present invention).

Claims

1. A temperature stress tolerance enhancer for plant reproductives comprising a compound represented by the following formula (I), a tautomer thereof, or an agrochemically acceptable salt thereof. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.) 2. In the above formula (I), R １ and R ２ are hydrogen atoms, and R ３ , R ４ and R ５ are methyl groups. The temperature stress resistance improving agent according to claim 1.

3. The temperature stress tolerance improving agent according to claim 1, comprising a microbial extract.

4. The temperature stress resistance improving agent according to claim 1, further comprising a liquid carrier.

5. The temperature stress tolerance improving agent according to claim 1, wherein the application rate of the compound represented by formula (I) or its tautomer or an agriculturally acceptable salt thereof is 0.5 g or more and 1000 g or less per 100 kg of the plant reproductive body.

6. The temperature stress tolerance improving agent according to claim 1, wherein the plant reproductive body is exposed to temperature stress for all or part of the period before germination.

7. The temperature stress tolerance improving agent according to claim 1, wherein the plant reproductive body is exposed to a temperature environment different from the optimal germination temperature range for all or part of the period until germination.

8. The temperature stress tolerance improving agent according to claim 1, wherein the plant reproductive body is a seed.

9. The temperature stress tolerance improving agent according to claim 1, wherein the temperature stress is caused by the plant reproductive body being exposed to a temperature environment exceeding the optimal germination temperature range for all or part of the period before germination.

10. The temperature stress tolerance improving agent according to any one of claims 1 to 9, wherein the temperature stress tolerance improving agent is an agent for improving reduced germination caused by temperature stress.

11. The temperature stress tolerance improving agent according to any one of claims 1 to 9, wherein the temperature stress tolerance improving agent is an agent for improving delayed germination caused by temperature stress.

12. A method for producing plant reproductive bodies with improved temperature stress tolerance, comprising the steps of: exposing the plant reproductive bodies to temperature stress for all or part of the period before germination; and applying a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof to the plant reproductive bodies to obtain plant reproductive bodies with improved temperature stress tolerance, wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.) 13. A method for producing a germinated plant, comprising the step of germinating a plant propagator produced by the method of claim 12 to obtain a germinated plant.

14. A method for producing a plant population including germinated plant bodies, comprising the steps of: exposing a plant reproductive body to temperature stress for all or part of the period before germination; germinating the plant reproductive body to obtain germinated plant bodies; applying a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof to a section in which the plant reproductive body is germinated; and obtaining a plant population including germinated plant bodies from the section, wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.) 15. A method for improving temperature stress tolerance in plant reproductive bodies, comprising the steps of: exposing the plant reproductive bodies to temperature stress for all or part of the period before germination; and applying to the plant reproductive bodies a compound represented by the following formula (I) or a tautomer thereof or an agriculturally acceptable salt thereof, wherein the application is carried out before germination. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.) 16. The method according to claim 15, wherein the method for improving temperature stress tolerance is a method for improving germination delay caused by temperature stress.

17. Use of a compound represented by the following formula (I) or its tautomer or an agrochemically acceptable salt thereof in the manufacture of a temperature stress tolerance enhancer for plant reproductives. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.) 18. Use of the compound represented by formula (I) below, its tautomer, or an agrochemically acceptable salt thereof, in improving the temperature stress tolerance of plant reproductive bodies. (In formula (I), R １ and R ２ R independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ３ , R ４ and R ５ (This independently represents an alkyl group having 1 to 4 carbon atoms.)

Images