Plant activator and growing method of plant

Abstract

To provide a plant activator having an activation action of plants such as a growth promotion action of plants and improving resistance to plant stress.SOLUTION: A plant activator of the present invention contains a compound with a specific structural formula as an active ingredient, preferably containing 3,3-diphenylpropa-2-en-trimethylammonium hexafluorophosphate or trimethyl-3,3-diphenylpropylammonium hexafluorophosphate, and can promote plant growth not only to the plants themselves but also by applying it to the soil, culture medium, or culture solution in which the plants grow.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a plant activator and a method for growing a plant. [Background technology]

[0002] Today, with the world's population increasing, it has become an issue to produce a sufficient supply of plants for food. In addition, the environment in which plants grow is changing due to global warming, and plants are subjected to various stresses (e.g. salt, freezing, cold, dryness, disease, etc.), which often causes problems in plant growth.

[0003] For example, methods for imparting salt tolerance to plants include (1) introducing salt tolerance genes into plants, (2) providing plants with osmotic regulators such as betaine, and (3) using several types of low-molecular-weight salt tolerance enhancers.

[0004] Patent Documents 1 and 2 disclose agents for improving the salt tolerance of plants, which contain a compound having a specific structure as an active ingredient. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] WO2020 / 054878 publication [Patent Document 2] JP 2018-52893 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, the above method (1) of inserting salt-tolerance genes into plants is strictly regulated by law, and it is generally difficult to use salt-tolerant plants. In particular, since there is almost no general use of genetically modified plants in Japan, this method is not realistic.

[0007] The method of using an osmotic pressure regulator in (2) above has problems in that it takes time and effort to determine the method of use and requires the administration of a large amount of the osmotic pressure regulator, while the salt tolerance enhancer in (3) above has problems in that the salt tolerance effect is insufficient and is expensive.

[0008] The present invention provides a plant activator having a plant activating effect, such as a plant growth promoting effect and / or an effect of improving a plant's resistance to stress. [Means for solving the problem]

[0009] The plant activator of the present invention is a plant activator characterized by containing a compound represented by formula (1) or formula (2) as an active ingredient. [ka] In the formula (1) and the formula (2), R 1 , R 2 and R 3 are each a substituted or unsubstituted alkyl group, R 4 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, or a substituted or unsubstituted amino group; R 5 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, a substituted or unsubstituted amino group, or a hydrogen atom; X is a carbon atom or a nitrogen atom; of two adjacent double lines of a solid line and a dotted line, one double line of a solid line and a dotted line is a single bond and the other double line of a solid line and a dotted line is a single bond or a double bond; Q - is a counter anion, n is a natural number from 1 to 5, and m is a natural number from 1 to 5.

[0010] The method for growing plants of the present invention is characterized in that the above-mentioned plant activator is used in plants or in the soil, medium or culture solution in which the plants are grown. Effect of the Invention

[0011] The plant activator of the present invention can activate plants, promote plant growth, or impart resistance to various stresses to plants.

[0012] According to the plant activator of the present invention, by applying it to a plant or to the soil, medium or culture solution in which the plant is grown, the plant can be activated for a long period of time. [Brief description of the drawings]

[0013] [Figure 1] 1 is a graph showing the evaluation results of the growth-promoting effect. [Diagram 2] 1 is a graph showing the evaluation results of the growth-promoting effect. [Diagram 3] 1 is a graph showing the evaluation results of salt stress tolerance. [Figure 4] 1 is a graph showing the evaluation results of salt stress tolerance. [Diagram 5] 1 is a graph showing the evaluation results of drought stress tolerance. [Figure 6] Photographs showing the results of low temperature and freezing stress resistance. [Figure 7] 1 is a graph showing the evaluation results of the growth-promoting effect. [Figure 8] 1 is a graph showing the evaluation results of the growth-promoting effect. [Figure 9] 1 is a graph showing the evaluation results of salt stress tolerance. [Figure 10] 1 is a graph showing the evaluation results of salt stress tolerance. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. In this specification, a numerical value connected with "~" means a numerical range that includes the numerical values ​​before and after "~" as the lower and upper limits.

[0015] The plant activator of the present invention contains a compound represented by formula (1) or (2) as an active ingredient, which will be described later. The plant activator contains the compound represented by formula (1) or (2) in an amount of preferably 50% by mass or more, more preferably 60% by mass or more, more preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, more preferably 99% by mass or more, and more preferably 100% by mass.

[0016] The plant activator of the present invention has a plant activating effect. The plant activating effect refers to an effect of activating plant growth. The plant activating effect is a concept that encompasses a plant growth promoting effect and an effect of improving a plant's resistance to stress (stress tolerance imparting effect). The plant activating effect may be at least one of the plant growth promoting effect and the stress tolerance imparting effect. The plant activator of the present invention can be used as a plant growth promoting agent that has a plant growth promoting effect and / or a plant stress tolerance imparting agent that has a stress tolerance imparting effect.

[0017] The plant growth-promoting effect refers to an effect of accelerating the growth rate of a plant, including, for example, growth-promoting effects such as elongation of stems, leaves or roots, an increase in the number of leaves, promotion of flowering or fruiting, an increase in the number of flowers or fruits, an increase in plant weight or crop yield, greening, or promotion of tillering.

[0018] The plant growth-promoting effect also includes effects such as root elongation, increase in the number of lateral roots, improvement of root survival rate, increase in nutrient absorption efficiency, induction of flower buds, promotion of flowering, increase in fruit yield, accumulation of sugar and other components, increased water-saving effect, induction of callus formation, increase in plant body size (e.g., elongation or enlargement of above-ground and below-ground parts), and wound repair.

[0019] The case where a plant growth promoting effect is exhibited includes a case where no growth is observed without the use of the plant activator, but where growth is observed by the use of the plant activator.

[0020] The stress tolerance-imparting effect refers to the effect of imparting tolerance (abiotic stress tolerance) to a variety of abiotic (environmental) stresses that a plant is subjected to. Examples of abiotic stress (environmental stress) include temperature stresses such as high temperature stress, low temperature stress, and freezing stress, chemical stress, light stress, drought stress, pH stress such as oxidative stress, salt stress such as osmotic stress and ion stress, hypoxic stress, herbicide stress, physical stress, and disease stress.

[0021] "Osmotic stress" refers to the phenomenon in which salt accumulation in the soil increases the osmotic pressure of the soil, restricting water absorption by the roots and resulting in water deficiency at the cellular level. "Ion stress" refers to phenomena such as reduced enzyme activity and inhibition of absorption of inorganic ions such as K+, caused by NaCl, the most abundant salt.

[0022] "Abiotic stress tolerance" means a trait that allows a plant to grow normally even under growth conditions that involve environmental stress, without substantially suffering from undesirable effects such as inability to grow (withering), poor growth (e.g., whitening or yellowing of the plant body, reduced root length, reduced number of lateral roots, or reduced number of leaves), reduced growth rate, or reduced plant weight or crop yield. By improving the abiotic stress tolerance of a plant with a plant activator, the plant can grow normally even in an external environment that would otherwise be affected by undesirable effects on the growth of a normal plant.

[0023] The plant activator contains a compound represented by formula (1) or formula (2) as an active ingredient. The compound represented by formula (1) is preferably a compound represented by formula (1a). The compound represented by formula (2) is preferably a compound represented by formula (2a). [ka]

[0024] [ka]

[0025] In the formulas (1), (2), (1a) and (2a), R 1 , R 2 and R 3 are each a substituted or unsubstituted alkyl group, R 4 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, or a substituted or unsubstituted amino group; R 5 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, a substituted or unsubstituted amino group, or a hydrogen atom; X is a carbon atom or a nitrogen atom; of two adjacent double lines of a solid line and a dotted line, one double line of a solid line and a dotted line is a single bond and the other double line of a solid line and a dotted line is a single bond or a double bond; Q - is a counter anion, n is a natural number from 1 to 5, and m is a natural number from 1 to 5.

[0026] In formulas (1), (2), (1a) and (2a), R 1 , R 2 and R 3are each a substituted or unsubstituted alkyl group. The alkyl group refers to an atomic group remaining after removing one hydrogen atom from an aliphatic saturated hydrocarbon. The hydrogen of the alkyl group may be substituted with another atom or atomic group (e.g., a hydroxyl group, etc.). The alkyl group may be either linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, and an n-pentyl group, and the like. The methyl group, the ethyl group, and the propyl group are preferred, and the methyl group and the propyl group are more preferred.

[0027] In formulas (1), (2), (1a) and (2a), R 1 , R 2 and R 3 is preferably a methyl group. 1 and R 2 is a methyl group and R 3 is preferably an isopropyl group. 1 , R 2 and R 3 When is the above-mentioned substituent, the plant activator has improved plant activating effect (plant growth promoting effect and / or stress resistance imparting effect).

[0028] In formula (1) and formula (1a), R 1 , R 2 and R 3 may be bonded to each other via a covalent bond to form a cyclic skeleton. The cyclic skeleton is preferably an alicyclic skeleton, and since the plant activating action of the plant activator (particularly the stress resistance imparting action of the plant activator) is improved, an alicyclic skeleton represented by the following formula (3) is more preferable. Note that *1 is a bond and means a single bond. Alicyclic means a hydrocarbon group having a cyclic structure that does not have aromaticity. In the alicyclic skeleton, hydrogen atoms may be substituted with other atoms or atomic groups (e.g., hydroxyl groups, etc.). Carbon atoms forming the cyclic skeleton of the alicyclic skeleton may be substituted with other atoms (e.g., oxygen atoms, nitrogen atoms, sulfur atoms, etc.).

[0029] [ka]

[0030] In formulas (1), (2), (1a) and (2a), R 1 and R 2 may be bonded to each other via a covalent bond to form a cyclic skeleton. The cyclic skeleton is preferably an alicyclic skeleton, more preferably a five-membered ring skeleton or a six-membered ring skeleton. In the alicyclic skeleton, hydrogen atoms may be replaced by other atoms or atomic groups (e.g., hydroxyl groups, etc.). Carbon atoms forming the cyclic skeleton of the alicyclic skeleton may be replaced by other atoms (e.g., oxygen atoms, nitrogen atoms, sulfur atoms, etc.). As the alicyclic skeleton, an alicyclic skeleton represented by formula (4) is preferred, since the plant activating action of the plant activator (particularly the plant growth promoting action of the plant activator) is improved. As the alicyclic skeleton, R 1 and R 2 are bonded via an oxygen atom (preferably an alicyclic skeleton represented by formula (4)), and an alicyclic skeleton represented by formula (5) are preferred. Note that *2 and *3 are bonds and represent single bonds.

[0031] [ka]

[0032] In formulas (1), (2), (1a) and (2a), R 4 and R 5 are independent of each other, and R 4 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, or a substituted or unsubstituted amino group; R 5 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, a substituted or unsubstituted amino group, or a hydrogen atom, and X is a carbon atom or a nitrogen atom.

[0033] In the present invention, the term "aryl group" refers to a monovalent atomic group obtained by removing one hydrogen atom on an aromatic ring from an aromatic compound. The aromatic ring may be a monocyclic aromatic ring, or may be a condensed aromatic ring formed by compounding monocyclic aromatic rings. The aromatic ring is not particularly limited, and examples thereof include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl, and a phenoxyphenyl.

[0034] Examples of the aryl group include a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, and an anthracenyl group. A phenyl group is preferred because it improves the plant activation effect (the plant growth-promoting effect and / or the stress resistance-imparting effect) of the plant activator.

[0035] In the aryl group, the hydrogen atom of the aromatic ring may be replaced by another substituent, such as an alkyl group, a halogen atom, an alkoxy group, a carboxy group, an ester group (e.g., -COOPh, -COOCH3, -COOEt, etc.).

[0036] The alkyl group is R 1 , R 2 and R 3 The description is the same as that in the above, and therefore will not be repeated. Some or all (preferably all) of the hydrogen atoms of the alkyl group may be substituted with halogen atoms. The halogen atom refers to a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. The alkoxy group refers to an atomic group in which the hydrogen atom of a hydroxyl group (-OH) is substituted with the above alkyl group. The alkoxy group is not particularly limited, and is preferably an alkoxy group having 1 to 5 carbon atoms, such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or a pentoxy group, and more preferably a methoxy group or an ethoxy group, since the plant activating effect of the plant activator (particularly the stress resistance imparting effect of the plant activator) is improved.

[0037] R 4 and R 5When is a phenyl group and a hydrogen atom of the aromatic ring is substituted with another substituent, the plant activating effect of the plant activator (particularly, the stress resistance imparting effect of the plant activator) is improved, and therefore the position of the substituent is preferably the para position or meta position.

[0038] In the present invention, the term "heteroaryl group" refers to an atomic group in which one or more carbon atoms of the above-mentioned aryl group are each independently substituted with one or more heteroatoms selected from the group consisting of nitrogen atoms, sulfur atoms, and oxygen atoms. In this case, the substitution with a nitrogen atom or a sulfur atom includes substitution with an N-oxide or N+, or an oxide or dioxide of S, respectively. The heteroaryl group is not particularly limited, and examples thereof include 5-15 membered heteroaryl groups such as a furanyl group, a thienyl group (thiophenyl group), a pyrrolyl group, an imidazolyl group, a pyrazolyl group, a triazolyl group, a tetrazolyl group, a thiazolyl group, an oxazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, an isothiazolyl group, a pyridyl group, a pyridinium-1-yl group, a pyridazinyl group, a pyrazinyl group, a pyrimidinyl group, a quinolinyl group, an isoquinolinyl group, and an indolyl group.

[0039] In the present invention, the term "cycloalkyl group" refers to an alicyclic alkyl group containing 3 or more carbon atoms. Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, and a cyclohexyl group, and the cyclohexyl group is preferred.

[0040] In the present invention, the term "substituted or unsubstituted amino group" refers not only to an amino group (-NH2) but also to an atomic group in which one or two hydrogen atoms of an amino group (-NH2) are replaced by other substituents (e.g., an alkyl group, etc.).

[0041] In formulas (1), (2), (1a) and (2a), X is a carbon atom or a nitrogen atom, and is preferably a carbon atom since the plant activating effect of the plant activator (the plant growth promoting effect and / or stress resistance imparting effect of the plant activator) is improved. When X is a carbon atom, one hydrogen atom is bonded to the carbon atom [when the double line of the solid and dotted lines (carbon-X bond) is a double bond] or two hydrogen atoms are bonded to the carbon atom [when the double line of the solid and dotted lines (carbon-X bond) is a single bond]. When X is a nitrogen atom, the double line of the solid and dotted lines (carbon-X bond) is a single bond.

[0042] In the formulas (1), (2), (1a), and (2a), the double line consisting of a solid line and a dotted line shown below represents a single bond or a double bond.

[0043] [ka]

[0044] In each of formula (1) and formula (2), when n and m are each 2 to 5, the repeating unit has two double lines of solid and dotted lines, and thus has a structure in which 4 to 10 double lines of solid and dotted lines are consecutive. In this structure, among adjacent double lines of solid and dotted lines, one double line of solid and dotted lines is a single bond and the other double line of solid and dotted lines is a single bond or a double bond. That is, among two adjacent double lines of solid and dotted lines, both double lines of solid and dotted lines are single bonds, or one double line of solid and dotted lines is a single bond and the other double line of solid and dotted lines is a double bond. The case in which adjacent double lines of solid and dotted lines are both double bonds is excluded.

[0045] In formula (1), n ​​is a natural number of 1 to 5, preferably a natural number of 1 to 3, more preferably 1 or 2, and more preferably 1. In formula (2), m is a natural number of 1 to 5, preferably a natural number of 1 to 3, more preferably 1 or 2, and more preferably 1. When n and m are within the above ranges, the plant activating effect of the plant activator (in particular, the stress resistance imparting effect of the plant activator) is improved.

[0046] In formula (1) and formula (2), it is preferred that all double lines of a solid line and a dotted line are single bonds, or that the double line of a solid line and a dotted line bonded to X is a double bond, since this improves the plant activating effect of the plant activator (in particular, the stress resistance imparting effect of the plant activator).

[0047] In formula (1a) and formula (2a), among adjacent double lines of a solid line and a dotted line, one double line of a solid line and a dotted line is a single bond and the other double line of a solid line and a dotted line is a single bond or a double bond. That is, among adjacent double lines of a solid line and a dotted line, both double lines of a solid line and a dotted line are single bonds, or one double line of a solid line and a dotted line is a single bond and the other double line of a solid line and a dotted line is a double bond. The case where both double lines of a solid line and a dotted line are double bonds is excluded.

[0048] In formulae (1a) and (2a), it is preferred that both the solid and dotted double lines are single bonds, since this improves the plant activating effect of the plant activator (particularly the stress resistance imparting effect of the plant activator).

[0049] In formulas (1a) and (2a), it is preferred that the double line consisting of a solid line and a dotted line on the left side is a single bond and that the double line consisting of a solid line and a dotted line on the right side (the bond bonding to X) is a double bond, in order to improve the plant activating effect of the plant activator (in particular, the stress resistance imparting effect of the plant activator).

[0050] In formula (1) and formula (1a), Q - is a counter anion. The counter anion is not particularly limited, and examples thereof include hexafluorophosphate anion (PF6 - ), tetrafluoroborate anion (BF4 - ), bisfluorosulfonylamide anion (FSA - ), bistrifluoromethylsulfonylamide anion (TFSA - ), halide ions [e.g., bromide ion (Br - ), chloride ion (Cl - )], and hexafluorophosphate anion (PF6 -), tetrafluoroborate anion (BF4 - ), bromide ion (Br - ) is preferred.

[0051] Specifically, examples of the compound represented by formula (1) or formula (2) include the following compounds, and the compounds represented by formulas (6) to (14) and (36) to (39) are preferred because the plant activator has an excellent plant activating effect (a plant growth promoting effect and / or a stress resistance imparting effect).

[0052] [ka]

[0053] [ka]

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] The compounds represented by the above formulas (1) and (2) can be produced by using a general-purpose synthesis method.

[0058] The compound represented by formula (1) can be produced, for example, by the following method. The first synthesis method is to prepare a quaternary ammonium salt (Z -is a counter anion. A raw material mixture containing an olefin represented by formula (B) is reacted in an organic solvent [e.g., dimethyl sulfoxide (DMSO)] under a nitrogen atmosphere while being irradiated with light to produce an intermediate product (Z - is a counter anion) (C1). The reaction of the raw material mixture is preferably carried out in the presence of 1 to 1000 mmol of the compound [Ir(ppy)3] represented by formula (D) and 0.3 to 2 mol of AgBF4 per mol of the quaternary ammonium salt represented by formula (A). - Examples of the anion include tetrafluoroborate anion (BF4 - ), hexafluorophosphate anion (PF6 - ), bromide ion (Br - The wavelength of the light irradiated onto the raw material mixture is preferably 250 to 500 nm, and more preferably 400 to 500 nm.

[0059] The reaction solution was compressed under reduced pressure to obtain a solid, which was then dissolved in dichloromethane. The intermediate product was then washed with an 8 to 12% by mass aqueous solution of sodium thiosulfate and water, and the organic layer was then further treated with a counter anion (Q - ) potassium salt (K + Q - ) to exchange the counter anion. The organic layer is then dried using sodium sulfate (Na2SO4) and filtered to obtain a crude product. The crude product obtained is recrystallized using dichloromethane and diethyl ether to obtain the compound represented by formula (1). The notations of the substituents and counter anions used in formulas (A) and (B) are the same as those used in formula (1), so their explanation is omitted.

[0060] [ka]

[0061] [ka]

[0062] In the second synthesis method, a raw material mixture containing a quaternary ammonium salt represented by formula (A) and an olefin represented by formula (B) is reacted in a mixed solvent of acetonitrile (MeCN) and water under a nitrogen atmosphere while being irradiated with light to produce an intermediate product (C2). The reaction of the raw material mixture is preferably carried out in the presence of 1 to 1000 mmol of a compound represented by formula (E) [Ir[(dmppy)2(dtbbpy)]PF6] and 1 to 3 moles of triethylamine per mole of the quaternary ammonium salt represented by formula (A). A crude product is produced from the intermediate product in the same manner as in the first synthesis method, and the crude product is recrystallized to obtain the compound represented by formula (1). The wavelength of the light irradiated to the raw material mixture is preferably 250 to 500 nm, more preferably 400 to 500 nm.

[0063] [ka]

[0064] [ka]

[0065] In the third synthesis method, a raw material mixture containing a quaternary ammonium salt represented by formula (A) and an olefin represented by formula (B) is reacted in a mixed solvent of acetonitrile (MeCN) and water under a nitrogen atmosphere while being irradiated with light to produce an intermediate product. The reaction of the raw material mixture is preferably carried out in the presence of 0.005 to 1 mol of a compound represented by formula (E) [Ir[(dmppy)2(dtbbpy)]PF6], 1 to 3 mol of triethylamine, and 0.1 to 0.3 mol of methyl thiosalicylate per 1 mol of the quaternary ammonium salt represented by formula (A). The wavelength of the light irradiated to the raw material mixture is preferably 250 to 500 nm, more preferably 400 to 500 nm.

[0066] The intermediate product was purified by flash column chromatography on NaBr-treated silica gel [dichloromethane:methanol (mass ratio)=100:0→80:20].

[0067] The purified intermediate product was dissolved in dichloromethane and the counter anion (Q - The organic layer is then dried over sodium sulfate (Na2SO4), filtered and concentrated under reduced pressure to give the compound of formula (1).

[0068] [ka]

[0069] [ka]

[0070] The compound represented by formula (2) can be prepared, for example, by synthesizing the compound represented by formula (1) in the manner described above and adding a substituent R 3 can be synthesized by substituting a hydrogen atom according to a known method (for example, the method described in Smith, PA et al., J. Org. Chem. 1999, 64, 1798).

[0071] The plant activator contains the formula (1) and / or the formula (2) as an active ingredient, and may contain additives within the range that does not inhibit the action of the active ingredient. Examples of such additives include carriers, surfactants, wetting agents, preservatives, adhesion agents, stabilizers, colorants, emulsifiers, dispersants, penetrating agents, thickeners, and antifoaming agents.

[0072] The plant enhancer may be in any form, for example, a solid (eg, powder, granules) or a liquid (eg, solution, suspension), but is preferably used in the form of a liquid, such as a solution or suspension.

[0073] The plant activator can be appropriately formulated by known methods into the form of a wettable powder, a water dispersible granule, a flowable formulation, an emulsion, a sprinkle, a dust, an aerosol, a paste, a suspension, a liquid, or the like.

[0074] Next, a method for using the plant activator will be described. The plant activator is used to promote plant growth or improve the plant's resistance to stress, thereby promoting plant development. The plant activator can be used as is, or diluted with a diluent to a predetermined concentration.

[0075] The target plant for the plant activator may be not only the whole plant (i.e., the complete plant body) but also parts of the plant such as plant tissues or organs (e.g., cut flowers, or vegetative propagation organs such as rhizomes, tubers, corms or runners), cultured cells and / or callus.

[0076] The plant enhancer can be applied to the whole plant or parts thereof at any stage of development, including before or after the plant emerges (eg, the whole plant, parts thereof, such as a seed, a seedling or a mature plant).

[0077] The plant activator can be applied not only to the plant itself, but also to the soil, medium or culture solution in which the plant is grown. By applying the plant activator to the plant in the growth stage or to the soil, medium or culture solution in which the plant is grown, the plant activation effect can be improved.

[0078] The plant to which the plant activator is applied is not particularly limited. The plant activator can be applied to various plants including angiosperms and gymnosperms. The plant to which the plant activator is applied is not particularly limited, and examples thereof include Brassicaceae plants such as Arabidopsis thaliana and rapeseed, legumes such as soybean, Poaceae plants such as rice, corn, wheat and barley, Convolvulaceae plants such as morning glory, Salicaceae plants such as poplar, Euphorbiaceae plants such as castor bean, cassava and jatropha, Vitaceae plants such as grape, and Solanaceae plants such as tomato.

[0079] The application method of the plant activator includes application to plants (foliage spray), application to soil in which plants are grown (soil application), application to paddy field water (water surface application), application to fields (seed treatment), etc. These applications may be carried out alone or in combination of two or more. The plant activator may be applied to plants only once or repeatedly multiple times.

[0080] The application amount of the plant activator varies depending on the plant to which it is applied, but in the case of foliage spraying, it is preferable to apply 50 to 300 L of a solution containing preferably 0.1 to 10,000 ppm, more preferably 1 to 10,000 ppm, and more preferably 10 to 1,000 ppm of active ingredient per 10 ares. In the case of soil application and water surface application, it is preferable to apply 0.01 to 100 g, more preferably 0.1 to 1,000 g, and more preferably 10 to 100 g of active ingredient per 10 ares. In the case of seed treatment, it is preferable to apply 0.0001 to 50 g of active ingredient per 1 kg of seeds, and more preferably apply 0.001 to 50 g of active ingredient.

[0081] The amount of plant activator applied will vary depending on the plant to which it is applied, but as a guideline, it is preferable to apply the plant activator to 1 / 2 MS medium so that the concentration is 0.001 μM or more, more preferably 0.005 μM or more, even more preferably 0.01 μM or more, preferably 0.05 μM or more, more preferably 0.06 μM or more, and even more preferably 0.08 μM or more. The plant activator is preferably applied to the 1 / 2 MS medium at a concentration of 10 μM or less, more preferably at 8 μM or less, more preferably at 6 μM or less, more preferably at 4 μM or less, more preferably at 2 μM or less, more preferably at 0.8 μM or less, more preferably at 0.7 μM or less, more preferably at 0.6 μM or less, and more preferably at 0.5 μM or less. By setting the application amount of the plant activator within the above range, the plant activating effect of the plant activator is improved. The 1 / 2 MS medium refers to a medium (agar 1.2 g / L) obtained by diluting the MS medium with water at a volume ratio of 1 / 2.

[0082] The plant activator can promote plant growth or improve the stress resistance of plants with a small application amount compared to conventional plant growth promoters, etc. Therefore, damage to the soil can be reduced and the soil can be easily maintained in a state suitable for plant growth. EXAMPLES

[0083] The present invention will be described in more detail below using examples, but the present invention is not limited thereto. Specific numerical values ​​of the blending ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the upper limit values ​​(numerical values ​​defined as "equal to or less than") or lower limit values ​​(numerical values ​​defined as "equal to or more than") of the blending ratio (content ratio), physical property values, parameters, etc. described in the "Means for solving the Problems" and "Forms for carrying out the Invention" that correspond to them.

[0084] The compounds used as the active ingredients of the plant activators were synthesized as follows. [Synthesis of compound represented by formula (6)] A stirrer was added to a dry reaction vessel. Next, 0.20mmol (1.0 equiv.) of iodomethyltrimethylammonium tetrafluoroborate, 0.20mmol (1.0 equiv.) of AgBF4, and 0.0040mmol (2.0mol%) of the compound represented by formula (D) [Ir(ppy)3] were added to the reaction vessel. The reaction vessel was filled with nitrogen by a conventional Schlenk method (degassing-refilling with nitrogen cycle).

[0085] A raw material mixture was prepared by supplying 1.0 mL of dimethyl sulfoxide (DMSO) and 0.30 mmol (1.5 equiv.) of 1,1-diphenylethylene to a reaction vessel. The raw material mixture in the reaction vessel was irradiated with blue light and cooled with a cooling fan while stirring for 2 hours to produce an intermediate product.

[0086] The reaction solution in the reaction vessel was compressed under reduced pressure to obtain a solid, which was dissolved in dichloromethane (CH2Cl2) and washed three times with a 10% by mass aqueous solution of sodium thiosulfate and water. Next, the organic layer in the reaction vessel was washed three times with a saturated aqueous solution of KPF6 to exchange the counter anion of the intermediate product. The organic layer in the reaction vessel was dried over Na2SO4, filtered, and concentrated under reduced pressure to obtain a crude product. The crude product was recrystallized using dichloromethane (CH2Cl2) and diethyl ether (Et2O) to obtain the compound represented by formula (6) (3,3-diphenylpropan-2-ene-trimethylammonium hexafluorophosphate).

[0087] [ka]

[0088] [Synthesis of compound represented by formula (7)] A stirrer was provided to a dry reaction vessel. 0.20mmoL (1.0 equiv.) of iodomethyltrimethylammonium tetrafluoroborate and 0.010mmoL (5.0mol%) of the compound represented by formula (E) [Ir[(dmppy)2(dtbbpy)]PF6] were provided to the reaction vessel. The reaction vessel was filled with nitrogen by a conventional Schlenk method (degassing-nitrogen refilling cycle). 1.0mL of acetonitrile (MeCN), 1.0mL of water, 0.40mmoL (2.0 equiv.) of triethylamine (NEt3), and 0.40mmoL (2.0 equiv.) of 1,1-diphenylethylene were provided to the reaction vessel to prepare a raw material mixture. The raw material mixture in the reaction vessel was stirred and reacted for 2 hours while being irradiated with blue light and cooled with a cooling fan to produce an intermediate product.

[0089] The reaction solution in the reaction vessel was compressed under reduced pressure to obtain a solid, which was dissolved in dichloromethane (CH2Cl2) and washed three times with water. The organic layer in the reaction vessel was then washed three times with a saturated aqueous solution of KPF6 to exchange the counter anion of the intermediate product. The organic layer in the reaction vessel was dried over Na2SO4, filtered, and concentrated under reduced pressure. The intermediate product was purified by flash column chromatography (CH2Cl2 / MeOH=100:0→90:10) on NaBr-treated silica gel.

[0090] To further exchange the counter anion of the intermediate product, the obtained intermediate product was dissolved in dichloromethane (CH2Cl2) and washed three times with a saturated KPF6 aqueous solution. The organic layer in the reaction vessel was dried over Na2SO4, filtered, and concentrated under reduced pressure to obtain a crude product. The crude product was recrystallized using dichloromethane (CH2Cl2) and diethyl ether (Et2O) to obtain the compound represented by formula (7) (trimethyl-3,3-diphenylpropylammonium hexafluorophosphate).

[0091] [ka]

[0092] [Synthesis of compound represented by formula (8)] A stirrer was added to a dry reaction vessel. The reaction vessel was then filled with nitrogen using a standard Schlenk technique (degassing-refilling with nitrogen cycles). 1.8 mL of acetonitrile (CH3CN) was added to the reaction vessel. 204 mg of 3,3-diphenylpropan-1-amine (F) was then added, and the reaction vessel was then placed in an ice bath.

[0093] After 164 mg of NaBH3CN was fed into the reaction vessel, 0.5 mL of aqueous formaldehyde solution was further fed. After stirring the inside of the reaction vessel at 25°C for 2 hours, 0.5 mL of aqueous formaldehyde solution was further fed. After stirring the inside of the reaction vessel for 45 minutes, 1 M hydrochloric acid was added to the reaction vessel until the pH became 2. Then, the inside of the reaction vessel was heated to 40°C and stirred for 1 hour. After the reaction solvent in the reaction vessel was distilled off, a separation operation was performed using sodium bicarbonate water and ethyl acetate to obtain a crude product. The obtained crude product was purified by silica gel flash column chromatography [hexane:ethyl acetate (volume ratio) = 5:1], and then concentrated by acid-base extraction to obtain a compound represented by formula (8) (N,N-dimethyl-3,3-diphenylpropan-1-amine).

[0094] [ka]

[0095] [Synthesis of compound represented by formula (9)] The compound represented by formula (9) was obtained in the same manner as in the synthesis of the compound represented by formula (6), except that iodomethyl isopropyl dimethyl ammonium tetrafluoroborate was used instead of iodomethyl trimethyl ammonium tetrafluoroborate.

[0096] [ka]

[0097] [Synthesis of compound represented by formula (10)] A stirrer was provided to a dry reaction vessel. Next, 0.20mmoL (1.0 equiv.) of 3-hydroxy-N-iodomethylquinuclidinium hexafluorophosphate and 0.010mmoL (5.0mol%) of the compound represented by formula (E) [Ir[(dmppy)2(dtbbpy)]PF6] were provided to the reaction vessel. The reaction vessel was filled with nitrogen by a conventional Schlenk method (degassing-nitrogen refilling cycle). A raw material mixture was prepared by providing 1.0mL of acetonitrile (MeCN), 1.0mL of water, 0.40mmoL (2.0 equiv.) of triethylamine (NEt3) and 0.40mmoL (2.0 equiv.) of 1,1-diphenylethylene to the reaction vessel. The raw material mixture in the reaction vessel was irradiated with blue light and cooled with a cooling fan while stirring for 2 hours to produce an intermediate product.

[0098] The reaction solution in the reaction vessel was compressed under reduced pressure to obtain a solid, which was dissolved in dichloromethane (CH2Cl2) and washed three times with water. Next, the organic layer in the reaction vessel was washed three times with a saturated aqueous solution of KPF6 to exchange the counter anion of the intermediate product. The organic layer in the reaction vessel was dried over Na2SO4, filtered, and concentrated under reduced pressure to obtain a crude product. The crude product was recrystallized using dichloromethane (CH2Cl2) and diethyl ether (Et2O) to obtain the compound represented by formula (10).

[0099] [ka]

[0100] [Synthesis of compound represented by formula (11)] The compound represented by formula (11) was obtained in the same manner as in the synthesis of the compound represented by formula (7), except that N-iodomethyl-N-methylpyrrolidinium hexafluorophosphate was used instead of iodomethyltrimethylammonium tetrafluoroborate.

[0101] [ka]

[0102] [Synthesis of compound represented by formula (12)] A stirrer was supplied to a dry reaction vessel. Next, 0.40mmoL (2.0equiv.) of iodomethyltrimethylammonium tetrafluoroborate, 0.40mmoL (2.0equiv.) of AgBF4, and 0.0040mmoL (2.0mol%) of the compound represented by formula (D) [Ir(ppy)3] were supplied to the reaction vessel. The reaction vessel was filled with nitrogen by a normal Schlenk method (degassing-nitrogen refilling cycle). 1.0mL of dimethylacetamide (DMA) and 0.20mmoL (1.0equiv.) of styrene were supplied to the reaction vessel to prepare a raw material mixture. The raw material mixture in the reaction vessel was stirred and reacted for 2 hours while being irradiated with blue light and cooled with a cooling fan to produce an intermediate product.

[0103] The reaction solution in the reaction vessel was compressed under reduced pressure to obtain a solid, which was dissolved in dichloromethane (CH2Cl2) and washed three times with a 10% by mass aqueous solution of sodium thiosulfate and water. The organic layer in the reaction vessel was then washed three times with a saturated aqueous solution of KPF6 to exchange the counter anion of the intermediate product. The organic layer in the reaction vessel was dried over Na2SO4, filtered, and concentrated under reduced pressure. The intermediate product was purified by flash column chromatography (CH2Cl2 / MeOH=100:0→85:15) on NaBr-treated silica gel.

[0104] To further exchange the counter anion of the intermediate product, the obtained intermediate product was dissolved in dichloromethane (CH2Cl2) and washed three times with a saturated aqueous solution of KPF6. The organic layer in the reaction vessel was dried over Na2SO4, filtered, and concentrated under reduced pressure to obtain the compound represented by formula (12).

[0105] [ka]

[0106] [Synthesis of compound represented by formula (13)] The compound represented by formula (13) was obtained in the same manner as in the synthesis of the compound represented by formula (7), except that 1,1-bis[3-(trifluoromethyl)phenyl]ethene was used instead of 1,1-diphenylethylene.

[0107] [ka]

[0108] [Synthesis of compound represented by formula (14)] A stirrer was added to a dry reaction vessel. Next, 0.20mmol (1.0 equiv.) of iodomethyltrimethylammonium tetrafluoroborate and 0.010mmol (5.0mol%) of the compound represented by formula (E) [Ir[(dmppy)2(dtbbpy)]PF6] were added to the reaction vessel. The reaction vessel was filled with nitrogen by a conventional Schlenk method (degassing-refilling with nitrogen cycle).

[0109] 1.0 mL of acetonitrile (MeCN), 1.0 mL of water, 0.40 mmol of triethylamine (NEt3) (2.0 equiv.), 0.40 mmol of phenyl 4-vinylbenzoate (2.0 equiv.), and 0.040 mmol of methyl thiosalicylate (20 mol%) were added to the reaction vessel. The mixture of raw materials in the reaction vessel was irradiated with blue light and cooled with a cooling fan while stirring for 2 hours to produce an intermediate product.

[0110] The intermediate product was purified by flash column chromatography (CH2Cl2 / MeOH=100:0→80:20) on NaBr-treated silica gel. To exchange the counter anion of the intermediate product, the intermediate product was dissolved in dichloromethane (CH2Cl2) and washed three times with saturated aqueous KPF6. The organic layer was dried over Na2SO4, filtered, and concentrated under reduced pressure to obtain the compound represented by formula (14).

[0111] [ka]

[0112] [Synthesis of compound represented by formula (36)] A dry reaction vessel was provided with a stir bar. The reaction vessel was then charged with 2.0 mmol (1.0 equiv.) of 1,1-diphenyl-1-propene, 2.0 mmol (1.0 equiv.) of N-bromosuccinimide (NBS), 0.04 mmol (2 mol%) of benzoyl peroxide (BPO), and 2 mL of tetrachloromethane (CCl4).

[0113] The reaction vessel was heated to 90°C for 22 hours while stirring to produce an intermediate product. The reaction solution was filtered and then compressed under reduced pressure to obtain a crude product (3-bromo-1,1-diphenyl-1-propene). The crude product was used as is in the next reaction.

[0114] [ka]

[0115] A separate dry reaction vessel was provided with a stir bar. The crude product, 3-bromo-1,1-diphenyl-1-propene, was then added to the reaction vessel. 3 mL of trimethylamine (2M in acetonitrile) was added to the reaction vessel. After the reaction was complete, diethyl ether was added until precipitation occurred. The resulting solid was filtered to obtain N,N,N-trimethyl-3,3-diphenylpropen-2-ene-1-aminium bromide salt.

[0116] [ka]

[0117] 0.5mmoL (1.0equiv.) of N,N,N-trimethyl-3,3-diphenylpropen-2-ene-1-aminium bromide salt was added to the separatory funnel, and 49.3mmoL (19equiv.) of NaBF (20mL) and methylene chloride were added to the separatory funnel. After separating the methylene chloride, it was dried over sodium sulfate and compressed under reduced pressure to obtain a crude product. The crude product was recrystallized using methylene chloride and diethyl ether, and then filtered to obtain the target product, N,N,N-trimethyl-3,3-diphenylpropen-2-ene-1-aminium tetrafluoroborate salt [formula (36)].

[0118] [ka]

[0119] [Synthesis of compound represented by formula (37)] A stirrer was added to the dry reaction vessel. 1,1-diphenyl-3-bromopropane was then added to the reaction vessel. 3 mL of trimethylamine (2M in acetonitrile) was added to the reaction vessel. After the reaction was completed, the mixture was compressed under reduced pressure and an acetonitrile / diethyl ether mixture was added until precipitation occurred. The resulting solid was filtered to obtain N,N,N-trimethyl-3,3-diphenylpropane-1-aminium bromide salt.

[0120] [ka]

[0121] 0.5mmoL (1.0equiv.) of N,N,N-trimethyl-3,3-diphenylpropen-2-ene-1-aminium bromide salt was added to the separatory funnel, and 49.3mmoL (19equiv.) of NaBF (20mL) and methylene chloride were added to the separatory funnel. After separating the methylene chloride, it was dried over sodium sulfate and compressed under reduced pressure to obtain a crude product. The crude product was recrystallized using methylene chloride and diethyl ether, and then filtered to obtain the target product, N,N,N-trimethyl-3,3-diphenylpropan-1-aminium tetrafluoroborate salt [formula (37)].

[0122] [ka]

[0123] [Synthesis of compound represented by formula (38)] A stir bar was added to a dry reaction vessel. Next, 2.0 mmol / L (1.0 equiv.) of 1,1-diphenyl-1-propene, 2.0 mmol / L (1.0 equiv.) of N-bromosuccinimide (NBS), 0.04 mmol / L (2 mol%) of benzoyl peroxide (BPO), and 2 mL of tetrachloromethane (CCl4) were added to the reaction vessel.

[0124] The reaction vessel was heated and stirred at 90°C for 22 hours to produce an intermediate product. The reaction solution was filtered and then compressed under reduced pressure to obtain a crude product (3-bromo-1,1-diphenyl-1-propene). The crude product was used as is in the next reaction.

[0125] [ka]

[0126] A stirrer was added to another dry reaction vessel. The crude product, 3-bromo-1,1-diphenyl-1-propene, was then added to the reaction vessel. 3 mL of trimethylamine (2M in acetonitrile) was added to the reaction vessel. After the reaction was complete, diethyl ether was added until precipitation occurred. The resulting solid was filtered to obtain the desired product, N,N,N-trimethyl-3,3-diphenylpropen-2-ene-1-aminium bromide salt [formula (38)].

[0127] TIFF2025059071000034.tif57170

[0128] [Synthesis of compound represented by formula (39)] A stirrer was added to the dry reaction vessel. 1,1-diphenyl-3-bromopropane was then added to the reaction vessel. 3 mL of trimethylamine (2M solution in acetonitrile) was added to the reaction vessel. After the reaction was completed, the mixture was compressed under reduced pressure and an acetonitrile / diethyl ether mixture was added until precipitation occurred. The resulting solid was filtered to obtain N,N,N-trimethyl-3,3-diphenylpropane-1-aminium bromide salt [formula (39)].

[0129] [ka]

[0130] A plant activator containing, as an active ingredient, any one of the compounds represented by the above-obtained formulas (6) to (14) and (36) to (39) was prepared.

[0131] The growth promoting activity, low temperature / freezing stress resistance, salt stress resistance, and drought stress resistance of the obtained plant activators were measured as described below, and the results are shown in Figures 1 to 10. In the figures, the compounds represented by formulas (6) to (14) and (36) to (39) are simply represented as (6) to (14) and (36) to (39), respectively.

[0132] (Growth promotion effect A) A plant activator containing any one of the compounds represented by formulas (6) to (14) as an active ingredient was prepared. MS medium was prepared and diluted with water to 1 / 2 by volume to prepare 1 / 2 MS medium (agar 1.2 g / L). The plant activator was added to the 1 / 2 MS medium so that the concentration of the compound, which is the active ingredient, was 0 μM (control, not contained), 0.1 μM, 1 μM, or 5 μM.

[0133] Wild-type Arabidopsis thaliana was sown and grown on 1 / 2 MS medium. The length of the taproot of wild-type Arabidopsis thaliana (Figure 1) or the growth rate (fold) of the taproot (Figure 2) was measured 15 days after sowing the wild-type Arabidopsis thaliana. The growth rate of the taproot was calculated by dividing the length of the taproot of wild-type Arabidopsis thaliana by the arithmetic mean value of the taproot length of wild-type Arabidopsis thaliana (Control). In the figure, the median of the measured values ​​is indicated by a horizontal line in the bar graph (excluding the horizontal lines at the top and bottom of the bar graph). The concentrations of the plant activators used and the compounds that are their active ingredients are indicated on the horizontal axis of the graph. For each plant activator, 16 wild-type Arabidopsis thaliana were used for evaluation.

[0134] The composition of MS medium (Murashige and Skoog medium) is as follows (per 1 L of this product, 4.6 g) (content in parentheses): KNO3 (1900mg / L), NH4NO3 (1650mg / L), CaCl2 2H2O (440mg / L), MgSO4 7H2O (370mg / L), KH2PO4 (170mg / L), Na2-EDTA (37.3mg / L), FeSO4 7H2O (27.8mg / L), MnS O4·4H2O(22.3mg / L), ZnSO4·7H2O(8.6mg / L), H3BO3(6.2mg / L), KI(0.83mg / L), Na2MoO4·2H2O(0.25mg / L), CuSO4·5H2O(0.025mg / L), CoCl2·6H2O(0.025mg / L)

[0135] (Growth promotion effect B) A plant activator containing any of the compounds represented by formulae (8) and (36) to (39) as an active ingredient was prepared. MS medium was prepared and diluted with water to 1 / 2 by volume to prepare 1 / 2 MS medium (agar 1.2 g / L). The plant activator was added to the 1 / 2 MS medium so that the concentration of the active ingredient compound was 0 μM (control, not contained), 0.01 μM, or 0.1 μM. The MS medium (Murashige and Skoog medium) used was the same as that used when measuring the growth promotion effect A.

[0136] Wild-type Arabidopsis thaliana was sown and grown on 1 / 2 MS medium. The length of the taproot of wild-type Arabidopsis thaliana was measured 12 days after sowing (Figure 7) and 14 days after sowing (Figure 8). In the figure, the median value of the measured values ​​is indicated by a horizontal line in the bar graph (excluding the horizontal lines at the top and bottom of the bar graph). The concentrations of the plant activators used and the compounds that are their active ingredients are indicated on the horizontal axis of the graph. For each plant activator, the number n of wild-type Arabidopsis thaliana used for evaluation is indicated at the top of the graph.

[0137] (Low temperature and freezing stress tolerance) A portion of the strawberry roots (including soil) at the time of seedling stage was immersed in water (fresh water without plant activator) or water containing 1 μM of the plant activator represented by formula (7) (plant activator water) for 5 days. The strawberry seedlings were then planted and grown in December 2022. When the strawberry seedlings were observed 108 days after planting, the strawberry seedlings immersed in the plant activator water were observed to have a more accelerated growth than the strawberry seedlings immersed in fresh water. The strawberries were grown in the winter of December, and it can be observed that the plant activator confers resistance to low temperature stress and freezing stress on the strawberry seedlings. A photograph showing the state of the strawberry seedlings 108 days after planting is shown in Figure 6. In Figure 6, strawberry seedlings soaked in plant activator solution (soak plants for 5 days in (7) solution before planting) are shown in the planter on the left (lower side), and strawberry seedlings soaked in fresh water (soak plants for 5 days in water before planting) are shown in the planter on the right (upper side).

[0138] (Salt stress tolerance A) A plant activator containing any one of the compounds represented by formulas (6) to (14) as an active ingredient was prepared. 1 / 2 MS medium was prepared in the same manner as in measuring the growth promotion activity. The plant activator was added to the 1 / 2 MS medium so that the concentration of the compound, which is the active ingredient, was 0 μM (control, not contained), 0.1 μM, or 1 μM. Furthermore, salt (NaCl) was added to the 1 / 2 MS medium so that the concentration was 100 mM, to prepare a medium containing excess NaCl.

[0139] Wild-type Arabidopsis thaliana was seeded and grown on the resulting medium containing excess NaCl. Twenty days after seeding, the length of the taproot of wild-type Arabidopsis thaliana (Figure 3) or the growth rate (fold) of the taproot (Figure 4) was measured. The growth rate of the taproot was calculated by dividing the length of the taproot of wild-type Arabidopsis thaliana by the arithmetic mean value of the length of the taproot of wild-type Arabidopsis thaliana (Control). In the figure, the median of the measured values ​​is indicated by a horizontal line in the bar graph (excluding the horizontal lines at the top and bottom of the bar graph). The concentrations of the plant activators used and the compounds that are their active ingredients are indicated on the horizontal axis of the graph. For each plant activator, 19 wild-type Arabidopsis thaliana were used for evaluation.

[0140] (Salt stress tolerance B) A plant activator containing any of the compounds represented by formulae (6) to (8) and (36) to (39) as an active ingredient was prepared. 1 / 2 MS medium was prepared in the same manner as in measuring the growth promotion activity. The plant activator was added to the 1 / 2 MS medium so that the concentration of the compound, which is the active ingredient, was 0 μM (control, not contained), 0.01 μM, or 0.1 μM. Furthermore, salt (NaCl) was added to the 1 / 2 MS medium so that the concentration was 100 mM, to prepare a medium containing excess NaCl.

[0141] Wild-type Arabidopsis thaliana was seeded and grown on the resulting medium containing excess NaCl. The length of the taproot of wild-type Arabidopsis thaliana was measured 14 days after seeding (FIG. 9) and 20 days after seeding (FIG. 10). In the figure, the median value of the measured values ​​is indicated by a horizontal line in the bar graph (excluding the horizontal lines at the top and bottom of the bar graph). The concentrations of the plant activators used and the compounds that are their active ingredients are indicated on the horizontal axis of the graph. For each plant activator, the number n of wild-type Arabidopsis thaliana used for evaluation is indicated at the top of the graph.

[0142] (Drought stress tolerance) 1 / 2MS medium was prepared in the same manner as in the measurement of growth promotion activity. Sorbitol was added to the 1 / 2MS medium to a concentration of 150 mM to prepare a dry medium (sorbitol 182.17 g / L, agar 1.2 g / L). The 1 / 2MS medium was supplemented with a plant activator so that the concentration of the compound, which is its active ingredient, was 0 μM (control, not included) or 0.1 μM.

[0143] Wild-type Arabidopsis thaliana was seeded and grown on the obtained dry medium. The number of lateral roots of wild-type Arabidopsis thaliana was measured 20 days after seeding (Figure 5). The median length of the primary root of wild-type Arabidopsis thaliana is shown by a horizontal line in the bar graph (excluding the horizontal lines at the top and bottom of the bar graph). The concentrations of the plant activators used and the compounds that are their active ingredients are shown on the horizontal axis of the graph. For each plant activator, 10 wild-type Arabidopsis thaliana were used for evaluation. The vertical axis shows the number of lateral roots (number of lateral roots) of wild-type Arabidopsis thaliana. [Industrial Applicability]

[0144] The plant activator of the present invention can activate plants, promote plant growth, or impart resistance to various stresses to plants by being applied to plants or to the soil, culture medium, or culture solution in which plants are grown.

Claims

1. A plant activator comprising a compound represented by formula (1) or (2) as an active ingredient. 【Chemistry 1】 In the formula (1) and the formula (2), R 1 , R 2 and R 3 are each a substituted or unsubstituted alkyl group, R 4 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, or a substituted or unsubstituted amino group; R 5 is a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a cycloalkyl group, a substituted or unsubstituted amino group, or a hydrogen atom; X is a carbon atom or a nitrogen atom; of two adjacent double lines of a solid line and a dotted line, one double line of a solid line and a dotted line is a single bond and the other double line of a solid line and a dotted line is a single bond or a double bond; Q － is a counter anion, n is a natural number from 1 to 5, and m is a natural number from 1 to 5.

2. 2. The plant activator according to claim 1, wherein the formula (1) has a structural formula represented by formula (1a). 【Chemistry 2】

3. The plant activator according to claim 1, characterized in that the formula (2) has a structural formula represented by formula (2a). 【Chemistry 3】

4. R 1 , R 2 and R 3 is an unsubstituted alkyl group and R 4 and R 5 The plant activator according to any one of claims 1 to 3, wherein is a substituted or unsubstituted phenyl group.

5. R 1 , R 2 and R 3 5. The plant activator according to claim 4, wherein: is a methyl group, and X is a carbon atom.

6. Q － The plant activator according to any one of claims 1 to 3, wherein is a hexafluorophosphate anion or a halide ion.

7. 2. The plant activator according to claim 1, wherein the compound represented by formula (1) is 3,3-diphenylprop-2-ene-trimethylammonium hexafluorophosphate or trimethyl-3,3-diphenylpropylammonium hexafluorophosphate.

8. 2. The plant activator according to claim 1, wherein the compound represented by formula (2) is N,N-dimethyl-3,3-diphenylpropan-1-amine.

9. The plant activator according to any one of claims 1 to 3, which is used as a plant growth promoter.

10. The plant activator according to any one of claims 1 to 3, which is used as an agent for imparting plant stress tolerance.

11. A method for growing a plant, comprising applying the plant activator according to any one of claims 1 to 3 to a plant or to soil, medium or culture solution in which the plant is grown.

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