JP6902748B2 - Plant growth regulator - Google Patents

Description

The present invention relates to plant growth regulators.

In the agricultural field, controlling plant growth is an important technique for improving productivity. Currently, various types of plant growth regulators for the purpose of controlling plant growth have been put into practical use, and plant growth regulators contribute to improving crop yield and product quality. Plant growth regulators include both those that promote and suppress the growth of any tissue in the plant. Therefore, a wide range of materials such as rooting promoters, fruit set promoters, fruit hypertrophy promoters, fruit tree plucking agents, fruit coloring promoters, dwarfing agents, and herbicides are included as plant growth regulators.

In the tissue of plants, roots play very important roles such as plant colonization, water absorption, nutrient absorption, and prevention of lodging, so it is important to promote their development.
The roots of plants are composed of taproots, lateral roots, and adventitious roots, which are collectively called the root system. The taproot is already developed at the seed stage and grows at the same time as germination. Therefore, if the growth of taproots can be promoted, the absorption of water and nutrients in the soil can be promoted from the initial stage, the initial growth can be promoted, and the initial drought stress tolerance can be imparted. Lateral roots differentiate and develop from taproot. Therefore, if the growth of lateral roots can be promoted, the surface area of the roots can be dramatically increased, the absorption of water and nutrients in the soil is promoted, the overall growth can be promoted, and the resistance to drought stress is imparted. can do. Adventitious roots differentiate and develop from tissues other than roots such as stems and leaves. For this reason, roots generated from cultured plant cells and roots generated from above-ground tissue sections such as cuttings and cuttings are classified as adventitious roots, and in order to promote so-called vegetative propagation efficiently, the development of adventitious roots should be promoted. Has become an important industrial technology. In monocots such as rice crops, the growth of radicles stops shortly after germination, and most roots except seed roots are adventitious roots that develop from the stem and are also called coronary roots. Promoting the development of these adventitious roots is important for ensuring the stable growth of grasses. Adventitious root formation is especially important for the growth and lodging prevention of major crops such as rice, wheat and corn.

A plant growth regulator having an action of promoting the development of these roots is desired. However, the number of plant growth regulators that promote rooting is small and the effect is not sufficient. Furthermore, conventional substances that promote root development often have unfavorable effects. For example, auxin compounds that act as plant hormones that are widely used as rooting agents are toxic to plants depending on the type and condition of the plant and the concentration at which they are applied. It has been pointed out that it has an unfavorable effect.
The following can be exemplified as the prior art.
WO2011 / 136285 (Patent Document 1) describes that a compound having a dichlorophenyl group, a difluorophenyl group, or the like causes adventitious roots of eucalyptus.
Further, Japanese Patent Application Laid-Open No. 5-260869 (Patent Document 2) describes that adventitious roots can be induced in sweet potato stems by using auxin and α-naphthalene acetic acid in combination.
Further, Japanese Patent Application Laid-Open No. 5-49484 (Patent Document 3) describes a technique for inducing adventitious roots by culturing lemon balm callus in a medium supplemented with auxin.

In addition, 4-chloro is used as a fruit set promoting action of auxin, a fruit setting promoting agent utilizing the fruit enlargement action, a fruit enlargement promoting agent, a fruit tree picking agent utilizing the ethylene generation promoting action of auxin, and a fruit coloring promoting agent. Phenoxyacetic acid, dichloroprop, ethylene and the like have been put into practical use. 2,4-D, 2,4-PA, MCPA, etc. have also been put into practical use as herbicides for broad-leaved plants utilizing the disturbing action of auxin's endogenous hormone. However, these plant growth regulators are also small in number, have insufficient effects, and often have more unfavorable effects.
As described above, among plant hormones having a rooting promoting action, chemically synthesized products developed based on auxin are also called superauxins and are mainly used as herbicides (Non-Patent Document 1). For example, 8-quinoline carboxylic acid derivatives such as quinclorac (Quinclorac, 3,7-dichloro-8-quinoline carboxylic acid (see Patent Documents 4 and 5)) and quinmerac (Quinmerac, 7-chloro-3-methyl-8-). There are quinoline carboxylic acids (see Patent Document 6) and the like. It has also been found that 5-chloro-3-methyl-8-quinoline carboxylic acids also have a herbicidal effect (see Patent Document 7). -Among the derivatives of quinolinecarboxylic acid, those in which a chlorine atom is bonded at the 3-position or a methyl group is substituted, or those in which a chlorine atom is bonded at the 7-position exhibit a herbicidal effect by exhibiting a strong auxin activity. However, it has been clarified that the 8-quinoline carboxylic acid derivative in which the 3- and 7-positions are unsubstituted has a plant growth-regulating effect without growth inhibition.

International Publication No. 2011/136285 Pamphlet Japanese Unexamined Patent Publication No. 05-260869 Japanese Unexamined Patent Publication No. 05-049484 U.S. Pat. No. 4,497,651 U.S. Pat. No. 4,632,696 German Patent Application Publication No. 3,233,089 Special Fair 04-075232.

Grossmann 2010. Auxin herbicides: current status of mechanism and mode of action. Pest Maneg. Sci. 66: 113-120.

An object of the present invention is to provide a plant growth regulator.

As a result of diligent research to solve the above problems, the present inventors have found that a specific compound of a quinoline-8-carboxylic acid derivative, which has not been found to have a plant growth-regulating effect in the past, promotes rooting and further roots. We have found that it has a plant growth-regulating action such as promoting the development of the present invention, and have completed the present invention.

That is, the present invention has the following configuration.
1. 1. A plant growth regulator comprising a compound represented by the general formula 1 or a salt thereof.

However, -A1-A2-A3-A4- and R1 to R3 in General Formula 1 have one of the following structures.
-A1-A2-A3-A4-is -N = CH-CH = CH-, or -NH-CH ₂ -CH ₂ -CH _2-
R1 = hydrogen atom, alkyl group, or halogen atom
R2 = hydrogen atom, alkyl group, or halogen atom
R3 = hydroxyl group or alkoxy group 2. The plant growth according to 1, wherein -A1-A2-A3-A4- is -N = CH-CH = CH-, R1 is a hydrogen atom, R2 is a hydrogen atom, and R3 is a compound having a hydroxyl group or a salt thereof. Conditioner.
3. 3. The plant growth according to 1, wherein -A1-A2-A3-A4- is -N = CH-CH = CH-, R1 is a hydrogen atom, R2 is a halogen atom, and R3 is a compound having a hydroxyl group or a salt thereof. Conditioner.
4. The plant growth regulator according to 3, wherein R2 is a chlorine atom or a bromine atom.
5. The plant growth according to 1, wherein -A1-A2-A3-A4- is -N = CH-CH = CH-, R1 is a hydrogen atom, R2 is a hydrogen atom, and R3 is a compound or a salt thereof. Conditioner.
6. 5. The plant growth regulator according to 5, wherein R3 is a compound having a methoxy group or a salt thereof.
7. -A1-A2-A3-A4-is -NH-CH ₂ -CH ₂ -CH _2- , and R1 is a hydrogen atom, R2 is a hydrogen atom, and R3 is a compound having a hydroxyl group or a salt thereof. Plant growth regulator.
8. Quinoline-8-carboxylic acid, 6-Chloro-quinoline-8-carboxylic acid, 6-Bromoquinoline-8-carboxylic acid -quinoline-8-carboxylic acid), quinoline-8-carboxylic acid methyl ester, 1,2,3,4-tetrahydroquinolin-8-carboxylic acid (1,2,3,4) -A plant growth regulator containing one or more compounds selected from (Tetrahydroquinoline-8-carboxylic acid).
A plant rooting agent containing the plant growth regulator according to any one of 9.1 to 8.
A fertilizer containing the plant growth regulator according to any one of 10.1 to 8.
A pesticide containing the plant growth regulator according to any one of 11.1 to 8.

The present invention provides a novel plant growth regulator. The plant growth regulator of the present invention has high rooting promoting activity.
In addition, the plant growth regulator of the present invention has extremely weak or no side effects as exhibited by superauxins such as chlorosis of stems and leaves.
The plant growth regulator of the present invention can be used as a rooting promoter at the time of cutting, raising seedlings, and transplanting.
In addition, since it promotes root system development, the absorption efficiency of fertilizer components is improved, the growth of plants is promoted, and the yield of crops is increased.

The plant growth regulator of the plant of the present invention contains a salt and an ester of the compound represented by the general formula 1 as active ingredients.

However, -A1-A2-A3-A4- and R1 to R3 in General Formula 1 have one of the following structures.
-A1-A2-A3-A4- ＝ -N = CH-CH = CH- or -NH-CH ₂ -CH ₂ -CH _2-
R1 = hydrogen atom, alkyl group, or halogen atom
R2 = hydrogen atom, alkyl group, or halogen atom
R3 = hydroxyl group or alkoxy group

The above compound is a compound known as 8-quinoline carboxylic acid, a derivative thereof, or a salt thereof. In the present invention, the compound represented by the above general formula 1 is used as an active ingredient of a plant growth regulator.
The substituent R1 is any one of a hydrogen atom, a halogen atom and an alkyl group. As the halogen atom, a chlorine atom, a bromine atom and an iodine atom are preferable. Alkyl groups include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, i-propyl group, i-butyl group, i-pentyl group and i-hexyl group. A lower alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is particularly preferable.

The substituent R2 is any one of a hydrogen atom, a halogen atom and an alkyl group. As the halogen atom, a chlorine atom, a bromine atom and an iodine atom are preferable. Alkyl groups include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, i-propyl group, i-butyl group, i-pentyl group and i-hexyl group. A lower alkyl group having 1 to 6 carbon atoms is preferable, and a methyl group is particularly preferable.

The substituent R3 is a hydroxy group or an alkoxy group. Alkoxy groups include methoxy group, ethoxy group, n-propoxy group, n-butoxy group, n-pentyloxy group, n-hexyloxy group, i-propoxy group, i-butoxy group, i-pentyloxy group and i. An alkoxy group having 1 to 6 carbon atoms such as a hexyloxy group is preferable, and a methoxy group is particularly preferable.

Examples of the salt of the compound represented by the general formula 1 include alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as calcium salt and magnesium salt, inorganic base salts such as ammonium salt, triethylamine salt and pyridine. Examples thereof include salts with organic base salts such as salts, picolin salts, ethanolamine salts, triethanolamine salts, dicyclohexylamine salts, or organic amine salts of N, N'-dibenzylethylenediamine salts.
In addition, salts such as inorganic acid salts such as hydrochlorides, sulfates and nitrates, and organic acid salts such as nitates, acetates, propionates, butyrates and lactates can be mentioned.

The compound represented by the general formula 1 can be synthesized by a known method disclosed in WO2008 / 059513. That is, as a method for synthesizing quinoline-8-carboxylic acid having an arbitrary substituent at the 6-position (R2), iodine and glycerol are mixed and stirred using anthranilic acid having an arbitrary substituent at the 5-position as a raw material. However, it can be synthesized by dropping concentrated sulfuric acid. At this time, the amount of iodine added is preferably 1 to 5 mol% and the amount of glycerol added is preferably 100 to 200% by mass with respect to the mass of the anthranilic acid derivative. The amount of concentrated sulfuric acid dropped is not particularly limited, but it is preferably 0.3 to 1 times the amount of the mother liquor in consideration of ease of operation. After completion of the reaction, the purified product can be collected from the reaction solution by appropriately adding cold water, adjusting the pH to 6 to 7 with aqueous ammonia, and filtering the solid form. When the purity is insufficient, the obtained solid form can be dissolved in an inert organic solvent such as chloroform, dichloromethane, ethanol, and methanol, and activated carbon can be added to remove impurities. The purified product can be further purified by the recrystallization method.

As an example of the substitution reaction, a substitution reaction using R3 as an alkoxy group will be illustrated.
Using a quinoline-8-carboxylic acid derivative as a raw material, R3 becomes an alkyl group by heating and refluxing in an alcohol such as methanol, ethanol, or propanol in the presence of an acid catalyst such as sulfuric acid or p-toluenesulfonic acid. Obtain a substituted compound. At this time, the quinoline-8-carboxylic acid derivative is preferably 1 to 20% by mass, particularly preferably 5 to 10% by mass.
Further, a compound in which R3 is substituted with a methyl group can be obtained by reacting with a quinoline-8-carboxylic acid derivative as a raw material in methanol in the presence of a methyl esterifying agent such as trimethylsilyldiazomethane. it can.
After the reaction, in order to collect the product from the reaction solution, the reaction solvent is distilled off, a product-soluble organic solvent that is not mixed with water and water are added, the pH of the aqueous phase is adjusted appropriately, and the solvent is extracted to perform organic. After recovering the solvent layer, it is dried, the organic solvent is distilled off, and then it may be recrystallized from a single solvent or a mixed solvent, if necessary. Further, if necessary, it may be isolated by a separation means such as high performance liquid chromatography (HPLC).
Substitution reactions other than the above can be easily carried out by known chemical reactions.

As a hydrogenation method for the condensed pyridine ring, quinoline-8-carboxylic acid having an arbitrary substituent is used as a raw material, dissolved in an alcohol such as ethanol together with platinum (II) oxide, and reacted in a hydrogen atmosphere. Can be synthesized by. At this time, the concentration of the quinoline-8-carboxylic acid derivative with respect to ethanol is preferably 3 to 10%, and the amount of platinum (II) oxide added is preferably 5 to 10 mol% with respect to the quinoline-8-carboxylic acid derivative. After the synthesis, the purified product can be obtained by setting the atmosphere in an argon atmosphere and adding a porous adsorbent such as Celite to remove impurities. When the degree of purification is insufficient, a purified product can be obtained by eluting with a non-hydrated organic solvent such as diethyl ether and distilling off the solvent. The purified product can be further purified by a recrystallization method.
It is desirable that the compound used in the present invention or a salt thereof is water-soluble. In the case of a water-insoluble compound, it can be used in the form of being dispersed in water.

Representative compound names and general formulas useful as plant growth regulators in the present invention are illustrated below. Naturally, the present invention is not limited to these compounds.

Compound 1
Quinoline-8-carboxylic acid

Compound 2
6-Chloro-quinoline-8-carboxylic acid

Compound 3
6-Bromo-quinoline-8-carboxylic acid

Compound 4
Quinoline-8-carboxylic acid methyl ester

Compound 5
1,2,3,4-Tetrahydroquinoline-8-carboxylic acid (1,2,3,4-Tetrahydroquinoline-8-carboxylic acid)

The plant growth regulator of the present invention can also be used in combination of two or more compounds having a plurality of active actions. It can also be used in combination with plant hormones such as auxin.

The term "plant growth regulation" used in the present invention includes, for example, plant dwarfing (elongation suppression), flowering time regulation, upright leaf induction (and associated improvement in photosynthetic efficiency, biomass increasing action), pollen growth. Suppression, flower freshness maintenance, plant anti-stress agent (heat, dryness, cold, etc.), weed control by reproductive control, plant aging suppression, root enlargement, fruit set promotion, fruit enlargement promotion, fruit drop prevention, peel coloring It needs to be interpreted in the broadest sense, including promotion. For example, a rooting promoter, a plant growth regulator, a root system development promoter, etc. are typical examples of the plant growth regulator of the present invention, but the plant growth regulator of the present invention is not limited to these. Absent.

The plant growth regulator of the present invention can use an aqueous solution of the compound as it is as a plant growth regulator, but it is used in ordinary plant growth regulators such as wettable powders, emulsions, granules, powders and surfactants. It may be formulated using a carrier. For example, as solid carriers, mineral powders (kaolin, bentonite, clay, montmorillonite, talc, caustic soil, mica, vermiculite, sekko, calcium carbonate, phosphorus lime, etc.), vegetable powders (soybean flour, wheat flour, wood flour, tobacco Powder, starch, crystalline cellulose, etc.), polymer compounds (petroleum resin, polyvinyl alcohol resin, polyvinyl acetic acid resin, polyvinyl chloride, ketone resin, etc.), alumina, waxes, etc. can be used. Examples of the liquid carrier include alcohols (methanol, ethanol, propanol, butanol, ethylene glycol, benzyl alcohol, etc.), aromatic hydrocarbons (toluene, benzene, xylene, etc.), and chlorinated hydrocarbons (chloroform, etc.). Carbon tetrachloride, monochlorobenzene, etc.), ethers (dioxane, tetrahydrofuran, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters (ethyl acetate, butyl acetate, etc.), acid amides (N, N-dimethylacetamide, etc.) , Ether alcohols (ethylene glycol ethyl ether, etc.), water, etc. can be used.

As the surfactant used for the purpose of emulsification, dispersion, diffusion and the like, any of nonionic, anionic, cationic and amphoteric surfactants can be used. Examples of surfactants that can be used in the present invention include polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, and oxyethylene polymer. , Oxypropylene polymer, polyoxyethylene alkyl phosphate, fatty acid salt, alkyl sulfate, alkyl sulfonate, alkylaryl sulfonate, alkyl phosphate, alkyl phosphate, polyoxyethylene alkyl sulfate, It is a quaternary ammonium salt, oxyalkylamine, lecithin, saponin and the like. Further, if necessary, gelatin, casein, sodium alginate, starch, agar, polyvinyl alcohol and the like can be used as an auxiliary agent.

The plant growth regulator of the present invention has no limitation on the shape of the preparation, and can be molded into any preparation form such as powder, granule, granule, wettable powder, flowable agent, emulsion and paste. It can be produced by mixing, stirring, spray-drying and the like other components according to a conventional method.
When applied to plants, it can be used as a soil treatment agent, a foliage treatment agent, a seed treatment agent before sowing, a treatment agent for plants before transplantation, a treatment agent for plants at the time of transplantation, and the like. Further, in hydroponics, it may be mixed with a hydroponic solution and used, and in tissue culture, it may be suspended or dissolved in a medium.
When the plant growth regulator of the present invention is applied to a target plant, the root amount and root density increase as the number of roots such as the number of lateral roots and the number of adventitious roots increases. The effects of growing, promoting growth, improving water absorption, improving fertilizer absorption, improving fertilizer component utilization rate, maintaining green color, improving photosynthetic ability, improving water stress tolerance, preventing lodging, and increasing yield can be obtained. In addition, since the heat climbing of gramineous plants is improved, the yield of rice and the like can be improved.

When the plant growth regulator of the present invention is used for spraying, the concentration used is preferably in the range of 0.01 to 10000 ppm, more preferably 1 to 5000 ppm, and particularly preferably 5 to 1000 ppm. In particular, when used for seedlings in the seedling raising stage, it is desirable to spray 50 to 200 mL of the diluted solution having the above concentration per 1 L of potting soil. In this case, a spreading agent may be used, and the type and amount of the spreading agent used are not particularly limited. It is also effective when sprayed on the foliage.
The amount to be used when directly applied to soil, including when mixed with fertilizer, is preferably 100 to 10000 g, particularly 500 to 5000 g per hectare. In particular, when used for seedlings in the seedling raising stage, it is desirable to use 0.001 to 10 g per 1 L of potting soil. In this case, it may be mixed in advance with the culture soil before sowing, or may be sprayed during the seedling raising period.

When used for seed treatment before sowing, water, alcohols (methanol, ethanol, etc.), ketones (acetone, etc.), aromatic hydrocarbons (toluene, benzene, etc.), chlorinated hydrocarbons (chloroform, chloride, etc.) Dilute to 0.01-100,000 ppm on a liquid carrier such as methylene), ethers (diethyl ether, etc.), esters (ethyl acetate, etc.) and spray on dried seeds, or immerse the dried seeds in a diluted solution. It can also be absorbed by the seeds. The immersion time is not particularly limited, but is preferably 1 second to 120 minutes. Further, the treated seeds may be air-dried, vacuum-dried, heat-dried, vacuum-dried, or the like to evaporate the liquid carrier. It is also possible to use a product formulated using a solid carrier of mineral powder such as clay by adhering it to the seed surface. It can also be mixed with a commonly used seed coating agent or seed coating film to coat the seeds.
When used in tissue culture or cell culture, the concentration in the medium is preferably 0.01 to 10000 ppm, particularly preferably 0.01 to 10,000 ppm, in a medium for plant tissue culture (MS medium, white medium, Gamborg's B5 medium, etc.) that is usually used. It can be used by dissolving or suspending in the range of 0.1 to 1000 ppm. In this case, as is usually done, sugars as carbon sources (sucrose, glucose, etc.), cytokinins (benzyladenine, kinetin, etc.), auxins (indoleacetic acid, naphthalene acetic acid, etc.), gibberellic acid (GA3) as various plant hormones. , GA4, etc.), abscisic acid, etc. can be added as appropriate.
When directly absorbed by a plant before transplantation, the root or the whole of the plant can be immersed in a solution diluted or suspended at a concentration of 0.1 to 1000 ppm. Further, if it is a cutting, cuttings, cuttings, etc., the base or the whole can be immersed and used. In this case, the immersion time is preferably 1 second to 1 week, particularly 1 minute to 3 days. A product formulated using a solid carrier of mineral powder may be attached to the root, or in the case of cuttings, cuttings, cuttings, etc., may be attached to the stem base.
The plant growth regulator of the present invention can be used at any time during the growing period, but when applied as a plant growth regulator, it is used before sowing, at the time of sowing, at the time of growing seedlings, and at the time of transplantation. It is especially effective before and after work involving cultivating root cutting, such as when root growth is hindered or root damage occurs due to meteorological factors.

The plant to which the plant growth regulator of the present invention is applied is not particularly limited, but for example, eggplants such as tomatoes, peppers, corns and eggplants, melons such as cucumbers, pumpkins, melons and watermelons, cerules and parsley. , Raw vegetables and spicy vegetables such as lettuce, green onions such as onions, onions and garlic, beans such as soybeans, lacquer, green beans, pea and azuki, other fruit vegetables such as strawberries, direct fruits such as corn, cub, carrot and gobo Roots, sweet potatoes, cassava, potatoes, sweet potatoes, potatoes and other potatoes, asparagus, spinach, honeybees and other soft vegetables, Turkish ginkgo, stock, carnation, kiku and other grains, rice, corn and other grains, bentgrass , Turbs such as melon, oil crops such as rapeseed and sunflower, sugar crops such as sugar beet and sugar beet, fiber crops such as cotton and igusa, forage crops such as clover, sorghum and dent corn, apples and pears. , Grains, deciduous fruit trees such as peach, citrus fruits such as unshu mikan, lemon and grapefruit, and woody plants such as satsuki, tsutsuji and sugi. Of these, tomatoes, peppers, capsicum, eggplant, cucumber, pumpkin, melon, watermelon, cellulie, parsley, lettuce, onion, onion, asparagus, Turkish guikyo, stock, rice, bentgrass, sardine, tensai, igusa, etc. are being cultivated. It is particularly effective for plants that are transplanted to tomatoes and plants that grow by rooting from cuttings or cuttings such as cucumbers, carnations, watermelons, capsicums, and grapes. In addition, examples of gramineous plants for the purpose of preventing lodging include rice, wheat, barley, rye, and corn. In particular, when rice and wheat are sprayed during the division period, many adventitious roots are generated, the growth of the entire root system is promoted, and the absorption efficiency of nutrients is improved. preferable.
By spraying the plant growth regulator of the present invention in the field or directly on the plant, it leads to the development of the root system of the cultivated plant, the shortening of the growing period, the increase in the number of divisions, the increase in yield and the like.

Further, for the purpose of improving the effect of the present invention, it can be used in combination with another plant growth regulator (plant hormone agent) as described above, and in some cases, a synergistic effect can be expected. For example, when raising seedlings under extremely long-term conditions such as high planting density, high humidity, and lack of sunshine, it has a strong stem elongation inhibitory effect for the purpose of growing high-quality seedlings with a small above-ground and underground weight ratio. It may be used in combination with an anti-gibberellin agent (paclobutrazol, uniconazole P, ansimidol, etc.), a growth inhibitor (daminozide, etc.), and an ethylene generator (ethephon, etc.). In cuttings, cuttings, cuttings, and tissue culture, it may be used in combination with an auxin-based compound (indoleacetic acid, indolebutyric acid, naphthylacetamide, naphthaleneacetic acid, etc.) for the purpose of enhancing the rooting promoting effect. At the time of seed treatment before sowing, it may be used in combination with a gibberellin agent having a germination promoting action.

The plant growth regulator of the present invention can also be mixed or used in combination with various insecticides, fungicides, microbial pesticides, fertilizers and the like. In particular, when used in combination with a fungicide, it is effective to use in combination with hydroxyisoxazole, metasulfocarb, metalaxil, etc., which have been reported to have a rooting promoting action in addition to the bactericidal action. It is particularly effective when used in combination with an insecticide that treats seeds directly or that is used during the seedling raising period (thiamethoxam, fludioxonyl, metalaxil, chlorantraniliprole, etc.).
When used in combination with fertilizer, it is particularly effective to use it in combination with a fertilizer for raising seedlings for the purpose of growing healthy seedlings and a fertilizer applied immediately before transplantation for the purpose of promoting survival. Mixing with a slow-release fertilizer for the purpose of sustaining the efficacy of the plant growth regulator of the present invention for a long period of time and improving the utilization rate of fertilizer components is also particularly effective.

Next, the present invention will be described in more detail with reference to Production Examples of Compounds 2 to 5, Test Examples of Compounds 1 to 5, and Examples, but the present invention is not limited to these Examples.

Production Example 1 (Compound 2: Synthesis of 6-chloroquinoline-8-carboxylic acid)
A mixture of 1.01 g of 5-chloroanthranilic acid and 26.6 mg of iodine in 0.76 g of glycerol is vigorously stirred, and 0.44 ml of concentrated sulfuric acid is added dropwise over 30 minutes at 65 ° C. to 70 ° C. at 140 ° C. It was allowed to react for 6 hours. At room temperature, 17 mL of water at 0 ° C. was added, the pH was 6.5 with 28% ammonia water, and the solid content was washed with cold water and then dried. The obtained residue was dissolved in chloroform, the insoluble matter was filtered off, activated carbon was added to adsorb impurities, and the activated carbon was removed by filtration. The residue obtained by distilling off the solvent was recrystallized under a mixed solution of chloroform and ethyl acetate, and the obtained crystals were washed with ethyl acetate. The solvent was distilled off to obtain 96.2 mg of the compound (yield 7.9%). The NMR, mass spectrum, and melting point of this compound were measured, and it was confirmed that it was compound 2 (6-chloroquinoline-8-carboxylic acid) having the structure of the general formula 3.

Production Example 2 (Compound 3: Synthesis of 6-bromoquinoline-8-carboxylic acid)
A mixture of 1.26 g of 5-bromoanthranilic acid and 23.3 mg of iodine in 0.76 g of glycerol is vigorously stirred, and 0.44 ml of concentrated sulfuric acid is added dropwise over 30 minutes at 65 ° C. to 70 ° C. at 140 ° C. It was allowed to react for 6 hours. At room temperature, 17 mL of water at 0 ° C. was added, the pH was 6.5 with 28% ammonia water, and the solid content was washed with cold water and then dried. The obtained residue was dissolved in ethanol and filtered, and the residue obtained by drying was dissolved in chloroform, activated carbon was added to adsorb impurities, and the activated carbon was removed by filtration. The residue obtained by distilling off the solvent was recrystallized under a mixed solution of chloroform and ethyl acetate, and the solvent was distilled off to obtain 28.7 mg (yield 2.0%) of the compound. The NMR, mass spectrum, and melting point of this compound were measured, and it was confirmed that it was compound 3 (6-bromoquinoline-8-carboxylic acid) having the structure of the general formula 4.

Production Example 3 (Compound 4: Synthesis of methyl quinoline-8-carboxylate)
85.6 mg of quinoline-8-carboxylic acid was placed in an argon atmosphere and dissolved in 2.5 ml of methanol and 2.5 ml of dichloromethane. 0.8 ml of trimethylsilyldiazomethane was added, the reaction was carried out for 30 minutes, and then the solvent was distilled off. The residue was purified by silica gel column chromatography using a 40% ethyl acetate 60% hexane mixed solution as a developing solvent, and the solvent was distilled off to obtain 69.4 mg (yield 77%) of the compound. The NMR, mass spectrum, and melting point of this compound were measured, and it was confirmed that it was compound 4 (methyl quinoline-8-carboxylate) having the structure of the general formula 5.

Production Example 4 (Synthesis of Compound 5: 1,2,3,4-Tetrahydroquinoline-8-carboxylic Acid)
174 mg of quinoline-8-carboxylic acid and 15.3 mg of platinum (II) oxide were dissolved in 3 ml of ethanol, reacted under a hydrogen atmosphere for 5 hours, and then under an argon atmosphere. Impurities were adsorbed by adding Celite and removed by filtration. The material obtained by distilling off the solvent was washed with warm diethyl ether, and the solvent was distilled off to obtain 140.8 mg (yield 79%) of the compound. The NMR, mass spectrum, and melting point of this compound were measured, and it was confirmed that it was compound 5 (1,2,3,4-tetrahydroquinoline-8-carboxylic acid) having the structure of the general formula 6.
The NMR measurement results and melting point measurement results of compounds 2 to 5 are shown in Table 1 below.

Test example <Confirmation test of adzuki bean root generation induction action by adzuki bean cut edge immersion treatment>
Compounds 1 to 5 are diluted with distilled water to prepare an aqueous solution having a concentration of 0.03 mM and 0.1 mM, and the pH is adjusted to 7 using dilute hydrochloric acid and an aqueous solution of sodium hydroxide. Azuki rooting promotion assay (Itagaki et al. 2003. Biological activities and structure-activity relationship of substitution compounds of N- [2- (3-indolyl) ethyl] succinamic acid and N- [2- (1-naphthyl) ethyl] succinamic acid, derived from a new category of root-promoting substance, N- (phenethyl) succinamic acid analogs. Plant Soil 255: 67-75.) Was performed. No test was conducted using a solution of only Compound 3 at 0.03 mM.
The base of the Azuki section was immersed in 0.03 mM and 0.1 mM test solutions for 72 hours, and the number of adventitious roots generated after 7 days was counted. The number of repetitions was set to 5. In addition, when measuring the activity of each compound, those treated with distilled water were cultured as a control, and the number of adventitious roots was measured in the same manner. Therefore, the control group showed the total average value measured multiple times.
The test results are shown in Table 2 below.

As shown in Table 2, the solutions containing compounds 1 to 5 were found to have a high adventitious rooting inducing effect and a rooting promoting effect as compared with the number of adventitious rooting in the control group.
In particular, Compound 1 showed a rooting rate of 300% or more at a concentration of 0.03 mM and 500% or more at a concentration of 0.1 mM. In addition, compounds 2 having a concentration of 0.03 mM and compounds 4 and 5 having a concentration of 0.03 mM and 0.1 mM showed a rooting rate of 200% or more. In addition, no signs such as chlorosis of stems and leaves were observed.

<Effect in the field>
Compounds 1 to 5 were mixed with fertilizer and sprayed on corn being cultivated in the field. For each compound, it was confirmed that the root system development and growth were significantly promoted and the yield was increased as compared with the field where only fertilizer was applied. In addition, the occurrence of chlorosis on stems and leaves due to spraying was not observed.

<Corn support root increase effect test>
For feed corn (variety LG3215; Snow Brand Seed Co., Ltd.), 1/1000 amount of spreading agent in 1 mM quinoline-8-carboxylic acid solution (approach BI: polyoxyethylene hexitane fatty acid ester: Maruwa Biochemical Co., Ltd.) The product to which the company) was added was foliar sprayed four times every two weeks from the third week after sowing.
Supporting roots were counted for 20 plants 4 months after sowing, and the average value was calculated.
The test results are shown in Table 3 below.

As shown in Table 3, the solution containing 1 mM quinoline-8-carboxylic acid of the present invention showed a strong supporting rooting effect as compared with the control group, and the compound of the present invention exhibited a strong rooting effect even in soil cultivation. It was clear to do.

Claims (4)

A plant rooting agent consisting of a compound represented by the general formula 1 or a salt thereof.

However, -A1-A2-A3-A4- and R1 to R3 of the general formula 1 have any of the following structures.
-A1-A2-A3-A4- is -N = CH-CH = CH-, or _{-NH-CH 2 -CH 2 -CH 2} -
R1 = hydrogen atom R2 = hydrogen atom , chlorine atom, or bromine atom R3 = hydroxyl group or methoxy group Quinoline-8-carboxylic acid, 6-chloroquinolin-8-carboxylic acid (6-Chloro-quinoline-8-carboxylic acid), 6-bromoquinolin-8-carboxylic acid (6-Bromo) -Quinoline-8-carboxylic acid), methyl quinolin-8-carboxylate (Quinoline-8-carboxylic acid methyl ester), 1,2,3,4-tetrahydroquinolin-8-carboxylic acid (1,2,3,4) -A plant rooting agent containing one or more compounds selected from (-Terrahydroquinoline-8-carboxylic acid). A fertilizer containing the plant rooting agent according to claim 1 or 2. A pesticide containing the plant rooting agent according to claim 1 or 2.