阅读说明：本技术 植物用生长辅助剂和植物的生长方法 (Growth auxiliary for plant and method for growing plant ) 是由 上田真澄 田中佑弥 飞永恭兵 于 2019-07-09 设计创作，主要内容包括：本发明的目的在于提供一种植物用生长辅助剂和植物的生长方法,其能够使药剂高效地摄取到叶内,并且药剂从颗粒的溶出特性优异。本发明涉及一种植物用生长辅助剂(X)和使用该植物用生长辅助剂(X)的植物的生长方法,该植物用生长辅助剂(X)含有中值粒径为1nm～300nm的颗粒(P),该颗粒(P)含有生物降解性树脂(A)和25℃的辛醇/水分配系数(LogPow)为1～10的疏水性药剂(B)。(The purpose of the present invention is to provide a plant growth auxiliary agent and a plant growth method, which enable efficient uptake of a drug into leaves and which have excellent dissolution characteristics of the drug from particles. The present invention relates to a growth auxiliary for plants (X) containing particles (P) having a median particle diameter of 1 to 300nm, the particles (P) containing a biodegradable resin (A) and a hydrophobic agent (B) having an octanol/water partition coefficient (LogPow) at 25 ℃ of 1 to 10, and a method for growing plants using the growth auxiliary for plants (X).)

1. A plant growth assistant (X) comprising particles (P) having a median particle diameter of 1 to 300nm, the particles (P) containing a biodegradable resin (A) and a hydrophobic drug (B) having an octanol/water distribution coefficient LogPow of 1 to 10 at 25 ℃.

2. A plant growth adjuvant according to claim 1, wherein the particles (P) further contain a surfactant (C) having an HLB value of 3 to 6.

3. The plant growth adjuvant according to claim 1 or 2, wherein the biodegradable resin (A) is at least one resin selected from the group consisting of polylactic acid, polycaprolactone, polyglycolic acid, a lactic acid-glycolic acid copolymer, and a resin having a segment composed of any of these resins and a segment composed of a resin having an SP value of 5 to 15.

4. A growth promoter for plants according to any one of claims 1 to 3, which is used for foliar application.

5. A method for growing a plant, which comprises using the growth auxiliary (X) for a plant according to any one of claims 1 to 4.

Technical Field

The present invention relates to a growth promoter for plants. In addition, the present invention relates to a method for growing plants.

Background

In agricultural applications, fertilizers are used for the stable production of crops. Generally, fertilizers are absorbed by roots by mixing into soil, thereby promoting the growth of plants. On the other hand, foliar application has been attracting attention as an auxiliary fertilization method for mixing into soil. By spreading on leaf surfaces, prevention of physiological disorders, early recovery from growth failure due to nutrient deficiency, enhancement of disease and pest resistance, and the like can be expected. In addition, it is important for the agricultural chemical to adhere to the leaves and permeate into the leaves, and the permeation of the agent into the leaves has been studied since long ago. In recent years, a technique has been disclosed for reducing the use ratio of an active ingredient by using a nanoparticle preparation having characteristics of relatively high dissolution rate and solubility in a solvent (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese Kohyo publication No. 2001-501959

Disclosure of Invention

Problems to be solved by the invention

However, the technique described in patent document 1 has problems that the uptake (absorption) of the granules into the plant and the elution of the drug from the granules are insufficient, and the plant growth performance is insufficient.

The purpose of the present invention is to provide a plant growth auxiliary agent which enables efficient uptake of a drug into leaves and which has excellent dissolution characteristics of the drug from particles.

Means for solving the problems

The present inventors have conducted studies to achieve the above object, and as a result, have completed the present invention. That is, the present invention relates to a plant growth adjuvant (X) comprising particles (P) having a median particle diameter of 1nm to 300nm, the particles (P) comprising a biodegradable resin (A) and a hydrophobic agent (B) having an octanol/water partition coefficient (LogPow) of 1 to 10 at 25 ℃; a method for growing a plant, which comprises using the above-mentioned growth auxiliary (X) for a plant.

ADVANTAGEOUS EFFECTS OF INVENTION

The growth assistant (X) for plants of the present invention exhibits the following effects.

(1) The drug can be efficiently taken into the leaf.

(2) Has an appropriate drug-eluting property from the granules, and is excellent in the sustained-release property of the drug and the persistence of the drug effect.

(3) According to the above (1) and (2), the growth of a plant can be promoted with a small amount of the compound, and the plant growth performance is excellent.

Detailed Description

The growth assistant (X) for plants contains particles (P) having a median diameter of 1 to 300nm, and the particles (P) contain a biodegradable resin (A) and a hydrophobic drug (B) having an octanol/water partition coefficient (LogPow) of 1 to 10 at 25 ℃. Hereinafter, the hydrophobic agent (B) having an octanol/water partition coefficient (LogPow) of 1 to 10 at 25 ℃ will be also referred to as the hydrophobic agent (B).

< biodegradable resin (A) >

The biodegradable resin (a) in the present invention is not particularly limited as long as it is a resin having biodegradability, that is, a resin capable of being decomposed by microorganisms, decomposed by enzymes, or ingested by living organisms. Among these resins, a resin satisfying the condition of easy degradability by the test method of OECD301C for evaluating biodegradability is preferably used. The biodegradable resin (a) may be used alone or in combination of two or more. From the viewpoint of being easily hydrolyzed and having an excellent balance between the elution property and the sustained-release property of the hydrophobic drug (B) from the particles (P), at least one resin selected from the group consisting of polylactic acid, polycaprolactone, polyglycolic acid, a lactic acid-glycolic acid copolymer, and a resin having a segment composed of any of these resins (a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer) and a segment composed of a resin having an SP value of 5 to 15 is preferable. In one embodiment, as the biodegradable resin (a), at least one selected from the group consisting of polylactic acid and a resin having a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and a segment composed of a resin having an SP value of 5 to 15 is more preferable, and polylactic acid and/or a resin having a segment composed of polylactic acid and a segment composed of a resin having an SP value of 5 to 15 is further preferable.

The segment composed of a resin having an SP value of 5 to 15 is preferably a segment composed of a homopolymer of ethylene oxide (hereinafter abbreviated as EO), a copolymer of EO and propylene oxide (hereinafter abbreviated as PO) (hereinafter abbreviated as EO-PO copolymer), or a polymer of an ionic monomer.

The weight average molecular weight (hereinafter abbreviated as Mw) of polylactic acid, polycaprolactone, polyglycolic acid, and lactic acid-glycolic acid copolymer is preferably 1,000 to 200,000, more preferably 20,000 to 80,000, and still more preferably 20,000 to 60,000. When Mw is 1,000 or more, the inclusion ratio of the hydrophobic drug (B) increases, and the sustained release property is good, and when Mw is 200,000 or less, the elution property of the hydrophobic drug (B) from the particles (P) is good.

The Mw in the present invention can be measured by gel permeation chromatography, for example, under the following conditions.

The device comprises the following steps: "HLC-8120 GPC" [ manufactured by Tosoh corporation ]

Column: "Guardcolumn H_XL-H "(1 root)," TSKgel GMH_XL"(2) [ all are manufactured by Tosoh corporation]

Sample solution: 0.25% by weight tetrahydrofuran solution

Solution injection amount: 100 μ L

Flow rate: 1 mL/min

Measuring temperature: 40 deg.C

The detection device comprises: refractive index detector

Reference substance: standard polystyrene

The polylactic acid, polycaprolactone, polyglycolic acid, and lactic acid-glycolic acid copolymer may be commercially available ones, or ones produced by a known method may be used. Examples of the production method include a method of ring-opening polymerizing a corresponding cyclic monomer using a catalyst.

The biodegradable resin (A) is preferably a resin having a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and a segment composed of a resin having an SP value of 5 to 15. The segment composed of a resin having an SP value of 5 to 15 is preferably a segment composed of a homopolymer of EO (polyethylene glycol), an EO-PO copolymer, or a polymer of an ionic monomer. Examples of such a resin include a resin in which a homopolymer of EO, an EO-PO copolymer, or a polymer of an ionic monomer is bonded to a terminal functional group of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer. The preferable range of Mw of the polylactic acid, polycaprolactone, polyglycolic acid, or lactic acid-glycolic acid copolymer constituting the segment is as described above.

The calculation method of the SP value in the present invention is based on the method described in the literature by Robert F Fedors et al (Polymer Engineering and Science, 2.1974, Vol.14, No. 2147-154).

Examples of the ionic monomer in the polymer of the ionic monomer include salts of inorganic acids (hydrochloric acid, sulfuric acid, phosphoric acid, and the like) or organic acids (acetic acid, and the like) such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, and allylamine; alkali metal salts or ammonium salts of unsaturated carboxylic acids [ (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid, etc. ] or organic sulfonic acids having an unsaturated double bond [ vinylsulfonic acid, styrenesulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, etc. ], and the like. "(meth) acrylate" means acrylate or methacrylate, and "(meth) acrylic acid" means acrylic acid or methacrylic acid.

The method for producing a resin having a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and a segment composed of a resin having an SP value of 5 to 15 is not particularly limited.

When a homopolymer of EO or an EO-PO copolymer is used, a carboxyl group (in the case of having only a hydroxyl group, after being converted into a carboxyl group by an acid anhydride or the like) of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer is reacted with a hydroxyl group of the homopolymer of EO or the EO-PO copolymer, whereby a resin having the above 2 segments can be obtained.

When an ionic monomer is used, for example, an unsaturated carboxylic acid anhydride is reacted with a hydroxyl group of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer to introduce an unsaturated double bond, and the ionic monomer is polymerized therewith to obtain a resin having the 2 types of segments.

Among the EO homopolymer, the EO-PO copolymer, and the polymer of the ionic monomer, the EO homopolymer and the EO-PO copolymer are preferable from the viewpoint of the balance between the elution property and the sustained-release property of the particle (P) of the hydrophobic agent (B).

The weight ratio of EO in the EO-PO copolymer is preferably 50 to 90 wt%, more preferably 65 to 85 wt%, in terms of the elution rate of the hydrophobic agent (B) and the acceleration of the elution rate. In addition, when the elution rate is retarded, the weight ratio of EO in the EO-PO copolymer is preferably 2% by weight or more and less than 50% by weight, and more preferably 5 to 45% by weight.

The number average molecular weight (hereinafter abbreviated as Mn) of the EO homopolymer and the EO-PO copolymer is preferably 1,000 to 80,000, more preferably 8,000 to 80,000, and further preferably 9,000 to 75,000. When Mn is 1,000 or more, the elution property of the hydrophobic drug (B) is good, and when Mn is 80,000 or less, the sustained release property of the hydrophobic drug (B) is good.

Mn in the present invention can be measured by gel permeation chromatography, for example, under the following conditions.

The device comprises the following steps: "Waters Alliance 2695" [ manufactured by Waters corporation ]

Column: "GuardColumn SuperH-L" (1 root), "formed by connecting 1 root of each of TSKgel SuperH2000, TSKgel SuperH3000, and TSKgel SuperH4000 (all manufactured by Tosoh Corp.)") "

Sample solution: 0.25% by weight tetrahydrofuran solution

Solution injection amount: 10 μ L

Flow rate: 0.6 mL/min

Measuring temperature: 40 deg.C

The detection device comprises: refractive index detector

Reference substance: standard polyethylene glycol

The weight ratio of the segment comprising polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer in the resin is preferably 30 to 80% by weight, more preferably 40 to 80% by weight, and still more preferably 50 to 80% by weight, based on the weight of the resin comprising the segment comprising polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and the segment comprising a homopolymer of EO, an EO-PO copolymer, or a polymer of an ionic monomer. When the segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or lactic acid-glycolic acid copolymer is 30% by weight or more, the inclusion rate of the hydrophobic drug (B) increases and the sustained-release property is good, and when it is 80% by weight or less, the elution property of the hydrophobic drug (B) from the particles (P) is good.

The content of the biodegradable resin (a) in the particles (P) is preferably 20 to 95% by weight, more preferably 20 to 80% by weight, and still more preferably 30 to 70% by weight, from the viewpoint of controlling the elution of the drug. In one embodiment, when the particles (P) contain at least one selected from the group consisting of polylactic acid, polycaprolactone, polyglycolic acid, a lactic acid-glycolic acid copolymer, and a resin having a segment composed of any of these resins and a segment composed of a resin having an SP value of 5 to 15 as the biodegradable resin (a), the total content of the polylactic acid, polycaprolactone, polyglycolic acid, lactic acid-glycolic acid copolymer, and the segment composed of any of these resins in the particles (P) is preferably 20 to 80% by weight, more preferably 30 to 70% by weight.

< hydrophobic drug (B) >

The hydrophobicity of the hydrophobic agent (B) in the present invention means that the octanol/water partition coefficient (LogPow) at 25 ℃ is larger than 0. The octanol/water partition coefficient (LogPow) can be measured by the method for measuring the partition coefficient (1-octanol/water) of a chemical substance specified in pharmacia No. 291, base 62, No. 171 OECDTest guidelines ([ C (81)30 Final attachment 1]) 107.

The hydrophobic drug (B) has an octanol/water partition coefficient (LogPow) at 25 ℃ of 1 to 10 in terms of the balance between the sustained release property and the dissolution property of the particles (P). Examples of the hydrophobic chemical (B) include pesticides and other chemicals having an octanol/water partition coefficient (LogPow) of 1 to 10 at 25 ℃, and known chemicals can be used for their medicinal effects without any particular limitation. The hydrophobic agent (B) used in the present invention is preferably a compound having a molecular weight of less than 2,000. The hydrophobic agent (B) preferably has an octanol/water partition coefficient (LogPow) at 25 ℃ of 1 to 8, more preferably 1 to 7, and still more preferably 1 to 6.

Examples of preferred hydrophobic agents (B) include tiadinil (LogPow ═ 3.68), S-methylbenzo [1, 2, 3] thiadiazole-7-thiocarboxylate (LogPow ═ 3.1), isotianil (LogPow ═ 2.96), benzylamine (LogPow ═ 1.09), cyclopropionamide (LogPow ═ 4.2), benomyl (LogPow ═ 1.3), pyroquilon (LogPow ═ 1.42), thiophanate (LogPow ═ 1.5), thiodicarb (LogPow ═ 1.62), fosthiazatine (LogPow ═ 1.68), thiuram (LogPow ═ 1.73), metronidazole (logp ═ 1.75), methidathiofenphoside (logp ═ 2), fenpicloram (logp ═ 2.2), thiuracilazathiocarb (logp ═ 2.92), thiuracil (logp.32), fenpropaquizamine (logp ═ 2.32), thiflufenacetrin (logp.8) Picolinamide (LogPow ═ 2.96), pyrifenoxaprop-p (LogPow ═ 3.0), isoprothiolane (LogPow ═ 3.01), diethofencarb (LogPow ═ 3.02), flualimide (LogPow ═ 3.04), procymidone (LogPow ═ 3.14), flutolanil (LogPow ═ 3.17), dithianon (LogPow ═ 3.2), cyazofamid (LogPow ═ 3.2), fenbuconazole (LogPow ═ 3.23), mepanipyrimethanil (LogPow ═ 3.28), diazinon (LogPow ═ 3.3), isoprothiolane (LogPow ═ 3.37), isoprothiolane (LogPow ═ 3.3), kresoxim-methyl (LogPow ═ 3.4), bifenthrin (logpofenpyraflufenthiuron (LogPow ═ 4.8), flufenthion (LogPow ═ 4.8), flufenpyraflufenthion (LogPow ═ 4.8), flufenpyraflufenpyraflufen-p (logfenthion) (LogPow ═ 4.8), flufenthiofen-p (logfenthion (LogPow ═ 4), flufenflurfenflurfenpyrazone-p (logfenthion) (logfenflurfenthiuron (LogPow ═ 3.5) Thiazoles nicotinic acid (LogPow ═ 3.89), transfluthrin (LogPow ═ 5.46), and the like (LogPow is LogPow at 25 ℃.

Further, as a hydrophobic agricultural chemical (LogPow at 25 ℃ is 1 to 10), which promotes the growth of plants, fat-soluble vitamins and the like are mentioned, and as other chemicals, which are being developed, LogPow at 25 ℃ is 1 to 10, sphingolipids and the like are mentioned. The hydrophobic agent (B) may be used alone or in combination of two or more.

< particles (P) >

The particles (P) in the present invention contain a biodegradable resin (a) and a hydrophobic agent (B).

In view of the elution property of the hydrophobic drug (B), the weight ratio of the biodegradable resin (a) to the hydrophobic drug (B) in the particles (P) is [ (a: (B) preferably, 5: 1-30: 1. more preferably 5: 1-20: 1.

the particles (P) may further contain a surfactant (C) having an HLB value of 3 to 6. Hereinafter, the surfactant (C) having an HLB value of 3 to 6 is also simply referred to as the surfactant (C). In the present invention, the surfactant (C) is preferably a compound having a molecular weight of 2,000 or more, more preferably a compound having a molecular weight of 2,000 to 80,000. The surfactant (C) may be used alone or in combination of two or more. A compound having an octanol/water partition coefficient (LogPow) of 1 to 10 at 25 ℃ is not included in the surfactant (C) in the present invention.

In the present invention, the HLB (hydrophilic-lipophilic Balance) value is a measure representing the Balance of inorganic/organic properties, and a higher HLB value means a higher inorganic property. The HLB value was calculated by the following calculation formula according to the microtia method.

HLB is 10 Xinorganic/organic

The Otta method is described, for example, in "surfactant entry" (published by Sanyo chemical industries, Ltd. 2007) at page 212. The organic and inorganic values for deriving the HLB value can be calculated using the values in the table described above on "entry of surfactant" page 213.

When the particles (P) contain the surfactant (C), the weight ratio of the surfactant (C) to the hydrophobic agent (B) in the particles (P) is [ (C: (B) preferably 30: 1-3: 1. more preferably 20: 1-5: 1.

when the surfactant (C) is used as the dispersant of the (B) when the biodegradable resin (a) and the hydrophobic agent (B) are mixed, the particles (P) contain the (C) in a form in which the (C) is present in the particles (P).

In addition, the particles (P) can be easily produced by, for example, dissolving the biodegradable resin (a) and the hydrophobic agent (B) in a hydrophilic solvent and then dropping the solution into water in which the surfactant (C) is dissolved, and in this case, the particles (P) contain the surfactant (C) in a form in which the surfactant (C) is adsorbed on the surface of the particles composed of the biodegradable resin (a) and the hydrophobic agent (B).

In one embodiment, when at least one resin selected from the group consisting of polylactic acid, polycaprolactone, polyglycolic acid, and a lactic acid-glycolic acid copolymer is used as the biodegradable resin (a), the particles (P) preferably contain the surfactant (C).

The surfactant (C) includes nonionic surfactants, anionic surfactants, cationic surfactants and amphoteric surfactants having HLB values of 3 to 6, and the nonionic surfactants are preferable from the viewpoint of balance between the elution property and sustained release property of the particles (P) of the hydrophobic agent (B), and particularly an EO-PO copolymer is preferable.

The weight ratio of EO in the EO-PO copolymer is preferably 50 to 90 wt%, more preferably 65 to 85 wt%, in terms of the elution rate of the hydrophobic agent (B) and the acceleration of the elution rate. When the elution rate of the hydrophobic drug (B) is retarded, the amount is preferably 2% by weight or more and less than 50% by weight, and more preferably 5 to 45% by weight.

The number average molecular weight (hereinafter abbreviated as Mn) of the EO-PO copolymer is preferably 2,000 to 80,000, more preferably 8,000 to 80,000, and still more preferably 9,000 to 75,000. When Mn is 2,000 or more, the elution property of the hydrophobic drug (B) is good, and when Mn is 80,000 or less, the sustained release property of the hydrophobic drug (B) is good.

When the surfactant (C) is used as the dispersant of the (B) when the biodegradable resin (a) and the hydrophobic drug (B) are mixed, the amount of the surfactant (C) used is preferably 5 to 20 times the weight of the hydrophobic drug (B) in terms of the balance between handling properties and dispersibility. In the case where the biodegradable resin (a) and the hydrophobic chemical (B) are dissolved in a hydrophilic solvent and then dropped into water in which the surfactant (C) is dissolved in the production of the particles (P), the amount of the surfactant (C) to be used is preferably 5 to 20 times the weight of the hydrophobic chemical (B) in terms of balance between handling properties and dispersibility.

Examples of the method for producing the particles (P) include the following methods: the biodegradable resin (a) and the hydrophobic agent (B) are dissolved in a hydrophilic solvent, and then added dropwise to water in which the surfactant (C) is dissolved under stirring, and the solvent such as the hydrophilic solvent is distilled off under reduced pressure, followed by freeze-drying. For example, when at least one selected from the group consisting of polylactic acid, polycaprolactone, polyglycolic acid, and lactic acid-glycolic acid copolymer is used as the biodegradable resin (a), it is preferable to produce the particles (P) by the above-mentioned method. The aqueous dispersion of the particles (P) before freeze-drying may be used as it is as the plant growth assistant (X) of the present invention.

Examples of the hydrophilic solvent include ketone solvents such as acetone and methyl ethyl ketone, ester solvents such as ethyl acetate, ether solvents such as dioxane and tetrahydrofuran, and amide solvents such as N, N-dimethylformamide, N-dimethylacetamide, and N-methyl-2-pyrrolidone. The hydrophilic solvent may be used alone or in combination of two or more.

The hydrophilic solvent in the present invention means a solvent in which 20g or more of water is dissolved in 100g of water at 20 ℃.

From the viewpoint of handling properties, the ratio of the total weight of (a) and (B) is preferably 0.5 to 5% by weight relative to the weight of a solution in which the biodegradable resin (a) and the hydrophobic agent (B) are dissolved in a hydrophilic solvent.

From the viewpoint of handling properties, the concentration of (C) in the aqueous solution of the surfactant (C) is preferably 0.01 to 1 wt%.

When the hydrophilic solvent solution of the biodegradable resin (a) and the hydrophobic agent (B) is added dropwise to the aqueous solution of the surfactant (C), the hydrophilic solvent solution is preferably added dropwise while stirring at 100 to 500rpm using a stirrer or the like.

When the biodegradable resin (a) has a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and a segment composed of a resin having an SP value of 5 to 15 (preferably an EO homopolymer, an EO-PO copolymer, or a polymer of an ionic monomer), the particles (P) can be obtained without using the surfactant (C). This is because the segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer includes the hydrophobic agent (B), and the segment composed of a resin having an SP value of 5 to 15 is disposed on the surface side of the particles, thereby forming particles in a so-called micelle shape. When a resin having a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and a segment composed of a resin having an SP value of 5 to 15 (preferably a homopolymer of EO, an EO-PO copolymer, or a polymer of an ionic monomer) is used, for example, the resin is dissolved in a hydrophilic solvent, then added dropwise to water under stirring, and the solvent such as the hydrophilic solvent is distilled off under reduced pressure, followed by freeze-drying, whereby the particles (P) can be produced.

Among the method using the surfactant (C) and the method using a resin having a segment composed of polylactic acid, polycaprolactone, polyglycolic acid, or a lactic acid-glycolic acid copolymer and a segment composed of a resin having an SP value of 5 to 15, the method using the surfactant (C) is preferable from the viewpoint of simplicity of the production method and cost.

The median diameter of the particles (P) is 1 to 300nm, preferably 5 to 250nm, and more preferably 10 to 200 nm.

If the median particle diameter is less than 1nm, the production is industrially difficult, and if it exceeds 300nm, the uptake of the particles (P) into plants is insufficient, and the elution of the hydrophobic drug (B) from the particles (P) is poor.

The median particle diameter in the present invention can be measured by a dynamic light scattering measurement apparatus [ for example, a dynamic light scattering particle size distribution measurement apparatus LB-550 (manufactured by HORIBA Co.), Zetasizer Ultra (manufactured by Malvern Panalytical Co., Ltd.), and DelsaMax CORE (manufactured by Beckman Coulter Co., Ltd.) ].

< growth auxiliary for plants (X) >

The plant growth assistant (X) of the present invention comprises particles (P) containing a biodegradable resin (A) and a hydrophobic agent (B).

The plant growth assistant (X) of the present invention may further contain a chemical agent (fertilizer such as ammonium sulfate, pesticide, etc.), a spreading agent (nonionic surfactant, anionic surfactant, cationic surfactant, silicone spreading agent, etc.) and the like, the water and octanol/water partition coefficient (LogPow) of which is less than 1, preferably 0 or less. As the spreading agent, a compound having a molecular weight of 2,000 or more (preferably 2,000 to 80,000) can be used.

The method for growing a plant of the present invention uses the above-mentioned growth auxiliary (X) for a plant. In this way, the plant growth adjuvant (X) is preferably spread or coated on the plant, more preferably spread or coated on the leaves, and particularly preferably spread on the leaves of the plant. The growth assistant (X) for plants of the present invention is suitable for foliar application or coating, and more suitable for foliar application.

In the case of spreading or coating on plants, it is preferably used in the form of an aqueous dispersion of the growth assistant (X) for plants. In the case of the leaf, it may be spread or applied to a part of the leaves of the plant, or may be spread or applied to all the leaves.

The weight ratio of the (X) in the aqueous dispersion of the plant growth assistant (X) is preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight, based on the weight of the aqueous dispersion, based on the weight ratio of the particles (P), from the viewpoints of dispersibility and plant growth.

In addition, when the dispersion is applied to the leaf by dispersion or the like, the amount of the particles (P) to be used (preferably the amount of dispersion) is preferably 1 to 200g/m in terms of the amount of the particles (P) to be used (the amount of dispersion) based on the area of the leaf (the amount of dispersion)²More preferably 3 to 100g/m²。

The foliar application or coating may be performed on either the front surface side or the back surface side of the leaf, or may be performed on both sides.

The growth auxiliary agent (X) for plants of the present invention enables a plant to efficiently take a drug, has an appropriate drug-eluting property from granules, is excellent in the sustained-release property of the drug and the persistence of the drug effect, is effective for the growth of a plant and the promotion of the growth of a plant, and is particularly useful for agricultural use. It is assumed that the growth-promoting effect of the plant growth adjuvant (X) is believed to be due to the fact that the growth-promoting effect is exerted by the uptake of the growth adjuvant (X) into the plant through the pores of the plant. The method for growing a plant of the present invention can be used as a method for promoting the growth of a plant.

As the plant to which the growth assistant for plants of the present invention is applied, a plant having leaves is preferable. Examples of the plant include rice, wheat (barley, wheat, rye, oats, etc.), fruits and vegetables, leaf vegetables, root vegetables, flowers, and the like. Examples of the fruits and vegetables include tomatoes, green peppers, peas, cucumbers, watermelons, green beans, melons, strawberries, green peppers, okra, eggplants, kidney beans, pumpkins, broad beans, and corn. Examples of the leafy vegetables include butterbur, shallot, minglotus, garlic, lettuce, allium chinense, broccoli, cabbage, perilla, cabbage, pakchoi, cress, angelica sinensis, spinach, pickles, cauliflower, lettuce, brussels sprouts, asparagus, cryptotaenia japonica, onion, parsley, leek, garland chrysanthemum, and parsley. Examples of the root vegetables include radish, turnip, burdock, carrot, potato, taro, sweet potato, yam, ginger, lotus root, and the like. Among them, preferred are cruciferous crops such as rice, tomato, watermelon, cucumber, strawberry, cabbage, and the like.

The growth assistant (X) for plants of the present invention is particularly preferably used in the stage of raising seedlings. When the growth assistant (X) for plants is used in the stage of raising seedlings, a material (Y) for a seedling raising sheet described later can be used as necessary. A seedling raising sheet (Z) having a seedling raising sheet material (Y) and a seedling raising sheet base material may also be used. The seedling raising sheet (Z) may be used by being set on the soil surface or in the soil. The seedling-raising sheet material (Y) may be used by being placed on or mixed with the soil surface or soil. A method for growing a plant using the growth auxiliary agent for a plant (X), the material for a seedling raising sheet (Y), and/or the seedling raising sheet (Z) having the material for a seedling raising sheet (Y) and the substrate for a seedling raising sheet in the stage of raising a plant is also one of preferred embodiments of the present invention. The method for growing a plant of the present invention is suitably used as a method for growing a seedling of a plant. The plant is preferably the above-mentioned plant.

The raising of the seedling includes sowing the seeds, germinating the seeds, greening, and may also include hardening after greening. In the present invention, it is preferable to apply (preferably spread) the growth assistant (X) for plants on the leaves of the seedlings during greening. In the case of hardening, the growth assistant for plants may be applied to the leaves during greening and/or hardening, preferably during greening. As an example of a preferable mode in the case of using the method for growing a plant of the present invention at a seedling stage, the following mode and the like can be given.

The seeds are sown in the soil provided with the seedling raising sheet material (Y) and/or the seedling raising sheet (Z), and are germinated to perform greening, and the plant growth auxiliary agent (X) is applied to the leaves of the seedlings during greening. The application (preferably, foliar application) of the growth assistant (X) for plants to the leaves may be performed on either the front surface side or the back surface side of the leaves, or may be performed on both sides of the leaves. The seedling raising sheet material (Y) and/or the seedling raising sheet (Z) may be set in a seedling box or the like, and it is preferable to place soil (bed soil) on the material (Y) and/or the sheet (Z) and seed.

The seed is preferably a seed of the above-mentioned plant. Before sowing, pretreatment of the seeds (screening, seed soaking, pregermination, etc. of the seeds) may be performed. The conditions for sowing, sprouting, greening and hardening of the bed soil and seeds may be selected or adjusted according to the kind of the plant. The seedlings are preferably transplanted into a paddy field or a upland field after hardening.

Hereinafter, a case of raising seedlings by using rice seeds as seeds will be described as an example.

Generally, a seedling planted by a rice transplanter is grown in a bed called a seedling bed, and for example, the following seedling growing process is preferable.

1) Pretreatment of seeds

1-1) rice seed screening: after sterilization, floating rice was removed by screening with brine, washed with water, and dried.

1-2) seed soaking: soaking for 5 days to make the rice seed absorb water uniformly.

During this period, oxygen replenishment was repeated by changing water and removing water every day.

1-3) pregermination: after oxygen supply, the seeds were soaked in warm water at 32 ℃ for 10 hours to form a chicken breast state.

2) Adjustment of bed soil

Soil having a granular structure with good air permeability and drainage was selected and the pH was adjusted to 5. And mixing the base fertilizer.

3) Ridging

And (4) planting bed soil in the seedling raising bed, and flattening to form a plane.

4) Seeding

Uniformly sowing in the seedbed, watering to make the rice seed be settled.

The seeding is not uniform.

5) Covering soil

Filling soil to a thickness of 5mm, and leveling to form a plane.

6) The sprouts were made to be uniform by using a seedling raising apparatus, and cultured at 32 ℃ for 2 days until the length of the sheath of the embryo was about 1.2 cm.

7) Pre-greening

After oxygen supply and watering, the seedling bed was irradiated with flickering light and managed at 25 ℃ for 1 day and at 20 ℃ for 1 day.

8) Greening

In the greenhouse, the water is repeatedly and fully watered for 8 days at 30 deg.C in the daytime and 12 deg.C at night, so that 2.5 leaves are spread.

9) Hardening of

Under the control of 20 ℃ in the daytime and 10 ℃ at night, seedlings of 3.5 leaf age adapted to natural conditions were cultured slowly for 10 days.

The seedling raising sheet (Z) is preferably set in the culture soil: 3) the inside of the front seedling bed. The location and method of installation may be arbitrary, and the installation is preferably performed on the bottom.

The growth assistant (X) for plants is more preferably used in greening: 8) but also during hardening: 9) is applied during the period of time (c).

< Material for seedling raising sheet (Y) >

The material (Y) for a seedling raising sheet preferably contains a water-absorbent polymer material (D), and may contain a fertilizer (E) as needed. Preferably, the material for a seedling raising sheet further contains a filler (F).

The water-absorbent polymer material (D) may be a water-absorbent resin or the like, and is not particularly limited, but is preferably a carboxyl group-containing hydrophilic crosslinked polymer, and more preferably polyacrylic acid (salt). The total amount (100% by weight) is not limited to the form of a polymer. The polyacrylic acid (salt) is a polymer having a repeating unit containing acrylic acid (salt) as a main component. Specifically, the acrylic acid (salt) is a polymer containing acrylic acid (salt) as a monomer other than the crosslinking agent, preferably 50 to 100 mol%, more preferably 70 to 100 mol%, still more preferably 90 to 100 mol%, and particularly preferably substantially 100 mol%. The salt of the polymer is preferably an alkali metal salt, an alkaline earth metal salt, or an ammonium salt, and among them, a monovalent salt or an alkali metal salt is preferable, and a potassium salt or a sodium salt is particularly preferable. The shape of the polyacrylic acid (salt) is not particularly limited, but is preferably granular or powdery.

The water-absorbing polymer material (D) has a water absorption capacity of ion-exchanged water at 25 ℃ of usually 80 to 1000 times, preferably 90 to 670 times, more preferably 120 to 530 times, and still more preferably 130 to 480 times. If the water absorption rate is less than 80 times, the water retention capacity of the water retention agent is reduced, and the water retention agent needs to be used in a large amount, so that the cost is increased and water needs to be frequently supplemented. When the water absorption capacity is large, a small amount of the water-absorbent polymer material may be used, and therefore, the water absorption capacity exceeding 1000 times is preferable, but there is a problem that the water permeability is lowered and the vegetation is deteriorated.

The water absorption capacity was measured by the following method.

[ measurement of Water absorption Capacity of ion-exchanged Water ]

A nylon mesh bag (250 mesh) was charged with a water-absorbent polymer material sample L (g), and the bag was immersed in an excess amount of ion-exchanged water. After 60 minutes of immersion, the bag was lifted into the air, left to stand and drained for 15 minutes, and then the weight M (g) was measured to determine the water absorption capacity by the following equation.

The same procedure as described above was carried out using only the mesh bag, and the weight n (g) was subtracted as a blank.

Water absorption capacity of ion-exchanged water (M-N)/L

The pH of the water-absorbent polymer material (D) when 1 part by weight of the water-absorbent polymer material absorbs 100 parts by weight of ion-exchanged water at 25 ℃ is preferably 4.5 to 7.5, more preferably 5.0 to 7.0, from the viewpoint of vegetation.

The pH was measured by the following method.

[ determination of pH value ]

1 part by weight of a water-absorbent polymer material was added to 100 parts by weight of ion-exchanged water at 25 ℃ and the mixture was left to stand at 25 ℃ for 8 hours to swell the water-absorbent polymer material, thereby producing a water-absorbent structure. The temperature of the water-absorbent body was confirmed to be 25 ℃ by a thermometer, and a pH meter was inserted into the water-absorbent body to confirm that the pH value was substantially stable, and the pH value was read. When the water absorption capacity of the water-absorbent polymer material is small, the water-absorbent material of the water-absorbent polymer material and the ion-exchanged water are separated into two phases, and therefore, the two phases are stirred uniformly, and then inserted into a pH meter to measure the value. When the mixture immediately separated into two phases again even after stirring and homogenization, a pH meter was inserted under stirring to measure the value.

Examples of the fertilizer (E) include general fertilizers such as nitrogen fertilizers, phosphoric acid fertilizers, potassium fertilizers, organic fertilizers, compound fertilizers, calcium fertilizers, silicic acid fertilizers, bitter earth fertilizers, manganese fertilizers, boron fertilizers, and trace element compound fertilizers, and other special fertilizers (slow release fertilizers). These fertilizer components are in the form of liquid or solid such as powder, and can be present in the material for seedling raising sheet or the like by adding to the water-absorbent polymer material (D) or by containing in water injected into the material (D)In the seedling raising sheet. The amount of the fertilizer (E) to be added may be arbitrarily determined in consideration of the type of crop to be cultivated, the type of fertilizer to be used, and the like, and is determined per unit area (m) of the seedling raising sheet²) For example, 1 to 500g, preferably 3 to 300 g. In the case of a material for a seedling raising sheet, it is preferable to use the material per unit area (m)²) The fertilizer (E) is mixed in the seedling raising sheet material in such a manner that the amount of the fertilizer (E) is in the above range.

The filler (F) is preferably a powdery, granular, fibrous or cotton-like filler. The filler (F) is preferably a filler having an appropriate air permeability so as not to inhibit the germination and growth of seeds, a filler which does not adversely affect the soil when installed on the ground, and/or a filler having a property of being easily decomposed on the surface or inside of the soil, and examples thereof include the fillers described below. Examples thereof include inorganic porous materials such as perlite, vermiculite and rock fiber, wood chips, rice hulls, buckwheat bran, rice bran, cotton, straw, grass peat, wool, sawdust, pulp, and paper dust. The filler (F) is added in an amount per unit area (m) to ensure air permeability and thickness²) The amount of the seedling raising sheet(s) is preferably 1 to 500g, more preferably 3 to 300 g. In the case of a material for a seedling raising sheet, it is preferable to use the material per unit area (m)²) The filler (F) is mixed into the material for the nursery sheet in a manner that the dosage of the filler (F) is in the range.

< seedling raising sheet (Z) >

The seedling raising sheet (Z) is a seedling raising sheet comprising the material (Y) for seedling raising sheet and a substrate for seedling raising sheet. As the base material of the seedling raising sheet, a sheet (G) can be mentioned.

Examples of the tablet (G) include a water-permeable tablet, a water-disintegrable tablet, and a water-soluble tablet, and a combination of 2 or more of these may be used. The thickness of the sheet (G) after molding into a seedling raising sheet is preferably 0.01 to 9mm, more preferably 0.02 to 3 mm. The weight of the sheet (G) is per unit area (m) to ensure shape retention and thickness of the seedling raising sheet²) The seedling raising sheet (Z) is, for example, 5 to 300g, preferably 10 to 100 g. Examples of the water-permeable sheet include a woven fabric (cloth) or nonwoven fabric of cellulose fibersAmong them, woven cloth, paper, woven or knitted fabric or film of water-soluble polyvinyl alcohol fibers, cardboard, etc., are preferred, and the degree of water permeability is preferably such that the water absorption rate is 5 minutes or less in the water absorption rate a method described in JIS L1096. In addition, in order not to inhibit the germination and growth of seeds, it is preferable to have appropriate air permeability and properties of being easily decomposed on the surface or inside of soil when the sheet is installed on the ground, and among them, cellulose paper and nonwoven fabric are preferable.

Examples of the water-disintegrable tablet include: paper in which pulp fibers of paper are bonded to each other with a water-soluble or hydrophilic adhesive, a water-swellable polymer, or the like, and the pulp fibers are disintegrated and dispersed by contact with water (dis solva MDP manufactured by sanshima corporation, or the like); and paper (DISSOLVO MDP-P manufactured by Sanshimo paper Co., Ltd.) to which moldability (thermal adhesiveness) is imparted by using a heat-sealing agent in combination. These papers are characterized by a high disintegration rate by absorbing water. Examples of the water-soluble sheet include water-soluble films such as a water-soluble polyvinyl alcohol film, a starch film, and a carrageenan film, and water-soluble nonwoven fabrics made of polyvinyl alcohol fibers ("ecomol", "Ecosorb", and the like, manufactured by Vilene corporation, japan). These tablets, when compared with each other at the same thickness, have a characteristic that the tablet strength in a dry state is high although the water-dissolving (disintegration) rate is lower than that of the above water-disintegrable paper.

Further, as a laminate sheet obtained by laminating the water-disintegrable paper and a water-soluble film, there may be mentioned a laminate sheet obtained by laminating at least one of the water-disintegrable papers and a water-soluble film by bonding them (dis solva a manufactured by the samsuna paper corporation in which a polyvinyl alcohol film is laminated on the above-mentioned "dis solva MDP"). These laminated sheets are characterized by fast dissolution (disintegration) in water and also by large film strength. This is because the thickness of the water-soluble film to be bonded can be reduced by the strength of the paper, and thus both the dissolution (disintegration) rate and the film strength can be improved as a whole. Among these water-soluble or water-disintegrable sheets, water-disintegrable paper and water-soluble nonwoven fabric are preferable. The time required for these water-soluble or water-disintegrable tablets to disintegrate or dissolve in water is, for example, 5 minutes or less, preferably 2 minutes or less, and more preferably 1 minute or less.

The seedling raising sheet (Z) is preferably a sheet containing a water-absorbent polymer material (D), and is preferably a seedling raising sheet which contains a water-absorbent polymer material (D) and a sheet (G) and in which the water-absorbent polymer material (D) is present on the surface of or in at least 1 sheet (G). In the seedling raising sheet (Z), a fertilizer (E) and a filler (F) may be further present in at least 1 sheet (G). The seedling raising sheet (Z) may be a sheet containing the water-absorbent polymer material (D), at least 1 sheet (G), and the fertilizer (E) and/or the filler (F), and the (D), the (E), and/or the (F) may be present on the surface of or in the interior of at least 1 sheet (G). When 2 or more sheets (G) are used as the seedling raising sheet (Z), the water-absorbent polymer material (D) may be present on the surface or inside of at least 1 sheet (G) as a whole. Examples of the seedling raising sheet using 2 or more sheets (G) include: a seedling raising sheet having a 5-layer structure comprising a layer of the sheet (G), a layer of the filler (F) and the water-absorbent polymer material (D), a layer of the sheet (G), a layer of the fertilizer (E) and a layer of the sheet (G); a seedling raising sheet having a 4-layer structure comprising 2 layers of (G), a layer formed by mixing (D) to (F), and a layer of (G); and the like.

Examples of the method for producing the seedling raising sheet (Z) include known methods such as a method of dipping the sheet (G) in the mixture of the above (D) to (F) or a method of applying the mixture to the surface of the sheet (G). When 2 sheets (G) are used, the following 2 methods may be used, for example, in addition to the method of stacking 2 sheets prepared by the same method as described above. (a) A method of uniformly spreading the mixture of (D) to (F) on one sheet (G), then superposing the other sheet (G), and further performing press molding such as embossing. (b) A method in which the mixture of (D) to (F) is added to an appropriate binder (H) described later, the resultant is applied to one sheet (G), and the other sheet (G) is superposed and molded, followed by drying.

Examples of the adhesive (H) for fixing (D) to (F) to the seedling raising sheet (Z) include natural polymers, synthetic resins, and natural or synthetic rubbers. Examples of the natural polymer include starch, carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl cellulose, sodium alginate, guar gum, xanthan gum, soybean gum, carrageenan, and gluten. Examples of the synthetic resin include acrylic resins, polyurethane resins, unsaturated polyester resins, polyamide resins, ethylene copolymer resins, and the like other than the water-absorbent polymer material (D). Examples of the natural or synthetic rubber include natural rubber, acrylic rubber, butyl rubber, polyisobutylene rubber, styrene-butadiene rubber, ethylene-propylene rubber, and chloroprene rubber. They may be used alone or in combination of two or more. Among these, water-soluble natural polymers such as starch, carboxymethyl cellulose, and sodium alginate are preferable.

Examples

The present invention will be further described below by way of examples and comparative examples, but the present invention is not limited thereto. LogPow is the octanol/water partition coefficient at 25 ℃.

The median diameter of the particles was measured by a dynamic light scattering measurement apparatus (product name: dynamic light scattering particle size distribution measurement apparatus LB-550, manufactured by HORIBA Co.).

< production example 1>

In a container, 50mg of polylactic acid [ Mw 60,000, available from SIGMA-ALDRICH co. ] and 5mg of tiadinil [ LogPow 3.68, fuji film and wako pure chemical industries ] were dissolved in 10mL of acetone. 50mg of EO-PO copolymer [ NewpolePE-128, number average molecular weight (Mn)31,000, EO/PO 6.1 (molar ratio) (weight ratio of EO in EO-PO copolymer: 82.2 wt%), HLB 4.89, manufactured by Sanyo chemical industries Co., Ltd.) was dissolved in 20mL of ion-exchanged water, and the above polylactic acid solution at 25 ℃ was added dropwise to the above aqueous solution at 25 ℃ stirred at 200rpm with a magnetic stirrer HS-30D [ manufactured by AS-1 Ltd ] for 5 minutes, and further stirred at 25 ℃ for 20 minutes at the same stirring speed. Thereafter, the solvent was distilled off under reduced pressure by an evaporator, and freeze-drying was performed, thereby obtaining particles (P-1). The median diameter of the particles (P-1) was 190 nm.

< production example 2>

Pellets (P-2) were obtained in the same manner as in production example 1, except that polylactic acid [ RESOMER R203S, Mw 23,000, manufactured by SIGMA-ALDRICH co. The median diameter of the particles (P-2) was 155 nm.

< production example 3>

Pellets (P-3) were obtained in the same manner as in production example 1, except that an EO-PO copolymer [ Newpole PE-78, Mn: 9,350, EO/PO: 4.8 (molar ratio) (weight ratio of EO in the EO-PO copolymer: 78.6 wt%), HLB: 5.01, and manufactured by sanyo chemical industries, co. The median diameter of the particles (P-3) was 180 nm.

< production example 4>

Pellets (P-4) were obtained in the same manner as in production example 1, except that an EO-PO copolymer [ Newpole PE-78, Mn-9,350, manufactured by sanyo chemical industries, ltd.) was used as the surfactant instead of the EO-PO copolymer used in production example 1, and polylactic acid [ RESOMER R203S, Mw-23,000, manufactured by SIGMA-ALDRICH, ltd.) was used as the polylactic acid. The median diameter of the particles (P-4) was 120 nm.

< production example 5>

The same operation as in production example 1 was carried out except that cyclopropanoamide [ LogPow 4.2, fuji film, wako pure chemical industries, inc.) was used instead of tiadinil as the hydrophobic drug, to obtain pellets (P-5). The median particle diameter of the particles (P-5) was 170 nm.

< production example 6>

Pellets (P-6) were obtained in the same manner as in production example 1, except that polylactic acid was changed to a lactic acid-glycolic acid copolymer [ resome RG505, Mw 61,500, SIGMA-ALDRICH co. The median particle diameter of the particles (P-6) was 186 nm.

< production example 7>

In a flask, 1.4g of polylactic acid [ Mw 60,000, manufactured by SIGMA-ALDRICH co., ltd ] and 0.7g of EO-PO copolymer [ Newpole PE-128, Mn 31,000, SP 9.24, manufactured by sanyo chemical industries, ltd ] were mixed, and heated and melted at 180 ℃. Then, a tin bis (2-ethylhexanoate) catalyst (1.4mg) was added thereto, and the mixture was heated at 180 ℃ for 15 hours after nitrogen substitution to obtain a polymer in which an EO-PO copolymer was bonded to polylactic acid. In a container, 50mg of the polymer obtained by bonding the EO-PO copolymer to the polylactic acid, and 5mg of tiadinil [ LogPow 3.68, fuji film, wako pure chemical industries, inc. ] were dissolved in 10mL of acetone. This solution was added dropwise to 20mL of 25 ℃ ion-exchanged water stirred at 200rpm with a magnetic stirrer HS-30D (manufactured by AS-1) at 25 ℃ for 5 minutes, and further stirred at 25 ℃ for 20 minutes at the same stirring speed, and then the solvent was distilled off under reduced pressure with an evaporator to obtain particles (P-7). The median diameter of the particles (P-7) was 180 nm.

< production example 8>

Pellets (P-8) were obtained in the same manner as in production example 1, except that an EO-PO copolymer (Mn: 31,000, EO/PO: 0.5 (molar ratio) (weight ratio of EO in EO-PO copolymer: 27.2 wt%) and HLB: 4.89) produced by the following method was used as the EO-PO copolymer. The median particle diameter of the particles (P-8) was 170 nm.

(production of EO-PO copolymer)

An autoclave equipped with a stirrer, a thermometer, a pressure gauge, a pressure-resistant dropping flask, and a reduced-pressure nitrogen gas introduction line was charged with 0.2 parts by weight (1 mol) of ethylene glycol and 0.43 parts by weight of potassium hydroxide, and after stirring was started, nitrogen gas was sealed and the temperature was raised to 130 ℃ and then dehydration was carried out for 1 hour under a pressure of-0.1 MPaG. Then, the temperature was raised to 160 ℃ and 72.3 parts by weight (388 moles) of 1, 2-epoxypropane was added dropwise over 6 hours under a pressure of 0.3MPaG or less, followed by stirring at the same temperature for 1 hour until the pressure was equalized. Subsequently, 27.4 parts by weight (194 mol) of ethylene oxide was added dropwise over 3 hours, and the mixture was stirred at the same temperature for 1 hour until pressure equilibrium was reached. Then, the mixture was cooled to 60 ℃ and neutralized with 0.32 part by weight of acetic acid to obtain an EO-PO copolymer.

< comparative production example 1>

Pellets (P' -1) were obtained in the same manner as in production example 1, except that non-biodegradable polystyrene [ Mw 50,000, fuji film, wako pure chemical industries, inc. ] was used instead of polylactic acid. The median particle diameter of the particles (P' -1) was 165 nm.

< examples 1 to 8 and comparative example 1>

A dispersion in which 20mg of the above particles (P-1) to (P-8) or (P' -1) were dispersed in 3mL of physiological saline was prepared, and 150mL of physiological saline as an external solution was dialyzed using a dialysis membrane having a molecular weight cut-off (MWCO) of 14,000. At predetermined intervals, the dissolution rate of the drug dissolved in the solution in the outer tank [100 × the weight of the dissolved drug/the weight of the drug in the primary particles (%) ] was measured using an HPLC apparatus. The results are shown in table 1.

The following methods use radioisotopes¹²⁵I agents labeled with hydrophobic agents, evaluation of uptake of particles (P) into plant leaves.

< production example 9>

Benzylamine [ LogPow ═ 1.09, Fuji film, and Wako pure chemical industries, Ltd]50 μ L and 0.1M phosphate buffer pH7.2[ Fuji film and Wako pure chemical industries, Ltd]50 μ L and mixed. To this solution was added 5. mu.L of Na¹²⁵Solution I (3.7GBq/mL, NENResearch Products). Chloramine T [ Fuji film and Wako pure chemical industries, Ltd. ] was dissolved in a 0.1M phosphate buffer solution (pH7.2)]200. mu.L of a chloramine T solution prepared at a concentration of 0.5mg/mL was added to the above-mentioned microcentrifuge tube, and the radioactive isotope labeling reaction was carried out at 25 ℃ for 2 minutes. Then, 200. mu.L of a 4mg/mL phosphate buffer solution of sodium disulfite (pH7.2) was added to stop the reaction. Unreacted Na which is not labeled¹²⁵I was removed by using a PD10 column (manufactured by GE Healthcare).

< production example 10>

The same operation as in production example 1 was carried out except for using the radioisotope-labeled benzylamine produced in production example 9 instead of tiadinil to obtain pellets (P-9). The median particle diameter of the particles (P-9) was 185 nm.

< production example 11>

The same operation as in production example 4 was carried out except for using the radioisotope-labeled benzylamine produced in production example 9 instead of tiadinil to obtain pellets (P-10). The median particle diameter of the particles (P-10) was 125 nm.

< comparative production example 2>

Pellets (P' -2) were obtained in the same manner as in production example 1, except that the radioisotope-labeled benzylamine produced in production example 9 was used in place of tiadinil, and polylactic acid [ RESOMER RG756S, Mw 96,000, manufactured by SIGMA-ALDRICH K.K. ] was used as polylactic acid. The median particle diameter of the particles (P' -2) was 360 nm.

< example 9>

A dispersion was prepared by dispersing 20mg of the particles (P-9) in 3mL of physiological saline. For 1 leaf of a commercially available potted vanilla seedling (diameter 9cm), 100. mu.L of a dispersion of the particles (P-9) (nanoparticle dispersion) was sprayed onto the surface side of the leaf, taking care not to overflow from the leaf. After standing at 25 ℃ for 1 hour, the leaves sprayed with the dispersion were cut off, immersed in a vessel containing ion-exchanged water for 1 minute, and then taken out of the vessel. The labeled chemical attached to the leaf surface was removed by replacing the water in the vessel with fresh ion-exchanged water, immersing and lifting the leaf in fresh ion-exchanged water in the vessel for 1 minute, and repeating this operation 3 times in total. The leaf (sample of the target leaf) was placed in a sample container of a gamma counter (manufactured by ARC-301B, Aloka), the radiation dose was measured, and the uptake (%) was calculated from the following equation.

Uptake rate (%) [ (dose of radiation of target leaf sample)/(dose of radiation of 100 μ L of nanoparticle dispersion) ] × 100

Further, another potted plant was used, and the dispersion was sprayed onto the plant in the same manner as described above, and then left standing at 25 ℃ for 3 hours, and the uptake rate of the granule (P-9) was measured also for the leaf. The results are shown in Table 2.

< example 10>

The same operation as in example 9 was carried out except that the particles (P-10) were used in place of the particles (P-9), and the uptake rate of the particles (P-10) into the leaves was measured. The results are shown in Table 2.

< comparative example 2>

The same operation as in example 9 was carried out except that the particles (P '-2) were used instead of the particles (P-9), and the uptake rate of the particles (P' -2) into leaves was measured. The results are shown in Table 2.

[ TABLE 2 ]

The inclusion rate of tiadinil contained in the particles (P-1), (P-4), (P-6) (nanoparticles (P)) was determined by the following method, and an ion-exchange aqueous dispersion of the nanoparticles (P) (particles (P-1), (P-4) or (P-6)) adjusted to a tiadinil content of 100ppm was used in the experiments described later.

< evaluation method of Inclusion Rate >

After 1mL of the aqueous dispersion of nanoparticles (P) in the microcentrifuge tube was sedimented by centrifugation (4 ℃, 15,000rpm, 30 minutes), the supernatant was removed. Acetonitrile was added to the nanoparticles (P) after centrifugal sedimentation to dissolve the polylactic acid, and the inclusion rate was calculated spectrophotometrically.

< examples 11 to 34 and comparative examples 3 to 8>

A material (Y-1) for a seedling raising sheet was obtained by mixing 4.9g of a water-absorbent resin SunfreshGT-1 (manufactured by Sanyo chemical Co., Ltd., water absorption capacity 400 times, pH7.0) with 17.5g of ground pulp (filler).

The resulting seedling sheet material (Y-1) was uniformly spread on a water-permeable sheet (580 mm. times.280 mm), and then another water-permeable sheet (580 mm. times.280 mm) was overlaid thereon, followed by embossing. Thus, a seedling raising sheet (Z-1) was produced.

Further, seedling raising sheets (Z-2) were produced by using the above filler (ground pulp) as a material (Y-2) for seedling raising sheets. The seedling raising sheet (Z-2) was produced in the same manner as the seedling raising sheet (Z-1) except that the water-absorbent resin Sunfresh GT-1 was not used for the production of the seedling raising sheet (Z-1).

[1] Conditions for growing seedlings

1. The test varieties are as follows: hinohikari (rice), House Momotaro (tomato)

2. Seedling raising box: inner side area 580X 280 mm/box

3. Seedling growing sheet: area 580X 280 mm/piece

4. Sowing: 180 g/box (conversion of dry rice)

5. Ridging: INAHO hilling (manufactured by INAHO-KAKO Co., Ltd.): 3, mud moss soil: 1 (volume ratio) (for bed soil, covering soil)

6. Medicament treatment: seed disinfection is treated with benzene-bacterium double-mixed agent (200 times solution) for 48 hours

7. And (3) sprouting treatment: stacking, heating to bud (32 ℃ X2 days)

8. Greening treatment: plastic greenhouse dry field seedling growing

Then, under the above seedling growing conditions [1], the seedlings are grown to 2 to 3 leaf ages (during the period of the seedling bed). Before being put into soil, the seedling raising sheets are arranged at the bottom of the seedling raising box. The evaluation results of "cultivation on seedling bed" in table 3 (rice) and table 4 (tomato) show the seedling state at 2 to 3 leaf ages. The seedling raising sheets used are shown in tables 3 and 4. In the evaluation of the state of seedling, the growth state of the roots and overground parts was evaluated by the following method.

< evaluation of growth status of roots and shoots and overground part during the period of growing the seedlings bed >

The growth state of the roots and shoots and the overground part during the period of the seedling bed was evaluated by measuring the length of each part.

Root out of strip

Very good: the root length is more than 8cm

O: the root length is more than 5cm and less than 8cm

And (delta): the root length is more than 3cm and less than 5cm

X: the length of the root is less than 3cm

Overground growth state

Very good: the length of the underground part is more than 12cm

O: the length of the underground part is more than 8cm and less than 12cm

And (delta): the length of the underground part is more than 4cm and less than 8cm

X: the length of the ground upper part is less than 4cm

To 1 leaf of the obtained seedling at 2 to 3 leaf stages, 100. mu.L of an aqueous dispersion of nanoparticles (P) or a 100ppm tiadinil solution (1 vol% DMSO, 12.5 vol% acetone, 0.01 wt% マイリノー (manufactured by Nippon pesticide Co., Ltd.)) adjusted so that the amount of tiadinil contained therein was 100ppm was sprayed, with care being taken not to spill out from the leaf. An aqueous dispersion of nanoparticles (P) or a 100ppm tiadinil solution was sprayed onto the surface side of the leaves. Using this, cultivation in paddy field was carried out by the following method. Resistance inducibility, phytotoxicity evaluation, and overground part growth ratio were evaluated by the following methods and compared with a control sample (comparative example). The results are shown in "paddy field cultivation" in table 3 (rice) and table 4 (tomato).

< evaluation of resistance inducibility >

2.9kg of paddy field soil (planting soil) was filled in a pot of one-to-five thousandth of an acre, 10 seedlings of 2 to 3 leaf stages cultivated by the above method were transplanted to a depth of 2cm, and water was added to make it a 3cm watered state. After leaving at 25 ℃ for a predetermined time (days after moving to a paddy field until evaluation), leaves to which the dispersion of nanoparticles (P) was sprayed (or tiadinil solution) were cut, immersed in a container containing ion-exchanged water for 1 minute, and then taken out of the container. After removing nanoparticles (P) (or tiadinil) attached to the leaf surface by replacing the water in the container with fresh ion-exchanged water and further immersing the leaf in fresh ion-exchanged water in the container for 1 minute and lifting the same for 3 times, the protein was extracted from the above leaf for 8 minutes using a total plant protein extraction kit (manufactured by Cosmo Bio corporation), and the amount of PR1 protein contained therein as a resistance-inducing marker was investigated as follows. The total protein amount was quantified using a Micro BCATM protein assay kit (manufactured by THERMO Fisher Scientific Co., Ltd.), and the extract solution of leaves having a large total protein amount was diluted with ion-exchanged water so that the total protein amount of leaves in each experiment was the same, and the thus-standardized extract solution was used for the subsequent electrophoresis.

Each of the 5 experiments was carried out, and the amount of PR1 protein was evaluated by Western blotting (including electrophoresis, transfer and color development) as described in detail below.

(1) Electrophoresis

Electrophoresis was performed under the following conditions using a mixed solution in which 10. mu.L of a sample buffer solution was added to 10. mu.L of an extract solution extracted from leaves.

Sample solution: the leaf extract obtained in each example or each comparative example

Polyacrylamide gel: E-R15L E-PAGEL (manufactured by ATTO Co., Ltd.)

Electrophoresis tank: WSE-1100P PageRun-R (manufactured by ATTO Co., Ltd.)

Electrophoresis time: 90 minutes

Sample buffer solution: 4X Laemmli sample buffer [ Bio-Rad Co., Ltd. ] 900. mu.L of a mixture with 100. mu.L of 2-mercaptoethanol

(2) Transfer printing

After electrophoresis under the above conditions, transfer was performed under the following conditions using a transfer film.

Transfer printing film: amersham Hybond P0.45 PVDF [ GE Healthcare Co., Ltd ]

Transfer printing liquid: a liquid obtained by diluting AE-1465ezFastBlot [ ATTO, Inc. ] by 10 times with pure water

Voltage/current: 12V/400mA

Transfer time: 30 minutes

(3) Color development

After the transfer under the above conditions, the transfer film is blocked, and then an antigen-antibody reaction is performed with a primary antibody and a secondary antibody. In this test, an anti-PR 1 antibody (rice, manufactured by MybioSource, tomato, manufactured by Agriera) was used as a primary antibody, a horseradish peroxidase HRP-labeled secondary antibody was used as a secondary antibody, and ImageQuant LAS4000 was used to develop color under the following conditions.

A detector: ImageQuant LAS4000 (Fuji film Co., Ltd.)

Sealing time: 45 minutes

Primary antibody reaction time: 120 minutes

The reaction time of the secondary antibody: 60 minutes

(4) Method for analyzing expression level

After the transfer film was detected as a band of PR1 protein after the operations (1) to (3), the concentration of the band was quantified using Image J (national institute of health). In examples 11 to 14, the concentration of the quantitative band in examples 11 to 14 was divided by the concentration of the band in comparative example 3, and the value was defined as the amount ratio of PR1 protein in examples 11 to 14. Similarly, the band concentration obtained in the example treated with the nanoparticles (P) for a prescribed time was divided by the band concentration obtained in the comparative example treated with the tiadinil solution on the same day, and the obtained value was taken as the PR1 protein amount ratio. The evaluation results are shown in tables 3 (rice) and 4 (tomato). The higher the amount ratio of PR1 protein, the higher the resistance.

When the amount ratio of PR1 protein is 1.0 to 100, good resistance is exhibited, and when it is less than 1.0, resistance to diseases is difficult to exhibit. On the other hand, if it is 100 or more, physiological functions having negative effects such as drug damage other than resistance are reflected in many cases, meaning that resistance cannot be evaluated accurately.

< evaluation of phytotoxicity after treatment of nanoparticles (P) or tiadinil >

In the same manner as described in the above < evaluation of resistance inducibility >, after seedlings were treated with nanoparticles (P) or tiadinil, the phytotoxicity on the leaf surface after a predetermined time (days after moving to the paddy field until evaluation shown in tables 3 to 4) was evaluated. Specifically, phytotoxicity was observed by visual observation with the following indices.

(phytotoxicity index)

0: harmless (healthy), 1: minor damage, 2: minor injury, 3: moderate injury, 4: severe injury, 5: complete death by death

< overground part growth ratio after treatment of nanoparticles (P) or tiadinil >

In the same manner as described in the above < evaluation of resistance inducibility >, seedlings were treated with nanoparticles (P) or tiadinil, and then the overground growth state was evaluated after a predetermined time (days after moving to a paddy field and until evaluation shown in tables 3 to 4). Specifically, the overground part growth state was evaluated by measuring the length of each part. The length of the overground part obtained in the example treated with the nanoparticles (P) for a predetermined time was divided by the length of the overground part obtained in the comparative example treated with the tiadinil solution for the same number of days, and the obtained value was calculated as the overground part growth ratio.

The values of the water-absorbent resin (D), the filler (F) and the water-permeable sheet (G) shown in tables 3 and 4 represent the weight (G).

Industrial applicability

The growth auxiliary agent (X) for plants of the present invention enables a plant to efficiently take a chemical, has an appropriate dissolution property of the chemical from a granule, is excellent in the sustained-release property of the chemical, and is excellent in the persistence of the chemical effect, and therefore is excellent in the growth property of a plant and the growth promotion of a plant, and is extremely useful for horticultural use and agricultural use.