Plant growth promoter and composition for promoting plant growth containing the same

Abstract

The present invention relates to a plant growth promoter containing polyhydroxyalkanoate (PHA), and a composition for promoting the growth of a plant containing this plant growth promoter. This plant growth promoter is excellent in biodegradability, biocompatibility, etc., is safe, environmentally friendly, and can efficiently promote the growth of plants.

Description

Technical Field

[0001] The present disclosure relates to a plant growth promoter containing a biodegradable polymer and promoting plant growth, and a composition for promoting the growth of plants containing the same.

Background Art

[0002] Plants are constantly exposed to biotic stresses caused by other organisms such as pests and diseases, and abiotic stresses caused by changes in physical or chemical environments such as heat, drought, and salinity. Due to such stresses, nutrients are lost from the soil, and the roots of plants are unable to absorb necessary substances, resulting in reduced plant growth and productivity. Therefore, plant growth promoters that help plants recover from stress by supplementing the elements necessary for plant growth have attracted attention.

[0003] These plant growth promoters are substances that assist in the growth and metabolism of plants. They serve as food for soil microorganisms, increase the nutrient absorption rate, enhance the efficiency and production of chlorophyll, have antioxidant effects, improve metabolism and soil water retention capacity, and promote the growth of new shoots, roots, and cell expansion of plants. Currently, commercially available plant growth promoter products contain, as main components, plant hormones such as auxin, cytokinin, gibberellin, humic acid, seaweed extract, and the like.

[0004] However, since these plant growth promoter products contain various chemical substances in addition to the above-mentioned main components, it has not been clearly confirmed whether plants treated with the plant growth promoter are harmless to the human body. Environmental problems such as soil pollution have also been pointed out.

[0005] Therefore, there is a demand for the development of a plant growth promoter that can promote the growth of plants safely and environmentally friendly.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Disclosure of the Invention

Problems to be Solved by the Invention

[0007] An object of the present disclosure is to provide a plant growth promoter that can promote the growth of plants while being excellent in safety and environmental compatibility.

[0008] Another object of the present disclosure is to provide a composition for promoting the growth of plants containing the above plant growth promoter.

Means for Solving the Problems

[0009] In order to solve the above problems, one aspect of the present disclosure provides a plant growth promoter containing polyhydroxyalkanoate (PHA).

[0010] In one form, the content rate of polyhydroxyalkanoate (PHA) can be 1 to 100% by mass with respect to the total weight of the plant growth promoter.

[0011] In another embodiment, the polyhydroxyalkanoate (PHA) may include a repeating unit derived from at least one selected from the group consisting of 3-hydroxybutyric acid (3HB), 4-hydroxybutyric acid (4HB), 3-hydroxypropionic acid (3HP), 3-hydroxyhexanoic acid (3HH), 3-hydroxyvaleric acid (3HV), 4-hydroxyvaleric acid (4HV), 5-hydroxybutyric acid (5HV), and 6-hydroxyhexanoic acid (6HH).

[0012] In another embodiment, the polyhydroxyalkanoate (PHA) may include a repeating unit derived from 4-hydroxybutyric acid (4HB).

[0013] In another embodiment, the content of the repeating unit derived from 4HB (4-hydroxybutyric acid) with respect to the total number of moles of the polyhydroxyalkanoate (PHA) can be 1 to 80 mol%.

[0014] In another embodiment, the polyhydroxyalkanoate (PHA) may be a poly(3-hydroxybutyrate-4-hydroxybutyrate) copolymer containing repeating units derived from 3-hydroxybutyric acid (3HB) and repeating units derived from 4-hydroxybutyric acid (4HB).

[0015] In another embodiment, the molar ratio of the repeating units derived from 3-hydroxybutyric acid (3HB) to the repeating units derived from 4-hydroxybutyric acid (4HB) can be from 20:80 to 99:1.

[0016] In another embodiment, the polyhydroxyalkanoate (PHA) can have a molecular weight of 200,000 to 1,000,000 g / mol.

[0017] In another aspect, the plant growth promoter may further contain a biodegradable polymer.

[0018] In another embodiment, the biodegradable polymer may contain at least one selected from the group consisting of polylactic acid (PLA), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), polybutylene adipate-co-terephthalate (PBAT), polybutylene succinate (PBS), polycaprolactone (PCL), and thermoplastic starch (TPS).

[0019] In another embodiment, the biodegradable polymer can be polylactic acid (PLA).

[0020] In another embodiment, the content of polyhydroxyalkanoate (PHA) can be 20 to 70% by mass based on the total weight of the plant growth promoter, and the content of the biodegradable polymer can be 30 to 80% by mass.

[0021] In contrast, according to another aspect of the present disclosure, there is provided a composition for promoting plant growth, which comprises a plant growth promoter containing polyhydroxyalkanoate (PHA).

[0022] In one form, the content of the plant growth promoter relative to the total weight of the composition for promoting plant growth can be 0.001 to 10% by mass.

Advantages of the Invention

[0023] The plant growth promoter according to the present disclosure contains polyhydroxyalkanoate (PHA) which is excellent in biodegradability and biocompatibility, and thus is harmless when applied to plants and soil. It is decomposed into organic substances in the soil, promoting the activities of microorganisms in the soil, and by their growth, it can promote the growth of plant roots and increase the nutrient absorption rate of plants.

[0024] Thereby, while solving the problems of safety and environmental pollution raised for conventional plant growth promoters, the plant growth promoter of the present disclosure can promote the growth of plants and contribute to the improvement of plant productivity.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0026] Hereinafter, the present disclosure will be described in more detail with reference to embodiments. It should be noted that the present disclosure is not limited to the disclosure shown below, and various modifications are possible without departing from the gist of the present invention, as in the case of the disclosure shown below.

[0027] In this specification, the term "comprising" is used to specifically identify a particular property, region, step, process, element, and / or component. Unless otherwise expressly stated to the contrary, it does not exclude the presence or addition of other properties, regions, steps, processes, members, elements, and / or components.

[0028] The numerical values and expressions regarding the amounts of components, reaction conditions, etc. used herein are, unless otherwise specified, within the range that can be understood even when modified by the term "about".

[0029] Plant growth promoter The plant growth promoter according to one embodiment of the present disclosure contains polyhydroxyalkanoate (PHA) having excellent biodegradability and biocompatibility.

[0030] Polyhydroxyalkanoate (PHA) has excellent biodegradability (the ratio at which the organic carbon of the test substance is converted into inorganic carbon as gaseous CO2) measured according to the ISO14855 standard. Therefore, when applied to the soil, it has biodegradability and can activate microorganisms in the soil. In addition, polyhydroxyalkanoate (PHA) has low immunogenicity and excellent biocompatibility. Therefore, when the plant growth promoter according to the present disclosure containing such polyhydroxyalkanoate (PHA) is applied to a plant, it can greatly assist the growth and metabolism of the plant and promote the growth of the plant. When the plant obtained thereby is ingested by a human, it can be harmless to the human body.

[0031] Specifically, the biodegradability of PHA (polyhydroxyalkanoate) measured in accordance with the ISO 14855 standard may be 50% or more, 60% or more, 70% or more, or 80% or more (for example, 50 to 100%, 50 to 95%, 50 to 90%, 55 to 90%, 60 to 85%, or 70 to 85%).

[0032] Polyhydroxyalkanoate (PHA) may contain repeating units derived from at least one kind (at least one monomer) selected from the group consisting of 3-hydroxybutyric acid (3HB), 4-hydroxybutyric acid (4HB), 3-hydroxypropionic acid (3HP), 3-hydroxyhexanoic acid (3HH), 3-hydroxyvaleric acid (3HV), 4-hydroxyvaleric acid (4HV), 5-hydroxyvaleric acid (5HV), and 6-hydroxyhexanoic acid (6HH).

[0033] Specifically, polyhydroxyalkanoate (PHA) may contain repeating units (4HB repeating units) derived from 4-hydroxybutyric acid (4HB). By including 4HB repeating units in polyhydroxyalkanoate (PHA), the biodegradability and growth promoting ability of the plant growth promoter can be enhanced.

[0034] The content of the 4HB repeating unit may be 1 to 80 mol% with respect to the total moles of polyhydroxyalkanoate (PHA) (total moles of the repeating units constituting PHA). Specifically, it may be 1 to 75 mol%, 2 to 70 mol%, 2 to 65 mol%, 2 to 50 mol%, 3 to 60 mol%, 4 to 55 mol%, 5 to 50 mol%, 6 to 45 mol%, 8 to 40 mol%, 9 to 35 mol%, or 10 to 33 mol%. By the content of the 4HB repeating unit being within the above range, the biodegradability and growth promoting ability of the plant growth promoter can be enhanced.

[0035] Specifically, polyhydroxyalkanoate (PHA) may be a poly(3-hydroxybutyric acid-co-4-hydroxybutyric acid) copolymer. Thereby, the biodegradability, biocompatibility, and growth promoting ability of the plant growth promoter can be maximally exerted.

[0036] The molar ratio of the repeating unit (3HB repeating unit) derived from 3-hydroxybutyric acid (3HB) and the repeating unit (4HB repeating unit) derived from 4-hydroxybutyric acid (4HB) in the poly(3-hydroxybutyric acid-4-hydroxybutyric acid) copolymer is not particularly limited, and can be 20:80 to 99:1, 25:75 to 99:1, 35:65 to 99:1, 40:60 to 95:5, 45:55 to 95:5, 50:50 to 95:5, 55:45 to 95:5, 60:40 to 90:10, or 65:35 to 90:10. If the molar ratio is within the above range, the biodegradability and growth promoting ability of the plant growth promoter can be enhanced.

[0037] On the other hand, the crystallinity of polyhydroxyalkanoate (PHA) may be adjusted according to the content of the 4HB repeating unit. It may be classified into semi-crystalline PHA (scPHA) and amorphous PHA (aPHA).

[0038] Specifically, the content rate of the 4HB repeating unit in scPHA can be 0.1 to 30 mol%, 1 to 25 mol%, 3 to 23 mol%, 5 to 20 mol%, 7 to 15 mol%, 8 to 13 mol%, or 9 to 11 mol% with respect to the total moles of polyhydroxyalkanoate (PHA). Specifically, the content rate of the 4HB repeating unit in aPHA can be 20 to 50 mol%, 23 to 45 mol%, 25 to 43 mol%, 26 to 40 mol%, 29 to 37 mol%, 31 to 35 mol%, or 31 to 34 mol% with respect to the total moles of polyhydroxyalkanoate (PHA).

[0039] Polyhydroxyalkanoate (PHA) may be composed of scPHA alone, aPHA alone, or a mixture of both.

[0040] The crystallinity of polyhydroxyalkanoate (PHA) is not particularly limited, but when measured using a differential scanning calorimeter (DSC), it may be 90% or less, 85% or less, 80% or less, 75% or less, or 70% or less (for example, 30 - 90%, 40 - 90%, 50 - 85%, or 60 - 80%).

[0041] The crystallization temperature (T c ) of polyhydroxyalkanoate (PHA) is not particularly limited, but specifically, it can be 60 - 120°C, 65 - 120°C, 70 - 115°C, 80 - 115°C, 85 - 110°C, 90 - 110°C, or 90 - 105°C. Also, the crystallization temperature (T c ) of polyhydroxyalkanoate (PHA) may not be measured.

[0042] The melting temperature (T m ) of polyhydroxyalkanoate (PHA) is not particularly limited, but specifically, it can be 90 - 180°C, 95 - 175°C, 100 - 170°C, 110 - 160°C, 115 - 150°C, 120 - 140°C, or 125 - 135°C. Also, the melting point (T m ) of polyhydroxyalkanoate (PHA) may not be measured.

[0043] The glass transition temperature (T g ) of polyhydroxyalkanoate (PHA) is not particularly limited, but it can be -45 - 80°C, -40 - 60°C, -35 - 50°C, -25 - 25°C, -20 - 20°C, -20 - 15°C, -15 - 10°C, or -10 - 0°C. Also, the glass transition temperature (T g ) of polyhydroxyalkanoate (PHA) may not be measured.

[0044] The molecular weight of polyhydroxyalkanoate (PHA) (for example, poly(3-hydroxybutyric acid-4-hydroxybutyric acid) copolymer) is not particularly limited and can be 200,000 to 1,000,000 g / mol, 230,000 to 980,000 g / mol, 250,000 to 950,000 g / mol, 280,000 to 930,000 g / mol, 300,000 to 900,000 g / mol, 320,000 to 900,000 g / mol, 340,000 to 880,000 g / mol, 350,000 to 850,000 g / mol, 380,000 to 850,000 g / mol, 400,000 to 830,000 g / mol, or 400,000 to 800,000 g / mol. When the molecular weight of polyhydroxyalkanoate (PHA) is within the above range, the promotion of plant growth can be enhanced.

[0045] The content of polyhydroxyalkanoate (PHA) may be 1 to 100% by mass based on the total weight of the plant growth promoter. Specifically, it may be 10 to 100% by mass, 15 to 100% by mass, 20 to 100% by mass, 10 to 95% by mass, 13 to 93% by mass, 15 to 90% by mass, 20 to 90% by mass, 22 to 88% by mass, 25 to 85% by mass, 25 to 80% by mass, 28 to 78% by mass, or 30 to 75% by mass. When the content rate of polyhydroxyalkanoate (PHA) is within the above range, the biodegradability, biocompatibility, and growth promotion ability of the plant growth promoter can be enhanced.

[0046] On the other hand, the plant growth promoter according to the present disclosure may be in a powder form or a liquid form. Specifically, the plant growth promoter according to the present disclosure may have a powder formulation composed of particles of polyhydroxyalkanoate (PHA) itself, or a dispersant formulation in which polyhydroxyalkanoate (PHA) particles are dispersed in a solvent.

[0047] The plant growth promoter according to the present disclosure may further contain a generally known biodegradable polymer (BP) in addition to polyhydroxyalkanoate (PHA). Specifically, the biodegradable polymer (BP) may be at least one selected from the group consisting of polylactic acid (PLA), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), polybutylene adipate-co-terephthalate (PBAT), polybutylene succinate (PBS), polycaprolactone (PCL), and thermoplastic starch (TPS). Preferably, it can be polylactic acid (PLA).

[0048] When the plant growth promoter according to the present disclosure contains polyhydroxyalkanoate (PHA) and a biodegradable polymer (BP), its content is not particularly limited, but PHA is 20 to 70% by mass (specifically, 25 to 70% by mass, 25 to 65% by mass, 28 to 60% by mass, 30 to 55% by mass, 30 to 50% by mass), and the biodegradable polymer (for example, polylactic acid (PLA)) is 30 to 80% by mass (specifically, 30 to 75% by mass, 35 to 75% by mass, 40 to 72% by mass, 45 to 70% by mass, 50 to 70% by mass) based on the total weight of the plant growth promoter.

[0049] The application amount when applying the plant growth promoter according to the present disclosure to plants is not particularly limited, but it may be 0.001 to 5% by mass, 0.005 to 4% by mass, 0.01 to 3% by mass, 0.05 to 2% by mass, 0.1 to 1% by mass, 0.001 to 0.1% by mass, 0.1 to 0.3% by mass, 0.3 to 0.5% by mass, 0.5 to 3% by mass based on the total weight of the soil in which the plants are planted. If the application amount is within the above range, the growth promotion of plants can be enhanced economically.

[0050] When the plant growth promoter according to the present disclosure is applied to the soil in which plant seeds are sown, the germination rate is 80% or more, 82% or more, 83% or more, 84% or more, 85% or more, 87% or more, 89% or more, 90% or more, 93% or more, 95% or more, 97% or more, 99% or more. Therefore, it can be seen that the plant growth promoting effect is excellent. Specifically, the germination rate of the seeds may be 80 - 100%, 82 - 100%, 83 - 99.9%, 83 - 99.8%, 84 - 99.7%, 85 - 99.6%, 88 - 99.5%, or 90 - 99.4%.

[0051] The plant growth promoter according to the present disclosure can promote the growth of various plants. Specifically, the plant may be at least one selected from the group consisting of rice, barley, lettuce, Arabidopsis thaliana, cucumber, and corn. In particular, the plant growth promoter according to the present disclosure can promote the growth of plant roots.

[0052] Composition for promoting plant growth The composition for promoting the growth of plants of the present disclosure contains the above-mentioned plant growth promoter. Specifically, the composition for promoting the growth of plants of the present disclosure can contain the above-mentioned polyhydroxyalkanoate (PHA) alone, or a plant growth promoter containing the above-mentioned polyhydroxyalkanoate (PHA) and the above-mentioned biodegradable polymer (for example, polylactic acid (PLA)). Since the composition for promoting the growth of plants according to the present disclosure contains the above-mentioned plant growth promoter for plants, when applied to the soil in which plant seeds are sown, the germination rate is 80% or more (specifically, 80 - 100%, 82 - 99.9%, 83 - 99.8%, 84 - 99.7%, 85 - 99.5%), the ecological toxicity is very low, and the plant growth promoting effect is excellent, so the productivity of plants is improved.

[0053] The content of the plant growth promoter contained in the composition for promoting plant growth can be 0.001 - 10% by mass, 0.005 - 5% by mass, 0.007 - 3% by mass, 0.009 - 2% by mass, or 0.01 - 1% by mass based on the total weight of the composition for promoting plant growth.

[0054] On the one hand, the composition for promoting the growth of plants according to the present disclosure may further contain an additive (active ingredient) capable of promoting the growth of plants. Specifically, the additive may contain at least one selected from the group consisting of a plant growth regulator, a fungicide, an insecticide, a miticide, a nematicide, and a herbicide.

[0055] The plant growth regulator can be at least one selected from the group consisting of L-glutamic acid, L-proline, aminoethoxyvinylglycine, chlormequat, chlorpropham, cyclanilide, dicamba, daminozide, ethylene, flurprimidol, flumetralin, forchlorfenuron, gibberellin, maleic hydrazide salt, mepiquat chloride, methylcyclopropene, benzylaminopurine, paclobutrazol, prohexadione, thidiazuron, tributyl phosphorotrithioate, trinexapac-ethyl, and uniconazole.

[0056] Specifically, the fungicide may be at least one selected from the group consisting of benzimidazole-based compounds, succinate dehydrogenase inhibitor compounds (SDHI-based compounds), strobilurin-based compounds, phenylamide-based compounds, dicarboximide-based compounds, anilinopyrimidine-based compounds, carbamate-based compounds, quinoline-based compounds, organophosphorus-based compounds, and carboxamide-based compounds.

[0057] Specifically, the insecticide can be at least one selected from the group consisting of carbamate-based compounds, pyrethroid-based compounds, nereistoxin compounds, neonicotinoid-based compounds, benzoylurea-based compounds, and organochlorine-based compounds.

[0058] Specifically, as this acaricide, at least one selected from the group consisting of acequinocyl, amidoflumet, amitraz, azocyclotin, bifenazate, bromopropylate, chlorfenapyr, chinomethionat, fenothiocarb, fenpyroximate, benzoximate, clofentezine, cyenopyrafen, flufenerim, hexythiazox, propargite (BPPS), piflubutrazone, pyridaben, pyrimidifen, spirodiclofen, spirotetramat, tebufenpyrad, tetradifon, asinomapyr, cyetepyrifene, and flupenthiophenox is preferably used.

[0059] Specifically, nematicide may be at least one selected from the group consisting of 1,3-dichloropropene (D-D), dichlorodiisopropyl ether (DCIP), methyl isothiocyanate, cadusafos, fosthiazate, imicyafos, nemadectin, cyclobutaprine, and thioxazefene.

[0060] Specifically, the herbicide may be at least one selected from the group consisting of amino acid-based compounds, cyclohexanedione-based compounds, acetamide-based compounds, bipyridinium-based compounds, aryloxyphenoxypropionic acid-based compounds, carbamate-based compounds, pyridine-based compounds, urea-based compounds, dinitroaniline-based compounds, phenoxyacetic acid-based compounds, and triazine-based compounds.

[0061] In addition, the composition for promoting the growth of plants according to the present disclosure may further contain an aqueous solvent (e.g., purified water, etc.) and / or soil for adjusting the concentration (or viscosity).

[0062] The composition for promoting the growth of plants according to the present disclosure can exhibit a growth-promoting effect on all common plants. Specific examples of plants include, for example, Poaceae such as rice, wheat, oats, rye, barley, triticale, corn, sugarcane, turfgrass, bentgrass, bermudagrass, fescue, ryegrass, etc.; Rosaceae such as whitebeam; Fabaceae such as soybean, peanut, cowpea, pea, adzuki bean, etc.; Convolvulaceae such as sweet potato; Solanaceae such as pepper, tomato, eggplant, potato, etc.; Polygonaceae such as buckwheat; Asteraceae such as lettuce, sunflower, etc.; Apiaceae such as carrot; Araceae such as taro; Anacardiaceae such as mango; Bromeliaceae such as pineapple; Caricaceae such as papaya; Ebenaceae such as kaki; Juglandaceae such as walnut; Musaceae such as banana; Oleaceae such as olive; Arecaceae such as coconut, date palm, etc.; Rutaceae such as mandarin orange, orange, grapefruit, lemon, etc.; Vitaceae such as grape; flower plants and foliage plants, garden trees other than fruit trees, other foliage plants, etc. In particular, the composition for promoting the growth of plants according to the present disclosure can have an excellent effect of promoting the growth of monocotyledonous plants such as Poaceae (e.g., barley, corn, etc.) and dicotyledonous plants such as Cucurbitaceae (e.g., cucumber, etc.), Brassicaceae (e.g., Arabidopsis thaliana, etc.).

[0063] Mode for Invention The present disclosure will be described in more detail with reference to the following examples, but the scope of the present disclosure is not limited to these examples.

[0064] Example 1 A plant growth promoter containing 100% by weight of a semi-crystalline polyhydroxyalkanoate (scPHA, P(3HB-co-4HB) copolymer) with a 4HB repeating unit ratio of 10 mol% and a molecular weight of about 400,000 g / mol was prepared.

[0065] Example 2 A plant growth promoter containing 100% by mass of a semi-crystalline polyhydroxyalkanoate (scPHA, P(3HB-co-4HB) copolymer) having a ratio of 10 mol% of 4HB repeating units and a molecular weight of approximately 800,000 g / mol was prepared.

[0066] Example 3 A plant growth promoter containing 100% by weight of an amorphous polyhydroxyalkanoate (aPHA, P(3HB-co-4HB) copolymer) with a 4HB repeating unit ratio of 33 mol% and a molecular weight of approximately 600,000 g / mol was prepared.

[0067] Example 4 A plant growth promoter was prepared containing 70% by weight of polylactic acid (Natureworks, M4032) and 30% by weight of an amorphous polyhydroxyalkanoate (aPHA, P(3HB-co-4HB) copolymer) with a molecular weight of about 400,000 g / mol and containing 33 mol% of 4HB repeating units.

[0068] Example 5 A plant growth promoter was prepared containing 50% by weight of polylactic acid (Natureworks, M4032) and 50% by weight of an amorphous polyhydroxyalkanoate (aPHA, P(3HB-co-4HB) copolymer) with a molecular weight of about 450,000 g / mol and containing 33 mol% of 4HB repeating units.

[0069] Comparative Example 1 A plant growth promoter containing 100% by mass of polylactic acid (PLA) (Nature Works, M4032) was prepared.

[0070] Comparative Example 2 A plant growth promoter containing 100% by mass of polyhydroxybutyrate-co-hydroxyvalerate (PHBV, P(3HB-co-3HV) copolymer) (China, Tian'an Co.) was prepared.

[0071] Comparative Example 3 A plant growth promoter containing 100% by weight of polybutylene adipate-co-terephthalate (PBAT) (ANKOR Co., Korea) was prepared.

[0072] Control Comparative Example 1 Natural soil prepared based on the EN17033 standard was used. Specifically, soil was collected from paddy fields in Cheorwon County, Gangwon Province. The physical properties of the collected soil were as shown in Table 1 below.

[0073]

Table 1

[0074] Control Comparative Example 2 A standard sample compliant with EN17033 (Sigma-Aldrich, PHB standard sample) was used.

[0075] Examples, comparative examples, and control comparative examples are summarized in Table 2 below.

[0076]

Table 2

[0077] Test Example 1 Evaluation of Germination Rate 1 Barley, a monocotyledonous plant, and lettuce, a dicotyledonous plant, were sown in this soil, and the germination rate was evaluated. Specifically, treatment groups in which 50 barley seeds and 50 lettuce seeds were each sown were placed in a growth chamber capable of controlling temperature, humidity, and light conditions. Germination was observed for approximately 3 days. For the treatment groups, a powdery plant growth promoter was mixed into the natural soil at 1.0% by mass based on the total weight of the soil, and it was stored in a temperature and humidity control chamber (23°C, 60% RH). Soil with a biodegradability of over 50% (water content of approximately 10% (w / w)) was used. Also, the germination conditions in the growth chamber were as follows. Germination (growth) temperature of barley seeds and lettuce seeds: 25 ± 2°C Humidity: 40 - 60% According to prior literature, if the germination rate of Control Comparative Example 1 exceeds 90%, it is interpreted that the ecological toxicity of the substance is low. If it is confirmed that the germination rate of the example is equal to or higher than that of Control Comparative Example 1, it is understood that the result of promoting germination has been obtained.

[0078] After the evaluation, the germination rate was converted to a percentage using the following formula (1). The results are shown in Tables 3 and 4 below.

[0079] [Equation 1] Germination rate (%) = S1 / S t × 100 S t : The number of seeds sown in the treatment group S1: The number of germinated seeds among the seeds sown in the treatment group (Seeds having radicles (embryonic roots) or plumules (plumules) were counted as germinated seeds.)

[0080]

Table 3

[0081]

Table 4

[0082] Test Example 2 Evaluation of Germination Rate 2 Barley, a dicotyledonous plant, and lettuce, a monocotyledonous plant, were sown in Petri dishes covered with mycelia, and the germination rate was evaluated. Specifically, the surfaces of barley seeds and lettuce seeds were sterilized with 3% H2O2 and washed three times with distilled water. Filter paper was placed in the Petri dishes, and a 1% concentration sample (a composition obtained by diluting the plant growth promoter of Example 1 with purified water) was placed thereon. The sterilized seeds were arranged linearly in each Petri dish, sealed with paraffin, and cultured in the dark at 23 °C for 3 days. Three days after the start of cultivation, it was observed that roots had grown from the seeds. The results are shown in FIG. 1.

[0083] FIG. 1(a) shows the germination level of barley seeds, and FIG. 1(b) shows the germination level of lettuce seeds. It was confirmed that roots grew from the seeds and germination was good.

[0084] Test Example 3: Evaluation of Dry Weight Recovery Rate A treatment group similar to the treatment group used in Test Example 1 was prepared. 50 lettuce seeds and 50 barley seeds were each sown and grown at room temperature for 14 days. Then, the grown lettuce and barley were harvested and dried at 65°C to remove moisture. After obtaining the dried product, its weight was measured. The measurement results are shown in Tables 5 and 6 below.

[0085]

Table 5

[0086]

Table 6

[0087] Test Example 4: Evaluation of Germination Rate 3 Corn and cucumber seeds were sown in soil to evaluate the germination rate. Specifically, treatment groups in which corn seeds and cucumber seeds were sown respectively were placed in a growth chamber where temperature, humidity and light conditions could be controlled, and germination was observed. The results are shown in Figures 2 and 3. For the treatment groups, 0.1% by mass of a powdery plant growth promoter was mixed with the total weight of the soil with respect to natural soil and stored in a temperature and humidity adjustment chamber (23°C, 60% RH). Soil with a biodegradability of more than 50% (water content of about 10% (w / w)) was used. Also, the germination conditions in the growth chamber were as follows. Germination (growth) temperature of corn seeds and cucumber seeds: 25°C Humidity: 60% Light: 16 hr / shade: 8 hr Figure 2 shows the evaluation results of the germination rate of cucumbers, and Figure 3 shows the evaluation results of the germination rate of corn. Referring to these results, in Examples 1, 2, 4, and 5 using the plant growth promoter according to the present disclosure, the germination rates were all equal to or higher than those of Control Comparative Example 1 and Comparative Examples 1 to 3 of the control, and it was confirmed that there was a plant growth promoting effect. In particular, referring to the evaluation results of the germination rate of cucumbers, when using the plant growth promoter of the present disclosure, germination occurred in a relatively short period (within 3 days), and it was confirmed that the plant growth promoter of the present disclosure could increase the germination rate.

[0088] Test Example 5 Evaluation of Plant Growth Promotion Effect 1 The growth promoting effect of corn was evaluated by the soil fertilizer application method. Specifically, a treatment group in which corn seeds were sown was placed in a growth chamber capable of controlling temperature, humidity, and light conditions. Growth was observed in about two weeks. For the treatment group, 0.1% by mass of a powdery plant growth promoter was mixed with respect to the total weight of the soil in natural soil and stored in a temperature and humidity adjustment chamber (23°C, 60% RH). Soil with a biodegradability of more than 50% (water content of about 10% (w / w)) was used. Also, the growth conditions in the growth chamber were as follows. The fresh weight (wet weight) of the roots of corn was measured. The results are shown in Figure 4. Germination (growth) temperature of corn seeds: 25°C Humidity: 60% Referring to Figure 4, in Examples 1, 2, 4, and 5 using the plant growth promoter according to the present disclosure, the fresh weight of the roots of corn was 60 to 80% more than that of Comparative Examples 1 to 3, and it was confirmed that an excellent plant growth promoting effect was obtained.

[0089] Test Example 6 Evaluation of Plant Growth Promotion Effect 2 The growth promotion effect of cucumbers was evaluated by this soil and fertilizer application method. Specifically, a treatment group in which cucumber seeds were sown was placed in a growth chamber capable of controlling temperature, humidity, and light conditions. Growth was observed over approximately 20 days. For the treatment group, a powdery plant growth promoter at 0.1% by mass based on the total weight of the soil was mixed with natural soil and stored in a temperature and humidity control chamber (23°C, 60% RH). Soil with a biodegradability of over 50% (water content of approximately 10% (w / w)) was used. Also, the growth conditions in the growth chamber were as follows. After growth, the fresh weight (wet weight) of the cucumber roots was measured. The results are shown in Fig. 5. Germination (growth) temperature of cucumber seeds: 25°C Humidity: 60% Referring to Fig. 5, it was confirmed that in Examples 1, 2, 4, and 5 using the plant growth promoters according to the present disclosure, the fresh weight of the cucumber roots was 40 to 160% greater than that in Comparative Examples 1 to 3, respectively, and an excellent plant growth promotion effect was obtained.

Claims

1. A plant growth promoter containing polyhydroxyalkanoate (PHA).

2. The plant growth promoter according to Claim 1, wherein the content of the polyhydroxyalkanoate (PHA) is 1 to 100% by mass based on the total weight of the plant growth promoter.

3. The plant growth promoter according to Claim 1, wherein the polyhydroxyalkanoate (PHA) contains a repeating unit derived from at least one selected from the group consisting of 3-hydroxybutyric acid (3HB), 4-hydroxybutyric acid (4HB), 3-hydroxypropionic acid (3HP), 3-hydroxyhexanoic acid (3HH), 3-hydroxypentanoic acid (3HV), 4-hydroxypentanoic acid (4HV), 5-hydroxypentanoic acid (5HV), and 6-hydroxyhexanoic acid (6HH).

4. The plant growth promoter according to Claim 1, wherein the polyhydroxyalkanoate (PHA) contains a repeating unit derived from 4-hydroxybutyric acid (4HB).

5. The plant growth promoter according to Claim 4, wherein the content of the repeating unit derived from 4-hydroxybutyric acid (4HB) is 1 to 80 mol% based on the total moles of the polyhydroxyalkanoate (PHA).

6. The plant growth promoter according to Claim 1, wherein the polyhydroxyalkanoate (PHA) is a poly(3-hydroxybutyric acid - CO - 4-hydroxybutyric acid) copolymer containing a repeating unit derived from 3-hydroxybutyric acid (3HB) and a repeating unit derived from 4-hydroxybutyric acid (4HB).

7. The plant growth promoter according to Claim 6, wherein the molar ratio of the repeating unit derived from 3-hydroxybutyric acid (3HB) to the repeating unit derived from 4-hydroxybutyric acid (4HB) is 20:80 to 99:

1.

8. The plant growth promoter according to Claim 1, wherein the molecular weight of the polyhydroxyalkanoate (PHA) is 200,000 to 1,000,000 g / mol.

9. The plant growth promoter according to Claim 1, further comprising a biodegradable polymer.

10. The plant growth promoter according to claim 9, wherein the biodegradable polymer comprises at least one selected from the group consisting of polylactic acid (PLA), polyvinyl alcohol (PVOH), ethylene vinyl alcohol (EVOH), polybutylene adipate-co-terephthalate (PBAT), polybutylene succinate (PBS), polycaprolactone (PCL), and thermoplastic starch (TPS).

11. The plant growth promoter according to claim 9, wherein the biodegradable polymer is polylactic acid (PLA).

12. The plant growth promoter according to claim 9, wherein the content of the polyhydroxyalkanoate (PHA) is 20 to 70% by mass and the content of the biodegradable polymer is 30 to 80% by mass based on the total weight of the plant growth promoter.

13. A composition for promoting the growth of plants, comprising the plant growth promoter according to any one of claims 1 to 12.

14. The composition for promoting the growth of plants according to claim 13, wherein the content of the plant growth promoter is 0.001 to 10% by mass based on the total weight of the composition for promoting the growth of plants.

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