JP2002305975A - Biodegradable plant supplement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a less-expensive plant supplement which slowly supplies water and nutrients to a plant and is finally led to biological decomposition with bacteria, by developing a single natural water-absorbing polymer having high water-absorbing performance, able to slowly release water and material and gelling only by adding water at normal temperature, and by discovering and using a natural water-absorbing polymer biodegradable with bacteria. SOLUTION: The biodegradable plant supplement is composed of a gel water- holding body produced by allowing a radiation-crosslinked body of γ- polyglutamic acid or a γ-polyglutamic acid salt to hold water or an aqueous solution of a plant supplement. The examples of the plant supplement include plant nutritional substances, plant medical substances, plant disease preventive substances, plant hormone substances, other plant additives, or the like. Especially, by using γ-polyglutamic acid or γ-polyglutamic acid salt produced by a γ-polyglutamic acid-producing bacterium, a natural and safe plant supplement can be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a plant supplement such as water and plant supplements (plant nutritional substances, plant medicinal substances, plant preventive substances, plant hormone substances, etc.) for agricultural and horticultural use. -A gel-like water retaining body is formed by retaining water or an aqueous solution of a plant replenishing substance in the radiation cross-linked body of polyglutamic acid or γ-polyglutamate, and the gel-like water retaining body is brought into contact with soil or plants to irrigate cultivated plants And biodegradable plant supplements that supply plant supplements slowly.

[0002]

2. Description of the Related Art In recent years, plants and plants such as flowers and vegetables have often been grown in pots and planters in order to obtain moisture. Also, as their hobbies grow deeper, some people grow bonsai and use their holidays to grow their home gardens.

[0003] The most troublesome thing in such farming and horticulture is that when the house is left for a long period of time on a trip or a business trip, it becomes impossible to spray water on the cultivated plants or fertilizer. Of these, watering must be done daily, which is particularly troublesome. Sometimes they ask their neighbors to water them, but if they can't afford it, they often die their cultivated plants.

[0004] Therefore, in order to allow the cultivated plants to be replenished with water for a certain period of time even when unmanned, water is absorbed by a water-absorbing polymer and dispersed in soil. If the water-absorbing polymer absorbs water, the water is slowly released from the water-absorbing polymer, and it becomes possible to supply a suitable amount of water to the roots of the plant for a long time.

As a soil water retention agent utilizing such a water-absorbing polymer, Japanese Patent Application Laid-Open Nos. 5-339567 and
No. 191777 is disclosed. Inorganic fertilizers and organic fertilizers are dissolved in the water of the water-absorbing polymer, and nutrients are absorbed by cultivated plants together with the absorption of water.

[0006]

However, most of the water-absorbing polymers conventionally used are synthetic polymers used for sanitary articles such as disposable diapers and sanitary articles. For example, hydrolysis product of starch-acrylonitrile graft polymer, neutralized product of starch-acrylic acid graft polymer, saponified product of vinyl acetate-acrylate copolymer, acrylonitrile copolymer or acrylamide copolymer Or cross-linked products thereof, acrylate-acrylate copolymers, self-cross-linked sodium polyacrylate, cross-linked polyacrylic acid partially neutralized products, and the like.

[0007] These water-absorbing polymers exhibit excellent water-absorbing power and can absorb 100 to 1000 times their own weight. However, these water-absorbing polymers are water-insoluble substances and are synthetic high-molecular polymers that cannot be decomposed by soil bacteria. In other words, it does not decompose spontaneously even if left in the soil, so it must be collected after the water runs out. In addition, since it is a synthetic polymer compound that does not exist in nature, it has a drawback of being incompatible with the environment.

[0008] Therefore, from the standpoint of environmental protection, a technology utilizing a natural water-absorbing polymer, for example, a natural polysaccharide, has been expected. As a pirate of this technology, Japanese Patent Application Laid-Open No. 60-5844
No. 3 has developed a water retention agent using natural polysaccharides. Natural polysaccharides include carrageenan, locust bean gum,
Xanthan gum, konjac mannan and the like.

However, these natural water-absorbing polymers have a drawback that the water absorption is about 100 times their own weight and is considerably smaller than the water absorption of the synthetic water-absorbing polymer. With such a low water absorption rate, it is necessary to dissolve the supplementary substance at a high concentration, but in this case, a high concentration of the supplementary substance is supplied to the plant, and there is a risk that the plant will die.

In addition, heating is an essential condition for gelling agar or carrageenan, and there is a drawback that it cannot be used as a replenishing substance that is altered by heating. Under these conditions, a water retention agent in which a polysaccharide produced by the microalga Polyphyllium kruentum is entangled with the carrageenan has been developed as JP-A-6-254393 in order to improve the water absorption.

It is stated that the water absorption is improved by intertwining the polysaccharide produced by the microalga Polyphyllium kruentum with the carrageenan. But,
The culture of the microalga Polyphyllium kruentum is suitable for desert climate, so it is difficult to set conditions for mass production in Japan.
In addition, this water retention agent has a drawback that the production cost is high because two types of natural high molecular polymers are combined through multiple steps, and that it is difficult to spread to general households.

Accordingly, the present invention has developed a single kind of natural water-absorbing polymer which has high water absorption and hydrogelation performance at room temperature, has a sustained release of water and a sustained release of a substance, and is biodegradable by bacteria. An object of the present invention is to provide an inexpensive plant growth agent that is finally biodegraded by bacteria while gradually supplying water and plant nutrients to plants by discovering and utilizing the natural water-absorbing polymer to be used.

[0013]

According to the first aspect of the present invention, a γ-
A biodegradable plant supplement characterized by comprising a gel-like water retention body in which water is retained in a radiation crosslinked product of polyglutamic acid or γ-polyglutamate.

A second aspect of the present invention is a biodegradable biodegradable solution comprising a gel-like water retaining body in which an aqueous solution of a plant supplement is retained in a radiation cross-linked product of γ-polyglutamic acid or γ-polyglutamate. It is a plant supplement.

[0015] The invention of claim 3 is the biodegradable plant supplement according to claim 2, wherein the plant supplement is a plant nutritional substance, a plant medicinal substance or another plant additive.

The invention of claim 4 is the biodegradable plant supplement according to claim 1 or 2, wherein the γ-polyglutamic acid or γ-polyglutamate is produced by a γ-polyglutamic acid-producing bacterium.

The invention according to claim 5 is the biodegradable plant supplement according to claim 1 or 2, which mainly comprises a radiation-crosslinked γ-polyglutamic acid or γ-polyglutamate having a molecular weight of 10,000,000 or more. It is.

According to a sixth aspect of the present invention, the gel-like water retaining body is sealed in a container, and the opening of the container is opened to bring the gel-like water retaining body into contact with the soil during use. It is a degradable plant supplement.

The invention of claim 7 is the biodegradable plant supplement according to claim 1 or 2, wherein the gel-like water retaining body is brought into contact with soil when used.

[0020] The invention of claim 8 is the biodegradable plant supplement according to claim 1 or 2, wherein the gel-like water retaining body is brought into contact with a seed or a plant.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the biodegradable plant supplement according to the present invention will be described in detail.

The present inventors have conducted intensive studies on natural polymers having high water absorption and sustained release of water. As a result, a radiation cross-linked product obtained by irradiating γ-polyglutamic acid or γ-polyglutamate has a high water absorption. It has been found that the present invention has the property of sustained release of water and the present invention, and has completed the present invention.

Generally, γ-polyglutamic acid is (—NH
(COOH) represented by substances _{CH-CH 2 -CH 2 -CO-)} n, subscript n gives the degree of polymerization. The starting material of the present invention, γ-polyglutamic acid, has a large molecular weight, especially those having a molecular weight of several hundred thousand to several million are preferable.
These molecular weights are variably adjusted by the degree of polymerization n. As described above, γ-polyglutamic acid having a large molecular weight has a greater water retention ability when crosslinked by radiation.

As the γ-polyglutamic acid according to the present invention, those produced by various production methods are used. Examples of the production method include a culture method using a microorganism and a chemical synthesis method. Γ-polyglutamic acid produced by microorganisms is a natural substance and is recommended from the viewpoint of safety.

In the microorganism culturing method, bacteria such as Bacillus subtilis, Bacillus anthracis, Bacillus megaterium, Bacillus natto and the like can be used. In particular, the F-2-01 strain of Bacillus subtilis is preferable in terms of production amount. It is. This strain produces .gamma.-polyglutamic acid having a molecular weight of hundreds of thousands to several millions and has a relatively large molecular weight, so that a crosslinked product can be efficiently produced by radiation.

The γ-polyglutamic acid produced by microorganisms is a natural product that is harmless to humans and livestock, and has a great feature of being biodegradable, as it has been eaten as a main component of natto sticky substance since ancient times. In other words, this γ-polyglutamic acid is excellent not only in that it has biodegradability, but also has no harm even if it is eaten accidentally, and conversely becomes a nutrient. Therefore, when added to a plant, it means not only safe for the plant itself, but also safe for humans and animals that feed on the plant.

The γ-polyglutamic acid produced by the microorganism is a linear γ-peptide having no branch and is a copolymer of L-glutamic acid and D-glutamic acid, that is, a heteropolymer. Γ-polyglutamic acid having this heteropolymer structure is the most suitable for use in the present invention.

The γ-polyglutamic acid produced by the microorganism is obtained by inoculating a microorganism in a liquid medium mixed with required nutrients, culturing at a required temperature for a required time, and isolating γ-polyglutamic acid from the culture solution. A solid medium other than the liquid medium may be used. In the present invention, not only γ-polyglutamic acid alone but also a culture solution itself or a culture containing γ-polyglutamic acid obtained by precipitation from the culture solution may be used.

As the chemically synthesized γ-polyglutamic acid, polymers having various structures such as a homopolymer of L-glutamic acid, a homopolymer of D-glutamic acid, and a mixture of these homopolymers are produced. These chemically synthesized γ-polyglutamic acids can also be used in the present invention.

The γ-polyglutamate used in the present invention is formed as a salt by a neutralization reaction between γ-polyglutamic acid and a basic compound. γ-polyglutamic acid and a basic compound are dissolved in a solvent such as water at room temperature, and efficiently produced by stirring with heating. Examples of the basic compound include hydroxides of alkali metals and alkaline earth metals, such as sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, and organic basic compounds such as amines. There is.

The heating temperature is preferably 5 to 100 ° C. under the reaction conditions of γ-polyglutamic acid and the basic compound.
If the temperature is lower than 5 ° C., the reaction will be slow. If the temperature is higher than 100 ° C., water, which is a kind of solvent, will boil and the reaction may not be stable.
Further, the pH is preferably in the range of neutral to basic, particularly pH.
Is preferably in the range of 5 to 10. Further, the amount of γ-polyglutamic acid and the basic compound is suitably a stoichiometric reaction amount without excess or deficiency.

As the γ-polyglutamic acid or γ-polyglutamate used in the present invention, those having a molecular weight of several hundred thousand to several million are suitable. In the case of microbial production, its molecular weight ranges from several hundred thousand to several million. Even in the case of chemical synthesis, those polymerized to hundreds of thousands or more are suitable.

In the present invention, the above-mentioned γ-polyglutamic acid or γ-polyglutamate is crosslinked by radiation to produce a crosslinked product having a molecular weight of 10,000,000 or more.

When this γ-polyglutamic acid is irradiated with radiation, CH ₂ is converted to CH— by a dehydrogenation reaction, and two straight chains of γ-polyglutamic acid are bonded via CH-HC, and [(—NH ( _{COOH) CH-CH-CH 2} -CO
-) It is considered to be crosslinked as in _n ] ₂ . When the degree of cross-linking is further increased, [(—NH (COOH) CH—
A radiation crosslinked product having a high molecular weight such as CH—CH ₂ —CO—) _n ] _m is produced. Here, m indicates the degree of crosslinking and gives the number of linear chains of γ-polyglutamic acid to be cross-linked.

By increasing the degree of crosslinking m, γ-
The molecular weight of the radiation crosslinked polyglutamic acid is set to 10,000,000 or more. Since γ-polyglutamic acid is a polypeptide chain, it has a network structure in which a large number of large spaces are formed inside by the connection of —CH—HC—.

The present invention has been made by discovering that a radiation crosslinked product of γ-polyglutamic acid has an extremely large water absorbing ability. It was confirmed that the water absorption reached about 1000 times, which was almost the same as the water absorption of the conventional superabsorbent polymer. The present invention dissolves plant supplements such as fertilizers and vitalizers in this water, and converts this solution to γ-
This is based on the idea of retaining water in a radiation crosslinked product of polyglutamic acid or γ-polyglutamate.

Although γ-polyglutamic acid and γ-polyglutamate do not themselves have a water-retaining property, the reason why the radiation crosslinked product has a water-retaining ability is considered as follows. As described above, it is considered that the network structure formed by the CH-HC bond forms a large number of bag-like spaces inside, and the absorbed moisture is stored in these bag-like spaces. Therefore, it is considered that the solution of the plant supplementary substance is also stored in the bag-like space, and the larger the bag-like space, the higher the water absorption.

The present invention is characterized in that radiation is used to crosslink γ-polyglutamic acid. When crosslinking is carried out by a thermochemical reaction, a high temperature is required, so that γ-polyglutamic acid or γ-polyglutamate as a raw material is susceptible to thermal denaturation. When radiation crosslinking is used, crosslinking can be performed at a low temperature, so that crosslinking can be realized without altering γ-polyglutamic acid. Therefore, a crosslinked γ-polyglutamic acid containing no denatured product can be obtained by radiation crosslinking.

In particular, γ-polyglutamic acid produced by microorganisms is a kind of polypeptide, and it is difficult to employ heat crosslinking, judging from the weak heat of amino acids. Considering that the viscous substance of natto is γ-polyglutamic acid,
You can understand the situation of heat denaturation when natto is heated. Therefore, the present invention is characterized in that radiation crosslinking is used to realize low-temperature crosslinking.

In addition to irradiating γ-polyglutamic acid or γ-polyglutamate alone, a culture solution or culture obtained by culturing a microorganism is irradiated with γ-polyglutamic acid or γ-polyglutamic acid. A radiation cross-linked form of the salt can be obtained.

As radiation for crosslinking, α-rays, β-rays, γ-rays
A line, an X-ray, an electron beam, a neutron beam, a meson beam, an ion beam and the like can be used. Among them, γ-ray,
X-rays and electron beams are preferred. As X-rays, both X-ray tube and non-tube types can be used, and radiated light radiated from an electron ring that has been widely used in recent years can also be used. For the electron beam, a known electron beam irradiation device can be used according to the beam energy.

Gamma rays are excellent in that a radiation source can be used. Cobalt 60, strontium 9
0, zirconium 95, cesium 137, cerium 14
1, ruthenium 177 and the like, but cobalt 60 and cesium 137 are preferable from the viewpoint of half-life and energy.

In the present invention, γ-polyglutamic acid or γ
-By radiation crosslinking of polyglutamate,
A radiation crosslinked γ-polyglutamic acid or radiation crosslinked γ-polyglutamate having a molecular weight of 10,000,000 or more is produced. When the molecular weight is crosslinked to 10,000,000 or more, the water absorption performance of the crosslinked γ-polyglutamic acid is sharply increased, and the characteristics of the plant supplement are improved.

To crosslink γ-polyglutamic acid or γ-polyglutamate to a molecular weight of 10,000,000 or more, γ-polyglutamic acid or
Irradiation of 1 to 500 kGy at an absorbed dose is required for the polyglutamic acid raw material. Crosslinking does not progress easily at 1 kGy or less, and crosslink progresses too much at 500 kGy or more, so the internal space formed by the network structure of the crosslinked body Becomes smaller, and conversely, the water absorbing power decreases. From the viewpoints of crosslinkability and water absorption, the absorbed dose is 5 to 10
0 kGy is more preferred.

Generally, γ-polyglutamic acid salt is soluble in water, but γ-polyglutamic acid is known to be insoluble in water. However, when radiation crosslinking is applied to both γ-polyglutamic acid and γ-polyglutamate, the surface of the radiation crosslinked product has an affinity for water or a water-containing organic solvent such as water-containing alcohol or water-containing acetone. Have been discovered by the present inventors.

The present invention has been made by paying attention to the property of surface modification of radiation-crosslinked γ-polyglutamic acid and γ-polyglutamate by radiation crosslinking. That is, by forming a radiation crosslinked product, both γ-polyglutamic acid and γ-polyglutamate have hydrophilicity.

This property means that the radiation crosslinked product of both substances dissolves in a large amount of water. However, in the intermediate state before dissolution, it means that water is absorbed to maintain a gel state or a sol state. According to our experiments,
It is known that the gel absorption is maintained up to about 1000 times as to the water absorption with respect to pure water, and when the amount of pure water is further increased, the state shifts to the sol state and gradually changes to a solution.

Further, both of the γ-polyglutamic acid radiation cross-linked product and the γ-polyglutamate radiation cross-linked product have a sustained-release property of water that, when left in a water-absorbing state, gradually releases water from the surface. Moreover, it was found that the sustained release of water was considerably larger than that of the conventional water-absorbing polymer.

In other words, both the γ-polyglutamic acid radiation cross-linked product and the γ-polyglutamate radiation cross-linked product have a unique property of gradually giving absorbed water to plants. The discovery of this sustained release of water has completed the present invention. This property is not only drying and evaporation from the surface but also releasing water as liquid water, which is a unique property not found in conventional water-absorbing polymers.

That is, it was confirmed by an experiment that plant hair roots enter into the γ-polyglutamic acid radiation cross-linked product and the γ-polyglutamate radiation cross-linked product, and water is returned to the plant by the water absorption of the hair root. . Therefore, it is a feature of the present invention that the γ-polyglutamic acid radiation cross-linked product and the γ-polyglutamate radiation cross-linked product have sustained water release as well as water absorption (water retention).

A further feature of the present invention is that the radiation crosslinked γ-polyglutamic acid and the radiation crosslinked γ-polyglutamate have biodegradability. That is, both of these substances have a property of being decomposed by bacteria and finally decomposed to plant nutrients. In particular, when γ-polyglutamic acid produced by microorganisms is used, the raw material is safe as a natural substance and is decomposed into nutrients that are ultimately absorbed by the plant. Supplies can be provided.

Even if the conventional water-absorbing polymer has a high water-absorbing power, it is a chemically synthesized product and is not decomposed by bacteria. The result is harm. In contrast, γ-polyglutamic acid radiation cross-linked products and γ-polyglutamate radiation cross-linked products have water absorption, sustained release of water and biodegradability, so it is clear that they are the most suitable plant supplements for the environment. is there.

The present invention is a biodegradable plant supplement obtained by absorbing water or an aqueous solution of a plant supplement to a radiation crosslinked product of γ-polyglutamic acid or γ-polyglutamate. In the present invention, plant supplements include plant nutrients such as fertilizers and vital substances, including water, plant medicinal substances necessary for treatment of plant diseases, plant preventive substances for preventing plant diseases, and other plant artificial substances. And the like, and plant supplements are those obtained by absorbing these plant supplements as aqueous solutions into radiation-crosslinked γ-polyglutamic acid or γ-polyglutamate.

As described above, in the present invention, water is considered as a kind of plant supplement, and a substance obtained by absorbing a simple substance of water into a radiation cross-linked body of γ-polyglutamic acid or γ-polyglutamate is also referred to as a plant supplement. Water is an essential substance that must be consumed daily for plants, and there is no reason to exclude water alone. .

In the present invention, water or an aqueous solution of a plant supplement is absorbed into a radiation-crosslinked γ-polyglutamic acid or γ-polyglutamate to form a gel. This radiation-crosslinked gelled γ-polyglutamic acid or γ-polyglutamate is referred to as a gel-like water retaining body.

When this gel-like water retaining body is placed on the surface of the soil where plants are grown or buried in the soil, the roots of the plants stick to the gel-like water retaining body, and the water or aqueous solution is absorbed by the water absorbing power. I will do it. Water or aqueous solution decreases at a rate determined by the balance between the water retention capacity of the gel-like water retention body and the water absorption capacity of the roots. The operation ends when the water or the aqueous solution is exhausted. If the rate of this decrease can be adjusted and changed, for example, from 3 days to January, the plants can survive without withering even in the absence of a maximum of January.

Further, even if the gel-like water retaining body is arranged not only in contact with the soil but also in contact with the root of the plant, the plant can absorb water and can survive without withering for a predetermined period. Furthermore, if plant seeds are placed on the gel-like water retaining body, the seeds can germinate on the gel-like water retaining body.

When the gel-like water retaining body is filled in a container and sealed, the gel-like water retaining body can be stored for a long time because there is no diffusion of water. Therefore, the sale of the gel-like water retaining body may be performed by sealing it in a container. Alternatively, a container, a plant supplement, and a radiation cross-linked body of γ-polyglutamic acid or γ-polyglutamate may be prepared separately, and water may be added as needed to form a solution, absorbed, and stored in the container. . Also, excluding the container, prepare a radiation-crosslinked body of a plant supplement and γ-polyglutamic acid or γ-polyglutamate, mix these with water to form a gel-like water retention body, Various forms such as placing a water retaining body on the soil surface can be adopted.

When the container is sealed, it is only necessary to open the opening (lid) and then bury the opening in the soil.
The roots of the plant move in the direction of the opening and absorb water or aqueous solution from the container.

[0060]

EXAMPLES Example 1 Production of Radiation Crosslinked Product of γ-Polyglutamic Acids As γ-polyglutamic acid-producing bacteria,
Bacillus subtilis F-2-01 was selected. The liquid medium was placed in a 1 × 10 ³ m ³ container for mass production. The medium composition was configured as follows. Glucose 0.5% by weight L-glutamic acid 8.0% by weight Peptone 0.7% by weight Urea 0.68% by weight NaNO3 0.5% by weight KH2PO4 0.24% by weight Purified water

The above strain was inoculated into this liquid medium,
After adjusting H to 7.5, it was kept at a constant temperature of 37 ° C. If the culture is continued for 6 days with aeration and stirring, γ-polyglutamic acid and its salts accumulate in the culture solution. The culture was centrifuged to separate cells from the culture, and the γ-polyglutamic acids were further isolated.

The production amount of γ-polyglutamic acid depends on the culture conditions, but is 5 to 50 (g / g) in the culture solution.
L), which proves that industrial mass production of γ-polyglutamic acids is possible. Also,
The molecular weight of the produced γ-polyglutamic acids is 500,000-
It turned out that it distributed to 2 million. Where γ-
The polyglutamic acids are a generic term for acids, salts or mixtures thereof.

A gamma ray of 20 kGy was applied to a 5% by weight aqueous solution of the γ-polyglutamic acid using a cobalt 60 radiation source.
(2Mrad) irradiation to produce a γ-polyglutamic acid radiation crosslinked product. The aqueous solution gels due to this irradiation, and the molecular weight of the γ-polyglutamic acid radiation crosslinked product is about 1
It was estimated to be 5 million. Dehydrate this gel-like substance to γ-
A powder of a radiation crosslinked polyglutamic acid was obtained. This powder was white. The gel-like substance and the dry powder can be used as a raw material of the gel-like water retaining body of the present invention.

Example 2 Plant Supplement Using Water as Plant Supplement According to Example 1, two types of γs having a radiation dose of 20 kGy (hereinafter referred to as 2M) and 40 kGy (hereinafter referred to as 4M) -Powder of radiation crosslinked polyglutamic acid was obtained. Tap water and soil permeated water were absorbed into 0.5 g of these two powders to produce a water-based plant supplement. At the same time, the limit water absorption was measured. Since 1 Gy is 100 rad in the old unit, 20 kGy becomes 2 Mrad and is displayed as 2M. For the same reason, 40 kGy is displayed as 4M.

The critical water absorption is shown in Table 1. <Table 1> Critical water absorption for 0.5 g of the radiation crosslinked product <2M> <4M> <Tap water> <Soil permeate> <Tap water> <Soil permeate> Water absorption (mL) 400 400 300 300 Water absorption magnification 800 800 600 600

As can be seen from Table 1, there was no difference in the water absorption limit between both tap water and soil permeated water. However, the limit water absorption capacity is 2 times larger at 800M and 4M.
Then it was 600 times. This is because 4M has an excessively high crosslinking density and a small bag-like space. This has been phenomenally proved by the fact that a 4M gel-like water retention body is harder than 2M.

Since it is desired that the gel-like water retaining body has a certain degree of hardness, it is considered that the water absorption ratio of the radiation-crosslinked γ-polyglutamic acid is preferably 100 to 500 times, and preferably 200 to 500 times. It is 300 times.

Next, for 2M and 4M, the effective moisture was reduced by the saturation method under reduced pressure (pF0) and the pressure plate method (pF1.5-2.7).
-It determined by the centrifugation method (pF3.0-4.2). The total available water (pF1.8-4.2) of the obtained pF value was 2M.
Was 68.1% and 4M was 61%, and there was no significant difference between the two. From this, it was found that most of the water contained in the radiation crosslinked product of γ-polyglutamic acids was water that worked effectively for plants. However, 2M is 4
Since the gel-like water retaining body is softer than M, 2M is considered to be superior.

Example 3 Test of Biodegradability of Water Plant Supplement The tap water prepared in Example 2 was absorbed 200 times.
M and 4M, and 2 which absorbed 200 times of soil permeated water
M and 4M were placed in a beaker by 150 mL each, and these 4
The samples were left indoors without any wrapping.
Also, in the same manner, 300 mL was placed in a beaker.
Each type of sample was lightly covered from above without tightly wrapping it, and left indoors with air flow but preventing fallout from above.

It is considered that bacteria in the soil are mixed in the soil permeated water, but there is no soil bacteria in the tap water. When the wrap is not performed, it is considered that the bacteria in the air fall. When the wrap is lightly wrapped, the bacteria in the air do not fall but there is air circulation.

The change without wrap was observed for 58 days and the results are summarized in Table 2. <Table 2> Changes when left without wrap <Soil permeated water><Tapwater> 2M Solidified to stick to the bottom, but was sticky. Solidified flat. The spoon stuck in the beaker. 4M Solidified into granules, brown. Solidified into a fine flat plate.

The change with a loose wrap was observed for 40 days and the results are summarized in Table 3. <Table 3> Changes when lightly wrapped <Soil permeated water><Tapwater> 2M Most muddy. There is cloudiness. As loose as tap water. Quite watery. 4M Second cloudy. Not cloudy. Somewhat hard eyes. Hard.

In the case where the lapping was not performed, the deposition was similarly reduced and solidified in about 2 weeks for all the samples. When soil permeated water was used, it tended to color as the volume decreased, and to solidify faster than when tap water was used. Therefore, it can be seen that the sample is reliably biodegraded by airborne bacteria and soil bacteria.

When lightly wrapped, there was almost no loss in any of the beakers, but the soil permeated water tended to be turbid and the tap water tended to be less turbid. Also, 2M tends to be soft,
4M tended to be hard.

That is, when there is no lap completely, 2
In a week, it was broken down and solidified so as to stick to the bottom of the beaker, but even if it was lightly wrapped, the hardening did not occur, and the volume hardly changed from the start of the experiment. This indicates that the bacteria in the air descend and perform the main decomposing action. It is thought that the soil bacteria contained in the soil permeate show an auxiliary decomposition effect.

Overall, γ-polyglutamic acids are originally easily decomposed, but when exposed to the outside air, they are decomposed by microorganisms in the outside air to be reduced in molecular weight. When the molecular weight was reduced, it was difficult to retain water, so that the evaporation was severely solidified, particularly in the case of an unwrapped sample. Conversely, it is considered that the wrapping alone can suppress the decomposition of microorganisms and the evaporation. Therefore, from this experiment, it can be determined that the plant supplement according to the present invention is finally decomposed by bacteria and is nontoxic and harmless to the environment.

[Example 4: Plant growth test with water plant supplement] Three komatsuna pots are prepared. In addition, two α-type containers having a narrow bottom opening and two β-type containers having a wide bottom opening were prepared. The tip openings of the two containers have the same area. The α-type container was inverted in one Komatsuna pot, the β-type container was inverted in another Komatsuna pot, and nothing was done in the last pot.

Tap water (60 mL) was retained in 0.3 mL of the 2M γ-polyglutamic acid radiation crosslinked product to form a 200-fold gel-like water retaining body. 30 mL of this gel-like water retaining body was put into the α-type and β-type containers, and the growth state of Komatsuna was observed.

Observation for 4 days showed that the α-type and β-type komatsuna were alive, but the komatsuna in the untreated pots had completely withered. In the komatsuna on which the gel-like water retaining body is placed, it can be seen that water is slowly transferred from the gel-like water retaining body to the root of the komatsuna. This proved the effect of the plant supplement that absorbed tap water.

[Example 5: Gel-like water retention test of liquid fertilizer] First, radiation-crosslinked γ-polyglutamic acid was prepared using a commercially available liquid fertilizer (trade name “Hana Plant”, manufactured by Takeda Pharmaceutical Co., Ltd.). It was tested whether a gel-like water retaining body could be formed.

The composition of the liquid fertilizer was 5% nitrogen, 10% water-soluble phosphoric acid,
%, Magnesia 0.08%, manganese 0.002%, boron 0.008%, and the remaining amount of purified water.

10 times, 100 times, 100 times of this liquid fertilizer
A 0-fold diluted solution is prepared, and the diluted solution is added to a 2M γ-polyglutamic acid radiation cross-linked product by 100 times, 200 times, 300 times,
It was tested whether the water was retained up to 400, 500 and 1000 times to form a gel. The results are given in Table 4.

<Table 4> Gelation test of liquid fertilizer <Fertilizer dilution ratio> <Water retention ratio> <Result> 10 times 100 times slightly hard sol 100 times 100 times gel 100 times 200 times sol 100 times 300 times not coagulated 100 1000 times 200 times hard gel 1000 times 300 times slightly hard gel 1000 times 400 times sol 1000 times 500 times sol 1000 times 1000 times without coagulation

As is clear from Table 4, gelling is difficult because 10-fold dilution is too thick. Gelling can be managed with 100-fold dilution. A 1000-fold diluted solution has a water retention capacity almost equal to that of water. If the gel is formed at a practical concentration, the gel-like water retaining body of the present invention can be used as a medium that does not use soil.

Example 6: Growth test of liquid fertilizer with plant supplement [gamma] -polyglutamic acid was irradiated with 2 Mrad of gamma rays, and a gelatinous water retaining body was formed with a 500-fold dilution of the liquid fertilizer. Komatsuna seeds (Tohoku Co., Ltd. for 2000) are placed on this gel-like water retaining body.
Germinated and grown.

In a greenhouse for plants set at 20 ° C., growth was observed while maintaining a constant illuminance with a fluorescent lamp. After sowing the seeds, the roots emerge two days later and gradually absorb nutrients three to four days later, and blue foliage emerges. After that, it grows in that state.

This gel-like water retention body was confirmed to be effective in supplying nutrients simultaneously with water. It was also found that it could be used as a medium instead of soil, not just as an auxiliary placed on the soil surface.

Example 7 Growth and Degradation Test of Liquid Fertilizer with Plant Supplement Irradiation of γ-polyglutamic acid with 4 Mrad of gamma rays, and gelation of the liquid fertilizer with a 100-fold dilution of the liquid fertilizer up to 500 times A water retention body was used. Komatsuna seeds (Tohoku Co., Ltd., 2000) were placed on the gel-like water retaining body, allowed to germinate and grow, and then the state of decomposition was observed.

In a plant greenhouse set at 20 ° C., the growth was observed while maintaining a constant illuminance with a fluorescent lamp. After sowing the seeds, the roots emerge two days later and gradually absorb nutrients three to four days later, and blue foliage emerges. Then the blue leaves stand up. Although he keeps growing for about 10 days, he can't bear the weight and sleeps sideways. Among them, those that cannot be touched by the air begin to rot. When the plant begins to rot, the bacteria also break down γ-polyglutamic acid itself,
The viscosity is lost.

From these results, it is possible to replenish water and nutrients simply by placing the gel-like water retaining body on the surface of the soil or burying it in the soil without using a plastic container, and furthermore, by adding bacteria. It was confirmed that the whole was decomposed.

The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications and design changes without departing from the technical idea of the present invention are included in the technical scope. No.

[0092]

According to the first aspect of the present invention, since the radiation cross-linked body of γ-polyglutamic acid or γ-polyglutamate is composed of a gel-like water retaining body in which water is retained, a large amount of water can be absorbed. Instead, the water can be gradually released to supply the plants with water unattended for a long period of time. In addition, since the radiation crosslinked product is finally decomposed into nutrients by bacteria, it does not pollute the environment even when left undisturbed, and is incorporated into the natural circulation as plant nutrients.

According to the second aspect of the present invention, since a radiation-crosslinked body of γ-polyglutamic acid or γ-polyglutamate is composed of a gel-like water retaining body in which an aqueous solution of a plant replenishing substance is retained, the plant is supplied with water. The substances can be released gradually and the plants can be fed unattended over a long period of time. In addition, this radiation cross-linked product is finally decomposed into nutrients by bacteria, so it will not pollute the environment even if it is left as it is, it will be incorporated into the natural circulation as plant nutrients and maintain and preserve the ecosystem. Can be.

According to the third aspect of the present invention, since a plant nutrient, a plant medicinal substance or other plant additive is used as the plant supplement, not only necessary substances such as nutrients but also plant recovery caused by disease can be recovered. A pharmaceutical substance for prevention of a disease, a substance for preventing a disease, and the like can be ingested by a plant for a long period of time in an unmanned state.

According to the fourth aspect of the present invention, since γ-polyglutamic acid or γ-polyglutamate produced by a microorganism is used, a plant which is made of a very safe raw material as a natural material and which is grown with this plant supplement Is extremely safe for human beings to eat.

According to the invention of claim 5, the molecular weight is 100
As a main component, radiation crosslinked γ-polyglutamic acid or γ-polyglutamate, which is 100,000 or more, can increase water retention and supply water and nutrients to plants for a longer period of time unmanned. can do.

According to the sixth aspect of the present invention, the gel-like water retaining body is sealed in a container, and the opening of the container is opened to bring the gel-like water retaining body into contact with the soil at the time of use. Since there is no water release and water is supplied only from the opening, the unmanned period can be prolonged by the amount of unnecessary water release.

According to the seventh aspect of the present invention, since only the gel-like water retaining body is brought into contact with the soil, a plastic container or the like is not required. There is an advantage not to leave.

According to the invention of claim 8, the gel-like water retaining body can be used as a culture medium, and a substitute for soil can be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 3/28 CFG C08J 3/28 CFG C12P 21/00 C12P 21/00 // C08L 77:04 C08L 77: 04 F term (reference) 2B022 AA05 BA21 BA24 BB02 4B064 AG01 BA18 CA02 DA11 4F070 AA01 AB13 AB17 AB22 AC12 AD10 CB14 HA03 HA04 HA05 HB01 4H061 AA01 DD04 EE35 FF05 HH03 HH14 KK07

Claims (8)

[Claims] 1. A biodegradable plant supplement comprising a gel-like water retaining body in which water is retained in a radiation cross-linked body of γ-polyglutamic acid or γ-polyglutamate. 2. A biodegradable plant supplement comprising a gel-like water retaining body in which an aqueous solution of a plant supplement is retained in a radiation cross-linked product of γ-polyglutamic acid or γ-polyglutamate. 3. The biodegradable plant supplement according to claim 2, wherein the plant supplement is a plant nutritional substance, a plant medicinal substance or another plant additive. 4. The biodegradable plant supplement according to claim 1, wherein the γ-polyglutamic acid or γ-polyglutamate is produced by a γ-polyglutamic acid-producing bacterium. 5. The biodegradable plant supplement according to claim 1, which mainly comprises a radiation crosslinked γ-polyglutamic acid or γ-polyglutamate having a molecular weight of 10,000,000 or more. 6. The biodegradable plant supplement according to claim 1, wherein the gel-like water retaining body is sealed in a container, and the opening of the container is opened to bring the gel-like water retaining body into contact with soil when used. . 7. The biodegradable plant supplement according to claim 1, wherein the gel-like water retaining body is brought into contact with soil when used. 8. The biodegradable plant supplement according to claim 1, wherein the gel-like water retaining body is brought into contact with a seed or a plant.