JPH0714286B2 - Method for producing gel-coated seed - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing gel-coated seeds.

(Prior Art) In general, seeds of plants (hereinafter simply referred to as seeds) are sowed directly on the soil of this field or seeded in advance on the nursery. When seeding on the nursery, the seeds are raised to a certain extent on the nursery and then transplanted to this field. However, in the case of direct sowing, the seeds are susceptible to diseases through the soil, and when the seed particles are minute, such as salad rapeseed, they are often washed away by rainwater or irrigation. Furthermore, in the case of direct sowing, the seeds are close to the topsoil, so they are often eaten by birds and other animals, and in order to prevent these, development of special techniques has been awaited in recent years.

Heretofore, among these preventive measures, for disease prevention, a method of immersing seeds in a chemical solution, a method of impregnating chemical powder on the seed surface, a method of dry heat treatment and the like are known, but the former two methods are known. Is not necessarily a satisfactory method because it has drawbacks such as the drug not sufficiently penetrating inside the seed and the powder coating is easily peeled off. In the latter method, there is a problem of applicability depending on the heat resistance characteristics of the seeds, and if the application conditions are incorrect, the seeds may be killed.

In addition, as measures to prevent seed runoff and feeding damage by animals,
It is known that a so-called coated seed is obtained by coating the surface of the seed with a coating agent to form large grains. By using coated seeds, it is possible to further easily and accurately sow the seeds by machine or manual work, and a fungicide,
Many studies and proposals have been made on coated seeds in recent years because of the advantage that insecticides, animal repellents, nutrients (fertilizers) and the like can be added to coating agents.

That is, as a basic material for seed coating, a material similar to clay or clay minerals, a mixture of fine sand and paraffin, a mixture of sand and sugar, etc. are known, and it is also known to use a gel as a seed supporting material. ing. Techniques using gels as seed-bearing materials are described in, for example,
55-3796 or JP-A-54-49807.

That is, the one disclosed in the former uses an aqueous gel as a growth medium of a plant or a storage medium in the case of transferring a plant, and the gel without adding water necessary for the growth or transfer period of the plant separately. It is to be supplied from the water in the inside, and as a suitable gel, clay-based gel, natural gel, synthetic organic gel, etc. are used, and it is said that it has a characteristic that it can be molded into a suitable three-dimensional shape such as a small bowl or tray shape. There is. The latter is related to hydroponics of paddy rice seedlings, and the seeds are gelled by supplying an aqueous solution of a gelatinous substance that gels when cooled to seeds (for example, a warmed aqueous solution of a polysaccharide). It is described that the layer is covered and retained, and it is said that the moisture necessary for preventing unexpected transfer of seeds during cultivation and for germination and growth of seeds can be supplied from the moisture in the gel as in the former case.

(Problems to be Solved by the Invention) Generally, as germination conditions of seeds, three requirements of water, temperature, and oxygen are indispensable requirements, but they were coated with the above-mentioned conventionally known coating agent or aqueous gel. In seeds,
Even if the two requirements of water content and temperature can be satisfied, a decrease in germination rate cannot be avoided because the supply of oxygen is limited by the water film. Further, when the seeds are held in a gel in a wet state where oxygen supply is insufficient for a long period of time, the seeds swell and so cannot be used for the purpose of long-term storage or the like.

The present invention has been made by paying attention to the conventional problems relating to coated seeds, in particular, the above-mentioned problems of gel-coated seeds, and it is possible to utilize the various advantages characteristic of gel-coated seeds as they are, and long-term storage of seeds is possible. It is an object of the present invention to provide a method for producing gel-coated seeds which is capable of supplying oxygen sufficiently to seeds and does not inhibit germination growth.

(Means for Solving the Problems) That is, the method for producing a gel-coated seed of the present invention is, as described in claim 1, in an aqueous gel in which a large number of fine bubbles are formed by stirring treatment. After the plant seeds are held, freeze-drying is performed to form pores in the aqueous gel film.

It is preferable to add a drug necessary for the growth of plant seeds to the aqueous gel to carry out the treatment (section 2).

The present invention will be described in more detail below.

First, seeds often differ in germination rate depending on the type of plant, and thus a pretreatment is usually performed to promote germination. As the pretreatment method, in addition to a method of immersing the seed in a solution of a germination accelerator such as gibberellic acid, a seed coat abrasion method, a high temperature treatment or a low temperature treatment method is appropriately selected according to the characteristics of the seed. On the other hand, the aqueous gelling agent is mixed with pure water so as to have a concentration of 4 to 10% by weight (hereinafter,% means% by weight), and left to stand for 1 to 2 hours to sufficiently swell with water and then stirred. To obtain a uniform fluid having strong viscosity. The aqueous gelling agent that can be used here is not particularly limited as long as it is a substance having such properties, and can be used in a wide range from natural gels, synthetic organic gels, inorganic gels and the like. Alginic acid alkali salt, carboxymethyl cellulose alkali salt, polyacrylic acid alkali salt, etc. can be safely used without affecting not only plants but also humans.

Next, the obtained aqueous gel fluid contains nutrients necessary for plant growth such as potassium nitrate (KNO ₃ ) and ammonium hydrogen phosphate (NH ₄ H ₂ PO ₄ ), and if necessary, well-known fungicides and insecticides. , Animal repellent, etc. are added in the required amount and the viscosity is adjusted to an appropriate value for the next process.

The aqueous gel fluid is then subjected to pore remaining treatment. This treatment is a method in which a large amount of fine bubbles are included in the viscous fluid by stirring artificially with the aid of an agitating device or a bubble-generating device as in the method of foaming egg white.

Then, the viscous fluid is charged into an extruder or a syringe having a nozzle or a small hole at the tip and a syringe or other similar device, and extruded from the nozzle or the small hole to form fluid particles having a diameter of 5 to 10 mm. The gel-coated seed of the present invention can be obtained by planting the seed pretreated with.

The seeding of the fluid particles can be automatically performed by feeding the seeds using a grooved roll or the like in synchronization with the formation of the fluid particles. Further, the shape of the viscous fluid after extrusion is not limited to a particle shape, and can be formed into an appropriate shape such as a band shape or a sheet shape. When molding into a strip or sheet, the seeds are planted one by one in a strip or sheet-like viscous fluid, preferably at equal intervals.

Next, in the case of obtaining a dried gel-coated seed, the viscous fluid in which the seed is planted is freeze-dried. The freeze-drying treatment is carried out using a known freeze-drying apparatus under freezing conditions of -20 ° C to -90 ° C and a pressure of about 10 mmHg or less. This treatment gives gel-coated seeds containing a large number of pores in the dried aqueous gel. or,
By this freeze-drying treatment, the water content of the coating gel around the seeds is dried to about 3-4%.

(Operation) The manufacturing process of the gel-coated seed according to the present invention and the operation during use will be described below with reference to the accompanying drawings. First, the viscous aqueous gel fluid extruded by the extruder 1 in FIG. 1 is formed into spherical fluid particles 2. Next, the seed B is planted in the fluid particle 2 to produce a second
An aqueous gel-coated seed A ₁ as shown in the figure is obtained. This aqueous gel-coated seed A ₁ is in a state in which a large number of fine bubbles 3 are contained in the fluid particle 2 as shown in the enlarged view of FIG. Then, this is freeze-dried to obtain dried aqueous gel-coated seed A according to the present invention in which the particle size is slightly reduced while maintaining the original shape as shown in FIG.

An enlarged conceptual diagram of the dried aqueous gel-coated seed A is as shown in FIG.
Is a porous substance containing both bubbles 3 contained therein by bubbles remaining treatment and bubbles generated by sublimation and vaporization of water in the gel by freeze-drying.

Generally, when seeds are stored at a temperature and humidity close to natural conditions, the germination of seeds decreases every summer. This is largely due to the high temperature and high humidity in summer, and when stored tightly with a desiccant at room temperature, even short-lived seeds can maintain germination for at least about 5 years. According to the present invention, the seeds are coated with the aqueous gel dried to a water content of 3 to 4% by freeze-drying, so that the seeds can be stored for a long time. Further, the aqueous gel around the seed, especially the dried aqueous gel has a buffering action for avoiding a large fluctuation of the seed moisture existing inside even if a large humidity change occurs in the external environment. That is, since the dried gel around the seed is porous, it has an action of repeatedly absorbing and releasing moisture according to the change in temperature and humidity of the external environment, and keeping the seed moisture constantly constant. Further, since the dry gel around the seed has excellent stability to the gel due to the addition of water, the seed according to the present invention is sown and the water around the seed is sufficiently absorbed by the dry gel around the seed so that the original It can return to a gel state and retain water to secure the water content necessary for germination of seeds. Oxygen required for germination is sufficiently supplied from a large number of pores contained in the gel, but when the gel further absorbs water, it deforms as shown in FIG. The upper part is exposed to the air, and the supply of oxygen is sufficient.

The medium for sowing the seeds according to the present invention may be not only ordinary soil but also a container such as a vat and is not particularly limited. Since seeds germinate if the three requirements of water, temperature and oxygen are adjusted, they can be treated like normal seeds.

In addition, depending on the type of seed, soil or artificial cultivation beds are unnecessary. For example, in the case of kaiware radish, seeds are generally sown directly on the urethane cultivation bed and germinated and grown by adding an appropriate amount of water, but when using the dried gel-coated seed according to the present invention, the urethane cultivation bed is not necessary. Become. That is, as the cultivation method in this case, put water to the extent that the lower half of the seed is immersed in a large vat,
Seed at an appropriate interval in this. After a while, the dried gel around the seed absorbs water and restores to the original gel,
As time passes, the gel further absorbs water and becomes a viscous fluid as shown in FIG. In this state, the seeds can move, but they are fixed to some extent by the viscosity of the fluid, and they exert a sufficient function as a nursery bed. Further, the water, nutrients and the like required for germination and growth of seeds are sufficiently supplied from the fluid, and the complexity of replenishing them again is eliminated.

When sowing seeds, for example, turf seeds on slope soil, conventional seeds are suspended in a fluid gel composed of a vinyl acetate superabsorbent resin, etc., and precision seeding is performed using a fluid seeder. However, if the gel-coated seed according to the present invention is formed into a sheet shape and used in such a case as well, it is possible to perform seeding easily and inexpensively without requiring a special device, Subsequent work management is also simplified.

(Effects of the Invention) Since the present invention has been described in detail above, various advantages and effects as listed below can be obtained.

(1) Since the seed produced by the present invention has a large number of micro bubbles and is coated with an aqueous gel in which pores are formed by freeze-drying treatment, it is possible to supply oxygen required for seed germination. In addition to being easy, it serves as a buffer medium for the external environment of the seed, and the moisture environment is kept constant.

(2) The seed moisture covered with the freeze-dried aqueous gel can be constantly maintained at a low moisture level and can be stored for a long period of time.

(3) Since a germicide, an insecticide, an animal repellent, a nutrient and the like can be mixed in the aqueous gel in advance, the pretreatment of seeds can be facilitated.

(4) The dried aqueous gel easily returns to its original gel state by absorbing water, and thus can be used as a simple medium.

(5) Since this simple medium has strong viscosity and adhesiveness, it can be used for wall surfaces and steep slopes.

(6) The method for producing coated seeds according to the present invention can be easily carried out, and the granularly shaped seeds can be used for both manual sowing and sowing with a seeder, and the sheet-shaped seeds can be used. It can be suitably used for sowing on wall surfaces and slopes.

[Brief description of drawings]

FIG. 1 is an explanatory view of a molding state of an aqueous gel fluid particle in a production process of the present invention, FIG. 2 is a conceptual view of an aqueous gel-coated seed according to the present invention in which a seed is planted in the aqueous gel fluid particle of FIG. FIG. 4 is an enlarged conceptual diagram of the aqueous gel-coated seed of FIG. 2, FIG. 4 is a conceptual diagram of the gel-coated seed of the present invention in which the aqueous gel-coated seed shown in FIG. 2 is freeze-dried, and FIG. FIG. 4 is an enlarged conceptual diagram of the gel-coated seed shown in FIG. 4, and FIG. 6 is a conceptual diagram of the state in which the aqueous gel-coated seed according to the present invention is deformed by water absorption. A ₁ …… Aqueous gel-coated seed, A …… Dried aqueous gel-coated seed, B …… Seed, 1 …… Extruder, 2 …… Aqueous gel coated particle, 2 ′ …… Dry gel, 2 ″ ... … A water-absorbing gel.

Claims (2)

[Claims] 1. A gel-coated seed, characterized in that a plant seed is retained in an aqueous gel in which a large number of microbubbles are formed by stirring treatment, and then pores are formed in the aqueous gel film by freeze-drying. Production method. 2. The method for producing a gel-coated seed according to claim 1, which is carried out by adding an agent necessary for the growth of plant seeds to the aqueous gel.