JPS63209502A - gel coated seeds - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to gel-coated plant seeds.

[Conventional technology]

Generally, plant seeds (hereinafter simply referred to as seeds) are sown directly in a field or in advance in a seedbed, and in the case of seedbed sowing, the seedlings are grown to a certain extent in the seedbed and then transplanted to the field. However, in the case of direct sowing, the seeds are easily susceptible to diseases through the soil, and when the particle size of the seeds is minute, such as saladana seeds, they are often damaged by rainwater or irrigation. Furthermore, in the case of direct sowing, the seeds are located near the topsoil, so they are often damaged by birds and other animals.

Also, recently, the method of sowing has changed from hand sowing to mechanical sowing, but there are many limiting factors in mechanical sowing. The main reasons for this are ■ large seeds, ■
The shape is close to spherical, and seeds of the same type have the same shape, and the seed surface does not have hairs or horns. Furthermore, even with mechanical sowing, it is very difficult to sow 3 to 4 seeds at a time, and conventional equipment can only sow in rows, so it is necessary to perform thinning operations that require a great deal of labor as management work after sowing. I need. Therefore, it has been virtually difficult to mechanically sow irregularly shaped seeds such as carrot and spinach seeds.

In addition, methods of soaking seeds in a chemical solution, adhering chemical powder to the surface of seeds, dry heat treatment, and the like are known for preventing diseases of seeds.

However, the former two methods are not always satisfactory as they have drawbacks such as the chemicals not sufficiently penetrating inside the seeds and the powder coating being easily peeled off. There are problems with its applicability due to such factors, and if the application conditions are incorrect, there is a risk that the seeds will die.

In addition, as a measure to prevent seed loss and damage caused by animals,
It is known that the surface of seeds is coated with a coating agent to make them larger, so-called coated seeds. By using coated seeds, seeding by machine or hand can be done easily and accurately, and fungicides, fungicides,
Many studies and proposals have been made regarding coated seeds in recent years because of the advantage that pesticides, animal repellents, nutrients (fertilizers), etc. can be added to the coating agent.

In other words, clay or clay mineral-like materials, mixtures of fine sand and paraffin, mixtures of sand and sugar, etc. are known as basic materials for seed coating, and gels are also known to be used as seed carrier materials. It is being Regarding the technique of using gel as a seed supporting material, see, for example, Japanese Patent Application Laid-Open No. 55-3796 or Japanese Patent Application Laid-open No. 54-49807.
There is something disclosed in the publication No.

That is, the method disclosed in the former uses an aqueous gel as a growth medium for plants or as a storage medium when transporting plants, and the gel is produced without separately adding water necessary for the growth or transport period of the plants. Suitable gels include clay gels, natural gels, synthetic organic gels, etc., which can be molded into suitable three-dimensional shapes such as small bowls or trays. There is. The latter disclosure relates to hydroponic cultivation of rice seedlings, and involves supplying seeds with an aqueous solution of a gelatinous substance that gels when cooled (for example, a heated aqueous solution of polysaccharide) to gel the seeds. It is described that the gel is coated and retained in a layer to prevent the seeds from being accidentally transferred during cultivation, and as in the former case, the moisture in the gel can supply the moisture necessary for the germination and growth of the seeds.

In addition, Japanese Utility Model Application Publication No. 56-20409 states that water-insoluble hydrophilic gels, such as grafted products of methacrylic acid and acrylonitrile, are suitable as seed coating gels, and seeds are coated directly with these gels. tablet type,
There is a description that it can be molded into any shape such as a pellet shape or a psycho-mouth shape.

Furthermore, this coating gel is said to have the role of supplying substances such as growth hormones and fertilizers from outside the waterside.

Furthermore, Utility Model Publication No. 61-24017 describes a germinated product structure in which seeds, bulbs, etc. are coated with a water-insoluble hydrophilic gel that swells when water is applied, and holes are provided in the gel. .

Further, JP-A No. 48-85311 describes capsule seeds in which seeds and powdered nutritional substances are enclosed in easily water-soluble capsules.

[Problem that the invention seeks to solve]

However, in general, the three requirements for seed germination are moisture, temperature, and oxygen. Even if this is satisfactory, a decrease in germination rate cannot be avoided because the supply of oxygen is restricted by the water film. In order to supply this oxygen, for example, there is a method of coating seeds with calcium peroxide (Cabs), but on the other hand, it is harmful to the plants, and it is also possible to coat the seeds with calcium peroxide (Cabs). If the seeds are kept in the container, the seeds will swell and cannot be used for long-term storage purposes. In addition, if the capsule seeds are easily water-soluble, such as the capsule seeds described in JP-A No. 48-85311, the capsules will easily flow out during irrigation after sowing, and the nutrients will be washed away quickly, resulting in a long-lasting effect. cannot be expected. In addition, the present applicant has filed a patent application regarding the invention of gel-coated seeds in which seeds are coated with an aqueous gel having a large number of pores or microbubbles in order to provide sufficient oxygen for seed germination. No. 61-104910 was filed, but since this gel coating is water-soluble, there was a problem in that drugs such as nutritional substances encapsulated in the coating layer were easily washed away.

In the case of conventional gel-coated seeds, the periphery of the seeds is directly coated with gel, so the oxygen necessary for seed respiration is not sufficiently supplied, resulting in a decrease in germination rate due to lack of oxygen and an adverse effect on the storage environment. This method was developed to address the issue of deterioration of the seeds, and by forming a water-insoluble gel coating layer with air bubbles inserted around the tiny, irregularly shaped seeds, it is possible to improve the optimal quality of the seeds. The purpose of the present invention is to provide gel-coated seeds that provide a good germination environment, are compatible with mechanized sowing, and are easy to manage post-sowing operations and storage.

[Means for solving problems]

That is, the present invention involves enclosing air bubbles in contact with the surface of seeds, forming a coating layer of an aqueous gel alkaline salt solution around the bubbles, and reacting the coating layer with a divalent or trivalent metal salt solution to form a water-insoluble material. gel-coated seeds obtained by drying the gel-coated seeds, and gel-coated seeds obtained by drying the same.

The present invention will be explained in detail below.

First, the germination rate of seeds differs depending on the type of plant due to the presence or absence of dormancy, and the germination state of the same plant also differs depending on the time of harvest. Therefore, pretreatment to promote germination is generally performed as a precautionary measure.

This pretreatment method includes immersing the seeds in an aqueous solution of a germination promoter, such as gibberellin, as well as a seed coat abrasion method, high-temperature treatment, low-temperature treatment, etc., which are appropriately selected depending on the characteristics of the seeds.

In addition, in advance, potassium nitrate (KNO2), which is normally necessary for plant growth, is added.
), ammonium hydrogen phosphate (NH, HgPO4), and other nutrients, as well as growth hormones, fungicides, insecticides, animal repellents, and other chemicals as necessary.This chemical treatment can be done in two ways: It can be done by the following method. That is, the first method is to add the required amount of these drugs directly into the aqueous gel for coating, and the second method is to encapsulate the drugs in the air bubble space between the seeds and the coating gel, or add them to the seeds. This is a method in which the material is coated in powder beforehand and then sealed.

In order to obtain an aqueous gel containing these drugs using the first method, first add appropriate amounts of all of these drugs as aqueous solutions into an aqueous gelling agent, and then add this to pure water at a gelling agent concentration of 2 to 30%. Dissolve to a concentration of 4% by weight, and add 1 to 2
The mixture is left for a period of time to sufficiently absorb water and swell, and then stirred to form a uniform viscous gel fluid. The aqueous gelling agent that can be used here is not particularly limited as long as it has such properties, but alkali salts such as natural gels, synthetic organic gels, and inorganic gels are used. Particularly desirable aqueous gelling agents include sodium alginate, sodium polyacrylate, etc., which are safe and harmless not only to plants but also to humans.

A method for producing gel-coated seeds of the present invention in which air bubbles are encapsulated on the seed surface using the above-mentioned chemically treated aqueous gel will be described below.

Figure 1 shows an overview of the manufacturing process using a nozzle using a plunger. That is, in the figure, the nozzle A has a substantially cylindrical gel pressurizing plunger 4 in the hollow part 3a of the hollow cylinder 3 communicating with the gel flow path 6, and a gel cutting plunger 5 having the seed passage 5a in the center. It has a double structure. First, with the gel cutting plunger 5 closing the nozzle hole 3b of the cylinder 3, the pressurizing plunger 4 is forcibly raised once to remove the gel 2.
is filled into the hollow part 3a of the cylinder 3 through the gel channel 6 (not shown). Next, as shown in (a), the pressurizing plunger 4 is lowered, and the gel in the hollow part 3a is pressurized. , the plunger 5 is pushed upward to open the nozzle hole 3b and the gel 2 flows out. When about half of the predetermined amount of gel 2 has flowed out, the seeds 1 are dropped through the seed passage 5a (
mouth).

When dropping the seeds 1, the pressure on the plunger 4 is stopped and the seed 1 is returned to its initial position by means such as a spring (not shown). As a result, the cylinder hollow portion 3a is filled with a gel corresponding to the amount flowing out. Furthermore, since the plunger 5 is not pressurized by the gel, it descends and closes the nozzle hole 3b.

However, the gel 2 and the seeds 1 are attached to the nozzle hole 3b.

At this time, the gel 2 is somewhat deformed by its own weight, so that air-filled spaces (air bubbles) are created around the seeds 1 (c).

Next, when the pressurizing plunger 4 is pushed down as shown in (d), the nozzle hole 3b opens in the same way as in (a).
Seed 1 is covered with gel 2 with air bubbles 7 enclosed around the seed 1.
covered by. A certain amount of gel 2 enters the cylinder hollow part 3
When pushed out from a, the pressure applied to the plunger 5 is lost and the plunger -5 descends, closing the nozzle hole 3b. In this state, the gel-coated seeds 8 fall away from the nozzle hole 3b due to their own weight (e). During the fall, the gel-coated seeds 8 are formed into a spherical shape due to the surface tension of the gel, and are formed into a spherical shape by a water insolubilization treatment solution (not shown). be put inside.

The above is a method for producing gel-coated seeds containing air bubbles using nozzle A using a plunger.
It can also be manufactured using a nozzle B as shown in FIG.

That is, the nozzle B has a configuration in which an annular gel flow path 10 with a constricted tip is formed on the outer periphery of the seed/air supply path 9, and the gel flow path 10 is connected to an existing extruder.
Further, the seed/air supply path 9 is connected to air supply means such as a near compressor. Gel 2 is extruded from the lower end nozzle hole 10a of the gel flow path 10 by an extruder, and
When the seeds 1 are formed into a roughly spherical shape at 0a, the seeds 1 are forcibly fed into the center along with air through the supply channel 9.Then, when the gel is allowed to flow out roughly, the gel-coated seeds fall under their own weight and are insolubilized in water in the next step. It is placed in the processing solution.

A divalent or trivalent metal salt aqueous solution is suitable for use as a water insolubilization treatment solution for gel-coated seeds.

Examples of this metal salt aqueous solution include chloride aqueous solutions of divalent metals such as calcium, magnesium, and barium, and aluminum chloride aqueous solutions, and these metal salt aqueous solutions are adjusted to about 20% by weight. . Note that water as a solvent is preferably water that does not contain many metal ions.

The gel-coated seeds immersed in these metal salt aqueous solutions are treated with an alkali metal (e.g. Na) as an aqueous gelling agent.
Substitution occurs between valent or trivalent metals (e.g. Ca),
A chemical change occurs from the surface of the water-insoluble material, which has optically extremely small pores, and the coated surface layer hardens in about 1 minute to obtain coated seeds with high elasticity and a gel-like interior.

FIG. 3 conceptually shows a cross-sectional view of the gel-coated seeds of the present invention thus obtained. In the figure, 1 is a seed, 2 is an uncured gel layer, 2a is a cured (water insolubilized) gel layer, and 7 is a bubble.

Further, in the case of the second method described above, that is, when a drug such as a nutritional substance is encapsulated between the seeds and the coating gel, the drug may be applied simultaneously with the seeds or coated on the seeds in the same manner as described above.

The gel-coated seeds obtained by the above production method can be used for sowing as is by sufficiently washing with water, but if they need to be stored until the sowing time, they should be dried, preferably freeze-dried. . In the freeze-drying process, the material to be dried is first dried by using a known freeze-drying device.
Prefreeze at around ℃ to prevent bubbles from bursting under reduced pressure. Then drying temperature -20℃~-90℃, pressure about 5T
It is carried out under reduced pressure conditions below orr.

When drying large quantities of seeds, use selective drying to vaporize the solvent at low temperatures without destroying the life of the seeds by using a volatile liquid such as alcohol instead of water as the gel solvent. Can be done.

[For production]

The effects of the gel-coated seeds of the present invention will be explained below.

The seeds of the present invention change into an elastic substance with extremely fine pores by insolubilizing the aqueous gel surrounding them, and do not swell due to water absorption, but have good water retention and air permeability. It will be excellent. In addition, since it contains air bubbles in contact with the surface of the seeds, it is possible to eliminate the oxygen shortage caused by the activation of seed respiration (oxygen demand) accompanying the rise in summer temperature. Moreover, the elimination of oxygen deficiency by this also leads to the elimination of the decrease in the germination rate of seeds.

Further, in the gel-coated seeds that have been dried, the moisture contained in the insolubilized gel layer is dehydrated, creating microspaces in those areas, further improving air permeability, and making the seeds suitable for storage, germination and growth.

Generally, when seeds are stored at temperatures and humidity close to natural conditions, their germination ability decreases each summer. The high temperature and humidity of summer is a major factor in this, and even short-lived seeds can maintain their germination ability for at least about five years when stored tightly at room temperature with a desiccant.

Therefore, according to the dried gel-coated seeds of the present invention, the seeds are covered with a gel layer dried to a moisture content of 3 to 4% and can be stored for a long period of time.

In addition, in the gel-coated seeds of the present invention, during irrigation after sowing, moisture and oxygen freely flow through the numerous micropores in the coating layer, and nutrients, fungicides, and other chemicals added or encapsulated inside are absorbed. By gradually dissolving, the area around the seeds can be maintained in optimal conditions for plant growth for a long period of time.

In addition, the hardness of the coating layer is determined by adjusting the gel concentration (
Practically speaking, it can be adjusted as desired by reducing the viscosity.

After the seeds germinate and grow, the covering layer is decomposed by carbonic acid in the soil, or it is attached to the plant and can be easily taken out of the soil.

In addition, the gel-coated seeds of the present invention can be handled in the same way as regular seeds. Especially when using a seeding machine, conventional seeds are so small that it is difficult to uniformly sow one to a few seeds, or the seeds are shaped differently. Even if the seeds are non-uniform, they can be easily applied because they are made into large spherical particles, and they also have the effect of eliminating the damage caused by animals of the court after sowing.

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

(11) Since the coating layer around the seeds contains air bubbles in contact with the seed surface, it can cope with the large amount of oxygen required by the seeds due to the rise in temperature in summer, and eliminates the decrease in germination rate due to lack of oxygen. .

(2) Since a large number of micropores are formed in the seed coating layer, oxygen and moisture are sufficiently supplied, and seeds germinate smoothly. This effect is particularly enhanced when drying is performed.

(3) By insolubilizing the coating layer, drugs such as nutritional substances added or encapsulated in the coating layer gradually flow out, and an optimal growth environment can be maintained for a long period of time.

(4) Drying treatment allows seeds to be stored for a long period of time.

(5) By processing microscopic, non-uniformly shaped seeds into spherical and large seeds, it is possible to improve the accuracy of sowing, facilitate mechanization, and reduce management labor.

(6) In the case of mechanical sowing, the coating layer can protect the seeds from scratches and cracks.

[Brief explanation of the drawing]

Figures 1 (a) to (e) are explanatory diagrams of the manufacturing process of gel-coated seeds of the present invention, Figure 2 (a) is an explanatory diagram of other manufacturing processes of gel-coated seeds of the present invention, Figure 2 (b) 2(a) is a cross-sectional view taken along the line AA in FIG. 2(a), and FIG. 3 is a cross-sectional view of the gel-coated seeds of the present invention. 1... Seed, 2... Gel, 3... Cylinder, 4...
... Plunger for pressurization, 5... Plunger for gel cutting, 6... Gel channel, 7... Air bubbles, 9... Seed/air supply channel, 10... Gel supply channel.

Claims (2)

[Claims] (1) Enclose air bubbles in contact with the surface of the plant seed, and form a coating layer of an aqueous gel alkaline salt solution around it, and make the coating layer insoluble in water by reacting with a divalent or trivalent metal salt solution. A gel-coated seed characterized by comprising: (2) Enclose air bubbles in contact with the surface of the plant seeds, and form a coating layer of an aqueous gel alkaline salt solution around the bubbles, and make the coating layer insoluble in water by reacting with a divalent or trivalent metal salt solution. A gel-coated seed characterized by being dried.