JPH06319528A - Method for multiplying va mycorrhizal fungus - Google Patents

Abstract

(57) [Summary] [Structure] When VA mycorrhizal fungi are grown by symbiotic plant roots with VA mycorrhizal fungi, the sparingly soluble calcium salt in the medium is used to grow VA mycorrhizal fungi. A method for growing VA mycorrhizal fungi, which comprises adding [Effect] According to the method of the present invention, a large amount of spores can be obtained by significantly proliferating VA mycorrhizal fungi. as a result,
The VA mycorrhizal preparation having high spore density and excellent activity can be manufactured at low cost. In addition, spores of VA mycorrhizal fungi that have increased in density are collected and mixed with a carrier of the product to
The mycorrhizal fungus inoculum can be produced efficiently and inexpensively. Therefore, the present invention is extremely useful in fields such as agriculture, horticulture, and civil engineering.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for multiplying VA mycorrhizal fungi useful in fields such as agriculture, horticulture, and civil engineering.
The present invention relates to a method capable of significantly growing A mycorrhizal fungi and producing a large amount of VA mycorrhizal spores.

[0002]

It is known that VA mycorrhizal fungus (Vesicular Arbuscular Mycorrhizae) infects various crops to promote growth and improve disease resistance of plants. ("Agriculture and gardening", No. 6
Volume 2, No. 8, pages 930-937, 1987; "Plant epidemics", Volume 42, No. 5, pages 259-266, 198.
8 years).

In order to prepare such an inoculum of VA mycorrhizal fungi, it is necessary to obtain a large amount of spores. Therefore, a method for efficiently producing VA mycorrhizal spores is required. Conventionally,
As a method for growing VA mycorrhizal fungi, zeolite (JP-A-3-247270), porous amphoteric ion exchanger (JP-A-63-87973), or charcoal is added to the medium (JP-A-SHO). No. 60-49717), a method of culturing using a porous body is known. According to the method of culturing using these porous bodies, although a certain amount of spores can be obtained, it cannot be said to be sufficient, and there is a need for a method of further promoting spore formation.

As a method of growing VA mycorrhizal fungi, a method of vigorously growing a host plant and, as a result, proliferating VA mycorrhizal fungi is known. Specifically, it is a method of applying a fertilizer for vigorously growing a host plant, for example, a method of growing a plant by adding a chemical fertilizer to the soil and infecting the root of the plant with VA mycorrhizal fungus (JP-A-2- 227
No. 068, Japanese Patent Application Laid-Open No. 3-76572) and a method of adding fertilizer to incineration ash of industrial waste (Japanese Patent Application Laid-Open No. 3-587).
No. 15) is known. However, if too much fertilizer, especially phosphoric acid, necessary for growing a host plant is given as in these methods, there is a risk that the growth of VA mycorrhizal fungus is rather inhibited.

[0005]

As a result of intensive studies to solve these conventional problems, the present inventors have found that VA mycorrhizal fungi are proliferated remarkably by adding a sparingly soluble calcium salt to the medium. Then, it was found that a large amount of spores can be obtained, and the present invention has been completed based on this finding.

That is, according to the present invention, when a VA mycorrhizal fungus is symbioticly grown in a plant root and the VA mycorrhizal fungus-infected plant is cultivated to grow the VA mycorrhizal fungus, a sparingly soluble calcium salt is added to the medium. The present invention provides a method for growing a VA mycorrhizal fungus, which is characterized by adding it.

[0007] VA mycorrhizal fungus is a kind of zygomycete existing in soil, and it is known that its hyphae form mycorrhizal roots of various plant roots and both of them coexist. There are various kinds of VA mycorrhizal fungi used in the present invention, for example, the genus Gigaspora, Glomus.
) Genus, Scutellospora genus, Acaulospora genus, Sclerocystis
Lerocystis, Entrophospora
) Genus and the like, but in the present invention, among these, especially among these Gigaspora (Gigaspora)
Genus, Glomus, Scatellospora (Scute
microorganisms belonging to the genus llospora, especially Gigaspora
It is effective against microorganisms belonging to the genus ora) and the genus Glomus.

Specific examples of these VA mycorrhizal fungi include, for example, Gigaspora margarita.
), Gigaspora albida,
Gigaspora gigantea,
Glomus fasciculatum
), Glomus caledonium
), Glomus mosseae, Glomus intraradicies
), Glomus etunicatum
), Scutellospora gregaria
egaria) and others, as well as Acaurospora laevis (Aca
ulospora laevis), Entrophospora infrequens, and Sclerocystis dussii.

As mentioned above, the present invention is particularly concerned with Gigaspora margarita.
), Gigaspora albida,
Gigaspora gigantea,
Glomus fasciculatum
), Glomus caledonium
), Glomus mosseae, Glomus intraradicies
) Etc. are suitable for proliferation.

As a method of collecting these VA strains,
A method of collecting from the natural world using a sieve (Tatsuhiko Suzuki, Problems on VA mycorrhiza 5, Agriculture and Horticulture, Vol. 62, No. 3
No. pp. 28-33, 1987) and a method using centrifugation (Japanese Patent Laid-Open No. 63-309178).
Moreover, a nutrient thin film culture method (Japanese Patent Laid-Open No. 55-118390) or a method using organ-cultured roots (Japanese Patent Publication No. 62-4).
No. 9037 gazette), etc., there is also a method of aseptically growing the VA bacterial inoculum to form spores, but the collecting method is not particularly limited. In addition, Gromus intraradices is sold as Nutri-Link (trademark) by NPI Corporation in the United States. Further, VA inoculum adhered to an inorganic or organic carrier can also be used.

In the present invention, the plant which is symbiotic with VA mycorrhizal fungus is a plant which is infected with VA mycorrhizal fungus (V
The host plant of A mycorrhizal fungus is not particularly limited as long as it is a plant that grows quickly and has well-rooted roots and is easily infected with VA mycorrhizal fungus. Specifically, for example, corn, buffalo, sorghum (also known as sorghum or sorghum), wheat, turfgrass, sudangrass, bahiagrass, guinea grass, etc., solanaceous plants such as eggplant, tomato, bell pepper, citrus, soybean, crow Pea plants such as wild peas, mung beans, peanuts, alfalfa, clover, red clover, marigold, sunflower, cineraria, chrysanthemums such as chrysanthemums, roses such as strawberries, lily plants such as leeks and onions, Preferable are plants such as Begonia. These plants are
In addition to sowing and seedling seedlings, they are used after seeding and raising seedlings, then transplanted and cultivated, vegetatively propagated, and grown and cultivated by cuttings, cuttings, grafts, bulbs and the like.

The method of the present invention is applied to the roots of such plants with V
When VA mycorrhizal fungi are proliferated by cultivating the VA mycorrhizal fungi-infected plant by symbiotic with A mycorrhizal fungi, a sparingly soluble calcium salt is added to the medium.

In the present invention, the medium (also referred to as a soil or a base material) used when infecting a plant with VA mycorrhizal fungi is not particularly limited, and various media can be mentioned.
It does not matter whether it is an inorganic substance or an organic substance. Examples of inorganic substances include montmorillonite, diatomaceous earth, attapulgite, zeolite, red tama soil, Kanuma soil, charcoal, sand, pumice stone,
Examples include foamed clay, talc, perlite, vermiculite, limestone, coke and the like. In addition, examples of organic substances include peat moss,
You may use the mixed culture medium which used these in combination.

Among these, those that are inorganic and are less likely to disintegrate due to the inclusion of water, and that are sterilized (including calcined) are preferable from the viewpoint of preventing contamination of various bacteria in the soil. Specifically, fired attapulgite,
Preference is given to calcined montmorillonite, calcined diatomaceous earth, zeolite, calcined akadoma earth, and the like. In particular, it is preferable to use one of these as a main component and further mix pumice to this.

Here, the calcined attapulgite, the calcined montmorillonite and the calcined diatomaceous earth each have a particle size of 0.5-5.
mm, preferably 1-3 mm, each with a firing temperature of 20
Those treated at 0 to 1300 ° C, preferably 300 to 1000 ° C are used. Alumina or the like can also be used as a binder, in which case it is preferable to adjust the pH to 5.5 to 7.5. Further, as the zeolite, those having a particle size of 0.5 to 5 mm, preferably 1 to 3 mm, a spherical surface, not smooth, and a grain plane structure are preferable. As the calcined red dough, one having a particle size of 0.5 to 5 mm, preferably 1 to 3 mm, which has been treated at a calcining temperature of 200 to 1300 ° C, preferably 200 to 1000 ° C is used.

In the present invention, a sparingly soluble calcium salt is added to the medium as described above. Here, the sparingly soluble calcium salt specifically means, for example, calcium silicate,
Calcium carbonate, calcium sulfate, calcium sulfite,
Examples include calcium phosphate, limestone, and shells, which exclude calcium chloride and magnesia lime. When calcium chloride or magnesia lime is added, a smaller amount of VA mycorrhizal spores can be obtained, as compared with the case where no calcium chloride is added. Among these, the sparingly soluble calcium salt used in the present invention is preferably at least one selected from calcium silicate, calcium carbonate, calcium sulfate, calcium sulfite, calcium phosphate and limestone.

As such a sparingly soluble calcium salt,
Usually, particles having a diameter of 10 mm or less, preferably 5 mm or less, more preferably 0.5 to 3 mm are used. When large particles are used, it is possible to obtain a high quality product by producing a VA mycorrhizal inoculum and then removing it to prevent contamination with the final product.

As a method of adding such a poorly soluble calcium salt to the medium, the medium and the poorly soluble calcium salt may be mixed, or the poorly soluble calcium salt may be placed on the upper part of the medium. Regarding the timing of adding the sparingly soluble calcium salt, it is usually before inoculation with VA mycorrhizal fungi, but it may be added after inoculation. When adding after inoculation, a sparingly soluble calcium salt may be placed on top of the medium.

Further, the addition amount of the sparingly soluble calcium salt is
Although it depends on the type, generally speaking, an amount is added such that even if the poorly soluble calcium salt gradually dissolves, it remains in the medium for at least one month or more. Specifically, for example, it is added at a rate of 0.1 to 70%, preferably 2 to 25%, relative to the weight of the medium. If the amount of the sparingly soluble calcium salt is too small, the spore formation of VA mycorrhizal fungi becomes insufficient, while if the amount of the sparingly soluble calcium salt is too large, the growth of plants and the growth of VA mycorrhizal fungus become poor, Neither is preferable.

In the method of the present invention, plants are cultivated using the medium thus added with a sparingly soluble calcium salt, and VA
Grow mycorrhizal fungi. Here, the method of infecting the host plant with VA mycorrhizal fungus will be described first. The application timing of VA mycorrhizal fungus may be either before or after adding the sparingly soluble calcium salt to the medium as described above. . The VA mycorrhizal fungus may be applied either before or after rooting of the host plant, but especially at the time of seed sowing or pretreatment of cuttings, at the same time as sowing or cutting, or at the time of transplanting seedlings. Is preferred. As an application method, it is preferable to mix it with a base material, apply it layered on the lower layer of seeds or shoots, or apply it in a planting hole at the time of planting. Further, the application amount of VA mycorrhizal fungus is not particularly limited, but usually 1 to 10,000 per plant
It is about 0.

Infection of the host plant with VA mycorrhizal fungus and cultivation of the host plant may be carried out by known methods. For example, the temperature is 10 to 50 ° C., preferably 15 to 35 ° C., pH of soil.
Is carried out under the conditions of 3 to 9.5, preferably 4 to 7.5.

When the host plant is cultivated in this manner, infection with VA mycorrhizal fungi is established as the host plant grows. In this way, a plant infected with VA mycorrhizal fungi is cultivated, and the roots of the plant are used to grow VA mycorrhizal fungi. That is, VA mycorrhizal fungi are symbiotic with plant roots, and the VA mycorrhizal fungi are grown by cultivating the plant. When cultivating the plant, a slow-release fertilizer or the like can be applied if necessary.

As the host plant grows, VA mycorrhizal fungi also actively propagate. Usually, after about 2 to 5 months have passed, when the host plant has grown sufficiently, the supply of water, nutrients, etc. is stopped, and if left for a while, the VA mycorrhizal fungi form spores. Therefore, the formed substrate to which the VA mycorrhizal spores are attached can be recovered and used as a VA mycorrhizal preparation. Further, it becomes possible to efficiently collect the VA mycorrhizal inoculum by collecting the spores of VA mycorrhizal fungi that have increased in density and mixing them with another carrier.
The VA mycorrhizal fungus preparation or the inoculum containing the isolated spores thus obtained is applied to a plant that can be infected with the VA mycorrhizal fungus, and is used for cultivation of various plants.

[0024]

EXAMPLES Next, the present invention will be described in detail with reference to Examples. Examples 1 to 4 and Comparative Examples 1 to 20 20 kg of granular red spheres having a particle size of 0.5 to 3 mm, and 1 k charcoal.
Various kinds of calcium salts shown in Table 1 were added to and mixed with 4 g of zeolite and 4 kg of zeolite at a ratio of 300 g to prepare a medium.
To 1 kg of this medium, 1 g of slow-release fertilizer (flower and vegetable fertilizer, manufactured by Mitsui Toatsu Co., Ltd.) was added. 1 kg of this medium was placed in a No. 5 plastic pot (1.5 liter capacity), and Gigaspora arvida (Gigaspora) was placed in a layer 3 cm below the upper surface.
albida) or Glomus Fasciculator (Glo
mus fasciculatum) [This strain was inoculated with 200 seeds per pot of the Institute of Biotechnology, Institute of Industrial Technology (former name: refused to be accepted by the Institute of Microbial Engineering, Institute of Industrial Science and Technology). Six layers of red clover seeds were inoculated in a layer 1 cm below the pot, 10 pots were made per ward, and the pots were cultivated in a greenhouse where the minimum temperature was kept at 25 ° C for 3 months. After 3 months, the irrigation was stopped, and the spores of VA mycorrhizal fungi were separated from the culture medium by the wet sieving method, and the number of spores was measured. The average value of 10 pots in each section is shown in Table 1.

[0025]

[Table 1]

Examples 5 to 7 and Comparative Example 4 In Examples 1 to 4 and Comparative Examples 1 to 3, the VA mycorrhizal fungus was Gigaspora margarit.
a) [This microorganism was used as a calcium salt (example 5) .About.7) or calcium chloride (Comparative Example 4) in a predetermined amount (300 g to 3 k) shown in Table 2.
The same procedure as in Examples 1 to 4 and Comparative Examples 1 to 3 was carried out to measure the spore number except that the spores were used. The results are shown in Table 2.

[0027]

[Table 2]

[0028]

According to the method of the present invention, by adding a sparingly soluble calcium salt to the medium, VA mycorrhizal fungi can be significantly grown and a large amount of spores can be obtained. As a result, it is possible to inexpensively produce a VA mycorrhizal preparation having a high spore density and excellent activity. Further, it is possible to collect the spores of VA mycorrhizal fungi that have increased in high density and mix them with a carrier of the product to efficiently and inexpensively make a VA mycorrhizal fungus inoculum. Therefore, the present invention is extremely useful in fields such as agriculture, horticulture, and civil engineering.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display area // (C12N 1/14 C12R 1: 645)

Claims (3)

[Claims] 1. A plant root containing a VA mycorrhizal fungus,
A method for growing a VA mycorrhizal fungus, which comprises adding a sparingly soluble calcium salt to a medium in growing the VA mycorrhizal fungus by cultivating a mycorrhizal fungus-infected plant. 2. The VA mycorrhizal fungus is a spore thereof.
The method described. 3. The method according to claim 1, wherein the sparingly soluble calcium salt is at least one selected from calcium silicate, calcium carbonate, calcium sulfate, calcium sulfite, calcium phosphate and limestone.