JPH0630764A - Method for proliferating va mycorrhizae - Google Patents

Abstract

PURPOSE:To efficiently and economically obtain VA mycorrhizae for promoting growth of a plant in high spore density by applying a fertilizer containing a humic acid and an inorganic phosphorus compound to a plant infected by VA mycorrhizae and culturing the plant. CONSTITUTION:Red granulated soil having 0.5-4mm grain diameter and subjected to sterilization treatment with methyl bromide and sufficiently degassed is packed into a pot and 50 spores of VA mycorrhizae (e.g. Scutellospora greraria) are inoculated thereon and further, the red granulated soil is packed in 1cm thickness and seeds of a plant (e.g. alfalfa) are sowed and covered with soil and cultured for 4 weeks in a glass greenhouse kept at 25-35 deg.C for 4 weeks to infect the VA mycorrhizae and then transplanted in a pot and a fertilizer containing at least a humic acid and an inorganic phosphorus compound is applied to the red granulated soil and the plant is cultured in the greenhouse at 25-35 deg.C for 10 weeks and then the resultant substrate is recovered and spores are separated by a wet sieving method. Thereby, VA mycorrhizae useful in fields such as agriculture and horticulture can be proliferated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for multiplying VA mycorrhizal fungi useful in fields such as agriculture and horticulture, and more specifically, applying a fertilizer containing at least humic acid and an inorganic phosphorus compound to produce VA.
The present invention relates to a method for efficiently growing mycorrhizal fungi.

[0002]

BACKGROUND OF THE INVENTION VA mycorrhizal fungus (Vesicular Arbuscular Mycorrhizae) promotes plant growth and improves plant disease resistance by coexisting with plant roots. , And its usefulness has been known for a long time (Makoto Ogawa: VA mycorrhiza and its function, Forest location, Volume 30 (2), 57-65, 19).
1988, Norihiko Kobayashi: Use of VA mycorrhizal fungi and soil diseases,
Plant Protection, Vol. 42, pp. 259-266, 1988). However, an artificially growing VA mycorrhizal fungus that can be used commercially as a VA mycorrhizal fungal inoculum has not been produced so far.

This is a VA mycorrhizal fungus, especially the genus Scutellospora, the genus Gigaspora,
Alternatively, it is said that large-scale culture of VA mycorrhizal fungi belonging to the genus Glomus is very difficult, and the culturing operation is complicated, and the cost is the main cause. Therefore, in order to make VA mycorrhizal fungi commercially available, there is a demand for a method that is simple in culture operation and can be mass-produced at low cost.

Therefore, some proposals have been made as a method for increasing VA mycorrhizal fungi. For example, VA mycorrhizal fungal infected plants are cultivated using soil and various plant cultivation bases,
Methods for growing VA mycorrhizal fungi have been investigated. On this occasion,
Liquid fertilizers and chemical fertilizers are used as fertilizers for promoting plant growth. Conventionally, as such a technique, 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 (Japanese Patent Laid-Open No. 227668/1990, pp.
No. 76572), a method of adding fertilizer to incinerated ash of industrial waste (Japanese Patent Laid-Open No. 3-58715), and the like. However, in these methods, fast-acting fertilizers are used, and there is a problem that the growth of VA mycorrhizal fungi is inhibited. See also VA Mycorrhiza, p19
0-191, CRC Press, Inc. 1984. And "Agriculture and Gardening", No.
62, No. 7, p27-28, 1987. and the like describe that the application of an excess of water-soluble phosphoric acid inhibits the growth of VA mycorrhizal fungi.

On the other hand, in order to avoid contact between a high-concentration chemical fertilizer and VA mycorrhizal fungi, a method using a low-concentration liquid fertilizer (Japanese Patent Laid-Open Nos. 55-118390 and 60-237987, 62-19028). No.), or a method of using organic fertilizer adsorbed on an absorber (Japanese Patent Laid-Open No. 63-87973), but preparation of fertilizer components is complicated and applied for plant growth. There are disadvantages that the number of times is large, it is troublesome, and an expensive ion exchanger is used.

The present inventor has conducted extensive studies to solve such conventional problems, and as a result, a plant infected with VA mycorrhizal fungus by applying a fertilizer containing at least humic acid and an inorganic phosphorus compound. It was found that the roots of the plant can be infected with VA mycorrhizal fungi to proliferate remarkably by cultivating, and the present invention has been completed based on this finding. In addition, up to now, there is no known example of efficiently growing VA mycorrhizal fungi by using humus phosphorus which is a slow-release phosphate fertilizer containing humic acid.

[0007]

That is, the present invention provides a VA
The present invention provides a method for growing VA mycorrhizal fungi, which comprises cultivating a plant infected with mycorrhizal fungus by applying a fertilizer containing at least humic acid and an inorganic phosphorus compound.

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 VA mycorrhizal fungi used in the present invention,
For example, the genus Scutellospora, the genus Glomus, the genus Gigaspora, the genus Acaulospora, the genus Entrofospora
ntrophospora), Sclerocysti
s) Examples include microorganisms belonging to the genus. These VA
Among the mycorrhizal fungi, VA mycorrhizal fungi belonging to the genus Scutellospora, the genus Gigaspora, the genus Glomus, and the like, which have been difficult to grow at high density, are suitable.

More specifically, for example, Scatellospora
Gregaria (Scutellospora gregaria)
Intraradices (Glomus intraradicies), Glomus mosseae (Glomus mosseae), Glomus etunicatamu (Glomus etunicatum), Glomus fasciculatum (Glomus fasciculatum), and others, Gigaspora margarita (Gigaspora margarit)
a), Acaulospora laevis
), Entrophos.
spora infrequens), Sclerocystis dassie (
Sclerocystis dussii) etc. can be mentioned.

These VA mycorrhizal fungi can be collected from nature using a sieve or the like (Tatsuhiko Suzuki, Problems on VA mycorrhiza 5, Agriculture and Horticulture, Vol. 62, No. 3, p. 28-3.
3, 1987) and collected by centrifugation (Japanese Patent Laid-Open No. Sho 63-63).
No. 309178) can be used. Furthermore, 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) and the like can be used. It should be noted that Gloms Intraradices (Glom
us intraradicies) is from NPI, Inc.
Sold as i-Link (trade name). Also,
VA mycorrhizal fungi attached to an inorganic or organic carrier can also be used.

In the present invention, a plant to be infected with VA mycorrhizal fungus, that is, a host plant for VA mycorrhizal fungus culture is VA
The plant is not particularly limited as long as it is infected with mycorrhizal fungi, but a plant that grows quickly, has well-rooted roots, and is easily infected with VA mycorrhizal fungi is preferable. Specifically, for example,
Maize, crabgrass, sorghum (also known as sorghum or sorghum), wheat, turfgrass, grasses such as Sudan grass, bahiagrass, guinea grass, solanaceous plants such as eggplant, tomato, bell pepper, citrus, red clover, soybean, mustard pea , Legumes such as mung beans, peanuts and alfalfa, and lilies such as leeks and onions. In addition to using seeds and seedlings, these plants are used by sowing and raising seedlings, then transplanting and cultivating, vegetatively propagating, multiplying and cultivating by cuttings, cuttings, grafts, bulbs, etc. .

The substrate (medium) used when infecting the host plant with VA mycorrhizal fungi is not particularly limited as long as it is a substrate on which the plant grows, and various substances can be mentioned. If it is, it does not matter whether it is an inorganic substance.
Examples of the inorganic material include zeolite, foamed clay (bre clay), talc, perlite, vermiculite, (calcined) red sphere, pumice, limestone, earth, sand, and coke. In addition, examples of the organic substance include peat moss and the like, and a mixed base material in which a plurality of these substances are used in combination may be used. However, a substrate having a high phosphoric acid absorption coefficient (1000 or more) is preferable. For example, Akatama soil, fired Akatama soil, Kanuma soil, Kuroboku soil and the like can be preferably used, and among them, from the viewpoint of preventing contamination of indigenous miscellaneous bacteria,
Those that have been sterilized (including calcination), such as sterilized soil and calcined red tama soil, can be used very suitably.

The method for inoculating and infecting the host plant with VA mycorrhizal fungus will be described. The application time may be either before or after rooting of the host plant, but especially at the time of sowing or pretreatment of cuttings, It is preferable to perform sowing and cutting at the same time, or at the time of transplanting seedlings. In addition, as the application method, VA mycorrhizal fungus is mixed with the above-mentioned base material, put in the root, applied layered to the lower layer of seeds or sprouts, or applied in planting holes at the time of planting. Preferably.

When a plant is infected with VA mycorrhizal fungi, it is usually 1 to 100,000, preferably 5 to 1 plant.
The plant may be inoculated with 10,000 VA mycorrhizal spores. V
The plant inoculated with the mycorrhizal fungus A is cultivated by a conventional method, for example, at a temperature of 5 to 60 ° C., preferably 10 to 45 ° C., and a substrate pH of 3 to 9.5, preferably 4 to 7. By culturing under the condition of 5, VA mycorrhizal fungi infect the roots of plants, and the infection is actively spread and proliferated. Irrigation or liquid fertilizer may be applied if necessary.

The VA mycorrhizal fungal infected plant thus obtained is fertilized to maintain vegetative growth. The method of the present invention is characterized in that at this time, a fertilizer containing at least humic acid and an inorganic phosphorus compound is applied. The fertilizer may be mixed with the base material or may be sprinkled during the cultivation of the plant. When it is mixed with the base material, it may be mixed into the base material from the beginning (that is, before infection with VA mycorrhizal fungi), or V may be added to the plant root in a normal base material.
After infecting the mycorrhizal fungus, it may be transplanted to a base material in which a fertilizer containing at least humic acid and an inorganic phosphorus compound is mixed.

Here, humic acid can be produced by decomposing lignite with nitric acid. Further, examples of the inorganic phosphorus compound include lime superphosphate, lime superphosphate, molten phosphorus fertilizer, molten phosphorus, heavy burned phosphorus, Linster, Dublin and the like. The amount of humic acid used is 0.002 to 15 g per liter of base material, while the amount of inorganic phosphorus compound used is 0.001 to 1 per liter of base material in terms of phosphoric acid concentration.
It is 0 g, preferably 0.1 to 5 g. In the present invention, it is necessary to apply a fertilizer containing at least humic acid and an inorganic phosphorus compound, and even if a fertilizer containing only one of them is used, the object of the present invention cannot be achieved.

In the present invention, the inorganic phosphorus compound is used in combination with humic acid as described above, but in practice, it is preferable to use humic phosphorus containing both of them. Here, humus phosphorus is
Lignite is decomposed with nitric acid to produce humic acid, which is mixed with molten phosphorus and heavy stones to react with each other and granulated into granules. Humic phosphorus contains about 35% of humic acid and is in a form in which phosphoric acid is wrapped with humic acid. Such humus phosphorus
The chelating action of humic acid prevents the fixation of phosphoric acid in the soil and maintains continuous fertilization. In addition, hard soil, lime,
It has a high absorption efficiency of silicic acid, is neutral, and does not change the acidity of the soil.

Thus, the vegetative growth of the VA mycorrhizal fungal infected plant is maintained, but the VA mycorrhizal fungal sporulation is induced at an appropriate time. Usually, after about 2 to 7 months have passed from the start of cultivation, when the plants were sufficiently grown and VA mycorrhizal fungi also proliferated, water, nutrition, etc. were cut off and left for a while, VA mycorrhizal fungi Form spores. Therefore, by separating and collecting the spores from the cultivation base material, a VA mycorrhizal preparation having a high concentration and excellent activity can be obtained. That is, when the spore density is sufficiently high, the base material is collected and VA
A mycorrhizal preparation is obtained, and dried if necessary for commercialization. The drying may be performed at a temperature at which spores and hyphae are not damaged, for example, 70 ° C or lower, preferably 20 to 50 ° C.

The method for growing VA mycorrhizal fungi according to the present invention can be used for the production of VA mycorrhizal fungi. Also,
It can also be used for plant cultivation. For example, vegetables
Good growth of plants can be achieved by inoculating these plants with VA mycorrhizal fungi at the time of raising seedlings of fruit trees or cultivating plants for appreciation.

According to the method of the present invention, a sufficient amount of the VA mycorrhizal fungus preparation and spores can be recovered in this manner, and V
Sporulation of VA mycorrhizal fungi can be induced again by transplanting a plant infected with A mycorrhizal fungus to another new substrate. Further, it is possible to prevent undesired contamination of indigenous VA mycorrhizal fungi and pathogenic bacteria.

That is, fertilizer and the like are applied to the VA mycorrhizal fungal-infected plant transplanted on a new base material in the same manner as described above,
While maintaining vegetative growth, induce spore formation, and when the spore density has risen sufficiently, collect the base material, dry it and commercialize it, isolate the VA mycorrhizal infected plant and separate it again. By transplanting to a new base material of V
It is possible to repeatedly obtain a sufficient amount of VA mycorrhizal spores from the A-mycorrhizal fungus infected seedling over a plurality of times.

[0022]

EXAMPLES The present invention will be described in more detail with reference to examples. Example 1 and Comparative Examples 1 and 2 Red soil (particle size 0.5 to 4 mm) that had been sterilized with methyl bromide and sufficiently degassed was placed in a 150 ml vinyl pot with a volume of 2/3. Filled up. On top of that VA mycorrhizal fungus [Scutellospora gr
egaria)] (Note that this fungus was refused to be accepted by the Institute of Microbial Technology, National Institute of Industrial Science and Technology), after inoculating 50 spores, it was further filled with red ball soil to a thickness of 1 cm and alfalfa seeds were added. Three seeds were sown and covered with soil. Prepare a total of 9 pots set in this way, grow them in a glass greenhouse at 25-35 ° C for 4 weeks, infect them with VA mycorrhizal fungi, and then in 3 pots of No. 5 plastic pots (1.5 liters). Y.).
At that time, as a base material, humus phosphorus (manufactured by Nippon Heavy Chemical Industry Co., Ltd.) was used as a base material so that the phosphoric acid concentration was 0.6 g / liter and the humic acid was 1.4 g / liter, that is, humus phosphorus was 4 g / liter. Of the base material added in the ratio (Example 1), lime superphosphate instead of humus phosphorus to a phosphoric acid concentration of 0.6 g / liter, that is, a base material added in the ratio of 3 g / liter (comparison Example 1), or a humic acid soil amendment containing no phosphate fertilizer (Azumin, manufactured by Kumiai Chemical Co., Ltd.) was added so that the humic acid concentration was 1.4 g / liter, that is, 2.8 g / liter. The base material (Comparative Example 2) was filled in 3 pots each for No. 5 plastic pot. In addition, Peters liquid fertilizer (2
0-10-20) 2000 times the solution was sprayed once a week. After transplanting, the plant was cultivated in a glass greenhouse at 25 to 35 ° C. for 10 weeks, then the supply of water was stopped, and the plant was left for 2 weeks. The obtained base material is recovered, and VA mycorrhizal fungi [Scutellospora gregari (Scutellospora gregari
a)] was separated and the number of spores was measured. Table 1 shows the average value for each 3 pots in each section.

[0023]

[Table 1]

Example 2 and Comparative Examples 3 and 4 VA mycorrhizal fungi used in Example 1 and Comparative Examples 1 and 2 [Scutellospora gregar
IA) instead of VA mycorrhizal fungus [Glomus intraradicies] (note that this fungus was rejected by the Institute for Microbial Technology, Institute of Industrial Science and Technology) and spores Example 1 and Comparative Examples 1 and 2 were repeated except that the number was increased from 50 to 100 and Sudangrass seeds were used instead of alfalfa seeds. As a result, the number of spores obtained was measured and shown in Table 2 as the average number of spores per 1 g of the substrate.

[0025]

[Table 2]

[0026]

INDUSTRIAL APPLICABILITY In the method of the present invention, since the fertilizer containing at least humic acid and the inorganic phosphorus compound is applied and cultivated, VA mycorrhizal fungi proliferate and mycelia of VA mycorrhizal fungi are efficiently produced. It grows well. Therefore, according to the method of the present invention,
A large amount of VA mycorrhizal fungi can be produced easily, efficiently and economically. Further, due to the spores of the grown VA mycorrhizal fungi, a VA mycorrhizal preparation having a high spore density and stable activity can be obtained at low cost. Therefore,
The present invention is extremely useful in fields such as agriculture and horticulture.

Claims (2)

[Claims] 1. A method for growing VA mycorrhizal fungi, which comprises cultivating a plant infected with VA mycorrhizal fungus by applying a fertilizer containing at least humic acid and an inorganic phosphorus compound. 2. The method according to claim 1, wherein the fertilizer is humus phosphorus.