JPH11171716A - Inoculant encapsulating microorganism symbiotic with plant root to plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inoculant to the plant by which microorganisms symbiotic with a plant root is protected enough from the soil microorganism when inoculating the inoculant to the plant and a habitat for the inoculant is secured by encapsulating the microorganisms symbiotic with the plant root, with a high molecular material produced by microorganisms. SOLUTION: The objective inoculant is obtained by encapsulating (A) microorganisms symbiotic with a plant root, with (B) a high molecular material produced by microorganisms. Mycorrhiza bacteria and leguminous bacteria or the likes are preferably used as the component A. Especially, a water- insoluble and biodegradable high molecular material, e.g. a microorganism cellulose and a microorganism polysaccharide curdlan or the like is preferably used as the component B. The inoculant is obtained by simultaneously culturing polymer-synthesizing microorganisms and the component A in a liquid in a one step process in which both of the culture and proliferation step of the component A, and the encapsulation step of the component A are carried out by one step. For example, acetic acid bacteria producing the cellulose, etc., are preferably used as the polymer-synthesizing microorganisms.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a novel inoculant for plants utilizing a plant root symbiotic microorganism.

[0002]

2. Description of the Related Art In the soil, there are various microorganisms which coexist with plant roots and help the growth of the plant. For example,
One of such microorganisms, rhizobia, infects plant roots, fixes nitrogen in the air and supplies it to plants, and mycorrhizal fungi also infect plant roots, It is known that by assisting the absorption of minerals and water such as the above, they promote the growth of plants infected with them, and enhance disease resistance and drought resistance.

[0003] Although such useful plant root symbiotic microorganisms are expected to be used in agriculture, forestry, and the like, great expectations are placed on them.
Simply adding these to the soil has the problem of adverse effects from other soil microorganisms, thus inhibiting infection of the plant. Even so, mycorrhizal fungi are poor in growth and require a long period of time to infect plants.

[0004] Therefore, in actual use of these plant root symbiotic microorganisms, they are protected from other soil microorganisms, and they are provided with a suitable place for growth so that infection to plants is likely to occur. Therefore, it has been studied to use it as an inoculant mixed with a carrier material or included in a carrier material. For example, various soils, clay, sand, coal, kaolin powder, sphagnum moss, peat, hydrophilic polymers, oil-based materials, pulp, cellulose, etc. may be added to soil as a carrier material for plant root symbiotic microorganisms, or seeds. Inoculation methods such as direct spraying on the vegetation have been studied.

[0005]

However, an inoculant of a type in which a carrier such as soil and a plant root symbiotic microorganism are mixed is insufficient in protection of the plant root symbiotic microorganism from soil microorganisms. In addition, a type of inoculant in which a plant-symbiotic microorganism is encapsulated in a carrier such as a hydrophilic polymer can almost completely protect the plant-symbiotic microorganism from soil microorganisms. In addition to preparing by culturing, at least one or more additional steps for encapsulating this in a carrier material under appropriate conditions are required.

[0006] An object of the present invention is to provide an inoculant for plant root symbiotic microorganisms and a method for producing the same, which overcomes the drawbacks of the conventional technology. That is, the plant root symbiotic microorganisms to be inoculated to the plant are sufficiently protected from soil microorganisms, and
An object of the present invention is to provide an inoculant for plant root symbiotic microorganisms, which secures a place for its growth and can be prepared extremely easily and has excellent infectivity to plants.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve such problems, and as a result, selected a microorganism-producing polymer substance as a carrier for an inoculant, and thereby used a plant-root symbiotic microorganism. When encapsulated and inoculated into a plant, the plant root symbiotic microorganisms are sufficiently protected from soil microorganisms, and are provided with a place for growth, and the infection rate to the plant is greatly increased. By simultaneously culturing the microorganisms that produce the plant and the plant root symbiotic microorganisms in a liquid, the process of culturing and growing the plant root symbiotic microorganisms and the process of encapsulating the plant root symbiotic microorganisms with a polymer substance can be performed in only one step. And completed the present invention.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.

[0009] About the plant root symbiotic microorganism used in the present invention
And there are no restrictions on the type, but those that help plants grow
Bacteria that are particularly useful as
Root fungi, rhizobia, etc. are the plant symbiotic microorganisms of the present invention.
It is preferable because the application is easy and the effect is large. An example
For example, among mycorrhizal fungi,ArbuscularFungus
Belongs to the root fungusGigasporaGenus,ScutellisporaGenus,Glomus
Genus,AcaulosporaGenus,Scl erocystisGenus,EntrophosporaGenus
Belongs to the orchid mycorrhizal fungiRhizoctoniaGenus, ericaceae
Belongs to mycorrhizal fungiPezizellaGenera etc. are ectomycorrhizal fungiA
manitaGenus,Tricho lomaGenus,RhizopogonGenus,Scleroderma
Genus,PisolitusGenus can be suitably used in the present invention, and
As a bacterial germRhizobiumGenus,BradyrhizobiumGenus etc.
It can be used favorably for obvious reasons. In the case of mycorrhizal fungi, the vesicles
Offspring, mycelia and fruiting bodies may be used as inoculants according to the invention.
In the case of rhizobia, all the cells are inoculated according to the present invention.
It can be used as an agent.

[0010] In addition, there is no limitation on the types of microorganism-producing macromolecular substances that can harbor plant symbiotic microorganisms as long as they have a function of enclosing plant root symbiotic microorganisms. . However, from the viewpoint of more effectively achieving the object of the present invention and environmental load, it is particularly preferable to use a water-insoluble biodegradable polymer substance, for example, microbial cellulose, microbial polysaccharide guard run and the like. Since these high molecular substances are water-insoluble, the inoculant containing the plant root symbiotic microorganisms using them does not disintegrate due to the moisture in the soil during use, and is used until the plant root symbiotic microorganisms infect the plants. During this time, it can be effectively protected from soil microorganisms and a place for its growth can be secured. On the other hand, since these high molecular substances are biodegradable, they do not decompose in soil and remain in the environment after a certain period of time.

Accordingly, the polymer-synthesizing microorganism used in the production of such a polymer substance in the present invention also produces a bacterium that produces a water-insoluble biodegradable polymer substance, for example, an acetic acid bacterium that produces cellulose and a guard run. Alcaligenes faeca
lis and the like are preferred. Specific examples of the cellulose-producing acetic acid bacteria include Acetobacter aceti and Acetobacterium .
A such as xylinum (hereinafter referred to as A. xylinum )
cetobacter , Pseudom onas , Achromobacter , Alca
Ligenes , Aerobacter , Rhizobium , Agrob acteriu
genus m , Azobacter genus, Sarcina genus and the like.

In the present invention, the step of culturing and growing the symbiotic plant root microorganisms and the step of encapsulating the symbiotic plant root microorganisms with a polymer substance are carried out by simultaneously culturing these polymer-synthesizing microorganisms and the plant root symbiotic microorganisms in liquid. Are performed in one stage.

The cultivation conditions are not particularly limited, and the conditions for production of the high molecular substance by the high molecular weight synthetic microorganism and the growth conditions of the plant root symbiotic microorganism are balanced, and the amount of the high molecular substance to be produced and the plant contained therein are balanced. The amount of the root symbiotic microorganisms is as short as possible and an appropriate ratio as an inoculant for the plant of the present invention, that is, an amount ratio at which an optimal value is obtained as the infection rate of the plant root symbiotic microorganisms to the plant. It may be set as follows.
In general, Hestrin-Schramm (hereinafter, HS) is used as a medium.
Abbreviated. ) Medium, Ohta medium, Hamada medium, Hagem medium, Mel
Using any of in-Norkans medium, Mastutake medium, etc.
The inoculant of the present invention can be obtained by culturing the polymer-synthesizing microorganism and the plant-symbiotic microorganism together under the conditions of a temperature of 16 to 30 ° C., a dark place and a pH of 4 to 8. Since the optimum growth temperature of mycorrhizal fungi and rhizobia, which are symbiotic plant root microorganisms, is slightly different, in order to more efficiently prepare the inoculant of the present invention, the fungal root symbiotic microorganisms must be used. The culture is preferably performed at a temperature of 20 to 25 ° C when using rhizobia, and at a temperature of 25 to 30 ° C when using rhizobia.

It is to be noted that the greater the amount of the plant root symbiotic microorganisms included in the high molecular substance, the higher the rate of infection of the plants with the symbiotic microorganisms. For protection from soil microorganisms,
It is also necessary to sufficiently protect the plant root symbiotic microorganisms with a high molecular substance. Therefore, the properties of the plant root symbiotic microorganisms (such as the level of resistance to soil microorganisms) and the properties of the soil in which such inoculants are used (the existing soil) Depending on the type and number of microorganisms, etc., there is an appropriate quantitative ratio between the plant-root symbiotic microorganism and the high molecular substance so as to maximize the infection rate of the plant-root symbiotic microorganism to the plant.

In the present invention, the culturing method is not particularly limited. As long as the polymer-synthesizing microorganisms and the plant-symbiotic microorganisms are simply liquid-cultured together, in the process, the plant-symbiotic microorganisms are naturally included in the polymer material produced by the polymer-synthesizing microorganisms. Inoculum to be prepared.
Therefore, if it is a liquid culture, any of stationary culture, shaking culture, swirl culture, etc., can be applied to the present invention alone or in combination, but the shape of the obtained inoculant depends on the culture method to be selected. It will be different. Therefore, according to the present invention, inoculants of various shapes can be prepared,
In various places in the field of actual use, for example, the granular form is buried or mixed in soil or a support to indirectly inoculate the plant, or the sheet form is wound around the plant root. It is possible to inoculate plants directly and use them properly.

Specifically, the granular inoculant can be prepared by shaking culture or swirling culture under the above culture conditions. Shaking or turning speed is 10
~ 180 rpm is preferred. When the speed is lower than 10 rpm, the inoculant tends to show a sheet-like shape rather than a granular shape, and when the speed exceeds 180 rpm, both the polymer-synthesizing microorganisms and the plant root symbiotic microorganisms have an activity due to a decrease in shearing force due to stirring. It may decrease. On the other hand, a sheet-shaped inoculant can be obtained by static culture.
When the polymer-synthesizing microorganism and the plant root symbiotic microorganism are statically cultured under the above-described culture conditions, a film of a polymer substance containing the plant root symbiotic microorganism is formed at the gas-liquid interface of the culture solution. Therefore, it may be cultured until the sheet thickness becomes appropriate.

Plants to be used as hosts for plant-root symbiotic microorganisms are also not limited in type. The origin may be any of seedlings, cuttings and clones. In the case of seedlings, the inoculant of the present invention can be used in each process such as sowing, germination / rooting, replanting, and hilling, and in the case of cuttings, cuttings, rooting, replanting and planting. In the case of cloned seedlings, the inoculant of the present invention can be used in each step of rooting, acclimatization, raising seedlings, replanting, planting, and the like.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

Example 1 Pisolitu , an ectomycorrhizal fungus
A spore was separated and collected from the fruiting body of S. s tinctrius (hereinafter, abbreviated as PT). The cells of xylinum (ATCC10245) were inoculated into a new HS medium, and shaking culture was performed at 23 ° C. in a dark place at a speed of 90 rpm.

After 10 days of cultivation, PT cells that have grown and proliferated to some extent become A. cerevisiae. Kishirinumu are in included in the microbial cellulose producing, since granular inoculum is obtained, which after germination 10 days Eucalyptus globulus (Euca
lyptus globulus : E. Described as globras. ) The seedlings were embedded in the soil near the roots of 20 seedlings in several places. Thirty days later, these seedlings were dug out, and their roots were treated with 0.05% trypan blue according to a standard method to stain the mycelium of mycorrhizal fungi and measure the infection rate. The results shown in Table 1 were obtained. Was.

[0021]

[Table 1] Comparison of infection rates for Eucalyptus globulus seedlings

In this table, the infection rate was determined by randomly extracting 30 roots among all the roots of one seedling subjected to the measurement, and of those roots stained with trypan blue. The ratio, that is, the ratio of roots infected with mycorrhizal fungi. Specifically, the root sample after trypan blue treatment was spread evenly in a Petri dish with grid lines at the bottom, and the number of grid intersections located within the root outline and the stained part of the root among those intersections Was counted under a microscope (about 20 times magnification) and calculated as a percentage of [the number of intersections located in the stained part of the root] to [the number of intersections located in the contour of the root].

Comparative Example 1 Instead of the inoculant of the present invention, P
Except for using the spores of T itself,
The transmission rate of T to these seedlings was determined. Table 1 shows the results.

[Example 2] In place of PT spores, endophytic mycorrhizal fungi Gi gaspor separated and collected from soil by a wet sieve method
A granular inoculant ( Gig aspora cells are included in microbial cellulose produced by A. xylinum) was prepared in the same manner as in Example 1 except that spores belonging to the genus a were used. The infection rate to Globras seedlings was measured. Table 1 shows the results.

Comparative Example 2 Instead of the inoculant of the present invention, Gi
The infection rate of Gigaspora to those seedlings was measured in the same manner as in Example 2, except that the spores of the genus gaspora were used. Table 1 shows the results.

Example 3 Instead of PT spores, Acacci
Example 1 except that rhizobia belonging to the genus Rh izobium were isolated and collected from the root nodules of a mearnsii root and pre-cultured in YM (yeast extract / mannitol) medium at 30 ° C. for 10 days in the dark. A granular inoculum ( R hizobium cells are contained in microbial cellulose produced by A. xylinum) was prepared in the same manner as in Example 1.

This inoculant was treated with Accaccia mea 10 days after germination.
The rnsii seedlings were embedded in the soil near the roots of 20 seedlings at several locations, and after 30 days, these seedlings were dug out and the number of nodules formed on the roots was counted. Table 2 shows the results.

[0028]

[Table 2] Table 2. Comparison of infection rates for Acaccia mearnsii seedlings

Comparative Example 3 Instead of the inoculant of the present invention,
The infection rate of Rhizobium to those seedlings was measured in the same manner as in Example 3 except that Rhizobium rhizobia after preculture was used in suspension in sterilized water. Table 2 shows the results.

As is clear from Tables 1 and 2, by using the inoculant of the present invention, the infection rate of the plant root symbiotic microorganism to the plant can be determined by whether it is mycorrhizal fungi or rhizobial fungi. Regardless of whether they were ectomycorrhizal fungi or endomycorrhizal fungi, they increased more reliably than when these fungi were added directly to the soil. That is, in the inoculant of the present invention, the polymer-synthetic microorganism and the plant-symbiotic microorganism are obtained by simply performing liquid culture simultaneously, but the plant-symbiotic microorganism is a polymer-synthetic microorganism. Thus, it can be seen that infection of plants with these plant root symbiotic microorganisms progressed in a relatively short period of time.

[0031]

EFFECT OF THE INVENTION In the inoculant of the present invention, a useful plant root symbiotic microorganism which is difficult to infect a plant by itself is encapsulated in a microorganism-producing polymer substance, thereby greatly increasing the infection rate to the plant. Achieved.

In addition, the step of culturing and growing the symbiotic plant root microorganisms and the step of encapsulating the symbiotic plant root microorganisms with the microorganism-producing polymer substance can be performed in only one stage. It can be easily created.

Further, if a biodegradable polymer substance is used as the microorganism-producing polymer substance, this inoculant is completely decomposed after a certain period of time even if it is sprayed on the soil. Therefore, there is no possibility that the load on the environment is imposed.

Claims (7)

[Claims] 1. An inoculant for a plant, comprising a plant-root symbiotic microorganism in a microorganism-producing polymer substance. 2. The inoculant for a plant according to claim 1, which is obtained by simultaneously performing liquid culture of a polymer-synthesizing microorganism and a plant-symbiotic microorganism. 3. The inoculant according to claim 1, wherein the microorganism-producing polymer substance is water-insoluble and biodegradable. 4. The inoculant according to claim 3, wherein the water-insoluble and biodegradable polymer substance is microbial cellulose. 5. The inoculant for a plant according to claim 1, wherein the plant root symbiotic microorganism is a mycorrhizal fungus or a rhizobial fungus. 6. The shape is granular or sheet-like,
An inoculant for a plant according to claim 1, 2, 3, 4, or 5. 7. Microbial productivity comprising simultaneously culturing a polymer-synthesizing microorganism and a plant-root symbiotic microorganism in a liquid culture, and encapsulating the plant-root symbiotic microorganism with a polymer substance produced from the polymer-synthesizing microorganism. A method for preparing an inoculant for a plant in which a plant-root symbiotic microorganism is encapsulated with a high molecular substance.