JPH11164683A - Promotion of infection of plant belonging to genus eucalyptlis with mycorrhizal fungus and infection promoter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the infection of a plant of the genus Eucalyptus with a mycorrhizal fungus useful for improving the growth of a plant of the genus Eucalyptus suitable as a pulp material, etc., by infecting a plant of the genus Eucalyptus with a mycorrhizal fungus in the presence of an extract of the root of the plant of the genus Eucalyptus with an aqueous organic solvent. SOLUTION: A plant of the genus Eucalyptus is infected with an ectotrophic mycorrhiza such as Pisolithus tinctrius, Scleroderma areolatum or S. citrinum as a mycorrhizal fungus in the presence of an infection promoter of a plant of the genus Eucalyptus with a mycorrhizal fungus comprising an extract of the root of the plant of the genus Eucalyptus with an aqueous organic solvent such as methanol, ethanol, propanol or butanol so that the period of the infection of the plant of the genus Eucalyptus with a mycorrhizal fungus is shortened, a infection ratio is improved and the infection of the plant of the genus Eucalyptus with a mycorrhizal fungus for improving growth of the plant of the genus Eucalyptus useful as a firewood, charcoal, a pulp material, etc., in soil deficient in phosphorus component is promoted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently inoculating mycorrhizal fungi into plants.

[0002]

2. Description of the Related Art In general, higher plants are known to be infected with filamentous fungi (mainly basidiomycetes) called mycorrhizal fungi. Mycorrhizal fungi, by their infection, obtain saccharides and the like from the host plant as a carbon source, and absorb water and nutrients from pores in the soil where fine hyphae can be expanded and plant roots can not enter, This forms a symbiotic relationship with the plant, which is supplied to the host plant. As a result, in many plants, a phenomenon is observed in which the growth is promoted or the drought resistance is improved when mycorrhizal fungi are infected.

[0003] There are endomycorrhizal fungi and ectomycorrhizal fungi in the mycorrhizal fungi. The endomycorrhizal fungi infect the host plant in a relatively short period of time, and the infection of the ectomycorrhizal fungus is Slightly later than. For this reason, in the natural world, endophytic mycorrhizal fungi first infect and proliferate in the host plant and dominate, and then ectomycorrhizal fungi infect and proliferate and dominate. Thus, if the tree is a perennial plant, the host will be predominantly infected by ectomycorrhizal fungi throughout most of its life cycle. In addition, ectomycorrhizal fungi wrap the infected roots by forming a structure called a mycelium (Hartichnet) and protect them from pathogens and the environment. It is also known to act to improve disease resistance, cold resistance and the like.

[0004] On the other hand, Eucalyptus is a tree species that is widely used for fuelwood and pulpwood, and this eucalyptus is also infected with mycorrhizal fungi, thereby growing on soils deficient in phosphorus. Has been reported (Commun. Soil Sci. Plant Anal., 23 (13 & 14),
1387-1396, 1992, Forest Ecology and Managemen
t, 54, 205-213, 1992, Plant and Soil, 153, 155-1
64, 1993).

In order to actively utilize these useful mycorrhizal fungi, generally, in addition to the cells themselves, spores, hyphae, and the like are mixed in soil and inoculated to plants. However, such an inoculation method requires a long period of 2 to 3 months from the time when the mycorrhizal fungus infects a host plant and its effect is observed.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a method for increasing the growth of eucalyptus plants and the like, when the mycorrhizal fungi are to be actively used to increase the mycorrhizal activity of a host plant. An object of the present invention is to provide an infection promotion method for shortening the infection period of bacteria and improving the infection rate, and an infection promotion agent therefor.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on such a method for promoting infection and an agent for promoting infection. The present inventors have found that it is promoted by an organic solvent extract, and have completed the present invention.

[0008]

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

The solvent used for extraction in the present invention can be used without any particular limitation as long as it is an aqueous organic solvent, that is, an organic solvent having an affinity for water, but typical examples thereof include methanol, ethanol, propanol, isopropanol, and the like. Examples thereof include butanol, isobutanol, tertiary butanol, acetone, ethyl acetate, acetonitrile, and mixtures thereof. These can be used in a water content range of 5 to 95% by weight. However, in order to efficiently extract an active ingredient that promotes the infection of mycorrhizal fungi in Eucalyptus plants (hereinafter referred to as an infection promoting ingredient). Preferably has a water content of 50 to 90% by weight.

There is no particular limitation on the eucalyptus plant which is a raw material for extraction.
Eucalyptus bicostata , E.camaldlensis , E.citriodr
a, E. globulus, E.grandis, E.maidenii , E.nitens, E.
Robusta , E. saligna , E. urophylla, etc. and their hybrids all contain some infection-promoting components in the aqueous organic solvent extract of their roots and are used as the raw material for extraction in the present invention. be able to. Above all, E.bicostat
When a , E.globulus and E.maidenii are used as the raw material for extraction, the extract can remarkably promote infection of mycorrhizal fungi on Eucalyptus plants.

[0011] These roots can be used either in a dried state or in a raw state as dug. When using raw roots, it is preferable to set the water content of the aqueous organic solvent used for extraction to be lower than in the case of using dry roots.

The extraction operation is performed, for example, by immersing the ground eucalyptus root in an aqueous organic solvent having a pH of 3 to 8 at room temperature or under heating for 1 to 24 hours, or by soxhlet extraction using the aqueous organic solvent. It is done by doing. As the infection-promoting agent of the present invention, this extract may be used as it is, or it may be concentrated or dried under reduced pressure to remove the aqueous organic solvent.

[0013] The mycorrhizal fungi to which the present invention is applied are also of any type. However, in many perennial plants such as trees, as described above, ectomycorrhizal fungi are predominantly infected throughout most of their life cycle,
In the present invention for the purpose of infecting plants of the genus Eucalyptus, it is considered preferable to use ectomycorrhizal fungi rather than endomycorrhizal fungi in order to more effectively utilize the effects. In the present invention, for example, as such ectomycorrhizal fungi, Pisolithus tinctriu s capable of infecting for Eucalyptus
(Acer edulis), Scleroderma areolatum ( Himetakashoro ) or S. citri num ( Niseishoro ) can be used.

The infection-promoting agent of the present invention can be used for seedlings, tissue-cultured seedlings, cuttings, and adult trees derived therefrom as long as they are eucalyptus plant individuals. The period of use may be any time before, during, or after inoculation of mycorrhizal fungi.

[0015]

[Effect] Mycorrhizal fungi are said to be absolutely symbiotic fungi that cannot grow unless they coexist with plant roots, and are supplied with carbon sources from the host plant, and are present in the roots or secreted from the roots It is thought that it grows under the influence of the ingredients.

Although the type of the active ingredient and its specific function are unknown at present, in the present invention, the active ingredient is obtained as an extractable component by extracting eucalyptus root with an aqueous organic solvent. Therefore, in the presence of an aqueous organic solvent extract containing the same, when mycorrhizal fungi are infected to a host plant, the aqueous organic solvent extract enhances the affinity between the plant roots and mycorrhizal fungi, It is considered that this active ingredient enhances the activity of mycorrhizal fungi, promotes hyphal growth, and promotes its infection.

[0017]

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

Example 1 Five-year-old tree grown in a field
After drying 100 g of E. globulus root, it is finely crushed into small pieces having a major axis of 5 mm or less, 1.5 l of 25% methanol is added, and reflux extraction is performed at 70 ° C. for 2 hours. This extract is made up to about 200 ml with a rotary evaporator. After concentration, an infection-promoting agent of the present invention having a solid content of 3.6% was obtained.

The infection-promoting agent is diluted about 10-fold with water at the time of use, and about 50,000 P. tinctrius spores are suspended in 300 ml thereof to prepare a spore suspension. 3m per plant at the base of 90 Eg lobulus seedlings
1 (about 500 spores). On the other hand, 90 similar seedlings were prepared as a control group, and a spore suspension prepared using water instead of the infection-promoting agent of the present invention was prepared in the same manner as the test group. Sprayed.

Table 1 shows the effects of the infection promoting method and the infection promoting agent of the present invention. This is the inoculation of mycorrhizal fungi 10, 20, 3
On day 0, 30 seedlings of the test group and the target group were dug out, and the results of investigating the presence or absence and infection rate of mycorrhizal fungi were summarized. Here, the presence or absence of mycorrhizal fungi was determined by examining the roots of
% Trypan blue and stained the mycelium of mycorrhizal fungi. In addition, the infection rate is based on the seedling 1
30 roots were randomly extracted from all the roots of an individual, and the percentage of the roots stained with trypan blue, that is, the percentage of roots infected with mycorrhizal fungi was shown. . 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].

[0021]

[Table 1] Table 1. Number of infected Eucalyptus globulus seedlings and their infection rate

Example 2 Five-year-old tree grown in a field
After drying 100 g of E. bicostata root, it is finely crushed into small pieces having a major axis of 5 mm or less, 1.5 l of 30% ethanol is added thereto , and reflux extraction is performed at 70 ° C. for 3 hours, and the extracted liquid is reduced to about 200 ml with a rotary evaporator. After concentration, an infection-promoting agent of the present invention having a solid content of 3.6% was obtained.

This infectious agent is diluted about 10-fold with water at the time of use, and about 50,000 spores of S. citrinum are suspended in 300 ml thereof to prepare a spore suspension. of
3 m per plant at the base of 90 E.citriodra seedlings
1 (about 500 spores) were sprayed, and the presence or absence of mycorrhizal fungi and the infection rate were examined in the same manner as in Example 1. Table 2 shows the results.

[0024]

[Table 2] Table 2. Number of infected Eucalyptus citrinum seedlings and their infection rate

Example 3 Six-year-old tree grown in a field
After drying 100 g of E. maidenii root, it is finely crushed into small pieces having a major axis of 5 mm or less, 1.5 l of 25% methanol is added thereto, and the mixture is refluxed and extracted at 70 ° C. for 2.5 hours. It was concentrated to 250 ml to obtain the infection-promoting agent of the present invention having a solid content of 3.2%.

The infection-promoting agent is diluted about 10-fold with water at the time of use, and a mycelium suspension (about 50,000) of S. areola tum is suspended in 300 ml thereof to prepare a mycelium suspension. 3 ml (approximately 500 mycelia) per plant was sprayed on the roots of 90 E. citriodra seedlings produced by the method described in Example 1, and the presence or absence of mycorrhizal fungi and the infection rate were investigated in the same manner as in Example 1. Table 3
Shows the results.

[0027]

[Table 3] Table 3. Number of infected Eucalyptus maidenii tissue culture seedlings and their infection rate

As is apparent from Tables 1 to 3, in the test group inoculated with mycorrhizal fungi together with the infection-promoting agent of the present invention,
In each case, the infection began to be observed on day 10 after inoculation of the mycorrhizal fungi, and on day 30 after inoculation, infection was observed in 70% or more of the seedlings subjected to the investigation. On the other hand, in the control group inoculated with mycorrhizal fungi without using the infection promoter of the present invention, 20
About 30% of the seedlings subjected to the investigation were infected with mycorrhizal fungi only 30 days after the inoculation, even after 30 days from the inoculation. In addition, the use of the infection-promoting agent of the present invention also improved the infection rate of mycorrhizal fungi. On the 30th day after inoculation, each test group showed a 1.5-fold or more infection rate to the control group. Was.

[0029]

As described above, according to the present invention, the period of infection of mycorrhizal fungi into Eucalyptus plants can be shortened, and the infection rate can be improved.

That is, according to the present invention, mycorrhizal fungi can be efficiently transmitted to Eucalyptus plants, and a greater effect can be expected by the infection.

Therefore, according to the present invention, it is possible to use mycorrhizal fungi on a business scale to improve the growth of Eucalyptus plants useful for pulpwood and the like.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kunimitsu Murakami 2-8-1 Iida-cho, Iwakuni-shi, Yamaguchi Japan Japan Paper Manufacturing Co., Ltd.

Claims (6)

[Claims] 1. A method for promoting the transmission of mycorrhizal fungi to Eucalyptus, wherein the mycorrhizal fungus is infected with a Eucalyptus plant in the presence of an aqueous organic solvent extract of a Eucalyptus root. 2. The bacterium against Eucalyptus according to claim 1, wherein methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert-butanol, acetone, ethyl acetate, acetonitrile or a mixture thereof is used as the aqueous organic solvent. How to promote infection of root fungi. 3. The method according to claim 1, wherein the aqueous organic solvent extract is Eucalyptus bi.
costata , E.camaldl ensis , E.citriodra , E.globulus ,
E.grandis , E.maidenii , E.nitens , E.robus ta , E.sali
The method for promoting infection of mycorrhizal fungi to Eucalyptus according to claim 1 or 2, which is extracted from roots of gna , E. urophylla and hybrids thereof or a mixture thereof. 4. The method according to claim 1, 2 or 3, wherein ectomycorrhizal fungi are used as mycorrhizal fungi. 5. An ectomycorrhizal fungus, Pisolithus tinctr
The method for promoting infection of mycorrhizal fungi with respect to the genus Eucalyptus according to claim 4, wherein ius , Scleroderma areolatum or S. citrinum is used. 6. The mycorrhizal fungi of Eucalyptus genus, which are obtained by extracting the roots of Eucalyptus plants with an aqueous organic solvent, can shorten the period of mycorrhizal infection of Eucalyptus and improve the infection rate. Infection promoter.