JPH0724507B2 - How the root system is formed - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for forming a root system when artificially cultivating mycorrhizal fungi and the like using a host tree, and particularly to a large-scale plant represented by Matsutake. The present invention relates to a method for forming a root system suitable for inoculating mycorrhizal fungi.

[Outline of Invention]

INDUSTRIAL APPLICABILITY The present invention increases the distribution of nutrient translocation to roots inoculated with the same host tree by selectively restricting the growth of roots of the host tree that are not inoculated with fungi, and increases the distribution of matsutake mushrooms, truffles, etc. It is intended to efficiently form a root system suitable for inoculating the mycorrhizal fungus.

[Conventional technology]

Conventionally, various attempts have been made over many years for artificial cultivation of edible mycorrhizal fungi represented by Matsutake mushrooms, truffles, honshimeji and the like. In particular, regarding artificial cultivation using host trees (Pinus densiflora) in forest land, including the method of operation, refer to the literature [for example, "Matsutake" by Hamada and Ohara (published in 1975, 7th edition) Agriculture, Mountain and Village Village Cultural Association, Matsutake. Research round-table conference "How to make Mt. Matsutake" (published in 1983), etc.]
Has been compiled into.

Among them, various inoculum sources (spore sap, fungal umbrella, spore dumplings, infected seedlings, fungal trees,
It has been described that various root collecting operations (such as the soil method, the groove cutting method, the root cutting method, and the laying method) are performed using cultured mycelia, etc. I haven't heard of any successful cases.

In view of such a situation, the present applicant has previously proposed that Japanese Patent Publication No.
In the specification, a completely new method for forming mycorrhiza was proposed. This method introduces new roots of the host tree into a space that is kept in high humidity and has good air permeability, and then inoculates these new roots with the prescribed mycorrhizal fungus to achieve the desired epiphytes. The feature is that 1) sterilization or semi-sterilization of the inoculation part can be achieved by a simple method of utilizing the growing point of the plant, 2) It can be kept in a clean and well-ventilated state, and the engraftment rate can be dramatically improved. 3) Inoculation fungi The agent for controlling filamentous fungi that inhibits the growth of mycorrhizal roots It has excellent advantages such as the fact that it is made possible by the simple principle of not bringing in assimilable substances of various bacteria regardless of the use of.

[Problems to be solved by the invention]

By the way, there are some problems to be solved when the above method is applied to artificial cultivation in forests and the like.

For example, the morphology of roots to be inoculated with mycorrhizal fungi has not been sufficiently examined, and there are many fine roots in the “white” (mycorrhizal aggregates) that have already formed in the natural state. The simple analogy that the morphology when inoculating a bacterium should be the same is a prejudice, and nutritional physiologic studies have not been made in consideration of translocation of nutrients to the root system.

Therefore, the applicant of the present application proposed a method of forming a root system suitable for inoculation of mycorrhizal fungi by selectively fertilizing the roots of the host tree in the specification of the patent application filed at the same time as the present application.

However, when the root area soil has a high fertility, or when a host tree with an extremely large number of branched roots grown by performing floor replacement, rooting, etc. in a fertile nursery through forced gardening is used, Since the inoculated roots also grow relatively well, the effect of selective fertilization may not be fully exerted.

In this case, pruning and removing these roots is one solution to this problem, but it is labor-intensive to dig the roots of host trees that have been planted in mature trees or cultivated beds in forests and perform pruning work. It is inefficient in view of the situation, and there is a risk that the survival rate of the host tree will be reduced if it is done when the plant is transplanted to the cultivation floor, and if it is a large tree, there is a labor problem.

Therefore, the present invention has been proposed in view of such circumstances, and particularly in a host tree having a large number of branched roots or a host tree grown in soil with high fertility, the roots to be inoculated are nutritional physiology. It is an object of the present invention to provide a method for forming a root system that can be made into a form suitable for inoculation.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention is characterized by selectively suppressing the nutrient absorption of the roots of the host tree and increasing the translocation distribution of the nutrients to the roots to be inoculated.

The growth of mycorrhizal fungi is primarily controlled by the nutritional physiological conditions of the host tree, which is the nutrient source. Therefore, in order to grow mycorrhizal fungi, it is necessary to secure a quantitative supply distribution of nutrients from the host tree to the mycorrhizal fungi.

Here, for example, when the root tip derived from one host tree is inoculated and settled with mycorrhizal fungi, the amount of nutrients (especially sugar here) supplied from this host mycorrhizal fungus per day Then, it can be roughly expressed by the following equation.

P _st : The amount of transmigrating sugar that can be used per day by a mycorrhizal fungal colony that has grown on the root tips derived from one host tree.

 n: Total number of root tips having a growing point.

ν: Number of root tips contained in mycorrhizal fungal colonies to which hyphae are connected.

m _x : Relative translocation ratio of the x-th root in the root tip in the mycorrhizal colony.

S _A : Amount of sugar synthesized by assimilation.

S _R : The amount of sugar consumed by respiration.

S _D : Amount of sugar consumed by catabolism.

In the formula (1), the sugar amount S _A synthesized by assimilation and the sugar amount S _R consumed by respiration are common items in plant cultivation in general, and the effective leaf area of the host tree, the average daily irradiation light intensity,
It depends on sunshine hours, photosynthetic efficiency, carbon dioxide concentration in leaf atmosphere, etc. The sugar content S _D consumed by catabolism is
Depends on the average fertility of the rhizosphere.

In the present invention, by reducing the total number n of root tips having a growing point, the amount of _{transmigrating} sugar Pst that can be used per day is increased and the supply distribution of nutrients from the host tree to mycorrhizal fungi is ensured. did.

The total number n of root tips having the above-mentioned growth point can be easily controlled by drying or some other method. That is,
For example, if the vicinity of the root which is not inoculated is dried, it becomes difficult to absorb the nutrients of the root in this portion, and the growth of the root is prevented. In contrast, the roots show good growth in the appropriately watered area. Therefore, if irrigation means, etc. are provided only in a specific area of the root area of the host tree, and the root area soil of the other part is dried, the roots will grow only in the above-mentioned irrigated area. .

The roots to be selectively grown inevitably have a high relative translocation ratio of nutrients, and are suitable for inoculating mycorrhizal fungi and the like.

[Action]

When the nutrient absorption of the roots of the host tree is selectively suppressed, the growth of the roots in the suppressed portion is stopped, and the total number n of root tips having a growth point is reduced.

As a result, the nutrient translocation distribution to the roots where the growth is sustained is increased.

〔Example〕

Hereinafter, examples in which the present invention is applied to the formation of a root system suitable for inoculation with Matsutake mushrooms will be described with reference to the drawings.

As shown in FIGS. 1 and 2, a cylindrical plastic net (2) (diameter 45 cm, height 20 cm) is placed inside the biscuit pot (1).
Then, it has a double structure with a reinforcing material of 10 mm and a net with a mesh that does not cover the soil. ), And the host tree (4) that was forcibly grown in the nursery in advance in the soil (3).
(About 5th grade red pine) was planted. The space between the pot (1) and the cylindrical plastic net (2) was filled with a lightweight soil (5).

Then, watering was uniformly carried out until the host tree (4) became rooted. When rooted, new roots appeared in a wide range from the side surface of the cylindrical plastic net (2).

Then, the uniform irrigation was stopped, and water or a dilute liquid fertilizer was selectively supplied from irrigation points (6) provided at a plurality of locations (three locations in this example).

While uniform watering was observed, there was no difference in root growth between the plastic net (2) and the clay pot (1), but near any one of the watering points (6). A water sensor (7) was installed in the water, and the irrigation conditions of each irrigation point (6) were adjusted so that the midpoint of each irrigation point (6) was in a sufficiently dry state (for example, pF2.7 to 2.8). Here, the starting point of irrigation was pF2.0, and the amount of irrigation each time was adjusted by a timer and a flow rate.

Then, in about 1 week, the roots that had emerged away from the irrigation point (6) withered, browned, and stopped growing. On the other hand, irrigation point (6)
The root (4a) emerging from the vicinity of the plant was observed to continue growing, and the root growth between the pot (1) and the plastic net (2) was reduced to about half. It was also found that the sugar content of the root (4a), which continued to grow, also increased at this time.

Therefore, the lightweight medium (5) buried between the pot (1) and the plastic net (2) was removed, and the roots (4a) emerging from the vicinity of the irrigation point (6) were collected, and cultured mycelium of matsutake fungus. The body was inoculated. The black browning of the roots was rapid after inoculation, demonstrating good settlement.

〔The invention's effect〕

As is clear from the above description, in the present invention, since the nutrient absorption of the roots of the host tree is selectively suppressed by a means such as drying to prevent its growth, the roots having the growing point of this host tree The total number of edges is reduced, resulting in a higher translocation of nutrients to the roots that continue to grow. Therefore, by inoculating the root system formed by the present invention with mycorrhizal fungi and the like, it becomes possible to secure a supply amount of nutrients from the host tree to the mycorrhizal fungi, etc., and promote good settlement and sustainable growth. Can be achieved.

In particular, the present invention is effective when the effect is not sufficient only by selective fertilization of inoculated roots, even for host trees having a large number of branch roots and host trees planted in soil with high fertility, mycorrhizal roots It is possible to form a root system morphology suitable for formation.

[Brief description of drawings]

FIG. 1 is a schematic plan view showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1 …… biscuit 2 …… plastic net 4 …… host tree 6 …… irrigation point

Claims (1)

[Claims] 1. A method for selectively suppressing nutrient absorption of roots of host trees,
A method for forming a root system, which comprises increasing the translocation distribution of nutrients to inoculated roots.