Mycorrhizal fungi and forest trees
Mycorrhizal fungi are ubiquitous fungi found in the soil and can form symbiotic associations with the roots of plants and forest trees. The symbiotic mycorrhizal fungi acquire carbohydrates and other nutrients from the tissue cells of the seedlings, and the mycorrhizal fungi also increase the ability of the seedlings to absorb water and nutrients, thereby promoting the growth of the seedlings. Mycorrhizal fungi can be divided into three major categories: ectomycorrhizae, endomycorrhizae, and ectendomycorrhiae. Its effectiveness on trees includes: promoting the growth of forest trees, improving the resistance of forest trees to physical and chemical change and enhancing the resistance to disease of forest trees.
The site where plants absorb nutrients and moisture is mainly the new grown roots. The infection of the roots with mycorrhizal fungi promotes the production of root hairs. Therefore, mycorrhiza not only has the effect of promoting nutrients and water absorption, but also has the ability to improve soil structure, increase soil aeration and water retention and promote plant growth and development.
In the cycle of nutrients, the drop litter of plants contains several ester and phenolic substances, which not only have toxic effects on plants and fungi, but also inhibit the decomposition of drop litter. The mycorrhizal fungi can secrete various types of enzymes and convert this non-decomposable toxic substance into nutrients that can be used by plants.
In the promotion of forest growth, the results of the study confirmed that the symbiosis between mycorrhizal fungi and young tree has a significant effect on the growth of the portions of the tree above or below ground. The seedlings inoculated with mycorrhizal fungi grew several times faster than uninoculated seedlings.
The mycorrhizal fungi can improve the drought resistance, freezing resistance, acid and toxic substances, salt tolerance, resistance to the impoverishment of soil nutrient, and resistance to heavy metals of host trees.
The ectomycorrhizal fungi have the effect of preventing or reducing the damage to plant diseases. For example, the seedlings of Pinus taeda, which is inoculated with Pisolithus tinctorius, are resistant to damping-off caused by Rhizoctonia solani, not only improving the survival rate of seedlings, but also promoting seedling growth.
Reference: All pictures are obtained from internet.