Question

How do mycorrhizae act as biofertilizers? Explain. Name a genus of fungi that forms a mycorrhizal association with plants.

Answer 1

Hint: Bio-fertilizers are microorganisms that enrich nutrients in the soil, increasing the availability of nutrients to plants. The microorganisms that serve as biological fertilizers are bacteria, blue-green algae (blue-green algae) and mycorrhizal fungi.

Complete answer:
Mycorrhiza is a symbiotic association between plant roots and fungi.
There are mainly two types of mycorrhizae these are Ectomycorrhiza and Endomycorrhiza.
Ectomycorrhiza-The fungus forms a layer(mantle) on the root surface. Inside, it is located in the intercellular space of the cortex. Root cells secrete sugar and other nutrients in the spaces between cells to feed the fungal hyphae. The revealed fungal hyphae expand the root surface several times.
Function performed by fungi for the growth of plants in Ectomycorrhizal association-
1.Antimicrobial substances secreted by fungi that protect young roots from pathogens. Ectomycorrhizal association occurs in trees such as Quercus, eucalyptus, pine, peach etc. Ectomycorrhizal fungal partners mostly belong to basidiomycetes.
2.It absorbs minerals in large quantities directly from the soil and transfers them to the roots. It is known that plants with Ectomycorrhiza absorb 2-3 times more nitrogen, phosphorus, potassium and calcium.
3.Water absorption
Endomycorrhiza-Mycorrhizal fungi attack root cells and are usually limited to cortical areas and rarely pass through the endoderm. Vesicular-arbuscular species form characteristic structures in cells. After prolonged cell growth, these structures degenerate and eventually disintegrate, providing the host with food. Thus, the host plants directly benefit from VAM
The main advantages of VAM association to the plants are
1. Intake of inorganic nutrients and increased water absorption.
2. Phosphate, which is usually found in an inaccessible form in the soil, becomes abundant in plants.
From the above points, it’s clear that mycorrhizal association enables the plant to get enhanced supply of water, nitrogen, phosphorus and minerals from the soil hence acting as bio fertilizer.
Many fungi belonging to the genus glomus.

Note: Endomycorrhizal associations are more widespread than ectomycorrhizal associations and are found in almost all groups of higher plants.
On mycorrhizal roots, there is a rare or dense growth of mycelium on the surface. In mycorrhizal roots, integumentary roots(root cap) and root hairs are also absent.
Endomycorrhizal fungi are completely localized in the roots and do not affect the green part of the plant.
Ectomycorrhizal fungal partners mostly belong to basidiomycetes.