Q.How is the mycorrhizal association helpful in absorption of water and minerals in plants?

Mycorrhiza is a symbiotic (mutualistic) association between the roots of many vascular plants and certain soil fungi. The fungal partner's thread-like hyphae spread extensively through the surrounding soil, penetrating far beyond the region that the plant's own root hairs could reach and greatly increasing the total absorptive surface area available to the plant. Because of their fine, extensively branching structure, these hyphae are especially effective at absorbing water and certain minerals (most notably phosphorus, but also others) from the soil and delivering them to the plant's roots. In return, the fungus receives carbohydrates (sugars) manufactured by the plant through photosynthesis, making the relationship mutually beneficial. In some plant species, thi …

Mycorrhiza literally means "fungus-root," and it refers to a mutualistic symbiotic association formed between the roots of a large majority of vascular plant species and certain species of soil fungi.

How mycorrhizal association aids water and mineral absorption:

• The fungal partner grows as a network of very fine, thread-like hyphae that either surround the root (ectomycorrhiza) or penetrate into root cells (endomycorrhiza), while also extending outward into the surrounding soil far beyond the zone that the plant's own roots and root hairs alone could reach.
• Because fungal hyphae are extremely thin and branch extensively, they achieve an enormously large total surface area in contact with the soil — much greater, relative to their mass, than roots or root hairs can achieve on their own.
• This vastly increased absorptive surface allows the fungal hyphae to explore, and take up water and minerals from, a much larger volume of soil than the plant's roots could exploit unaided, effectively extending the plant's absorptive reach.
• Mycorrhizal fungi are particularly efficient at absorbing certain minerals that are otherwise present in the soil in relatively immobile or scarce forms — most notably phosphorus, and also other nutrients — and translocating them to the plant's roots.
• In return, the plant supplies the fungus with organic nutrients — principally sugars produced by photosynthesis — that the fungus, lacking chlorophyll, cannot manufacture for itself. This exchange of resources (minerals/water for sugars) is what makes the relationship truly symbiotic and mutually beneficial, rather than one organism simply parasitising the other. …

Define mycorrhiza as a mutualistic plant root–fungus association, explain the structural basis of its benefit (hyphae hugely increasing absorptive surface area beyond the reach of roots), specify that phosphorus uptake is especially enhanced …

• Describing the association as purely one-sided (only benefiting the plant) and omitting that the fungus receives sugars in return — it is a mutualistic, not parasitic, relationship. …