Question

how is gaseous nitrogen fixed by plants?state its significance.

Answer 1

Plants that fix atmospheric nitrogen have nitrogen fixing bacteria living in their root nodules in a symbiotic relationship. These bacteria contain an enzyme, nitrogenase, that combines nitrogen gas from the atmosphere with hydrogen to produce ammonia. The bacteria exchange ammonia for carbohydrates. Some nitrogen fixing bacteria, such as Rhizobium, live in the root nodules of legumes (such as peas or beans).
Nutrient-poor soils can be planted with legumes to enrich them with nitrogen.