Question

Leguminous plants are important in agriculture because
(a)They are disease resistance
(b)They have a high amount of protein
(c)They require less nitrogen for growth
(d)Nitrogen bacteria are symbiotically associated in them

Answer 1

Hint: Leguminous plants show a type of mutualistic relationship with certain organisms which help in increasing the fertility of the soil and thus supports their growth. A close physical association exists between legumes and certain organisms.

Complete answer:
Atmospheric nitrogen cannot be used directly by most organisms. Certain bacteria and cyanobacteria can reduce atmospheric nitrogen gas to ammonium called nitrogen fixation and organisms are called nitrogen fixers. Nitrogen-fixing bacteria like Rhizobium is closely associated with the roots of leguminous plants. This is a type of mutualistic relationship known as symbiosis. The bacteria obtain nutrition from the plants and in turn, it helps with the process of nitrogen fixation and hence both species are benefited.

Additional Information: -The legumes are all members of a single plant family, the Fabaceae e.g. beans, pea, lentils, soya beans, peanuts, alfalfa, clover, etc.
-Legumes contain bacteria in the root which convert atmospheric nitrogen gas into usable forms.
-Flowering plants cannot use atmospheric nitrogen but must absorb nitrate or ammonium nitrogen through the roots.
-The association of bacteria and legumes provides food and shelter to bacteria where bacteria supply fixed nitrogen to the plant.
-The association of two partners bacteria and host is recognized by chemical lectins, a phyto agglutinins which is a carbohydrate-containing plant protein produced by the plants.

So, the correct answer is, ‘Nitrogen bacteria are symbiotically associated with them.’

Note: -Fabaceae family is also known as a legume family or pea family whose seed contains two large cotyledons.
-The farmer often rotates legumes with crops that deplete soil nitrogen.