Question

Leguminous plants are important in agriculture because-

• A. They are disease resistant.
• B. They have a high amount of proteins.
• C. They require less amount of nitrogen for growth.
• D. Nitrogen-fixing bacteria are symbiotically associated with them

Answer 1

The correct option is D

Nitrogen-fixing bacteria are symbiotically associated with them

The correct answer is option D.

Explanation of the correct answer:

1. Leguminous plants are a very rich source of proteins, thus it is very important to cultivate these plants.
2. In the roots of leguminous plants, bacteria called Rhizobium lives which helps in the process of nitrogen fixation.
3. The bacteria live in the roots of these plants in a symbiotic association.
4. In the process of nitrogen fixation, ammonia is formed from the free nitrogen available in the atmosphere.
5. The bacteria like Rhizobium, act on the atmospheric nitrogen using the enzyme nitrogenase and convert it into a usable form for plants.

Figure showing the process of nitrogen fixation by Rhizobium:

Explanation of the incorrect options:

Option A:

Leguminous plants are naturally not disease-resistant, they can get diseases due to some microbes or pathogens.

Option B:

The seeds developed from the leguminous have high protein content in them because of which they are quite useful, but it is not the only reason for them to be useful.

Option C:

Leguminous plants need a high amount of nitrogen for their growth and development.

Final answer: Leguminous plants are important in agriculture because nitrogen-fixing bacteria are associated with them.