Question

Nodulated roots occur in -
(a)Pea
(b)Wheat
(c)Mustard
(d)Rice

Answer 1

Hint: Nodulated roots occur mainly in leguminous plants whose roots are invaded by symbiotic bacteria. The bacteria nodulate the roots and fixate substances present in the soil, which are beneficial for the host plant.

Complete answer: - Nodulated roots are found mainly on legume plants and they form a symbiotic relationship with nitrogen-fixing bacteria.
- The pea plant, Pisum sativum, is a legume plant that has nodulated roots. The nodule contains the Rhizobium bacteria that fix nitrogen into assimilated substances for the plant.
- In legume root nodules, the nitrogen gas from the atmosphere is converted to ammonia and then assimilated to amino acids and other nutrients that are supplied to the entire plant through the phloem.
- The process of nodulation occurs above the zone of root elongation and below the emerging root hairs.
- Root nodulation in plants helps in the reduction in the usage of the chemical fertilizers as the plants no longer require nitrogen-based fertilizers.

Additional information: - The pea belongs to the family Fabaceae or Leguminosae. The plants are also known as the legume or pulses.
- Other plants that are legumes are beans, lentils, chickpeas, soybeans, etc.
- As most legumes have nodulated roots that carry out nitrogen fixation, they have a role in crop rotation.
- The nodules contain leghemoglobin that is similar to myoglobin in the animal bodies that carry out respiration using oxygen.

So, the correct answer is ‘Pea’.

Note: - The rice and wheat plants belong to monocots and the Poaceae family. The mustard plants belong to the Brassicaceae family and are dicotyledons.
- Nodules are classified as determinate and indeterminate.