Explain the root nodule formation of leguminous plant explain for 5 mark answer
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Answer:
Root nodules are found in plants belonging to the family Fabaceae or Leguminosae.They include leguminous plants like beans, peas, peanuts etc.It is formed due to the symbiotic association between the leguminous plant and the host-specific bacteria called the rhizobium.The steps involved in root nodule formation are- 1) Rhizobium bacteria divides to form colonies which surround the root hairs and epidermal cells of the plant.
2) The root hair gets curled and get invaded by the bacteria.
3) After the invasion, it forms an infection thread that carries the bacteria into the cortex of the root.
Later the bacteria gets modified into rod-shaped bacteria called bacteroids.
4) As a result, the cells in the cortex and pericycle undergo cell division, which forms the root nodules.
5) These root nodules get connected with the vascular tissues of the roots for nutrient exchange and help in nitrogen fixation.