Question

Consider the following steps involved in nodule formation in the root of a legume.
(i) Bacteria release chemicals and enzymes.
(ii) Bacteria stop dividing and form baceroides.
(iii) Roots secrete chemical attractants.
(iv) Formation of infection thread.
(v) Formation of nodules.
(vi) Division of infected cortical cells.
(vii) Curling of root hair and degradation of their cell wall.
(viii) infection thread grows along with multiplication of bacteria.
Arrange the steps in the right sequence and mark the correct option.

• A. (iii), (i), (vii), (iv), (viii), (vi), (v), (ii)
• B. (iii), (iv), (viii), (i), (vi), (vii), (ii), (v)
• C. (i), (iv), (iii), (vi), (v), (vii),(viii), (ii)
• D. (i), (iii), (vi), (iv), (viii), (ii), (v), (vii)

Answer 1

The correct option is A (iii), (i), (vii), (iv), (viii), (vi), (v), (ii)

While the formation of root nodules, firstly the roots secrete chemical attractants, then bacteria releases some enzymes which lead to curling or root hair after that infection thread grows which leads to the infection and division of infected cortical cells which leads to swelling of root and nodules are formed.

So, the correct option is '(iii), (i), (vii), (iv), (viii), (vi), (v), (ii)'.