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 bacteroides.
(iii). Roots secrete chemical atractants.
(iv). Formation of infection thread.
(v). Formation of nodules.
(v). Formation of nodulues.
(vi). Division of infected cortical cells.
(vii) Curlinig 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

Correct Answer - A
Roots of a legume secrete chemical attractants. Bacteria collect over the root hair, release certain hormones and enzymes, which cause curling of root hair around bacteria degradation of cell wall and formation of an infection thread enclosing the bacteria. infection thread grows along with multiplication of bacteria. the inifected cortical cells of root divide and make direct connection with vascular tissues. it produces swellings called nodules. Infected cells enlarge. Bacteria stop dividing and form irregular polyhedral strutures called bacteroides.