Question

What is the fate of primary xylem in a dicot root showing extensive secondary growth
(1) It is retained in the centre of the axis
(2)It gets crushed
(3)May or may not get crushed
(4)It gets surrounded by primary phloem​

Answer 1

Explanation:

(2) it gets crushed due to secondary growth

Answer 2

The correct option is (1) that is:-

It is retained in the center of the axis.

Explanation:-

During secondary development of dicot root:

1. The cells of cambium strips generated inward differentiate into secondary xylem elements and those generated outside differentiate into secondary folium.
2. The primary phloem remains in its original position at the center of the spindle but the primary phloem is pushed outwards and crushed.

Hence option (1) is the correct one:- It is retained in the center of the axis.