Question

Read the different components from (a) to (d) in the list given below and tell the correct order of the components with reference to their arrangement from outer side to inner side in a woody dicot stem:
(a) Secondary cortex
(b) Wood
(c) Secondary phloem
(d) Phellem
The correct order is:

• A. (d),(c),(a),(b)
• B. (c), (d), (b), (a)
• C. (a),(b),(d),(c)
• D. (d), (a), (c), (b)

Answer 1

The correct option is D (d), (a), (c), (b)

The outer cells of the cork cambium or phellogen differentiate into cork or phellem. The cork is impervious to water due to suberin deposition in the cell wall.
The inner cells of the cork cambium differentiate into secondary cortex or phelloderm. The cells of secondary cortex are parenchymatous.
Cells displaced towards the outside of the vascular cambium differentiate into secondary phloem whereas the cells formed toward the inside are called secondary xylem or wood.