Question

______ is a couple of layers thick, made of narrow, thin walled and nearly rectangular cells. It cuts off cells on both sides. The outer cells differentiate into __________ or __________ while the inner differentiate into _________ or ____________. The three together is called ____________.
Select the right sequence of words to complete the above.

• A. Phellogen, cork, phellem, secondary cortex, phelloderm, periderm
• B. Phellem, phelloderm, cork, secondary cortex, phellogen, periderm
• C. Phellogen, cork, periderm, secondary cortex, phellem, phellem
• D. Phellem, secondary cortex, periderm, cork, phellogen, phelloderm

Answer 1

Answer: (A)

Phellogen is thick with a couple of layers. It is made of narrow, thin-welled and nearly rectangular cells. Phellogen cuts off cells on both sides. The outer cells differentiate into cork or phellem, whereas the inner cells differentiate into secondary cortex or phelloderm. The cork is impervious to water due to suberin deposition in the cell wall. The cells of the secondary cortex are parenchymatous. Phellogen, phellem and phelloderm are collectively known as periderm.