Question

Complementary cells of lenticels develop from:
A. Phellem
B. Phelloderm
C. Endodermis
D. Phellogen

Answer 1

Hint: Lenticels are the pores which are present in the woody stem. These lenticels help in the exchange of gases between the external environment and the internal tissues. They also help the plant in transpiration. Transpiration that takes place with the help of lenticels is known as lenticular transpiration.

Complete answer:
To solve the given question, we must know about the lenticels.
When a layer of the hypodermis becomes meristematic, it gives rise to cork cambium. Cork cambium is also known as the phellogen. The layer of cells cut cells from the outer sides and is then called the phellem. Phellem is also known as cork cells. When phellogen cuts the cells from its inner side it is known as the phelloderm or the secondary cortex.
The phellem consists of dead cells. These cells have deposition of fatty substances called the suberin in them. Thus these cells are said to be suberized. Suberin provides the phellem with buoyancy.
The phellem, phellogen and the phelloderm together constitute the periderm. The main function of the periderm is to provide protection to the plant.
There are some loosely arranged areas in the periderm. These areas are known as the lenticels. Certain portions of the phellogen become more active. Due to this increase in the activity the cells are cut off rapidly. The result of this is that intercellular spaces are formed in them.
These loosely arranged cells are known as the complementary cells while the loosely arranged areas are the lenticels.

Therefore, the correct answer to the question is option D i.e Phellogen.

Note: Here it must be noted that Lenticels are not only present on the woody bark and root of the dicots but also on some fruits like the apple. These pores or the lenticels might allow the entry of certain bacteria through these pores. These fruits are also prone to fungal infection.