Question

Intine and Exine layers of pollen grains are made up of which of the following substances
A. Pecto Cellulosic-Sporopollenin respectively
B. Sporopollenin-Pectin Cellulose respectively
C. Pectin Cellulose-Chitin respectively
D. Chitin-Sporopollenin respectively

Answer 1

Hint: Pollen grains consist of an outer coat which has two layers exine and intine. These layers protect the pollen grain from an external hostile environment.

Complete answer:
In order to solve this question, we need to know about the pollen grain.
A pollen grain is a minute particle which can vary in shape and size and structure.
These are microscopic, tiny bodies which flow freely in the air. These grains pollinate by various methods such as wind, water or insect etc. and then reach the female part and therefore, seed formation occurs. This process is termed as fertilization.
Thus, we can see pollen grains of utmost importance in the fertilization process.
So, that is why it contains a wall which acts as a barrier for the outer environment and protects the pollen.

> Cytoplasm: It is found in the center of pollen grains. It consists of nutrients and thus acts as a source of nuclei.
Tube cells are also found here.

> Intine: It is the inner layer as clear from the name. It is made up of cellulose (hemicellulose) and Pectin.
It is less resistant as compared to excine.

> Excine: It is the outer layer of pollen grain. It is extremely resistant to cold, heat, bases and thus forms a chemical material named sporopollenin.

So, the correct option is option pectin cellulose-sporopollenin respectively.

Note:
- Anemophily is the process in which pollen reaches the plant by wind.
- Entomophily is the process in which pollen reaches the plant by insect.
- Hydrophily is the process in which pollen reaches the plant by water.