Question

Exine of pollen grain is composed of
(a) pectocellulose (b) lignocellulose
(c) sporopollenin (d) lignin

Answer 1

Pollen grain is a uninucleate cell with two layered cell wall. Exine is the outer covering of pollen grain which is highly sculptured with sporopollenin; a chemically inert polymer of carotenoid ester which is highly resistant to degradation by any enzyme, as known so far. Option C is correct. 

The inner thin cell layer of cellulose/pectin cellulose makes intine; this makes option A incorrect. 

Lignin may or may not be present in the outer wall which makes option B incorrect. Correct answer is B. 

The sticky oily covering found around surface of pollens is termed as pollen kit. It is not part of pollen wall. This make option D incorrect.

Therefore, the correct answer is option C.

Answer 2

Explanation:

$\tt\pink{\underline{Exine}}$

→ It age outer layer of pollen grain and very hard.

→ It age made up of sporopollenin in which is most resistance organic material present in nature .

→Sporopollenin is Resistance to high temperatures stronger acids and alkaline and also to enzyme .