Question

(a) Name the organic material which makes up exine of the pollen grain. How is this material advantageous to pollen grain?

(b) Still it is observed that it does not form a continuous layer around the pollen grain. Give reason.

(c) How are 'pollen banks' useful? [3]

Answer 1

(a) The hard outer layer called exine is made up of sporopollenin which is one of the most resistant organic material. [0.5]

• It can withstand high temperature
• It is resistant to strong acids
• It is resistant to strong alkali
• It is resistant to enzymes [1/2] (any one can be written)

(b) Exine does not form a continuous layer around the pollen grain as it has germ pores through which the pollen tube emerges. [1]

(c) Pollen grains are stored in pollen banks for future use such as in plant breeding programs and also biochemical and physiochemical studies. [1]