question_answer

Draw a labelled diagram of the sectional view of a mature pollen grain of angiosperm. Explain the features of each of its labelled parts.

Answer:

Sectional view of mature pollen grain.

Features:

(a) Exine: It is the hard outer layer made up of sporopollenin which is resistant to physical and biological decomposition. It protects the pollens from environmental extremes.

(b) Inline: The inner wall of pollen grain is called intine. It is a thin and continuous layer made up of cellulose and pectin.

(c) Vegetative cell: It is the bigger cell and has abundant food reserve.

(d) Generative cell: It is small and floats in cytoplasm of the vegetative cell. It divides mitotically to give rise to two male gametes.