Question

1. Given alongside is a diagrammatic
sketch of the sectional view of a
germinating pollen grain. Study
the same and then answer the
buy questions that follow :
(a) Name the parts labelled 1, 2,
3, 4 and 5
(b) Where does the germination
of the pollen grain takes place and how?
(c) What is the function of the part labelled
4 ?
(d) What happens to the part labelled '5' during
the process ?
​

Answer 1

Answer:

a) The given diagram shows generating pollen.

b) 1-Exine

2-Intine

3-Pollen Tube

4-Vegetative nucleus

5-Generative nucleus

c) The stage is found when the pollen reaches a stigma of a flower and the chemical reaction stimulate the tube elongation and subsequent fertilisation.

d) The vegetative nucleus synthesizes the pollen tube.

e) The Generative nucleus bifurcates into two male gametes out of which one fuses with the polar nuclei in triple fusion to form endosperm and the other male nuclei fuse with the egg cell to form the zygote and subsequent embryo.