(i) Diagram from next page in the given figure,
A represents the pollen grain
B represents the pollen tube
C represents the ovule
D represents the male germ cells
(ii) The transfer of pollen grains from the anther to the stigma of a flower is known as pollination.
Significance of pollination :
(a) It is a significant event because it precedes fertilization.
(b) It brings the male and female gametes closer for the process of fertilization.
(c) Cross-pollination introduces variations in plants because of the mixing of different genes. These variations further increase the adaptability to plants towards the environment or surroundings.
(iii) Double fertilization is a characteristics feature of flowering plants. In this process, out of the two sperm nuclei, one sperm nucleus fuses with the egg nucleus to form an embryo (process is called syngamy) and another fuses with the polar nucleus to form an endosperm (process is called triple fusion). Because two kinds of fusion—syngamy and triple fusion—take place, the process
is known as double fertilisation. After fertilisation,
(i) the ovule develops into a seed.
(ii) the ovary develops into a fruit.
