Question

(a) Draw a neat diagram of a flower showing its various parts.
(b) What is pollination? How does pollination occur?
(c) Describe the process of fertilisation in a flower with the help of labelled diagrams.
​(d) What changes take place in the flower after fertilisation which lead to the formation of seeds and fruit?

Answer 1

(a)


(b) Pollination is the process in which the transfer of pollen grains takes place from anther to stigma for the purpose of fertilization in plants.

Pollination can occur by two ways -

• Self pollination: When the pollen reaches the stigma of the same flower, the process is known as self pollination.

• Cross pollination: When the pollen reaches the stigma of a different flower on the same plant, or the flower of a different plant of the same kind, the process is known as cross-pollination.

(c) Fertilisation is the process of fusion of male and female gametes. In plants this process is called as double fertilisation. It is a characteristic 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 (this process is called syngamy) and another fuses with the polar nucleus to form an endosperm (this process is called triple fusion). Because two kinds of fusion, syngamy and triple fusion, take place, the process is known as double fertilisation.



(d) After the process of fertilisation, the following changes take place.

• The ovary gives rise to the fruit while the other structures of the flower fall down.

• The ovules present inside the ovary develop into seeds. Seeds contain an embryo, which is protected by the seed coat.