Question

Write the two events involved in the sexual reproduction of flowering plants.
(a) Discuss the first event and write the types.
(b) Give advantages and disadvantages of that.

Answer 1

The sexual reproduction of flowering plants involves:

(1) Pollination (2) Fertilization

(a) Pollination is the transfer of pollen grains from the anther to the stigma of a flower. Pollen grains are transferred by agents like air, water, insects etc.

Types of pollination-

Self-pollination (Autogamy): When the pollen grains are transferred from the anther of a flower to the stigma of the same flower or another flower of the same plant it is known as self-pollination.

Cross-pollination (Allogamy): When the pollen grains are transferred from the anther of a flower to the stigma of the another flower of the different plant, it is known as cross-pollination.

(b) Advantages self-pollination are

(1) Self-pollination is certain in bisexual flowers.

(2) Flowers need not depend on agents.

(3) No wastage of pollen grains.

Disadvantages of self-pollination

(1) Seeds are less in number.

(2) Seeds produce weak plants due to the minute endosperm.

Advantages of cross-pollination

(1) It leads to the production of new varieties.

(2) More viable seeds are produced.

Disadvantages of cross-pollination are

(1) Plants have to depend on agents for Pollination.

(2) Wastage of Pollen grains occurs.