Question

Self-incompatibility is a device for:
I. Ensuring cross-pollination
II. Preventing self-pollination
III. Ensuring self-fertilisation
IV. Genetic control to prevent self-fertilisation

Choose the option containing correct statements from those given above.

• A. I, II and III
• B. I, II, III and IV
• C. I, III and IV
• D. I, II and IV

Answer 1

The correct option is D I, II and IV

Flowering plants have developed many devices to discourage self-pollination. In some species, pollen release and stigma receptibility is non-synchronised, i.e., either the pollen is released before the stigma becomes receptive or stigma becomes receptive much before the release of pollen.

In some other species, the anther and stigma are placed at different positions so that the pollen cannot come in contact with the stigma of the same flower. Both these devices prevent autogamy.

The third device to prevent inbreeding is self-incompatibility. This is a genetic mechanism and prevents self-pollination (from the same flower or other flower of the same plant) by inhibiting pollen germination or pollen tube growth in pistil.

Hence, I, II, and IV are correct statements.