Choose the correct statement regarding self-incompatibility:

(I) Self-incompatibility ensures cross-pollination.

(II) Self-incompatibility prevents self-fertilization.

(III) Self-incompatibility ensures self-fertilization.

(IV) Self-incompatibility ensures both self and cross-pollination.

Choose the correct statements from those given above.

I and II

The correct answer is Option (3) -I and II

Self-incompatibility is a mechanism observed in certain plant species that serves multiple purposes in the reproductive process. It plays a crucial role in promoting outcrossing (cross-pollination) by preventing self-fertilization and maintaining genetic diversity within plant populations. Here is a detailed explanation of the different aspects of self-incompatibility.

I. Ensuring cross-pollination:  Cross-pollination refers to the transfer of pollen from the anther of one flower to the stigma of another flower on a different plant. Self-incompatibility mechanisms evolved as a way to promote cross-pollination, which has several advantages. Cross-pollination allows for the exchange of genetic material between different individuals, leading to increased genetic diversity in the offspring. This genetic diversity enhances the adaptability and survival chances of the plant population.

II. Preventing self-fertilization:  Self-fertilization, also known as selfing or self-pollination, occurs when the pollen from the anther of a flower is transferred to the stigma of the same flower or another flower on the same plant. self-incompatibility prevents self-pollen (from the same flower or other flowers of the same plant) from fertilising the ovules by inhibiting pollen germination or pollen tube growth in the pistil.

Overall, self-incompatibility is a complex and diverse mechanism that promotes cross-pollination, prevents self-fertilization. It is an important evolutionary adaptation that ensures genetic diversity and promotes the long-term survival and adaptation of plant populations.