Read the passage and answer the following questions.

Flowering plants employ various mechanisms to discourage self-pollination and promote cross-pollination. These mechanisms include temporal separation of pollen release and stigma receptivity, spatial separation of anther and stigma, self-incompatibility, and the production of unisexual flowers. In some species, the timing of pollen release and stigma receptivity is not synchronized. This prevents self-pollination as either the pollen is released before the stigma becomes receptive or the stigma becomes receptive before the pollen is released. Similarly, in other species, the anther and stigma are positioned in a way that prevents self-pollination by avoiding contact between the pollen and stigma of the same flower. Self-incompatibility is a genetic mechanism that prevents self-pollen, whether from the same flower or other flowers of the same plant, from fertilizing the ovules. It achieves this by inhibiting pollen germination or pollen tube growth in the pistil.The production of unisexual flowers is another device to prevent self-pollination. For example, in plants like castor and maize, which are monoecious, having both male and female flowers on the same plant prevents self-pollination (autogamy) but not pollination between flowers on the same plant (geitonogamy). On the other hand, in species like papaya, male and female flowers are present on different plants (dioecy), effectively preventing both autogamy and geitonogamy.During pollination, the pistil may encounter pollen of the wrong type, either from other species or from the same plant if it is self-incompatible. The pistil has the ability to recognize whether the pollen is of the right type (compatible) or the wrong type (incompatible). If the pollen is compatible, the pistil accepts it and promotes post-pollination events leading to fertilization. However, if the pollen is incompatible, the pistil rejects it by preventing pollen germination on the stigma or pollen tube growth in the style.The recognition and acceptance or rejection of pollen by the pistil involve a continuous dialogue between the pollen grain and the pistil. This dialogue is facilitated by chemical components present in both the pollen and pistil. In recent years, scientists have made progress in identifying some of these components and understanding the interactions that lead to the recognition, acceptance, or rejection of pollen by the pistil.

What is the purpose of self-incompatibility in flowering plants?

To prevent inbreeding depression

The correct answer is Option (2)- To prevent inbreeding depression

Inbreeding depression refers to the negative effects that can occur when closely related individuals mate and produce offspring. It can lead to reduced genetic diversity and increased susceptibility to diseases and other environmental challenges.

Self-incompatibility is a genetic mechanism that prevents self-pollen from fertilizing the ovules in the same flower or other flowers of the same plant. It achieves this by inhibiting pollen germination or pollen tube growth in the pistil. By preventing self-fertilization, self-incompatibility promotes outcrossing, which is the transfer of pollen between different individuals of the same species.

Cross-pollination, brings genetically diverse pollen from one plant to another, increasing the genetic variation within the population. This genetic diversity is advantageous for the population's overall fitness and adaptability to changing environmental conditions. By preventing self-pollination and promoting outcrossing, self-incompatibility helps maintain genetic diversity within a population, reducing the risk of inbreeding depression.

It's important to note that self-incompatibility does not synchronize pollen release and stigma receptivity directly. The timing of pollen release and stigma receptivity can still vary among individuals within a population. Self-incompatibility acts as a genetic barrier to prevent self-pollen from fertilizing the ovules, irrespective of the timing of pollen release and stigma receptivity.