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 happens when incompatible pollen lands on the stigma of a flowering plant?

The stigma rejects the pollen and prevents fertilization.

The correct answer is Option (2) - The stigma rejects the pollen and prevents fertilization.

When incompatible pollen lands on the stigma of a flowering plant, the stigma typically rejects the pollen and prevents fertilization.

Incompatible pollen refers to pollen that is not of the right type or species that can successfully fertilize the ovules of the plant. This could include pollen from other species or pollen from the same plant if it is self-incompatible.

The stigma plays a crucial role in the pollination process as it acts as the landing site for pollen grains. Upon landing on the stigma, compatible pollen grains have specific interactions with the stigma that allow for successful fertilization. However, when incompatible pollen lands on the stigma, the stigma recognizes that it is not of the right type.

The pistil has the ability to recognise the pollen, whether it is of the right type (compatible) or of the wrong type (incompatible). If it is of the right type, the pistil accepts the pollen and promotes post-pollination events that leads to fertilisation. If the pollen is of the wrong type, the pistil rejects the pollen by preventing pollen germination on the stigma or the pollen tube growth in the style. The ability of the pistil to recognise the pollen followed by its acceptance or rejection is the result of a continuous dialogue between pollen grain and the pistil. This dialogue is mediated by chemical components of the pollen interacting with those of the pistil.