What is the function of the stigma in the pistil?

Reception of pollen grains

The correct answer is Option (3) - Reception of pollen grains.

The stigma is a crucial part of the pistil, which is the female reproductive organ of a flower. It plays a vital role in the process of pollination and fertilization. The primary function of the stigma is the reception of pollen grains.

When a flower is ready for pollination, the stigma serves as a landing platform for pollen grains. It is often located at the top of the pistil, positioned to receive pollen from visiting pollinators or through other means of pollination, such as wind or self-pollination.

The surface of the stigma is specialized to facilitate pollen grain adhesion and capture. It may have specific structures or surface features that enhance its ability to attract and retain pollen grains. These adaptations can include microscopic hairs, sticky substances, or grooves that aid in the retention of pollen.

Once the pollen grains land on the stigma, they may adhere to its surface due to the sticky or textured nature of the stigma. This adhesion is an essential step in pollination, as it allows for the subsequent transfer of pollen to the female reproductive structures within the pistil.

After pollen grains are captured by the stigma, they may undergo germination and form pollen tubes. These pollen tubes then grow through the style, a slender tube-like structure connecting the stigma and the ovary, towards the ovules, where fertilization takes place.

In summary, the function of the stigma in the pistil is to receive pollen grains. It acts as a landing platform for pollen and facilitates their adhesion, providing a crucial step in the pollination process and enabling successful fertilization in flowering plants.