What is the function of the stigma in a flower?

The stigma plays a vital role in the reproductive process of flowering plants by germinating pollen. When pollen lands on the stigma, it adheres to its surface, and this is where the process of fertilization begins. The stigma is specifically designed to capture pollen grains, facilitating the transfer of male gametes to the ovary where fertilization occurs. This germination process involves the growth of the pollen tube down the style toward the ovary, allowing sperm cells to reach the ovule for fertilization.

The other options refer to different functions that do not pertain to the role of the stigma. While nectar is produced by nectarines to attract pollinators, the stigma's primary purpose is distinct and specifically tied to the fertilization process.