In plants, the stigma is the sticky, receptive tip of the female reproductive part of a flower, specifically the pistil. It plays a crucial role in plant reproduction by receiving pollen grains.
The Stigma's Role in Plant Reproduction
The stigma's primary function is pollen reception. Its surface is often sticky, hairy, or otherwise modified to effectively capture pollen grains, which are then transferred down the style to the ovary for fertilization. This sticky or waxy texture helps the stigma securely hold pollen until germination can occur.
Structure and Location
- Located at the apex of the pistil, the stigma is the most prominent part of the female reproductive organ.
- It sits atop the style, a stalk-like structure connecting the stigma to the ovary.
- The stigma's morphology varies greatly depending on the plant species, reflecting the method of pollination (e.g., wind, insects, etc.).
Pollination and Fertilization
The stigma’s ability to capture and retain pollen is vital for successful fertilization.
- Wind-pollinated plants often have feathery or branched stigmas to maximize surface area for pollen capture.
- Insect-pollinated plants may have sticky stigmas that adhere to pollen grains carried by insects.
Once pollen adheres to the stigma, it germinates, growing a pollen tube down the style to reach the ovules within the ovary. This process leads to fertilization and the formation of seeds.
