Pistil

Definition

The pistil is the female reproductive structure of a flower, consisting of the ovary, style, and stigma. It plays a critical role in reproduction by facilitating the processes of pollination and fertilization, allowing for the development of seeds and fruit. The pistil is essential for plant reproduction, as it houses the ovules and serves as the site where pollen grains germinate and fertilization occurs.

5 Must Know Facts For Your Next Test

1. Pistils can be found in flowers that are either solitary or part of a cluster, and they can be simple (single) or compound (multiple fused together).
2. In many flowering plants, each flower can have multiple pistils, which can lead to the development of multiple seeds in a single fruit.
3. The shape and structure of the pistil can vary widely among different plant species, influencing their reproductive strategies and pollinator interactions.
4. Pollination occurs when pollen from an anther lands on a stigma; this can happen through various mechanisms such as wind, water, or animals.
5. After successful pollination, the ovary develops into a fruit containing seeds, which are crucial for the propagation of the plant species.

Review Questions

• How does the structure of the pistil facilitate pollination and fertilization in flowering plants?
  • The structure of the pistil is specifically designed to facilitate pollination and fertilization. The stigma's sticky surface captures pollen grains, while the style allows pollen tubes to grow down toward the ovary. This pathway enables sperm cells to reach the ovules within the ovary for fertilization, resulting in seed formation.
• Compare and contrast simple and compound pistils, including their implications for seed development.
  • Simple pistils consist of a single carpel, while compound pistils are made up of multiple fused carpels. This structural difference influences how seeds develop; simple pistils typically produce one seed per ovule, whereas compound pistils can lead to multiple seeds being formed within a single fruit. The complexity of compound pistils may allow for greater genetic diversity and adaptation in flowering plants.
• Evaluate the role of different pollination mechanisms on the evolution of pistil structure in angiosperms.
  • Different pollination mechanisms, such as biotic (animal-mediated) and abiotic (wind or water-mediated) pollination, have significantly influenced the evolution of pistil structure in angiosperms. For example, plants that rely on insect pollinators may evolve longer styles or specialized stigmas to ensure effective pollen transfer. In contrast, plants that depend on wind might have less complex pistils since they do not require specific targeting by pollinators. This evolutionary adaptation reflects a balance between attracting pollinators and maximizing reproductive success based on environmental factors.

Related terms

stigma:

The sticky tip of the pistil that captures and holds pollen grains during pollination.

ovary:

The swollen base of the pistil that contains one or more ovules, which develop into seeds after fertilization.

style:

The slender stalk that connects the stigma to the ovary, providing a pathway for pollen tubes to grow down to the ovules.