E-Lecture - Reproduction in Flowering Plants

Flowering plants reproduce sexually through a process called pollination. The flowers contain male sex organs called stamens and female sex organs called pistils.

Reproductive Structure of a Flower

Androecium

Each stamen comprises two parts, namely, anther and filament. The tip of the anther is supported by the filament. Here pollens are produced by meiosis and disappear eventually.

  • Anther: is a four-lobed sac-like structure responsible for pollen formation. The transverse section of an anther is microsporangia that further forms a pollen sac. The pollen sac contains pollen grains.
  • Filaments: is a long stalk like structure that supports the anther.

Gynoecium

Through meiosis, ovules produce megaspores which in turn develops into female gametophytes. As a result, egg cells are produced.

Pistil: each pistil has three parts:

  • Ovary: is a chamber where ovules (eggs) are stored, waiting for fertilization.
  • Stigma: is attached to the top of the carpel, where the pollen from other flowers lands.
  • Style: is a tubular structure that connects the ovary and the stigma. It is responsible for the transportation of pollen from the stigma to the ovary.

Pollination

There are two types of pollination:

  • Self-Pollination: This process occurs when the pollen grains from the anther is deposited on the stigma of the same flower, or another flower on the same plant.
  • Cross-Pollination: This process occurs when the pollen grains are transferred from the anther of one flower into the stigma of another flower of different plants of the same species.