Stages of Pollen Pistil Interaction

Pollen Pistil Interaction:

Plant sexual reproduction is based on the interaction between pollen and pistil. These largely extracellular interactions lead to the cellular activities within the pollen, enabling the male gamete the growth of pollen tubes to the ovules for fertilization. These studies together with the genetic analysis of sexual reproduction have revealed the mechanisms behind the pollen-pistil interaction.

Stages of Pollen Pistil Interaction:

1. Pollen falls on the stigma of the flower.

2. A continuous dialogue is initiated between the pollen and the pistil. The reactions occur between the chemicals produced by pollen and the pistil.

3. The stigma recognizes the pollen.

4. The incompatible pollen is rejected by the stigma. So, it can’t germinate.

5. Moisture and sugars present on the surface of the stigma induce the germination of the compatible pollen.

6. Intine grows out through the germ pore as a pollen tube which produces pectinase and other hydrolyzing enzymes.

7. The tissue of the stigma and style are digested and the pollen tube elongates through the style and reaches the ovule.

8. The elongation of the pollen tube is aided by the Calcium-Boron-Inositol-Sugar-Complex formed in the cycle.

9. The pollen tube enters the embryo sac through one of the synergids at the micropyle.

10. The pollen tube is guided into the embryo sac by the filiform apparatus present on the synergid.