Question

Mention any four strategies adopted by flowering plants to prevent self-pollination.

Answer 1

Various strategies adopted by flowering plants to prevent self-pollination are:

• Dichogamy: It is the condition in which anthers and stigma mature at different times. Either anther matures before stigma (protandry) or stigma becomes receptive before anthers (protogyny). For example, in Aristolochia, protogyny occurs.
• Dicliny: It is the presence of unisexual flowers in a plant. The plant may be monoecious if it has both male and female flowers or dioecious if male and female flowers are present on two different plants.
• Herkogamy: It is the presence of a mechanical barrier between compatible pollen and stigma due to which self-pollination becomes impossible. For example, in Iris, a hood like covering covers the stigma.
• Self-incompatibility: It is the inability of pollen to germinate on the surface of the stigma of a flower of same species. Due to self-incompatibility, viable pollen is not able to germinate on the surface of the stigma of the same species.