Sexual Reproduction in Flowering Plants

Sexual Reproduction in Flowering Plants

• Plants require each other to complete their life cycles.

Pollination

• Observe flowers of various plants (e.g., Cucumber, Mango, Peepal) to identify visiting animals and potential pollinators.
• Characteristics of a flower are linked to the visiting animal.
• Only animals contacting anthers and stigma can cause pollination.
• Some insects (pollen/nectar robbers) consume pollen or nectar without pollinating.

Self-Pollination

• Most flowering plants have hermaphrodite flowers, increasing the likelihood of pollen contacting the same flower's stigma.
• Continuous self-pollination leads to inbreeding depression.
• Plants have developed devices to discourage self-pollination and encourage cross-pollination.

Outbreeding Devices

• Some species have unsynchronized pollen release and stigma receptivity to prevent self-pollination.
• Anther and stigma positions can prevent autogamy by making pollen-stigma contact impossible.
• Self-incompatibility prevents self-pollen from fertilizing ovules by inhibiting pollen germination or pollen tube growth.
• Production of unisexual flowers prevents self-pollination (e.g., castor, maize).
• Dioecy (male and female flowers on separate plants) prevents both autogamy and geitonogamy (e.g., papaya).

Pollen-Pistil Interaction

• Pollination doesn't guarantee compatible pollen transfer.
• The pistil recognizes compatible or incompatible pollen and accepts or rejects it accordingly.
• If compatible, the pistil promotes post-pollination events.

Quiz about the life cycles of flowering plants, including pollination and the roles of animals and insects in the process.