Pollen Grains and Stigma Interaction

The question asks which pollination type introduces pollen grains that are genetically different from the recipient plant's genetic makeup. Let's examine the options:

Understanding Pollination Types

• Autogamy: Pollen transfer occurs within the same flower. This results in genetically similar pollen.
• Geitonogamy: Pollen transfer happens between different flowers on the same plant. While the flowers are different, the pollen is genetically identical to the parent plant's pollen.
• Xenogamy: Pollen transfer occurs between flowers on different plants of the same species. This process brings pollen that is genetically different from the pollen normally produced by the recipient plant's flowers.
• Cleistogamy: This is a type of autogamy where flowers remain closed, ensuring self-pollination. The pollen is genetically similar.

Identifying the Correct Pollination Type

Based on the definitions, Xenogamy is the only type that guarantees the transfer of genetically different pollen grains to the stigma, as it involves pollen from a different individual plant.

Therefore, Xenogamy brings genetically different types of pollen grains to the stigma.