Pollination in Angiosperms

Pollination

Definition

Pollination in angiosperms

Transfer of pollen grains from dehisced anther to the receptive stigma is known as pollination. Pollination is of two types; self pollination and cross pollination.

1. Self pollination

Self pollination is also known as autogamy. In self pollination pollen grains of a flowers pollinate the stigma of same flower. In autogamy, chances of variation is reduced because male gametes and female gamete have the same genetic constituents. The phenomenon of self pollination is also known as 'selfing' or 'in-breeding'. It promotes homozygousity.

2. Cross pollination

Self pollination is also known as allogamy. In allogamy, pollen grains of flower pollinate the stigma of other flower. The phenomenon of cross pollination is known as 'out-breeding'. It promotes 'heterozygousity' and improve the vigor of coming generations.
Allogamy is of two types.

A. Geitonogamy

In this type of cross pollination, pollen grain of a flower pollinates the stigma of other flower, but of the same plant. Geitonogamy in true sense is not a cross pollination, because, both the pollen grain as well as egg cell are of same plant and have same genetic constituents.

B. Xenogamy

In this type of cross pollination, pollen grain of a flower pollinates the stigma of a flower growing on other plant. Xenogamy in true sense is cross pollination, because, pollen grain and egg cell are of different plants (dioeceous) and vary in genetic constituents.

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First published on 13-04-2021
Last updated on 24-02-2022