All of you know that pollination is of two types.
1. Autogamy / Inbreeding
2. Allogamy / Outbreeding
Some conditions in bisexual flowers favour Inbreeding ( contrivances of self pollination). We call these conditions as Inbreeding devices.
Major Inbreeding devices are:
1. Bisexuality:
The flower is having both stamen and carpel and they're close to each other.
Note: Bisexuality is the main Inbreeding device.
2. Homogamy:
Here, both anther and stigma of bisexual flower mature at the same time i.e
synchronisation between release of pollen grains and receptivity of stigma.
3. Cleistogamy:
Interestingly, some flowers are bisexual but remain closed even after maturity ex. Commelina, Viola. Hence, pollen grains self-pollinated the stigma of same flower.
Note: Cleistogamous flowers always show autogamy and also show assured seed formation.
4. Bud pollination:
Some bisexual flowers of plants like Rice,Wheat,Pea show bud condition even after maturity. So Inbreeding occurs.
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Regards,