What is xenogamy ? write its contrivances of xenogamy found in angiosperm
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This is when fertilization occurs as a result of pollen from the anther of a genitally different plant to that of the stigma being fertilized.
The contrivances (or mechanisms that aid) xenogamy,are:
1)Dichogamy: This is where the style and carpel of the same flower (bisexual flowers) in a plant mature at different times to avoid self pollination.
Protandry and protogyny: the pollen and the stigma ripen at different times in a bisexual flower and hence fertilization cannot occur as a result of the two.
2)Self-sterility or incompatability: In this case the stigma of a flower cannot be fertilized by the pollen of the flowers of the same plant or even its strain. Leaving cross pollination as the only alternative.
3)Dicliny or Unisexuality (dioecious ): In this case the flowers of a plant are either just female or male, meaning they require to fertilize by other flowers if female of fertilize other plants if male.
4)Herkgamy: presence of mechanical barriers such as pollinia on stigma to prevent self pollination.
5)Male sterility: in this case male flowers are not fertile and the flowers of such plant depend solely on cross-pollination.
6)Herostyly: The stamens and carpels in a flower have varying lenghts making self pollination impossible.
The contrivances (or mechanisms that aid) xenogamy,are:
1)Dichogamy: This is where the style and carpel of the same flower (bisexual flowers) in a plant mature at different times to avoid self pollination.
Protandry and protogyny: the pollen and the stigma ripen at different times in a bisexual flower and hence fertilization cannot occur as a result of the two.
2)Self-sterility or incompatability: In this case the stigma of a flower cannot be fertilized by the pollen of the flowers of the same plant or even its strain. Leaving cross pollination as the only alternative.
3)Dicliny or Unisexuality (dioecious ): In this case the flowers of a plant are either just female or male, meaning they require to fertilize by other flowers if female of fertilize other plants if male.
4)Herkgamy: presence of mechanical barriers such as pollinia on stigma to prevent self pollination.
5)Male sterility: in this case male flowers are not fertile and the flowers of such plant depend solely on cross-pollination.
6)Herostyly: The stamens and carpels in a flower have varying lenghts making self pollination impossible.
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