Question
Mention two strategies evolved to prevent self pollination in flowers.
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Answer
Most of the flowers have evolved various strategies to prevent sefl-pollination and to encourage cross-pollination. The following are the two strategies to prevent self-pollination.
(i) Self sterility : It is a mechanism in which the pollen grains of the same flower cannot fertilize their own ovules due to various reasons. It is a natural barrier. Examples, Malva, Petunia ascillaris tobacco, potato, tea, etc.
(ii) Unisexuality or Dicliny : In unsexual flowers, self pollination is impossible. A plant may posses male and female reproductive organs borne in the same flower (eg. maize) or in different unisexual flowes but on the same plant (eg. papaya). Through cross pollination, the pollen grain from a unisexual male flower is transferred to the stigma of another unisexual female flower.
(i) Self sterility : It is a mechanism in which the pollen grains of the same flower cannot fertilize their own ovules due to various reasons. It is a natural barrier. Examples, Malva, Petunia ascillaris tobacco, potato, tea, etc.
(ii) Unisexuality or Dicliny : In unsexual flowers, self pollination is impossible. A plant may posses male and female reproductive organs borne in the same flower (eg. maize) or in different unisexual flowes but on the same plant (eg. papaya). Through cross pollination, the pollen grain from a unisexual male flower is transferred to the stigma of another unisexual female flower.
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