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Reproduction in Lower and Higher Plants — BIOLOGY STD 12 Science — Question

Maharashtra BoardEnglish MediumSTD 12 ScienceBIOLOGYReproduction in Lower and Higher Plants3 Marks
Question
Short Answer Questions
Describe three devices by which cross pollination is encouraged in Angiosperms by avoiding self-pollination?
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Answer

  1. Unisexuality, dichogamy, prepotency, heteromorphy and herkogamy are the outbreeding devices.
  2. Unisexuality : The plants bear either male or female flowers. Due to unisexual nature, self-pollination is avoided. Plants are either dioecious, e.g. Papaya or monoecious, e.g. maize.
  3. Heteromorphy : In same plants different types of flowers are produced. In these flowers, stigmas and anthers are situated at different levels. There is heterostyly and heteroanthy. This prevents self-pollination e.g. Primrose.
  4. Herkogamy : In bisexual flowers we may come across mechanical device to prevent self-pollination. Natural physical barrier avoids contact of pollens with stigma. E.g. Calotropis where pollinia are situated below the stigma.

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