Question

Some flowers are unisexual, this property of unisexuality of flowers prevents which kind of pollination?

• A. Both Autogamy and Geitonogamy
• B. Both Geitonogamy and Xenogamy
• C. Geitonogamy but not Xenogamy
• D. Autogamy but not Geitonogamy

Hint:

In unisexual flowers, since the male and female organs are on separate plants or flowers, autogamy and geitonogamy are not possible, but xenogamy (cross-pollination) is still possible.

Answer 1

The Correct Option is C

Impact of Unisexuality on Pollination 

Step 1: Understanding the Terms Involved in the Question

• Autogamy refers to self-pollination where the pollen from the same flower or the same plant fertilizes the ovule.
• Geitonogamy refers to pollination between flowers of the same plant, but different individuals.
• Xenogamy refers to cross-pollination, where the pollen from one plant fertilizes the ovule of a different plant.

Step 2: Analyzing the Impact of Unisexuality

- In unisexual flowers, the male and female reproductive organs are separated, so the pollen from a male flower cannot directly pollinate the female flower of the same plant. 
- As a result, Autogamy is not possible, since self-pollination is blocked by the separation of sexes. 
- Geitonogamy is also prevented, as it requires pollen to be transferred between different flowers of the same plant. 
- However, Xenogamy, which involves pollen transfer between different plants, is still possible because it doesn't depend on the same plant's male and female flowers.

Step 3: Conclusion

The property of unisexuality of flowers prevents Geitonogamy, but does not prevent Xenogamy. Hence, the correct answer is option (C).