What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.
Chasmogamous flowers are flowers with exposed anthers and stigma, similar to flowers of other species. These are one of the two types of flowers produced by plants like Viola (common pansy), Oxalis, and Commelina.
No, cross-pollination cannot occur in cleistogamous flowers. The reasons are:
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Cleistogamous flowers do not open at all, keeping reproductive parts enclosed.
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The anthers and stigma lie close to each other within the closed flower.
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When anthers dehisce in the flower buds, pollen grains come in contact with the stigma directly.
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There is no chance of cross-pollen landing on the stigma as the flower remains closed.
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Therefore, cleistogamous flowers are invariably autogamous (self-pollinating) and produce assured seed-set even in the absence of pollinators.
Explanation
This question tests understanding of flower types and their pollination mechanisms. Chasmogamous flowers open normally with exposed reproductive parts allowing potential cross-pollination, while cleistogamous flowers remain permanently closed, ensuring only self-pollination. This distinction is important in understanding plant reproductive strategies.