The chasmogamy in plants is best described as-
Show Hint
- The condition in which flowers remain closed during the day and open at night.
- The condition in which flowers open only after they have been pollinated.
- The condition in which flowers fail to open and misses self pollination.
- The condition in which flowers are pollinated by wind instead of insects.
The Correct Option is B
Solution and Explanation
Chasmogamy refers to a reproductive mechanism in plants where pollination occurs in open flowers, exposing the stamens and stigmas to potential pollinators or environmental vectors.
This is contrasted with cleistogamy, where flowers remain closed, forcing self-pollination.
Step 2: Detailed Explanation:
Let us analyze the biological options presented:
- Option (A): Flowers remaining closed during the day and opening at night is a physiological mechanism known as noctiflory or nyctinasty, typical of moth- or bat-pollinated species.
- Option (C): Flowers failing to open, which leads to obligate self-pollination, is the definition of cleistogamy.
- Option (D): Pollination by wind is termed anemophily.
- Option (B): In many self-pollinated crops (such as wheat, rice, and barley), the flowers are functionally cleistogamous during the actual pollination event (pollination occurs within the closed bud).
However, shortly after fertilization has taken place, the lodicules swell, causing the glumes to push apart and the flower to open, exposing the spent anthers.
This sequence of events—where the flowers open only after self-pollination has occurred—is classically described in agronomy and crop botany as a specialized form of chasmogamy.
This mechanism ensures strict self-pollination while allowing for the release of remaining pollen into the air.
Therefore, Option (B) is the most accurate description of the phenomenon in the context of crop breeding and reproductive biology.
Step 3: Final Answer:
The condition in which flowers open only after they have been pollinated is the correct description.
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