Question

Given below are two statements:
Statement (I): Most typical tropical crops are short-day plants while those of higher latitudes are generally long-day plants.
Statement (II): The duration of night or complete darkness is more important than the length of the day.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both Statement (I) and Statement (II) are correct.
• B. Both Statement (I) and Statement (II) are incorrect.
• C. Statement (I) is correct but Statement (II) is incorrect.
• D. Statement (I) is incorrect but Statement (II) is correct.

Hint:

Tropical = Short-day (long nights); Higher latitudes = Long-day (short nights). Night length drives flowering.

Answer 1

The Correct Option is A

Both statements are correct and related to plant photoperiodism:
- Statement (I) is correct: Photoperiodism refers to plants’ responses to day and night lengths. {Short-day plants (e.g., rice, sugarcane), common in tropical regions, flower when the day length is shorter than a critical period (or night length is longer). {Long-day plants (e.g., wheat, barley), typical in higher latitudes, flower when the day length exceeds a critical period (or night length is shorter). This aligns with the climatic patterns of tropical and temperate regions.
- Statement (II) is correct: For many plants, the duration of uninterrupted darkness (night length) is the critical factor triggering flowering, rather than the length of daylight. For example, short-day plants require a long, continuous dark period to initiate flowering, and any interruption (e.g., artificial light) can inhibit it. This explains why night length is more significant in photoperiodism. Since both statements are true and Statement (II) supports the understanding of Statement (I), option (1) is correct.