The critical day length of Hyoscyamus for flowering is :
Correct answer: A. 15.5 hours
- A. 15.5 hours
- B. 9 hours
- C. 11 hours
- D. 13 hours
Explanation
Hyoscyamus, like many plants, has a specific photoperiod requirement known as the critical day length, which is the minimum daylight hours necessary to trigger flowering. For Hyoscyamus, this is 15.5 hours. If the day length is less, the plant will not flower. The other options provide shorter day lengths, which are insufficient to meet the plant's photoperiodic needs. Understanding photoperiodism is crucial in botany, as it significantly influences plant development and reproductive cycles.
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Plant growth regulators are chemical messengers that control growth, development and responses to the environment. The topic covers auxins, gibberellins, cytokinins, abscisic acid and ethylene, including cell elongation, apical dominance, tropisms, seed germination, dormancy, fruit ripening and leaf fall, with growth promoters distinguished from inhibitors.
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