If a long-day plant has a critical night length of 9 hours, which 24-hour cycle would prevent flowering?
A) 16 hours light/8 hours dark
B) 14 hours light/10 hours dark
C) 15.5 hours light/8.5 hours dark
D) 4 hours light/8 hours dark/4 hours light/8 hours dark
E) 8 hours light/8 hours dark/light flash/8 hours dark

Question

Quizplus · Accepted Answer

Long-day plants require a night period shorter than their critical night length to flower. A cycle with 14 hours of light and 10 hours of dark exceeds the critical night length of 9 hours, preventing flowering.

If a Long-Day Plant Has a Critical Night Length of 9