Distinguish between short-day and long-day plants and state what actually determines flowering.

A short-day plant flowers when the day length is shorter than a critical period, and a long-day plant when it is longer. What actually matters is the length of the uninterrupted dark period rather than the day length: interrupting the night with a flash of light prevents a short-day plant from flowering.

No citable source has been recorded for this record. Treat it as practice material, not as fact.

Explanation

The leaves perceive the photoperiod and a hormonal signal moves to the shoot apex.