What term describes how plants are affected by the length of daylight, influencing flowering and other seasonal processes?

What term describes how plants are affected by the length of daylight, influencing flowering and other seasonal processes?

• A. Photoperiodism
• B. Geotropism
• C. Thigmotropism
• D. Tropism

Answer: (A)

Photoperiodism is the plant response to the length of day and night that controls when flowering and other seasonal processes occur. Plants use light-sensing pigments and an internal circadian clock to gauge night length, which then triggers hormonal signals that move to the growing tips and initiate flowering or other seasonal changes. Depending on the species, long-day plants flower when days are long and nights are short, while short-day plants flower when nights are sufficiently long. Other terms describe responses to different cues: geotropism is growth in response to gravity, thigmotropism is growth in response to touch, and tropism is the general term for directional growth toward or away from a stimulus. So the term that best describes daylight-length effects on flowering and seasonal activities is photoperiodism.

Photoperiodism is the plant response to the length of day and night that controls when flowering and other seasonal processes occur. Plants use light-sensing pigments and an internal circadian clock to gauge night length, which then triggers hormonal signals that move to the growing tips and initiate flowering or other seasonal changes. Depending on the species, long-day plants flower when days are long and nights are short, while short-day plants flower when nights are sufficiently long. Other terms describe responses to different cues: geotropism is growth in response to gravity, thigmotropism is growth in response to touch, and tropism is the general term for directional growth toward or away from a stimulus. So the term that best describes daylight-length effects on flowering and seasonal activities is photoperiodism.