If a plant is described as a long-day plant, what is true about its flowering in relation to day length?

If a plant is described as a long-day plant, what is true about its flowering in relation to day length?

• A. Flowers in short days
• B. Flowers in the middle of the day only
• C. Flowers only in darkness
• D. Flowers when day length exceeds 12 hours

Answer: (D)

Long-day flowering is driven by the length of daylight. These plants need days longer than a certain threshold to trigger flowering, so they typically bloom when daylight lasts for longer periods—often around 12 hours or more—which happens in late spring or early summer. This contrasts with short-day plants, which flower when days are shorter than the threshold, and with day-neutral plants, which are not strongly influenced by day length. The key idea is that flowering is tied to the duration of light, not to a specific time of day or to darkness alone.

Long-day flowering is driven by the length of daylight. These plants need days longer than a certain threshold to trigger flowering, so they typically bloom when daylight lasts for longer periods—often around 12 hours or more—which happens in late spring or early summer. This contrasts with short-day plants, which flower when days are shorter than the threshold, and with day-neutral plants, which are not strongly influenced by day length. The key idea is that flowering is tied to the duration of light, not to a specific time of day or to darkness alone.