AP BIOLOGY

Detailed explanation-1: -Note: Chrysanthemum is a short-day plant, which means that long nights (11 to 12 hours of darkness or a longer time, depending on the cultivar) are required for the rapid flower initiation and its development.

Detailed explanation-2: -Chrysanthemum (Chrysanthemum morifolium) is a short-day plant, which flowers when the night length is longer than a critical minimum. Flowering is effectively inhibited when the required long-night phase is interrupted by a short period of exposure to red light (night break; NB).

Detailed explanation-3: -Short-day Plants Examples of short day plants include: chrysanthemum, rice, soybean, onion, violet, Christmas cactus, and poinsettia.

Detailed explanation-4: -A plant that requires a long period of darkness is termed a “short-day” (long-night) plant. Short-day plants form flowers only when day length is less than about 12 hours. Many spring-and fall-flowering plants are short-day plants, including chrysanthemums, poinsettias and Christmas cactus.

Detailed explanation-5: -Plants that require less exposure to light are called short-day plants. Short day plants cannot be observed in places where the length of the night is less. Examples are sunflower, rice, tobacco, etc.