AP BIOLOGY

Detailed explanation-1: -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. If these are exposed to more than 12 hours of light per day, bloom formation does not occur.

Detailed explanation-2: -Short-day Plants Examples of short day plants include: chrysanthemum, rice, soybean, onion, violet, Christmas cactus, and poinsettia.

Detailed explanation-3: -A Poinsettia’s Inner Clock (Plants whose flowering is not dependent on the length of daylight are called day-neutral-they flower when the plant gets large enough or reaches a certain stage of development.)

Detailed explanation-4: -Long-day plants flower and grow when the daylight they obtain is more than their critical (required) photoperiod, like in summer season. They need more light than short-day plants and usually flower when the temperature becomes warmer. Examples of long day plants are spinach, lettuce, radish, sugar beet, etc.

Detailed explanation-5: -They are: Long Day Plants: They require the periodic exposure of light exceeding the critical period to induce flowering. Short Day Plants: They require the periodic exposure of light less than the critical period to induce flowering. Day-neutral Plants: The flowering in many plants does not depend on the photoperiod.