AP BIOLOGY

Detailed explanation-1: -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-2: -7. Green grams, marijuana, cotton, soyabean, jowar and rice are examples of short day plants.

Detailed explanation-3: -Short-day plants flower when the natural day length is at a minimum during the late fall and winter.

Detailed explanation-4: -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.