ANIMAL BEHAVIOR
INTRODUCTION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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A plant that flowers only after being exposed to light periods longer than a certain critical length, as in summer
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A plant that flowers only after being exposed to light periods shorter than a certain critical length, as in early spring or fall
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Detailed explanation-1: -A plant that flowers only after being exposed to light periods longer than a certain critical length, as in summer. Spinach, lettuce, and some varieties of wheat are long-day plants.
Detailed explanation-2: -If these are exposed to more than 12 hours of light per day, bloom formation does not occur. Other plants require only a short night to flower. These are termed “long-day” plants. These bloom only when they receive more than 12 hours of light.
Detailed explanation-3: -The light period which is essentially required to induce flowering in plants is known as critical photoperiod. A long day plant will only flower when the light period is longer than a critical number of hours. Spinach, lettuce, and some varieties of wheat are long-day plants.
Detailed explanation-4: -Examples of long day plants are spinach, lettuce, radish, sugar beet, etc. Thus, the correct answer is Spinacia oleracea (spinach).
Detailed explanation-5: -critical daylength (critical day, critical photoperiod)The length of day or light period in a 24-hour cycle required to induce flowering of long-day plants or to inhibit flowering of short-day plants.