PLANT PHYSIOLOGY
PHOTOSYNTHESIS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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In a cactus, carbon is fixed only during the day.
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In grass, carbon is fixed only during the night.
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In a cactus, carbon is fixed only during the night.
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None of the above
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Detailed explanation-1: -Expert-Verified Answer. The answer is In a cactus, carbon is fixed only during the night.
Detailed explanation-2: -The leaves of a cactus are reduced to thin spines to prevent the loss of water through transpiration. These spines cannot really perform photosynthesis. Instead, photosynthesis is carried out by the thick green stem.
Detailed explanation-3: -All plants photosynthesize, collecting carbon dioxide through holes in their leaves called “stomata” and converting it into sugar and oxygen. Cacti utilize CAM photosynthesis, a process unique to succulents.
Detailed explanation-4: -Typically, the leaves of the plants play the greatest role in photosynthesis. However, in cacti, the leaves are modified into spines in order to reduce the surface area available for transpiration and thus reduce the loss of water. Therefore, it is the stem that performs the process of photosynthesis in these plants.
Detailed explanation-5: -In a common plant, the leaves are the site of manufacturing organic complex food by the process of photosynthesis.