Question

In succulent plants, like Opuntia R.Q. value will be _________.

• A. Infinity
• B. Zero
• C. Less than 1
• D. More than 1

Answer 1

The correct option is B Zero

• The ratio of the volume of carbon dioxide evolved to the volume of oxygen consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio.
• The respiratory ratio depends upon the type of substrate used during respiration. For carbohydrates, RQ is 1, for proteins is 0.9 and for fats is 0.7.
• Opuntia which is succulent respiration takes place at night when stomata are open which results in the formation of oxygen without evolving carbon dioxide. This results in incomplete oxidation of food without evolving carbon dioxide. Thus, the RQ is always zero in succulents.

So, the correct answer is option B.