Question

In germinating seeds of castor, RQ is:

• A. Zero
• B. Less than one
• C. One
• D. More than one

Answer 1

The correct option is B Less than one

Respiratory quotient (RQ) is the ratio of the volume of carbon dioxide evolved to the volume of oxygen absorbed in respiration. The respiratory substrate produced during the germination of the castor seed is fat. The RQ value is less than one when fat is consumed during respiration, as the volume of $C{O}_2$ evolved is less than the volume of $O_2$ consumed.

E.g. 2 $\left(C_{51}{H}_{98}{O}_6\right)$ + 145$O_2$ → 102${\mathrm{CO}}_2$ + 98$H_{2}O$

RQ = (102 ${\mathrm{CO}}_2$ / 145 $O_2$)
= 0.7