Botany - Respiration in Plants Question with Solution | TestHub

Respiratory Quotient:

R.Q. is the ratio of the volume of carbon dioxide released to the volume of oxygen taken in respiration and it is mathematically expressed as:

$R.Q. = \frac{Volume of C{O}_2 evolved}{Volume of O_2 consumed}$ 
The value of R.Q. varies with the substrate. Thus the measurement of R.Q. gives some idea of the nature of the substrate being respired in a particular tissue. R.Q. is usually measured by Ganong's respirometer.

Fats/Oils: When fats or oils are used as the respiratory substrate like germinating linseed, castor, mustard, til seeds, etc. R.Q. value is generally less than one around 0.7. For example in the case of tripalmitin, the reaction can be written as follows:

$2C_{51}{H}_{98}{O}_6 + 145 O_2 \to 102C{O}_2 + 196H_{2}O + Energy$

$R.Q. = \frac{Volume of C{O}_2 evolved}{Volume of O_2 consumed} = \frac{102}{145} = 0.70$