RESPIRATORY QUOTIENT
- The ratio of the volumes of CO2 liberated and O2 used during respiration in a given period of time.
- Also called the respiratory coefficient.
PHOTOSYNTHETIC QUOTIENT
- The ratio of the volumes of O2 evolved and CO2 absorbed during photosynthesis in a given period of time.
DIFFERENCE BETWEEN RESPIRATORY QUOTIENT AND PHOTOSYNTHETIC QUOTIENT
| Respiratory Quotient (R.Q.) |
Photosynthetic Quotient (P. Q.)
|
| The ratio of the volumes of CO2 liberated and O2 used during respiration in a given period of time :
RQ= (Volume of CO2 liberated) / (Volume of O2 used)
| The ratio of the volumes of O2 evolved and CO2 absorbed during photosynthesis in a given period of time.
P. Q. = (Volume of O2 evolved) / (Volume of CO2 absorbed)
|
| Food material is being oxidized during respiration because different food materials like carbohydrates, fats, proteins, and organic acids possess different R.Q. values. | Food material is being synthesized during photosynthesis.
|
| The value of R. A. varies with varying respiratory substrates. The value of R. Q. maybe unity or one ( e. g., in carbohydrates), less than (eg protein and fats) or more than one (eg organic acids)
| The value of P. Q. is nearly always unity or one. In CAM plants in light, the value of P. A. becomes more than one. Such plants contain high acid contents and when they get highly illuminated, de-acidification starts. They liberate O2 without absorption of CO2 from the atmosphere. In leaves containing low acid, the value of P. Q. becomes less than one. |
| It is measured by the apparatus called Ganong’s respirometer.
| It is measured by the apparatus called Ganong’s photosynthometer. |