Question

If a plant is kept on ${\text{CO}}_2$ compensation point, the immediate effect on plant is :-

• A. Plant will died
• B. Growth will stop
• C. Respiration will stop
• D. Photosynthesis will stop

Answer 1

The correct option is B Growth will stop

Carbon dioxide is the major limiting factor for photosynthesis. The concentration of ${\text{CO}}_2$ is very low in the atmosphere (between $0.03$ and $0.04$ percent).

${\text{CO}}_2$ concentration at which ${\text{CO}}_2$ fixation in photosynthesis is equal to volume of ${\text{CO}}_2$ released in respiration is called "${\text{CO}}_2$ compensation point”, when plant is saturated with full light. Higher ${\text{CO}}_2$ concentration is toxic to plant and also closes stomata. As stomata closes photosynthesis and transpiration reduces.
So, if a plant is kept on ${\text{CO}}_2$ compensation point, the immediate effect on plant is that growth will stop.