Question

Observe the graph given below and choose the correct option.

• A. Light is a liimiting factor at the region marked $A$
• B. At the point $D$ of light intensity the rate of photosynthesis is maximum
• C. Both $1$ and $2$
• D. The region marked $C$ shows continuous increase in the rate of photosynthesis

Answer 1

The correct option is A Light is a liimiting factor at the region marked $A$

Photosynthesis is a complex process of photochemical or light harvesting stage and an enzymatic or carbon-assimilating stage that involves a chemical reaction.

At low to medium light intensities the rate of photosynthesis increases as the intensity increases. As the intensity goes to a higher level, the rate becomes constant or saturated. Other factors like temperature, availability of water and photorespiration influence the rate.

In region A, the rate of photosynthesis has increased with light intensity. Beyond A the rate has become constant with increase in intensity. Thus, light controls among of photosynthesis in A.

At point D, the rate of photosynthesis is least. or zero.

Region C shows a constant or saturated rate of photosynthesis.