Study the graph showing the effect of intensity of light on rate of photosynthesis. Which of the following statement regarding this is correct? Rate of photosynthesis Light intensity
O a) Rate of photosynthesis is not increasing by light intensity
O b) Rate of photosynthesis initially increases with light intensity, attains a high value, and then remains apparently unchanged
O c) Both a) and b)
O d) None of these
Answers
Answer:
A limiting factor is defined as a factor which is deficient to such an extent that increase in its magnitude directly increases the rate of the process.
In the given graph, rate of photosynthesis initially increases with an increase in light intensity (region A ) but soon it levelled off. Thus, initially light intensity was limiting the rate of photosynthesis. However, when light intensity was present in sufficient amounts (region C), rate of photosynthesis did not increase further. This is due to the fact that in region C, some other factor (e.g. CO
2
concentration) became the limiting factor. At this region, the rate of photosynthesis could be further enhanced only by the ingress in availability of other limiting factor (e.g. CO
2
). So, the correct answer is 'All of these'.