Figure 13.10 shows the effect of light on the rate of photosynthesis. Based on thegraph, answer the following questions: (a) At which point/s (A, B or C) in the curve is light a limiting factor?
Explanation In the process of photosynthesis, the plant convert the captured light energy and use water, carbon-di-oxide and minerals to produce chemical compounds and oxygen. The chemical compounds are energy rich compounds which are used to generate energy required to perform any biological process. During the process of photosynthesis, if any of the required factors are absent or is present in too low or too high can affect the rate of the process. The limiting factors can be described as the factors that affect the rate at which a process is carried on. The major factors that act as limiting factors for photosynthesis are light, temperature and carbon-di-oxide levels. The intensity of light act as a limiting factor for photosynthesis as at both too low and too high levels, the rate of photosynthesis declines. In case of light energy, the increase in the light energy causes an increase in the rate of photosynthesis until a certain point is reached where the rate attains a saturation level. In the given graph, rate of photosynthesis is least at point A, which suggests that light act as a limiting factor for photosynthesis and a little increase or decrease in light intensity will have a significant impact on rate of photosynthesis. Final Answer At point A in the curve, light is the limiting factor.
