Question

The law of limiting factor for photosynthesis was given by
A. R. Hill
B. Krebs
C. Calvin
D. Blackman

Answer 1

Hint: It was formulated in the year 1905. It determines the rate of photosynthesis. The factor which is present in a small amount acts as a limiting factor.

Step by step answer:
Blackman was a plant physiologist who proposed the law of limiting factor in 1905. This law describes that when a process depends on a number of factors, the slowest factor limits the rate. It means the factor which is present in a small amount acts as a limiting factor.
 The main factors that limit the rate of photosynthesis are light intensity, carbon dioxide concentration, and temperature. The scarcity of any of the components affects the process of photosynthesis.
The rate of reaction gets affected by any change in the limiting factor, it can only get regulated by the regulation of the limiting factor. When the rate of the process becomes constant due to a limiting factor
Blackman’s law described CO₂ concentration as a limiting factor in the rate of oxygen production in photosynthesis. If CO2 supply is maximum, light intensity acts as a limiting factor in photosynthesis.
If CO2 and light intensity is maximum, temperature acts as a limiting factor.

So, the answer is D. Blackman

Note: Blackman faced criticism in this law. According to some of his co-workers, photosynthesis declines gradually not abruptly as described by Blackman. The reason behind it is that all chloroplasts are not in a similar environment, some receive more sunlight and CO₂ than the other leaves. Photosynthesis will be affected in only some chloroplasts, which results in a gradual decrease in photosynthesis.