Photosynthesis Question 53

53. With reference to factors affecting the rate of photosynthesis, which of the following statements is not correct?

[2017]

(a) Increasing atmospheric $CO_2$ concentration up to $0.05 %$ can enhance $CO_2$ fixation rate

(b) $C_3$ plants respond to higher temperatures with enhanced photosynthesis while $C_4$ plants have much lower temperature optimum

(c) Tomato is a greenhouse crop which can be grown in $CO_2$ - enriched atmosphere for higher yield

(d) Light saturation for $CO_2$ fixation occurs at $10 %$ of full sunlight

Show Answer

Answer : b

Hints & Solution

(b) In $C_3$ plants photosynthesis decreases at higher temperature due to increased photorespiration. $C_4$ plants have higher temperature optimum because of the presence of enzyme called pyruvate phosphate dikinase, which is sensitive to low temperature.