Factors Influencing Photosynthesis Effects or Characteristics A. Carbon Dioxide (CO2) 1. C4 plants show saturation at about 360 µL L⁻¹ CO2. B. Temperature 2. Dark reactions are temperature controlled, and the temperature optimum varies with the plant habitat. C. Water 3. Water stress causes stomatal closure and reduced CO2 availability, leading to wilting and decreased metabolic activity.

Step-by-step solution

A - 1: C4 plants show saturation of photosynthesis at around 360 µL L⁻¹ CO2, while C3 plants show saturation only beyond 450 µL L⁻¹. B - 3: Water stress impacts photosynthesis indirectly by causing stomatal closure, reducing CO2 availability, and leading to wilting and decreased leaf surface area and metabolic activity. C - 2: Temperature affects dark reactions significantly and the optimum temperature for photosynthesis varies depending on the plant’s habitat, with tropical plants having a higher optimum compared