Oxygen Inhibition of Photosynthesis: II. Kinetic Characteristics as Affected by Temperature

The response of whole leaf photosynthesis of wheat (Triticum aestivum L.) in relation to soluble CO₂ available to the mesophyll cells, under low (1.5%) O₂ at 25, 30, and 35 C, followed Michaelis-Menten kinetics up to saturating CO₂ but deviated at high CO₂ levels where the experimental V_max is considerably less than the calculated V_max. The affinity of the leaves for CO₂ during photosynthesis was similar from 25 to 35 C with Km (CO₂) values of approximately 3.5 to 5 μM.