Figure 14.8 Plant species show characteristic variation in the way photosynthetic tissue responds to temperature. Maize (a subtropical C4 species) has a high maximum rate of CO2 assimilation with a high optimum temperature, while wheat (a temperate C3 species) has a lower maximum rate and a lower optimum temperature. (a) Absolute values; (b) shows those same data normalised to 100% at optimum temperature.

Alpine plants (C3 species) have an even lower optimum temperature and may show CO2 assimilation below 0 °C, but their maximum rates of photosynthesis are often low compared with warmer climate species. (Based on Wardlaw 1979)