Modelling temperature effects on growth–respiration relations of maize

The temperature dependence of plant growth rate is related to the temperature dependence of respiratory metabolism. To determine how the effects of temperature on respiration rate and efficiency are transmitted to growth, this study measured the dark metabolic heat rate ( q ) and CO₂ production rate ( R _CO2) in excised shoots of seedlings of 14 maize cultivars ( Zea mays L.) at several temperatures. The temperature coefficients of q and R _CO2 differ within a given cultivar and also differ among the cultivars. Both q and R _CO2 exhibit an isokinetic temperature of 20 ± 3 °C. The measured temperature dependences of q and R _CO2 were used to model the temperature dependences of both growth and substrate carbon conversion efficiency. This procedure may be useful in determining the suitability of cultivars for growth in a given climate and in understanding metabolic adaptation to climate.