AbstractBackground and Aims
Carbon gain depends on efficient photosynthesis and adequate respiration. The effect of temperature on photosynthetic efficiency is well understood. In contrast, the temperature response of respiration is based almost entirely on short-term (hours) measurements in mature organisms to develop Q10 values for maintenance and whole-plant respiration. These Q10 values are then used to extrapolate across whole life cycles to predict the influence of temperature on plant growth.Methods
In this study, night temperature in young, rapidly growing plant communities was altered from 17 to 34 °C for up to 20 d. Day temperature was maintained at 25 °C. CO2 gas-exchange was continuously monitored in ten separate chambers to quantify the effect of night-temperature on respiration, photosynthesis and the efficiency of carbon gain (carbon use efficiency).Key Results
Respiration increased only 20–46 % for each 10 °C rise in temperature (total respiratory Q10 of between 1·2 to about 1·5). This change resulted in only a 2–12 % change in carbon use efficiency, and there was no effect on cumulative carbon gain or dry mass. No acclimation of respiration was observed after 20 d of treatment.Conclusions
These findings indicate that whole-plant respiration of rapidly growing plants has a small sensitivity to temperature, and that the sensitivity does not change among the species tested, even after 20 d of treatment. Finally, the results support respiration models that separate respiration into growth and maintenance components.