Three physiological parameters capture variation in leaf respiration of Eucalyptus grandis, as elicited by short-term changes in ambient temperature, and differing nitrogen supply.

摘要: We used instantaneous temperature responses of CO2 -respiration to explore acclimation dynamics for Eucalyptus grandis grown with differing nitrogen supply. A reduction in ambient from 23 19 °C reduced light-saturated photosynthesis by 25% but increased respiratory capacity 30%. Changes were not reversed after temperatures subsequently 27 °C. Temperature sensitivity respiration measured at prevalent varied little between treatments was significantly ~105 kJ mol-1 when supply N weak, ~70 kJ mol-1 it strong. across a broader range (20-40 °C) could be fully described 2 exponent parameters an Arrhenius-type model (i.e., activation energy low reference and parameter describing the dependence energy). These strongly correlated, statistically explaining 74% observed variation. Residual variation linked treatment-induced changes or capacity. Leaf contents starch soluble sugars suggest that varies source-sink imbalances carbohydrate utilization, which combination shifts carbon-flux mode, serve maintain homeostasis growth temperature.