Photosynthetic responses of two eucalypts to industrial-age changes in atmospheric [CO2] and temperature

摘要: The unabated rise in atmospheric (CO2) is associated with increased air temperature.Yet,few CO2-enrichment studies have considered pre-industrial or warming. Conse- quently, we quantified the interactive effects of growth and temperature on photosynthesis faster-growing Eucalyptus saligna slower-growing E. sideroxylon. Well-watered -fertilized tree seedlings were grown a glasshouse at three (290, 400, 650 m LL -1 ), ambient (26/18 °C, day/night) high (ambient + 4 °C) temperature. Despite differences rate, both eucalypts responded similarly to treatments few effects. Light-saturated (Asat) light- (CO2)-saturated (Amax) by ~50% ~10%, respectively, each step-increase (CO2), underpinned corresponding 6-11% up-regulation maximal electron transport rate (Jmax). Maximal carboxylation (Vcmax) was not affected (CO2). Thermal photosynthetic acclimation occurred such that Asat Amax similar ambient- high-temperature-grown plants. At temperature, thermal optimum 2-7 °C across treatments. These results are first suggest well-watered eucalypt will remain strongly responsive increasing future, warmer climate.