Effect of Artificial Warming on Chlorophyll Contents and Net Photosynthetic Rate of Quercus variabilis Seedlings in an Open-field Experiment

摘要

We investigated the effect of artificial warming on chlorophyll contents and net photosynthetic rates of 2-year-old Quercus variabilis seedlings in a nursery open-field experiment site. 64 seedlings were each planted in lmxlm plots (n = 4) and warmedwith infrared lamps. The air temperature in warmed plots was 3°C higher than that of control plots. Chlorophyll contents and net photosynthetic rates were measured in May, July, August, September and October, 2011. In May, September and October chlorophyll contents and net photosynthetic rates were significantly higher in warmed plots than in control plots. However, there were no significant differences in chlorophyll contents and net photosynthetic rates between warmed plots and control plots in Julyand August. It seemed that early developed leaves of warmed plots in May with higher chlorophyll contents could lead to higher net photosynthetic rates whereas there was no difference in net photosynthetic rates due to saturation of chlorophyll contentsin July and August. Increased biosynthesis of chlorophyll due to warming might increase net photosynthetic rates in September and October.