Abstract: Atmospheric CO2 concentration has been increasing, it is necessary to reveal the impact of elevated CO2 concentration and temperature on rice growth and yield, which could provide basis references for national food security evaluation in future climate change. A modified open-top chamber was used to simulate relative 60μL·L-1 CO2 concentration increment and 2℃ temperature increasing in late rice field. Three treatments were arranged in randomized blocks and three replicates. Treatments were the control OTC (CK, ambient CO2 concentration and temperature), temperature increased by 2℃ (IT), temperature increased by 2℃ plus CO2 concentration elevated by 60μL·L-1 (IT+IC). The plant height, tillers, Chlorophyll content, leaf area index, yield and yield components of late rice were investigated. The results showed that elevated temperature increased significantly the plant height, with 3cm improvement in whole growth season, while there was no influence under elevated atmospheric CO2 concentration and temperature synchronously. About 20 days after transplanting, the elevated temperature had positive effects on tillers and increased 1 stem per hole, but the combination of elevated CO2 and temperature had no influence. The elevated temperature improved 0.8 SPAD leaf chlorophyll content and leaf area index, while elevated CO2 and temperature had no influence on chlorophyll content. Elevated CO2 and temperature increased significantly grain yield by 14.0%. But the elevated temperature was not significant influence, because elevated temperature increased the sterile rate and decreased thousand grain weights, which resulted in the insignificant increase of grain yield.

Key words: Open-top chamber, Temperature, CO2 concentration, Plant height, Leaf chlorophyll content, Yield components