INTERACTIVE EFFECTS OF INCREASED CO2 AND TEMPERATURE ON GROWTH PARAMETERS, GAS EXCHANGE RATE AND SEED YIELD OF RICE.
Proponents of global climate models predict a doubling of world CO2 concentration from 350 to 600 ppm by the year 2030, concurrent with a 2-5°C temperature increase. Consequences of this “greenhouse effect” on Oryza sativa L. were determined using four rice lines selected for their widespread use in cultivation and research. A 2×2 factorial design was used with CO2 at 350 and 600 ppm and day/night temperature regimes of 31/27°C and 37/33°C. Combined effects of CO2/temperature were determined during 5 harvests from seeding to reproductive maturity. Elevated CO2 enhanced dry weight and photosynthetic capacity over both temperature regimes relative to plants grown at ambient CO2. The 37/33°C day/night temperature regime increased sterility in rice by decreasing pollen shed.