Elevated Temperature and CO₂ Impacts on Pollination, Reproductive Growth, and Yield of Several Globally Important Crops

抄録

　Experiments were conducted to determine effects of elevated temperature and doubled carbon dioxide (CO₂) on pollination, reproductive growth, and yield of rice, soybean, peanut, and dry bean. Diurnal temperature treatments were 28/18, 32/32, 36/26, 40/30, and 44/34°C, at 350 or 700 µmol CO₂ mol^-1. Vegetative growth was tolerant of high temperature; however, reproductive growth failed at stressfully high temperatures. Above 25°C, rice grain yield and harvest index (HI) declined progressively, reaching zero at 36°C mean temperature, associated with decline in filled grain percentage attributed to failed pollination. Dry bean was more sensitive, with highest yield and seed size at 23°C, reaching zero at 32°C. Soybean and peanut were more tolerant than rice; their grain yield and HI declined as temperature exceeded 26°C, reaching zero at 40°C. Pollen viability of bean and peanut followed a temperature response similar to grain yield and was a major factor in yield decline, although seed size also decreased. Rice maintained grain-size with rising temperature whereas soybean, peanut, and bean seed size declined at elevated temperatures. While elevated CO₂ increased grain yield, there were no beneficial interactions of CO₂ with elevated temperature. Detrimental effects of elevated temperature on reproductive processes will be very important under future global change.