干旱、CO2和温度升高对春小麦光合、蒸发蒸腾及水分利用效率的影响

研究了干旱、CO2 浓度和温度升高对春小麦生育期、光合速率 (Pn)、蒸发蒸腾 (ET)及水分利用效率 (WUE)的影响 .结果表明 ,大气CO2 浓度升高 (5 5 0、70 0 μmol·mol-1)虽可延长抽穗 成熟期 ,但高温 (日平均温度高于正常日平均温度约 4 .8℃ )对生育期的影响远大于高CO2 影响 ,使得高CO2 、高温下抽穗 成熟期缩短 ,且种子提前萌发 ;CO2 浓度升高和高温共同作用使各水分处理的小麦光合增强、气孔阻力增加、叶片水平的水分利用效率 (WUEl)和群体水平的水分利用效率 (WUE)增大 ,但对蒸腾速率影响不显著 .对蒸发蒸腾的影响因不同的土壤水分而不同 ,在高 (田间持水量的 75 %～ 85 % )、中 (田间持水量的 5 5 %～6 5 % )水分条件下 ,高温和高CO2 使蒸发蒸腾增加 ,而在低水分条件 (田间持水量的 35 %～ 4 5 % )下 ,高温和高CO2 使蒸发蒸腾减少

Effects of drought,CO2 concentration and temperature increasing on photosynthesis rate,evapotranspiration,and water use efficiency of spring wheat

The effects of drought, CO2 concentration and temperature increasing on development period, photosynthesis rate (Pn), evapotranspiration (ET), and water use efficiency of spring wheat were investigated. The results showed that elevated CO2 concentration (550, 700 mumol.mol-1) could lengthen heading-ripening period, but high temperature (average diurnal temperature increase 4.8 degrees C), which made heading-ripening period shorten and speeded the seedling under treatment of both high CO2 concentration and high temperature, affected growing period more than high CO2 concentration. The combined effects of elevated CO2 concentration and temperature enhanced Pn, stomatal resistance (r), leaf water use efficiency (WUEl), and whole-canopy water use efficiency (WUE), while transpiration rate (E) were not significantly affected. The effects on ET depended on soil moisture. High CO2 concentration and high temperature enhanced ET under high (75%-85% field water capacity) and middle (55%-65% field water capacity) soil moisture, but decrease ET under low soil moisture (35%-45% field water capacity).