土壤水分和CO_2浓度增加对小麦、玉米、棉花蒸散、光合及生长的影响

Effects of Soil Water and the Atmospheric CO2 Concentration Increase on Evapotranspiration, Photosynthesis, Growth of Wheat, Maize and Cotton

通过在大型人工气候室内的试验、设计了350和700μl/L,两种CO_2浓度水平和高、中、低三种土壤水分处理,其土壤含水率范围分别为85％～1OO％、65％～85％和45％～65％(占田间持水量的百分数),分析了土壤水分条件和大气CO_2浓度增加的共同作用对小麦、玉米、棉花等作物蒸发蒸腾、光合速率、生长状况与干物质积累、水分利用效率的影响。结果表明:大气CO_2浓度增加对小麦、玉米、棉花等作物的影响在不同土壤水分条件下明显不同,光合速率增加的效应低水分处理明显大于高水分处理,而使单位叶片蒸腾速率降低的效应略小于高水分处理的;总蒸发蒸腾量减小的幅度则是低水分条件明显小于高水分条件的;株高、叶面积指数增加的比例低水分处理明显大于高水分处理的。大气CO_2浓度增加对光合速率和生长的正效应及其对蒸发蒸腾的抑制作用削弱了水分胁迫对作物光合和生长产生的不利影响,在低水分条件下作物水分利用效率增加的比例大于高、中水分条件的。

Crops were exposed to both 350 and 700 ul/L of CO2 in the plant growth chamber designed with high, middle and low soil moisture treatments, with the soil water contents of 85% -100%, 65%-85% and 45%- 65% (percentage of field capacity) respectively. This paper analysed the combined effects of the atmospheric CO2 concentration and soil moisture on photosynthesis rrte, evapotranspiration, growth, dry matter storage, water use efficiency of crops etc. The study showed that there were obviously different crop (wheat, maize and cotton)responses to CO2 enriched under different soil moisture treatments, photosynthesis rate, plants height and leaf area index (LAI) in low soil moisture treatment than high soil moisture treatment , also a decreasing effects of transpiration rate per leaf and total evapotranspiration content in low soil moisture treatment than high soil moisture treatment responses to doubling CO2 concentration. The positive effects of photosynthesis and growth, and diverse effects of to evapo-transpiration with elevated CO2 reduce the unfavorable effects of crop photosynthesis and growth owing to water stress. There was an increasing extent of crop water use efficiency(WUE)in low soil moisture regime than high and middle soil moisture regimes.