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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。
Through experiments in a large artificial climate chamber, three soil moisture treatments of 350 and 700 μl / L, two CO 2 levels, and high, medium and low soil moisture were designed. The soil moisture content ranged from 85% to 100% and from 65% 85%, and 45% -65% (accounting for the percentage of field water holding capacity). The combined effects of soil moisture and atmospheric CO 2 concentration on the transpiration, photosynthetic rate, growth status and dry matter accumulation of crops such as wheat, corn and cotton , The impact of water use efficiency. The results showed that the effects of increasing CO2 concentration on wheat, maize and cotton were significantly different under different soil moisture conditions. The effects of increasing photosynthetic rate on low-moisture treatments were significantly higher than those on high-moisture treatments, while the effects of decreasing the transpiration rate per unit leaf were slightly Less than that of high-moisture treatment. The decrease of total evapotranspiration was significantly lower than that of high-moisture under low-moisture condition. The ratio of plant height and leaf area index increased significantly lower than that of high-moisture treatment. The positive effect of atmospheric CO 2 concentration on photosynthesis rate and growth and its inhibitory effect on evapotranspiration weakened the adverse effects of water stress on crop photosynthesis and growth. The proportion of water use efficiency of crops increased under high water conditions Moisture condition