水分胁迫对春小麦光合和渗透调节物质的影响

为进一步了解春小麦的抗旱生理机制,以春小麦品种陇春26号为材料,采用盆栽法研究了中度和重度水分胁迫下春小麦旗叶光合参数和渗透调节物质含量的变化.结果表明,随土壤水分的减少,春小麦旗叶的叶绿素含量、光合速率、气孔导度、胞间CO2浓度、蒸腾速率逐渐降低,可溶性糖和可溶性蛋白含量及酸性转化酶活性呈先增后减趋势,脯氨酸和丙二醛含量及过氧化物酶活性逐渐增强.中度水分胁迫的可溶性糖含量和酸性转化酶活性显著高于重度水分胁迫和正常供水对照；重度水分胁迫的可溶性蛋白含量显著低于中度水分胁迫和正常供水对照,而脯氨酸和丙二醛含量显著高于中度水分胁迫和正常供水对照.说明中度或重度干旱胁迫下春小麦旗叶光合速率降低是叶绿素含量降低和光合原料缺乏所致,脯氨酸含量和过氧化物酶活性升高有助于春小麦抵御干旱胁迫.

Effect of Water Stress on Photosynthetic Parameters and Osmotic Regulation Substances of Spring Wheat

Photosynthetic parameters and osmotic regulators in flag leaf of spring wheat were studied by pot growing experiment so as to understand the physiological mechanism of drought tolerance in wheat in semi arid and arid conditions. The results showed that along with the soil moisture from 80% to 60%,and to 40%,the chlorophyll content,photosynthetic rate,stomatal conductance,intercellular CO₂ concentration,transpiration rate were gradually reduced while the contents of soluble carbohydrate and soluble protein,and the activities of acid invertase were increased at first and then reduced,and the contents of proline and malonaldehyde,and the activity of peroxidase were gradually increased. The soluble carbohydrate content and acid invertase activity under 60% soil moisture were significantly higher than that under soil moisture of 40% and 80%. The soluble protein content under 40% soil moisture was significantly lower than that under soil moisture of 60% and 80%,But the contents of proline and malonaldehyde as well as peroxidase activity under 40% soil moisture were significantly higher than that under soil moisture of 60% and 80%. This suggested that the flag leaf of spring wheat was sensitive to water stress,low chlorophyll content and CO₂ shortage accounted for the low photosynthetic rate under moderate and severe water stress. High contents of proline and peroxidase activity were the drought tolerant mechanism of spring wheat in semi arid and arid conditions.