氮量及减灌对冬小麦旗叶生理参数和细胞保护酶活性的影响

为给小麦水氮高效栽培提供依据，以水氮响应特征不同小麦品种保麦10（适合高水肥）和石麦22（节水型）为材料，通过田间试验，研究了不同施氮量及春季灌水次数对小麦旗叶光合色素含量、保护酶活性和产量的影响。结果表明，増施氮素和增加灌水次数能提高供试品种旗叶叶绿素a、b含量、可溶隆蛋白含量、超氧化物气化酶（SOD）和过氧化氢酶（CAT）活性，改善产量构成因素及产量，减少细胞膜质过氧化产物丙二醛（MDA）累积量。高水氮组合（N225结合春季2次灌水）下保麦10和石麦22旗叶生理生化参数及产量性状的差异较小；在高氮、低氮灌1水下，与保麦10相比，石麦22旗叶生长中后期被测细胞保护酶活性、游离脯氨酸、可溶性糖含量显著增加，MDA含量显著降低，产量得到明显改善。石麦22较强的耐低氮及干旱能力与其水氮胁迫下植株上位叶维持较高光合色素含量、较多渗透物质含量和较强细胞保护酶活性有关。

Effect of Nitrogen Amount and Limited Irrigation on Physiological Features of Flag Leaf and Cellular Protective Enzyme Activities in Wheat

To provide basis for wheat cultivation with high use efficiency of water and nitrogen,we used two wheat varieties showing contrasting response to water and fertilizer supplies,Baomai 10(suitably planted under affluent water and fertilizer) and Shimai 22(a water saving variety),to study the effects of nitrogen application amount and irrigation frequency on photosynthetic pigments and antioxidant enzymatic activities of the flag leaves as well as on yield in wheat under field growing conditions. Results indicated that the affluent nitrogen and water treatment could drastically increase the contents of chlorophyll a and b,content of soluble protein,the activities of superoxide dismutase(SOD) and catalase(CAT) in flag leaves,improve the yield components and yield,but decrease the accumulation of malondialdehyde(MDA),a product reflecting cytosol membrane peroxidation. Under the treatment with affluent supplies of N and water(N225 together with twice irrigation),similar behaviors were observed for the above physiological parameters of flag leaves and yield traits between Baomai 10 and Shimai 22. In contrast,under the treatments with lowered water(one irrigation in spring) combined with both low N and high N amounts,Shimai 22 exhibited improved physiological and biochemical parameters,such as enhanced antioxidant enzyme activities as mentioned above,together with increased contents of free proline and soluble sugar in flag leaves,increased yields,and reduced MDA accumulation compared with those of Baomai 10. Our investigation suggested that Shimai 22 possesses improved tolerance to drought and N deficiency,which is associated with the increased photosynthetic pigment contents,elevated osmolyte accumulative amounts,and enhanced antioxidant enzymatic activities in upper leaves under stress conditions of water deficit and N deprivation.