施氮时期对地膜春小麦叶片衰老的影响

Effect of Nitrogen Application Stage on the Index of Leave Senescence for Spring Wheat Mulched with Plastic Films

为探索施氮时期对地膜春小麦衰老的影响,以春小麦陇春20号为材料,采用管栽模拟试验的方法,研究了不同施氮时期地膜春小麦叶片的叶绿素、蛋白质、丙二醛(MDA)含量和细胞质膜相对透性。结果表明,在分蘖期、拔节期、孕穗期追施氮肥较对照(不追施处理)叶片叶绿素含量分别增加125%、70.83%和52.08%;叶片蛋白质含量在施氮后15-20 d迅速上升,拔节期和孕穗期施肥较明显,比对照分别增加8.06%和10.84%;而叶片MDA含量和电导率在拔节期和孕穗期均呈下降趋势,较对照叶片MDA含量分别降低16.26%和15.02%,电导率分别降低5.65和3.62个百分点。由此可见,中后期施氮能延缓地膜春小麦叶片衰老,延长叶片功能期。

In order to understand the influence of nitrogen application stage on leaf senescence of spring wheat mulched with plastic films, the effect of nitrogen application at different growth stages on chlorophyll content, soluble protein content, the malondialdehyde （MDA） content and the relative conductivity of leaves were determined for spring wheat Mulched with Plastic Films by using simulated tube cultivation and with the variety of Long-chun 2 as material. The results indicated that the chlorophyll content in leaves increased as supplement nitrogenous application at tillering stage, jointing stage and booting stage than no supplement nitrogenous application with 125.00%, 70.83% and 52. 08%respectively. During 15-20 d after supplement nitrogenous application, the soluble protein content in leaves were rapidly increased at jointing stage and booting stage, and were 8. 06% and 10.84% higher than that of no supplement nitrogenous application. The malondialdehyde （MDA） content and the relative conductivity in spring wheat leaves decreased, MDA was 16.26% and 15.02% lower, the relative conductivity was 5.65 and 3. 62 percentage points lower than no supplement nitrogenous application. So supplement nitrogenous application could delay the senescence and prolong function of leaves of spring wheat mulched with plastic films at middle and late stage.