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氮素水平与小麦后期旗叶衰老有着密切关系。中氮和高氮处理与低氮和无氮处理相比,显著提高了SOD和POD的活性,相对改善了细胞中活性氧产生与清除之间的平衡,减少了细胞内过氧化物的积累,减缓了叶片衰老;但平作栽培小麦264kg/hm2水平(N3处理)与165kg/hm2水平(N2处理)间的SOD、POD活性、MDA含量以及叶绿素含量等生理指标差异不显著,表明施氮量达到一定水平后继续增加施氮量对延缓小麦旗叶衰老无显著效应。通过对垄作和平作2种栽培模式的比较发现,小麦旗叶衰老进程分为两个阶段;平作小麦以花后14天,垄作小麦以花后21天为拐点,前期为缓慢衰老期,后期为急剧衰老期。在缓慢衰老期,旗叶POD、SOD活性,叶绿素含量会略有上升;而进入急剧衰老期后,上述3个生理指标都急剧下降。平作小麦比垄作小麦提前进入急剧衰老期。氮素水平为165kg/hm2时,2种栽培模式均可以获得中产以上产量;264kg/hm2水平下能够获得更高的产量,且垄作栽培小麦的增产优势较平作小麦更明显。
Nitrogen levels are closely related to flag leaf senescence in the late wheat stage. Compared with low-N and high-N treatments, medium-nitrogen and high-nitrogen treatments significantly increased the activities of SOD and POD, relatively improved the balance between reactive oxygen species generation and clearance in cells, reduced the accumulation of intracellular peroxide, But the leaf senescence was slowed down. However, the physiological indexes of SOD, POD activity, MDA content and chlorophyll content of 264kg / hm2 (N3 treatment) and 165kg / hm2 After a certain level continue to increase the amount of nitrogen to delay flag leaf senescence had no significant effect. The comparison of two cultivation modes of peace planting by ridge found that the process of flag leaf senescence of wheat was divided into two stages. For wheat, the wheat was planted for 14 days after anthesis and ridged wheat was inflected 21 days after anthesis. The early stage was slow aging and the later was Rapid aging. During the slow senescence period, the activities of POD and SOD and the contents of chlorophyll in the flag leaves increased slightly, while the sharp changes of the above three physiological indexes were observed after entering the acute senescence period. Flat for wheat ahead of the period of rapid aging than the ridge of wheat. When the nitrogen level was 165 kg / hm2, the above middle-yield could be obtained in both of the two cultivation modes. Higher yield could be obtained at the level of 264 kg / hm2, and the yield-increasing advantage of ridge-cropping wheat was more obvious than that of wheat.