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研究表明，氮素营养提高了旗叶老化过程中的叶绿素含量和光合速率，延缓了叶片衰老和光合功能衰退，增加了旗叶内细胞分裂素类物质（ZRs）含量，减少了促表激素ABA的累积量。氮素处理使旗叶老化过程中光合机构的RuBPcase活性和PS1、PS2活性均得以增加，但氮素对RuBPcase活性下降的延缓效果更为明显，相对增加了叶片老化过程中RuBPcase活性与PS1和PS2活性的比值，使光合机构光反应与暗反应之间的平衡状况得到改善，过剩还原力减少。此外，氮素营养使旗叶老化过程中超氧阴离子（O-2）的产生速率降低，H2O2的累积量减少，并提高细胞中活性氧清除酶SOD和CAT的活性。氮素营养可能主要通过调节细胞内的激素平衡，以及改善光合机构的自身运转平衡状况，减少了细胞中对生物体具有强烈伤害的活性氧的产生速率及其累积数量、提高了活性氧清除酶的活力，由此在很大程度上延缓了旗叶的衰老和光合功能衰退，延长了旗叶的光合功能期。
The results showed that nitrogen nutrition increased the chlorophyll content and photosynthetic rate of flag leaf during aging, delayed the decline of leaf senescence and photosynthesis, increased the contents of cytokinin (ZRs) in flag leaf, reduced the activity of promoting hormone ABA The cumulative amount. Nitrogen treatment increased the RuBPcase activity and PS1 and PS2 activities of photosynthetic organs during the flag leaf aging, but the delayed effect of nitrogen on the decrease of RuBPcase activity was more obvious, which increased the activities of RuBPcase and PS1 and PS2 Activity ratio, the photosynthetic mechanism of light reaction and dark reaction between the balance of the situation is improved, reduced excess reduction. In addition, nitrogen nutrition reduced the generation rate of superoxide anion (O-2), reduced the accumulation of H2O2, and enhanced the activity of active oxygen scavenging enzymes SOD and CAT in cells. Nitrogen nutrition may be mainly through the regulation of intracellular hormone balance, as well as to improve the balance of their own functioning of the photosynthetic machinery, reduce the cells of the organism has a strong impact on the production of reactive oxygen species and the cumulative number of increased reactive oxygen species scavenger Which greatly delayed the decline of senescence and photosynthetic function of flag leaves and prolonged the photosynthetic functional period of flag leaves.