【摘要】 UV-B辐射作为全球气候变化背景下重要的环境胁迫因子,严重威胁稻田生态系统氮循环平衡。本文综述了UV-B辐射胁迫对水稻(Oryza sativa)氮代谢的硝酸还原和氨同化过程、氮分配策略、氮素气态损失的影响及其响应机制,以及UV-B辐射胁迫对土壤造成氮素损失的机制。探讨了水稻-牧草轮作体系缓解UV-B辐射胁迫诱导的稻田氮亏损的可能机制,即:通过构建生态屏障避免UV-B辐射的长期直射;豆科牧草生物固氮对后茬水稻的氮补偿效应;水稻秸秆还田对土壤有机氮库的补充;根系分泌物和根际微生物对轮作体系中氮固持、转化的调控作用。理解水稻-牧草轮作系统的氮补偿机制为应对全球气候变化下的稻田可持续生产提供新思路。更多还原

【Abstract】 As an important environmental stressor under global climate change, UV-B radiation poses a serious threat to the nitrogen cycle balance of paddy ecosystems. This paper reviews the effects of UV-B radiation stress on the nitrogen metabolism of rice(Oryza sativa), including the processes of nitrate reduction and ammonia assimilation, nitrogen allocation strategies and their response mechanisms, as well as the mechanisms underlying soil nitrogen deficiency induced by UV-B radiation. The possible mechanisms by which rice–forage rotation systems alleviate UV-B stress-induced nitrogen deficits in paddy fields were also discussed. These include:(1) constructing ecological barriers to reduce prolonged direct exposure to UV-B radiation;(2) the nitrogen compensation effect of biological nitrogen fixation by leguminous forages on the subsequent rice crop;(3) replenishment of soil organic nitrogen pool by rice straw returning to the field; and(4) regulatory effects of root exudates and rhizosphere microorganisms on nitrogen sequestration and transformation in crop rotation systems. Understanding the nitrogen compensation mechanisms of rice–forage rotation systemsprovides a new insightsfor achieving sustainable rice production underglobal climate change.更多还原