豆科植物根瘤衰老机制与影响因素研究进展

Research progress in mechanism and influencing factors of root nodule senescence in leguminous plants

摘要:

豆科植物根瘤中的生物固氮作用对农业可持续发展和自然生态环境保护具有重要意义。依据根瘤的不同发育时期可将根瘤分为初生期、活跃期和衰老期3个时期，其中的衰老期是一个复杂的生理过程，涉及多种基因和环境因素的相互作用，可以通过调节固氮酶活性、豆血红蛋白基因表达水平等来调节根瘤的功能和寿命。同时，各种生物与非生物胁迫也会加速根瘤的衰老，降低豆科植物的生物积累量与生产力。本文系统阐述了根瘤衰老的形态、生理生化与分子变化机制，梳理了影响根瘤衰老的生物与非生物因素，探讨了能有效延迟共生根瘤的衰老，从而延长共生结瘤固氮功能，提高土壤氮利用效率，增加豆科植物种子灌浆期间种子发育的总体氮供应的策略，可在增强粮食安全的同时又减少化学肥料对环境的不利影响。

Abstract:

The nitrogen fixation in legume root nodules is of great significance for sustainable agricultural development and natural eco-environment protection. The growth period of root nodules can be divided into young, active, and senescence stages. Root nodule senescence is a complex physiological process involving the interactions of multiple genes and environmental factors. The functions and lifespan of root nodules can be altered by regulating nitrogenase activity and leghemoglobin gene expression levels. Biotic and abiotic stresses can accelerate the senescence of root nodules and reduce the biomass and productivity of leguminous plants. This article expounds the mechanism of morphological, physiological, biochemical, and molecular changes of root nodules during senescence and summarizes the biotic and abiotic factors that affect root nodule senescence. Furthermore, the measures for delaying the senescence of root nodules are discussed. These measures will prolong the symbiotic nitrogen fixation, improve the nitrogen utilization efficiency, and increase the overall nitrogen supply for seed filling of leguminous plants, thereby enhancing food security and reducing the adverse effects of chemical fertilizers on the environment.