Pintó-Marijuan Marta, Munné-Bosch Sergi
Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028 Barcelona, Spain.
Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 643, 08028 Barcelona, Spain
J Exp Bot. 2014 Jul;65(14):3845-57. doi: 10.1093/jxb/eru086. Epub 2014 Mar 28.
Inside chloroplasts, several abiotic stresses (including drought, high light, salinity, or extreme temperatures) induce a reduction in CO2 assimilation rates with a consequent increase in reactive oxygen species (ROS) production, ultimately leading to leaf senescence and yield loss. Photo-oxidation processes should therefore be mitigated to prevent leaf senescence, and plants have evolved several mechanisms to either prevent the formation of ROS or eliminate them. Technology evolution during the past decade has brought faster and more precise methodologies to quantify ROS production effects and damage, and the capacities of plants to withstand oxidative stress. Nevertheless, it is very difficult to disentangle photo-oxidative processes that bring leaf defence and acclimation, from those leading to leaf senescence (and consequently death). It is important to avoid the mistake of discussing results on leaf extracts as being equivalent to chloroplast extracts without taking into account that other organelles, such as peroxisomes, mitochondria, or the apoplast also significantly contribute to the overall ROS production within the cell. Another important aspect is that studies on abiotic stress-induced leaf senescence in crops do not always include a time-course evolution of studied processes, which limits our knowledge about what photo-oxidative stress processes are required to irreversibly induce the senescence programme. This review will summarize the current technologies used to evaluate the extent of photo-oxidative stress in plants, and discuss their advantages and limitations in characterizing abiotic stress-induced leaf senescence in crops.
在叶绿体内部，多种非生物胁迫（包括干旱、强光、盐度或极端温度）会导致二氧化碳同化率降低，进而使活性氧（ROS）生成增加，最终导致叶片衰老和产量损失。因此，应减轻光氧化过程以防止叶片衰老，植物已经进化出多种机制来防止ROS的形成或清除它们。过去十年的技术发展带来了更快、更精确的方法来量化ROS的产生效应和损害，以及植物抵御氧化胁迫的能力。然而，要区分导致叶片防御和适应的光氧化过程与导致叶片衰老（进而死亡）的光氧化过程非常困难。重要的是要避免在不考虑其他细胞器（如过氧化物酶体、线粒体或质外体）也对细胞内ROS的总体产生有显著贡献的情况下，将叶片提取物的结果等同于叶绿体提取物的结果来进行讨论。另一个重要方面是，关于作物非生物胁迫诱导叶片衰老的研究并不总是包括所研究过程的时间进程演变，这限制了我们对哪些光氧化胁迫过程是不可逆地诱导衰老程序所必需的了解。本综述将总结目前用于评估植物光氧化胁迫程度的技术，并讨论它们在表征作物非生物胁迫诱导叶片衰老方面的优点和局限性。
