Chlorophyll a fluorescence transient during freezing and recovery in winter wheat
Chlorophyll a fluorescence transient during freezing and recovery in winter wheat
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DOI：
10.1007/s11099-007-0069-2
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发表时间：
2007-01-01
期刊：
影响因子：
2.7
通讯作者：
Rapacz, M.
中科院分区：
文献类型：
--
作者：
Rapacz, M.
叶绿素（Chl）的荧光测量作为植物耐冻性的评价往往不够敏感，以检测早期的代谢变化，开始暴露于冻结温度。利用冷驯化的冬小麦，我分析了多相瞬态（从50亩秒到1秒）的叶绿素a荧光。这使得能够详细研究最初暴露于冰冻温度直到植物恢复阶段后光系统2（PS2）复合体内的渐进能量流动和效率。轻度霜冻可能导致初级损害的初始后果涉及对Q（A）（PS2的初级醌电子受体）之后的能量转移的干扰。另一方面，较低的冻结温度可能会阻止PS2反应中心（RC），Chl和Q（A）之间的能量流动。所有的主要损坏只能部分修复。进一步冷冻触发的PS2 RC和Q（A）之间的电子转移功能障碍与可能导致PS2失活的二次损伤有关。主要和次要的冻害都反映在PI（ABS）降低，性能指数的基础上平等的吸收，所有的能量biftircations在PS2的特征。PI（ABs）也分化品种与对比冻耐性无论是在发病后的冻结或在恢复阶段。与此相反，PS2的潜在量子产额（F（v）/F（m），），表征能量捕获效率的PS2 RC，只有不同的品种在不同的耐冷冻性在恢复阶段。
Chlorophyll (Chl) a fluorescence measurements as evaluators of plant freezing tolerance are frequently insufficiently sensitive to detect the early metabolic changes that are initiated following exposure to freezing temperatures. Using cold-acclimated winter wheat, I analysed the polyphasic transience (from 50 mu s to 1 s) of Chl a fluorescence. This enabled detailed studies of the progressive energy flows and efficiencies within the photosystem 2 (PS2) complex that ensue following initial exposure to freezing temperatures right through to the plant recovery stage. The initial consequences of mild frosts that may cause primary damage involve a disturbance to the energy transfer subsequent to Q(A) (the primary quinone electron acceptor of PS2). Lower freezing temperatures, on the other hand, may deter energy flow between the PS2 reaction centre (RC), Chl, and Q(A). All primary damage could only be repaired partially. Further freezing-triggered dysfunction of the electron transfer between the PS2 RCs and Q(A) was connected with secondary damage that could lead to PS2 deactivation. Both primary and secondary freezing damages were reflected in decreased PI(ABS), the Performance Index based on equal absorption that characterizes all energy biftircations in PS2. PI(ABs) also differentiated cultivars with contrasting freezing-tolerance either subsequent to the onset of freezing or during the recovery stage. In contrast, the potential quantum yield of PS2 (F(v)/F(m),), which characterizes efficiency of energy trapping in the PS2 RCs, was only different in cultivars with contrasting freezing-tolerance during the recovery stage.