; Light intensity dependent photosynthetic electron transport in eelgrass (Zostera marina L.)
; Light intensity dependent photosynthetic electron transport in eelgrass (Zostera marina L.)
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DOI：
10.1016/j.plaphy.2017.02.011
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发表时间：
2017
影响因子：
6.5
通讯作者：
Sheng Zi Tong
中科院分区：
文献类型：
--
作者：
Yang Xiao Qi;Zhang Quan Sheng;Zhang Di;Sheng Zi Tong
研究了电子传递对三种辐射水平（20、200和1200 μmol光子m−2s− 1 PAR;暴露分别称为LL、ML和HL）的响应。利用叶绿素荧光技术。ML和HL处理降低了光系统II（PSII）的最大量子产率（Fv/Fm）和MR/MRO的最大斜率下降（VPSI），表明PSII和光系统I（PSI）都发生了光抑制。由于PSII半衰期恢复时间较长，Fv/Fm恢复速度较慢，下降幅度较其他高等植物低40%，说明PSII的恢复能力较差。相比之下，PSI表现出高弹性和PSI周围的循环电子传递（CEF）保持高活性。随着持续暴露，动力学分量（L1和L2）的幅值、电子从PSII向质体醌库转移的概率（EET 20）以及PSII单元间的连接性降低，能量耗散增强。主成分分析表明，VPSI和Fv/Fm都贡献了同一个组分，这与PSII和PSI之间的高连通性相一致，表明两个光系统之间存在密切的协调关系。这种协调可能有利于强光的适应。暴露于LL显著增加PSI和CEF的活性，这可能导致光捕获增加。此外，如由L1、L2、EET 20的增强和电子传输到最终PSI受体侧的可能性所指示的平滑电子传输可以有助于光利用效率的增加。
Responses of electron transport to three levels of irradiation (20, 200, and 1200 μmol photons m−2s−1PAR; exposures called LL, ML and HL, respectively) were investigated in eelgrass (ZosteramarinaL.) utilizing the chlorophyllafluorescence technique. Exposure to ML and HL reduced the maximum quantum yield of photosystem II (PSII) (Fv/Fm) and the maximum slope decrease of MR/MRO(VPSI), indicating the occurrence of photoinhibition of both PSII and photosystem I (PSI). A comparatively slow recovery rate ofFv/Fm due to longer half-life recovery time of PSII and 40% lower descending amplitude compared to other higher plants implied the poor resilience of the PSII. Comparatively, PSI demonstrated high resilience and cyclic electron transport (CEF) around PSI maintained high activity. With sustained exposure, the amplitudes of the kinetic components (L1andL2), the probability of electron transfer from PSII to plastoquinone pool (ψET2o), and the connectivity among PSII units decreased, accompanied by an enhancement of energy dissipation. Principle component analysis revealed that bothVPSIandFv/Fm contributed to the same component, which was consistent with high connectivity between PSII and PSI, suggesting close coordination between both photosystems. Such coordination was likely beneficial for the adaption of high light. Exposure to LL significantly increased the activity of both PSI and CEF, which could lead to increased light harvesting. Moreover, smooth electron transport as indicated by the enhancement ofL1,L2,ψET2oand the probability of electron transport to the final PSI acceptor sides, could contribute to an increase in light utilization efficiency.