PSI photoinhibition is more related to electron transfer from PSII to PSI rather than PSI redox state in Psychotria rubra
PSI photoinhibition is more related to electron transfer from PSII to PSI rather than PSI redox state in Psychotria rubra
复制标题
PSI 光抑制与 PSII 到 PSI 的电子转移更相关，而不是与 Psychotria rubra 中的 PSI 氧化还原状态相关
DOI：
10.1007/s11120-016-0275-5
复制
发表时间：
2016-07-01
影响因子：
3.7
通讯作者：
Zhang, Shi-Bao
中科院分区：
文献类型：
--
作者：
Huang, Wei;Yang, Ying-Jie;Zhang, Shi-Bao
尽管人们认为野生型植物能够在强光下保护光系统I（PSI），但我们之前的研究表明，在遮荫树种九节树中，PSI对强光敏感。然而，其潜在的生理机制尚不清楚。本文研究了林可霉素（Lin）、敌草隆（DCMU）和甲基紫精（MV）处理的红色青霉（P. rubra）的PSI光抑制过程中，PSII向PSI的电子传递和PSI的氧化还原状态的作用。在暴露于2000 μmol光子m（-2）s（-1）2 h后，用H2O、Lin、DCMU和MV处理的样品中PSI活性分别降低了35%、29%、3%和49%。同时，MV处理的样品比H2O处理的样品显示出更高的P700氧化率，这表明在强光下PSI光抑制伴随着高水平的P700氧化率。PSI光抑制在DCMU处理的样品中减轻，但在MV处理的样品中加速，表明PSI光抑制在红色的P. rubra主要是由电子转移从PSII到PSI。因此，红花紫珠的PSI光抑制机制与拟南芥和黄瓜的PSI光抑制机制不同，可能更多地与电子从PSII传递到PSI有关，而不是与PSI的氧化还原状态有关。
Although it has been believed that wild-type plants are capable of protecting photosystem I (PSI) under high light, our previous study indicates that PSI is sensitive to high light in the shade-established tree species Psychotria rubra. However, the underlying physiological mechanisms are unclear. In this study, we examined the roles of electron transfer from PSII to PSI and PSI redox state in PSI photoinhibition in P. rubra by treatments with lincomycin (Lin), diuron (DCMU), and methyl viologen (MV). After exposure to 2000 μmol photons m(-2) s(-1) for 2 h, PSI activity decreased by 35, 29, 3, and 49 % in samples treated with H2O, Lin, DCMU, and MV, respectively. Meanwhile, the MV-treated samples showed higher P700 oxidation ratio than the H2O-treated samples, suggesting the PSI photoinhibition under high light was accompanied by high levels of P700 oxidation ratio. PSI photoinhibition was alleviated in the DCMU-treated samples but was accelerated in the MV-treated samples, suggesting that PSI photoinhibition in P. rubra was mainly controlled by electron transfer from PSII to PSI. Taking together, PSI photoinhibition is more related to electron transfer from PSII to PSI rather than PSI redox state in P. rubra, which is different from the mechanisms of PSI photoinhibition in Arabidopsis thaliana and cucumber.