| 微量元素锰对威氏海链藻生长及叶绿素荧光的影响 |
| 摘要点击 1304 全文点击 692 投稿时间：2018-04-01 修订日期：2018-05-24 |
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| 中文关键词 锰 威氏海链藻(C.weissflogii) 生长 叶绿素荧光 活性氧 |
| 英文关键词 manganese Conticribra weissflogii growth chlorophyll fluorescence reactive oxygen species |
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| 中文摘要 |
| 微藻和高等植物的光系统Ⅱ中的放氧复合体（oxygen-evolving complex，OEC）是裂解水与释放氧气、质子和电子的部位，其中水裂解的反应中心由4个锰原子组成的锰族构成.叶绿素荧光诱导动力学分析技术是研究光合作用特征的有效方法，可以指示不同环境压力下光系统各构件的变化.利用该技术研究了锰添加（0~9000 nmol·L-1 Mn）对威氏海链藻（Conticribra weissflogii）生长及叶绿素荧光特性的影响.结果表明，除最高浓度锰（9000 nmol·L-1 Mn）外，其余浓度锰对威氏海链藻生长的影响均不显著；锰对威氏海链藻叶绿素荧光参数的影响与锰添加的浓度范围有关，且随培养时间的增加而增强：其中，较低浓度锰（90 nmol·L-1 Mn）对各叶绿素荧光参数都呈现了强影响效果.尽管锰可能不是威氏海链藻生长的限制因子，但是锰从两方面促进了其光合作用：①促进光系统Ⅱ供体侧OEC结构的完整性和从OEC到电子传递中间体Tyr之间的电子传递；②促进光系统Ⅱ受体侧的能量转化和QA之后的电子传递.研究还发现，光合作用中与能量转化相关的荧光参数和活性氧（reactive oxygen species，ROS）之间呈显著相关（P<0.01），表明锰在威氏海链藻光合作用过程及ROS的产生中都扮演着重要角色. |
| 英文摘要 |
| The manganese (Mn4) cluster, as a part of the oxygen-evolving complex (OEC) in the photosystemⅡ (PS Ⅱ) of microalgae and plants, assists in the electrolysis of water to oxygen, protons, and electrons. To examine the relationships among manganese (Mn) concentrations in the culture medium, algae growth, and chlorophyll fluorescence characteristics, we exposed the diatom Conticribra weissflogii to a broad range of Mn concentrations from 0 to 9000 nmol·L-1. Chlorophyll fluorescence induction dynamics analysis, an effective way to investigate photosynthetic characteristics, can be used as indicator of the photosynthetic apparatus of photosynthesizers under different stressors. Here, we studied the effects of Mn exposure on C. weissflogii using this fluorescence analysis method. The results show that the growth of C. weissflogii is independent of the Mn exposure at concentrations below 9000 nmol·L-1. Moreover, chlorophyll fluorescence parameters of C. weissflogii respond to exposed Mn concentrations, whereby the strongest induction occurred at 90 nmol·L-1 Mn and the responses are enhanced over time. Although Mn in culture media may not be a major limiting factor of the growth of C. weissflogii, it significantly enhances the photosynthesis of C. weissflogii via two ways. First, Mn improves the integrity of the OEC structure and electron transfer from OEC to Tyr on the donor side of PS Ⅱ; second, Mn also enhances the energy transfer and electron transport after reaching the primary quinone acceptor (QA) on the acceptor side of PS Ⅱ. Energy transfer-related fluorescence parameters are positively correlated with the level of ROS in C. weissflogii, indicating that Mn plays an important role in both photosynthesis processes and reactive oxygen species(ROS)production. |
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