Effects of the heavy metal cadmium on photosynthetic activity and the xanthophyll cycle in Phaeodactylum tricornutum

作     者：JI Yan XIE Xiujun WANG Guangce 季琰;解修俊;王广策

作者机构：School of Biological and Chemical EngineeringQingdao Technical College Key Laboratory of Experimental Marine BiologyInstitute of OceanologyChinese Academy of Sciences Laboratory for Marine Biology and BiotechnologyQingdao National Laboratory for Marine Science and Technology 

出 版 物：《Journal of Oceanology and Limnology》 (海洋湖沼学报（英文）)

年 卷 期：2018年第36卷第6期

页      面：2194-2201页

核心收录：

学科分类：0710[理学-生物学] 0908[农学-水产] 07[理学] 0707[理学-海洋科学] 0815[工学-水利工程] 

基　　金：Supported by the National Natural Science Foundation of China(No.41506172) the International S&T Cooperation Program of China(No.2015DFG32160) 

主　　题：heavy metal cadmium photosystemⅠ photosystemⅡ Phaeodactylum tricornutum 

摘      要：A bstract Cadmium(Cd) is one of the most common and widespread heavy metals in the environment. Cd has adverse effects on photosynthesis that are countered by photosystem I(PSI) and photosystem II(PSII); however, the protective responses of these photosystems to heavy metal stress remain unclear. Using the model diatom P haeodactylum tricornutum, a biological indicator that is widely used to assess the impact of environmental toxins, we simultaneously measured the effects of Cd on PSI and PSII and examined the levels of pigments in response to high light treatments before and after Cd exposure. Cd significantly reduced the quantum yield and electron transport rates of PSI and PSII. The quantum yield of non-photochemical energy dissipation in PSI due to donor side limitation increased faster than the quantum yield due to acceptor side limitation. The Cd treatment activated the P. tricornutum xanthophyll cycle under artificial light conditions, as indicated by an increased diatoxanthin content. Xanthophyll is important for photoprotection; therefore, the accumulation of diatoxanthin may down-regulate PSII activities to reduce oxidative damage. Together, our results suggest that the rapid reduction in PSII activities following Cd exposure is an adaptive response to heavy metal stress that reflects the variable exposure to external stressors in the native P. tricornutum environment.