摘要
为了研究重金属镉对藻类光合系统毒性效应及能量分配特征,以拟柱孢藻(Cylindrospermopsis raciborskii)为研究对象,分析了不同镉浓度下拟柱孢藻的生长、单位叶绿素a含量、光合系统Ⅱ(PSⅡ)叶绿素荧光及其能量分配模型.结果表明:不同浓度镉培养拟柱孢藻96 h后,0.2 mg/L Cd2+对拟柱孢藻单位细胞叶绿素a含量及PSⅡ活性无显著影响,而0.5mg/L Cd2+培养时拟柱孢藻的单位细胞叶绿素a含量为对照组的62.97%.当Cd2+浓度高于5 mg/L时,拟柱孢藻的PSⅡ活性受到抑制并导致表征量子产额分配的φEo和ψo分别下降了15.35%和13.52%.此外,当Cd2+浓度高于5 mg/L时,藻体PSⅡ能量分配表现为TRO/CSm和ETO/CSm显著减小,DIO/CSm差异不显著,类囊体能量分配表现为ABS/RC、TRO/RC和DIO/RC显著增大,明显区别于0.2、0.5和1 mg/L Cd2+处理组.这些结果表明PSⅡ反应中心是镉对拟柱孢藻光合作用影响的重要作用位点,且Cd2+高于5 mg/L时显著影响了拟柱孢藻PSⅡ反应中心并且抑制了PSⅡ电子传递链供体侧的电子传递,而拟柱孢藻则可能通过改变PSⅡ的能量分配来保护和缓解镉对其光合结构的损伤.
In order to investigate the toxic effects and energy distribution of photosynthetic system in algae exposed to heavy metal cadmium,the growth,chlorophyll-a,chlorophyll fluorescence and the energy model of PSⅡ were measured in Cylindrospermopsis raciborskii cultured at different cadmium concentrations. The results showed that it had no significant effect on the chlorophyll-a content per cell and PSⅡ photochemical activity of C. raciborskii after 96 h exposed to 0.2 mg/L Cd2+,while chlorophyll-a content per cell only 62.97% of the control group was found after 96 h exposed to upon 0.5 mg/L Cd2+. A significant inhibition in the photosynthesis of C. raciborskii when cultured in the media containing upon 5 mg/L Cd2+,and as quantum yield distribution parameters,φEo and ψo also showed a reduction by 15.35% and 13.52%. Moreover,the energy distribution of PSⅡ,such as TRO/CSm and ETO/CSm,was significantly decreased and DIO/CSmdid not markedly vary in algae cells. However,ABS/RC,TRO/RC and DIO/RC markedly increased in thylakoid,which significantly distinguished from treatments of 0.2,0.5 and 1 mg/L Cd2+. These results suggested that the PSⅡ reaction center was an important action site on the photosynthesis of C. raciborskii and the electron transfer on the donor side was inhibited when exposed to high cadmium concentration of more than 5 mg/L. However,the damage of photosynthetic structure might be protected and alleviated in C. raciborskii through the change of PSⅡ energy distribution.
作者
贺新宇
刘黎
付君珂
杨燕君
米文梅
施军琼
吴忠兴
HE Xinyu;LIU Li;FU Junke;YANG Yanjun;MI Wenmei;SHI Junqiong;WU Zhongxing(Key Laboratory of Eco-environments in Three Gorges Reservoir Region(Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources Research in Three Gorges Reservoir Region, Southwest University, Chongqing 400715, P. R. China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2019年第6期1612-1622,共11页
Journal of Lake Sciences
基金
国家自然科学基金项目(41877410)
中央高校基本科研业务费专项资金项目(XDJK2017B010,XDJK2019C044)联合资助
关键词
拟柱孢藻
镉
光合系统Ⅱ
能量分配
毒性效应
Cylindrospermopsis raciborskii
cadmium
PSⅡ
energy distribution
toxic effects
