铜藻应对强光胁迫的光合适应  

Photosynthetic adaptation of Sargassum horneri in response to strong light stress

作　　者：张琦 李凌雪 何健龙 王宁 刘凯 刘丽娟 徐智广 ZHANG Qi;LI Lingxue;HE Jianlong;WANG Ning;LIU Kai;LIU Lijuan;XU Zhiguang(School of Life Sciences,Ludong University,Yantai 264025,Shandong,China;Shandong Institute of Marine Resources and Environment,Yantai 264006,Shandong,China;Marine Economy Promotion Center,Marine Ecological Civilization Comprehensive Experimental Area of Changdao,Yantai 265800,Shandong,China)

机构地区：[1]鲁东大学生命科学学院,山东烟台264025 [2]山东省海洋资源与环境研究院,山东烟台264006 [3]长岛综合试验区海洋经济促进中心,山东烟台265800

出　　处：《陕西师范大学学报（自然科学版）》2024年第1期103-114,共12页Journal of Shaanxi Normal University：Natural Science Edition

基　　金：国家自然科学基金(42276119);山东省自然科学基金(ZR2020MD092);山东省藻类产业技术体系项目(SDAIT-26)。

摘　　要：近年来,以漂浮种群出现的铜藻金潮频繁暴发,其作为一种特殊的生物入侵现象,对海洋生态系统造成巨大负面影响。金潮暴发时,藻体于海水表面漂浮会接受更高的光强,但铜藻应对强光胁迫的光合响应机制尚不明确。设置低光(460μmol/(m^(2)·s))、中光(920μmol/(m^(2)·s))、高光(1380μmol/(m^(2)·s))3个强光水平,探讨铜藻在强光胁迫下的光合响应及适应。结果显示,经120 min强光处理后,铜藻的光合效率显著降低,最大光化学量子产量(F_(v)/F_(m))随光照时间和强度的增加逐渐下降,高光条件下F_(v)/F_(m)值最小。相应地,强光处理后,单位反应中心吸收、耗散的能量以及捕获用于还原质体醌A的能量均显著增加,电子传递受到抑制,低、中、高3个强光水平的最大相对电子传递速率(R_(max))较初始状态分别降低了28.83%、40.34%、54.14%。同时,铜藻通过提高光系统Ⅱ反应中心净关闭率、增强非光化学淬灭和提高类胡萝卜素含量来抵御高光胁迫。恢复弱光240 min后,3种光强处理下铜藻的F_(v)/F_(m)、R_(max)和色素含量均有不同程度的恢复,且F_(v)/F_(m)和叶绿素a、叶绿素c、类胡萝卜素含量在低光处理组均恢复到初始值。以上结果说明,在不同强度的强光下,铜藻光合作用受到不同程度的胁迫,同时铜藻能通过多种光保护手段减轻胁迫,推测漂浮于海水表面的铜藻在中午受到强光胁迫后,可能经下午和晚上的弱光周期得到很大程度的恢复,使得铜藻能够适应漂浮生活并在其他条件适宜的情况下引起金潮暴发。研究结果为揭示铜藻金潮形成的生理生态机制提供了数据支持。In recent years,the golden tide of drifting Sargassum horneri occurs frequently.As a specific bio-invasive phenomenon,it has huge negative impacts on marine ecosystems.When the golden tide outbreaks,the algae floating on the surface of seawater will receive higher solar radiation,but the photosynthetic response of this species to strong light stress remains unclear.In this study,the photosynthetic response and adaptive response of Sargassum horneri to strong light stress at three light levels(low light of 460μmol/(m^(2)·s),medium light of 920μmol/(m^(2)·s)and high light of 1380μmol/(m^(2)·s))were investigated.The results showed that the photosynthetic efficiency of Sargassum horneri significantly reduced after strong light treatments for 120 min,and the maximum photochemical quantum yield(F_(v)/F_(m))gradually decreased with the increasing of light intensity and exposure duration.In addition,the absorption energy,dissipated energy and energy captured for plastoquinone A reduction per reaction center significantly increased after strong light treatments.It also showed that the maximum relative electron transfer rate(R_(max))reduced by 28.83%,40.34%and 54.14%respectively at low,medium and high light levels compared with the initial rate.Meanwhile,algae exhibited resistance to light stress by increasing the net shutdown rate of PSⅡreaction center,enhancing non-photochemical quenching and increasing carotenoid content.After recovering the weak light for 240 min,the F_(v)/F_(m),R_(max)and pigment contents of Sargassum horneri under three light treatments recovered to different degrees,and the F_(v)/F_(m)as well as the contents of chlorophyll a,chlorophyll c and carotenoid were restored to their initial values in the low light treatment.These results indicated that the photosynthesis of Sargassum horneri was stressed under different levels of strong light,and the alga could mitigate this stress by various photoprotective strategies,thus speculating that after strong light stress at midday,Sargassum horneri may

关 键 词：铜藻 光照强度 光合作用 光损伤 光修复 叶绿素荧光 

分 类 号：TS251[轻工技术与工程—农产品加工及贮藏工程]