摘要
海洋暖化导致海水上部混合层变浅,使营养盐限制情况加剧,也导致硅藻接收到的阳光辐射量增加。高光及营养盐限制的双重胁迫会影响硅藻的光合产量。该研究主要探索硅藻应对磷饥饿及高光胁迫的光合生理调控,以进一步了解海洋环境变化对硅藻光合作用的影响。将体积不同的假微型海链藻(Thalassiosira pseudonana)和威氏海链藻(T.weissflogii)在磷饥饿条件下培养,监测其光系统Ⅱ (PSII)功能变化,并将其置于高光强下,研究其光合生理响应。结果表明:磷饥饿条件下,体积较小的假微型海链藻PSII活性逐渐下降,从与D2蛋白结合的质体醌QA–到与D1蛋白结合的质体醌QB的电子传递效率降低,单位反应中心捕获的用于电子传递的能量下降,并诱导产生非光化学淬灭,而体积较大的威氏海链藻则能够维持较长时间的PSII活性;假微型海链藻在磷充足条件下相比威氏海链藻具有较高的PSII光失活功能截面(σi)值,易发生光抑制,但同时也具有高的PSII修复速率,磷饥饿对其光抑制敏感度无显著影响,而威氏海链藻在磷饥饿条件下的σi显著升高,其对高光强的耐受能力显著降低。在营养盐限制及辐射水平增强情况下,体积较大的威氏海链藻可能倾向于分布在真光层的下部海域。该研究表明海洋环境变化可能会改变不同粒径硅藻的生态位,并影响其初级生产力。
Aims As the ocean warms,the upper mixed layer becomes shallower,increasing nutrient limitation and sunlight exposure for diatoms.The photosynthetic yield of diatoms was affected by the dual stress of high light and nutrient limitation.This study mainly explored the photophysiological regulation of diatoms in response to phosphorus starvation and high light stress to further understand the effects of marine environmental changes on diatom photosynthesis.Methods We cultured the two different-sized diatom species Thalassiosira pseudonana and T.weissflogii under the condition of phosphorus starvation to monitor the changes of photosystem Ⅱ(PSⅡ)function and to investigate their photophysiological responses to high light.Important findings Under the condition of phosphorus starvation,the PSII activity of smaller T.pseudonana gradually declined,the electron transport efficiency from plastoquinone QA-which binds to D2 protein to plastoquinone QB which binds to D1 protein descended.Thus,the energy captured for electron transport per unit reaction center decreased,and the non-photoquenched was induced,while the PSII activity of larger T.weissflogii could be maintained for a longer time;T.pseudonana had higher value of PSII photoinactivation cross section(σi)under phosphorus sufficient condition than T.weissflogii,which was prone to photoinhibition and exhibited a higher repair rate for PSII.Phosphorus starvation had no significant effect on its sensitivity to photoinhibition,while T.weissflogii had significantly higherσi under phosphorus starvation condition,and its tolerance to high light intensity was significantly reduced.Under the condition of nutrient limitation and increased light exposure,the larger T.weissflogii may tend to distribute in the lower euphotic layer.In summary,this study suggests that marine environmental changes may change the niche of diatoms with different cell sizes and affect their contribution to primary production.
作者
刘海燕
臧纱纱
张春霞
左进城
阮祚禧
吴红艳
LIU Hai-Yan;ZANG Sha-Sha;ZHANG Chun-Xia;ZUO Jin-Cheng;RUAN Zuo-Xi;WU Hong-Yan(College of Life Sciences,Ludong University,Yantai,Shandong 264025,China;Tai’an Hydrology Center,Tai’an,Shandong 271000,China;Institute of Marine Biology,Shantou University,Shantou,Guangdong 515063,China)
出处
《植物生态学报》
CAS
CSCD
北大核心
2023年第12期1718-1727,共10页
Chinese Journal of Plant Ecology
基金
国家自然科学基金(42076206)
山东省自然科学基金(ZR2020QC025)
广东省自然科学基金(2020A1515011073)。
关键词
硅藻
磷饥饿
光系统Ⅱ功能
光合作用
diatoms
phosphorus starvation
photosystem Ⅱ function
photosynthesis