Non-photochemical quenching of chlorophyll fluorescence and xanthophyll cycle responses after excess PAR and UVR in Chaetoceros brevis, Phaeocystis antarctica and coastal Antarctic phytoplankton
Non-photochemical quenching of chlorophyll fluorescence and xanthophyll cycle responses after excess PAR and UVR in Chaetoceros brevis, Phaeocystis antarctica and coastal Antarctic phytoplankton
复制标题
DOI：
10.3354/meps09000
复制
发表时间：
2011-01-01
影响因子：
2.5
通讯作者：
Buma, Anita G. J.
中科院分区：
文献类型：
--
作者：
de Poll, Willem H. van;Lagunas, Marcos;Buma, Anita G. J.
研究了南极洲乔治王岛波特湾沿岸浮游植物对近地表光照抑制的敏感度与夏季融水流入形成的水文条件的关系。对3个不同入沙影响的站点，在过量的光合作用有效辐射(PAR)和PAR+紫外线辐射(UVR)恢复过程中，测量了慢(指示PSII损伤)和快(指示叶绿素循环活性)松弛非光化学叶绿素荧光猝灭(NPQ)。此外，组合在室外培养，以研究在PAR和PAR+UVR暴露期间的叶黄素循环活动。作为比较，测定了高光驯化的短毛角藻和南极洲棕囊藻的NPQ和叶黄素循环活性。色素分析(CHEMTAX)显示硅藻在所有地点占优势(平均74%)，触生植物次之(平均13%)。所有站点都按垂直密度梯度分层，而最内侧站点的泥沙入流量明显较高。不同站位的分类组成、NPQ特性和光保护色素比率没有差异。在叶绿素高峰期，浮游植物在所有地点都表现出高光驯化，在过量PAR和PAR+UVR之后，NPQ以快速松弛为主。低于叶绿素最大值的样品富含触生植物，表现出较低的光保护色素比率，降低了NPQ的能力，并增加了缓慢松弛NPQ的贡献。高光和弱光驯化的短冠锦鸡儿和南极洲锦鸡儿的光保护能力存在显著差异。南极洲赤潮藻诱导的NPQ较少，慢弛豫NPQ组分强于硅藻，尤其是在弱光习服后。尽管田间样品经UVR处理后，总NPQ减少，缓慢松弛NPQ增加，但培养物的NPQ和叶黄素循环去环氧化状态不受UVR的影响。硅藻的光保护能力高于触生植物，这可能是它们在受分层融水影响的南极沿海水域占优势的原因。
Sensitivity to photoinhibition from near-surface irradiance was determined in coastal phytoplankton from Potter Cove (King George Island, Antarctica) in relation to hydrographic conditions shaped by summertime meltwater influx. Slow (indicative for PSII damage) and fast (indicative for xanthophyll cycle activity) relaxing non-photochemical chlorophyll fluorescence quenching (NPQ) was measured during recovery from excess photosynthetically active radiation (PAR) and PAR + ultraviolet radiation (UVR) for 3 stations differentially affected by sediment influx. Additionally, assemblages were incubated outside to study xanthophyll cycle activity during PAR and PAR+UVR exposure. For comparison, NPQ and xanthophyll cycle activity were determined for high (125 mu mol photons m(-2) s(-1)) and low (20 mu mol photons m(-2) s(-1)) light acclimated Chaetoceros brevis (Bacillariophyceae) and Phaeocystis antarctica (Haptophyceae) cultures. Pigment analysis (CHEMTAX) revealed diatom dominance (average 74%) at all locations, with haptophytes being of minor importance (average 13%). All stations were stratified by a vertical density gradient, whereas sediment influx was significantly higher at the innermost station. Taxonomic composition, NPQ characteristics, and photoprotective pigment ratios were not different among stations. At the chlorophyll maximum, phytoplankton showed high light acclimation at all locations, and fast relaxing NPQ dominated after excess PAR and PAR+UVR. Samples from below the chlorophyll maximum were enriched in haptophytes, showed lower photoprotective pigment ratios, reduced capacity for NPQ, and increased contribution of slow relaxing NPQ. The photoprotective capacity of high and low light acclimated C. brevis and P. antarctica differed significantly. P. antarctica induced less NPQ and there was a stronger slow relaxing NPQ component than in the diatom, particularly after low light acclimation. Although total NPQ decreased and slow relaxing NPQ increased after UVR in field samples, NPQ and the xanthophyll cycle de-epoxidation state of cultures were not affected by UVR. A higher photoprotective capacity of diatoms over haptophytes may explain their dominance in stratified meltwater-affected coastal Antarctic waters.