GROWTH AND PHOTOPROTECTION IN THREE DINOFLAGELLATES (INCLUDING TWO STRAINS OF ALEXANDRIUM TAMARENSE) AND ONE DIATOM EXPOSED TO FOUR WEEKS OF NATURAL AND ENHANCED ULTRAVIOLET-B RADIATION
GROWTH AND PHOTOPROTECTION IN THREE DINOFLAGELLATES (INCLUDING TWO STRAINS OF ALEXANDRIUM TAMARENSE) AND ONE DIATOM EXPOSED TO FOUR WEEKS OF NATURAL AND ENHANCED ULTRAVIOLET-B RADIATION
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DOI：
10.1111/j.1529-8817.2008.00618.x
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发表时间：
2009-02-01
影响因子：
2.9
通讯作者：
Roy, Suzanne
中科院分区：
文献类型：
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作者：
Laurion, Isabelle;Roy, Suzanne
研究了两种甲藻[Alexandiumtamarense（M. Leuca）Balech、At和Heterocapsa triquetra（Euca b.）F. Stein，Ht]，包括两株A. tamarense，一种来自西班牙，另一种来自英国，还有一种硅藻种（Thalassiosira damanaHasle et Heimdal）。我们研究了是否可变的光保护（类菌孢素氨基酸[MAAs]和叶黄素循环色素）影响光合性能，浮游植物光吸收和生长。生长速率显着降低下增强UVB的英国应变的AT和HT（都增长非常小）以及硅藻（保持高增长率），但没有影响西班牙应变的AT。甲藻的MAA浓度很高，但在硅藻中检测不到，而不是使用叶黄素循环进行光保护。在At的UK菌株中观察到最高的MAA和光保护色素的细胞浓度，沿着具有最低的生长速率和F-v/F-m，表明高应力水平。与此相反，西班牙菌株表现出逐步驯化的实验条件下，治疗之间的增长没有显着差异。总MAA的增加线性地跟随前一天的累积UVB，并且在该菌株中总MAA和初级MAA都保持在较高的组成水平。驯化增强UVB的硅藻导致PSII活性的增加和减少非光化学猝灭，表明增加了抗光抑制几周后。所有四个物种都表现出增强UVB下浮游植物光吸收增加。较大的菌株内差异表明，需要考虑更密切的种内变异的紫外线研究。
Long-term growth response to natural solar radiation with enhanced ultraviolet-B (UVB) exposure was examined in two species of dinoflagellates [Alexandrium tamarense (M. Lebour) Balech, At, and Heterocapsa triquetra (Ehrenb.) F. Stein, Ht], including two strains of A. tamarense, one from Spain and another from UK, and one diatom species (Thalassiosira pseudonana Hasle et Heimdal). We examined whether variable photoprotection (mycosporine-like amino acids [MAAs] and xanthophyll-cycle pigments) affected photosynthetic performance, phytoplankton light absorption, and growth. Growth rate was significantly reduced under enhanced UVB for the UK strain of At and for Ht (both grew very little) as well as for the diatom (that maintained high growth rates), but there was no effect for the Spanish strain of At. MAA concentration was high in the dinoflagellates, but undetectable in the diatom, which instead used the xanthophyll cycle for photoprotection. The highest cell concentrations of MAAs and photoprotective pigments were observed in the UK strain of At, along with lowest growth rates and F-v/F-m, indicating high stress levels. In contrast, the Spanish strain showed progressive acclimation to the experimental conditions, with no significant difference in growth between treatments. Increase in total MAAs followed linearly the cumulative UVB of the preceding day, and both total and primary MAAs were maintained at higher constitutive levels in this strain. Acclimation to enhanced UVB in the diatom resulted in an increase in PSII activity and reduction in nonphotochemical quenching, indicating an increased resistance to photoinhibition after a few weeks. All four species showed increased phytoplankton light absorption under enhanced UVB. Large intrastrain differences suggest a need to consider more closely intraspecific variability in UV studies.