Taxon-specific differences in photoacclimation to fluctuating irradiance in an Antarctic diatom and a green flagellate
Taxon-specific differences in photoacclimation to fluctuating irradiance in an Antarctic diatom and a green flagellate
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DOI：
10.3354/meps288009
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发表时间：
2005-03
影响因子：
2.5
通讯作者：
Van Leeuwe;B. V. Sikkelerus;W. Gieskes;J. Stefels
中科院分区：
文献类型：
--
作者：
Van Leeuwe;B. V. Sikkelerus;W. Gieskes;J. Stefels
研究了2种南极微藻--硅藻、短毛壳藻和鞭毛藻对光照快速变化的光适应。(Prasinophyceae)。这两种植物都经历了3种不同的光照条件。两个垂直混合区(1：1h和3：3h强光：弱光)叠加在一个模拟太阳正弦的日光周期上。两种藻类的最大生长量都出现在最快的光波动速率(1：1h)。光照条件对鞭毛虫的生长速度影响不大，但在适当的混合速度(3：3h)下，硅藻的生长速度显着降低。虽然两个物种的叶黄素循环都很活跃，但用双调制荧光仪进行的荧光分析表明，光合作用效率的下调在Pyramimonas sp.(约50%)而不是短毛隐杆藻(约30%)。光保护剂与叶绿素a的比值不受光照条件的显著影响，无论是在鞭毛还是在硅藻中。在鞭毛中，状态转换在高照度期间提供了一种额外的能量耗散方式。硅藻明显适应了平均光强，而不是最大光强。可以推测，这一策略导致了3：3h循环过程中的光损伤。有人认为，与必要的维修过程相关的维护费用增加可以解释观察到的增长率下降的原因。简要讨论了大型水华形成硅藻物种的生态后果。
Photoacclimation towards rapid changes in irradiance was studied in 2 Antarctic microalgae, the diatom Chaetoceros brevis (Bacillariophyceae) and the flagellate Pyramimonas sp. (Prasinophyceae). Both species were subjected to 3 different light regimes. Two regimes of vertical mixing (1:1 h and 3:3 h high light:low light) were superimposed on a diurnal light cycle mimicking the solar sine. For both species, maximum growth was recorded at the fastest rates of light fluctua- tion (1:1 h). The light regimes had a minor effect on growth rates of the flagellate but growth in the diatom was reduced significantly at moderate rates of mixing (3:3 h). While xanthophyll cycling was active in both species, fluorescence analysis with a dual-modulated fluorometer showed that down-regulation of photosynthetic efficiency was more pronounced in Pyramimonas sp. (ca. 50%) than in C. brevis (ca. 30%). The ratio of photoprotectors to chlorophyll a was not significantly affected by the light regime, neither in the flagellate nor in the diatom. In the flagellate, state tran- sition offered an additional means of energy dissipation during the periods of high irradiance. The diatom apparently acclimated to the average light intensity received and not to the maximum irra- diance. It can be reasoned that this strategy led to photodamage during the 3:3 h cycling. It is argued that enhanced maintenance costs associated with necessary repair processes can explain the reduced growth rate that was observed. The ecological consequences for large bloom-forming diatom species are briefly discussed.