Chekanov Konstantin, Shibzukhova Karina, Lobakova Elena, Solovchenko Alexei
Department of Bioengineering, Faculty of Biology, Lomonosov Moscow State University, 1-12 Leninskie Gory, 119192 Moscow, Russia.
Plants (Basel). 2022 May 27;11(11):1431. doi: 10.3390/plants11111431.
UV-A is the main ultraviolet component of natural (solar) radiation. Despite it, its effect on phototrophs is studied less than UV-B. Effects of UV-A on photosynthetic apparatus of three carotenoid-producing microalgae were elucidated. Photosynthetic activity was studied using chlorophyll fluorescence analysis. Cell extracts were evaluated by absorbance spectroscopy. On the one hand, there were some common features of three strains. In all cases the changes involved PSII primary photochemistry and antennae size. All strains accumulated UV-absorbing polar compounds. On the other hand, some responses were different. Upregulation of non-photochemical quenching was observed only in BM5/15, whereas in other cases its level was low. BM7/13 and sp. NAMSU 934/2 accumulated secondary carotenoids, whereas BM5/15 accumulated primary ones. Microscopic features of the cultures were also different. BM7/13 and sp. NAMSU 934/2 were represented mostly by solitaire cells or small cell clusters, lacking their green color; the cells of BM5/15 formed aggregates from green cells. Cell aggregation could be considered as an additional UV-protecting mechanism. Finally, the strains differed by their viability. BM5/15 was most resistant to UV-A, whereas massive cell death was observed in two other cultures.
紫外线A是自然（太阳）辐射中的主要紫外线成分。尽管如此，相较于紫外线B，其对光合生物的影响研究较少。本研究阐明了紫外线A对三种产类胡萝卜素微藻光合机构的影响。采用叶绿素荧光分析法研究光合活性。通过吸收光谱法评估细胞提取物。一方面，这三种藻株有一些共同特征。在所有情况下，变化都涉及光系统II的原初光化学和天线大小。所有藻株都积累吸收紫外线的极性化合物。另一方面，一些反应有所不同。仅在BM5/15中观察到非光化学猝灭上调，而在其他情况下其水平较低。BM7/13和NAMSU 934/2藻株积累次生类胡萝卜素，而BM5/15积累初生类胡萝卜素。培养物的微观特征也有所不同。BM7/13和NAMSU 934/2主要由单独的细胞或小细胞团组成，缺乏绿色；BM5/15的细胞由绿色细胞形成聚集体。细胞聚集可被视为一种额外的紫外线保护机制。最后，这些藻株在活力方面存在差异。BM5/15对紫外线A最具抗性，而在其他两种培养物中观察到大量细胞死亡。
