BackgroundPhotosynthetic characteristics and the effect of UV radiation and elevated temperature measured were studied in Chlorella sp. isolated from a snow microalgal community at King George Island, Maritime Antarctica through the chlorophyll florescence (rapid light curves and maximum quantum yield, respectively). The environmental context was monitored through measurements of spectral depth profiles of solar radiation (down to 40 cm) in the snowpack as well as a through continuous recording of temperature and PAR using dataloggers located at different depths (0–30 cm) within the snow column.ResultsThe photochemistry of Chlorella sp. was affected by UV radiation in a 12-h laboratory exposure under all studied temperatures (5, 10, 15, 20 °C): the algae exposed to PAR + UV-A radiation were inhibited by 5.8 % whilst PAR + UV-A + UV-B radiation decreased Fv/Fm by 15.8 %. In both treatments the 12-h recovery after UV exposure was almost complete (80–100 %). Electron transport based P-I curve parameters maximal electron transport rate (ETRmax), photosynthetic efficiency (α) and the saturating irradiance (Ek) no varied in response to different temperatures.ConclusionsResults revealed that Chlorella sp. not only shows high photosynthetic efficiency at ambient conditions, but also exhibits tolerance to solar radiation under higher temperatures and possessing a capacity for recovery after inhibition of photosynthesis by UV radiation.

中文翻译：

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南极雪藻小球藻的光合紫外线胁迫耐受性。通过提高温度进行修改？

背景研究了小球藻的光合作用特性以及紫外线辐射和高温的影响。通过叶绿素荧光（分别为快速光曲线和最大量子产率）从南极洲乔治王岛的雪微藻群落中分离出来。通过测量积雪中太阳辐射的光谱深度剖面（低至 40 厘米）以及使用位于雪柱内不同深度（0-30 厘米）的数据记录器连续记录温度和 PAR 来监测环境背景.结果小球藻的光化学。在所有研究温度（5、10、15、20°C）下，在 12 小时实验室暴露中受到紫外线辐射的影响：暴露于 PAR + UV-A 辐射的藻类受到 5 的抑制。8 % 而 PAR + UV-A + UV-B 辐射使 Fv/Fm 降低了 15.8%。在两种处理中，紫外线照射后 12 小时的恢复几乎完成（80-100%）。基于电子传输的 PI 曲线参数最大电子传输速率 (ETRmax)、光合效率 (α) 和饱和辐照度 (Ek) 对不同温度的响应没有变化。不仅在环境条件下表现出高光合作用效率，而且在较高温度下表现出对太阳辐射的耐受性，并在紫外线辐射抑制光合作用后具有恢复能力。光合效率 (α) 和饱和辐照度 (Ek) 对不同温度的响应没有变化。不仅在环境条件下表现出高光合作用效率，而且在较高温度下表现出对太阳辐射的耐受性，并在紫外线辐射抑制光合作用后具有恢复能力。光合效率 (α) 和饱和辐照度 (Ek) 对不同温度的响应没有变化。不仅在环境条件下表现出高光合作用效率，而且在较高温度下表现出对太阳辐射的耐受性，并在紫外线辐射抑制光合作用后具有恢复能力。