Cho Sung Mi, Lee Hyoungseok, Hong Soon Gyu, Lee Jungeun
Unit of Research for Practical Application, Korea Polar Research Institute, Incheon 21990, Korea.
Division of Polar Life Sciences, Korea Polar Research Institute, Incheon 21990, Korea.
Plants (Basel). 2020 Jan 9;9(1):85. doi: 10.3390/plants9010085.
Antarctic lichens have been used as indicators of climate change for decades, but only a few species have been studied. We assessed the photosynthetic performance of the fruticose lichen under natural and laboratory conditions using the PAM fluorescence system. Compared to that of sun-adapted Usnea sp., the photosynthetic performance of exhibits shade-adapted lichen features, and its chlorophyll fluorescence does not occur during dry days without rain. To understand its desiccation-rehydration responses, we measured changes in the PSII photochemistry in under the average light intensity of dawn light and daylight and the desiccating conditions of its natural microclimate. Interestingly, samples under daylight and rapid-desiccation conditions showed a delayed reduction in Fv'/Fm' and rETRmax, and an increase in Y(II) and Y(NPQ) levels. These results suggest that the photoprotective mechanism of C. borealis depends on sunlight and becomes more efficient with improved desiccation tolerance. Amplicon sequencing revealed that the major photobiont of was , which has not been reported in Antarctica before. Collectively, these results from both field and laboratory could provide a better understanding of specific ecophysiological responses of shade-adapted lichens in the Antarctic region.
几十年来，南极地衣一直被用作气候变化的指标，但仅有少数物种得到了研究。我们使用脉冲幅度调制（PAM）荧光系统，评估了枝状地衣在自然和实验室条件下的光合性能。与适应阳光的松萝属物种相比，该物种的光合性能表现出适应阴蔽的地衣特征，并且在无雨的干燥日子里其叶绿素荧光不会出现。为了解其脱水-复水反应，我们在黎明光和日光的平均光强以及其自然微气候的干燥条件下，测量了该物种光系统II（PSII）光化学的变化。有趣的是，在日光和快速干燥条件下的样本显示，光系统II最大光化学效率（Fv'/Fm'）和最大相对电子传递速率（rETRmax）的降低有所延迟，而光系统II实际光化学量子产量（Y(II)）和非光化学淬灭系数（Y(NPQ)）水平有所增加。这些结果表明，北方石蕊的光保护机制依赖于阳光，并且随着耐旱性的提高而变得更加有效。扩增子测序显示，该物种的主要共生光合生物是以前在南极洲未曾报道过的。总体而言，来自野外和实验室的这些结果能够让我们更好地理解南极地区适应阴蔽地衣的特定生理生态反应。
