Department of Botany, Ecology and Plant Physiology, University of La Laguna (ULL), Tenerife, Spain.
Department of Plant Biology and Ecology, University of the Basque Country (UPV/EHU), Leioa, Spain.
Physiol Plant. 2021 Jul;172(3):1506-1517. doi: 10.1111/ppl.13342. Epub 2021 Feb 16.
Snowmelt in alpine ecosystems brings ample water, and together with above-freezing temperatures, initiates plant growth. In this scenario, rapid activation of photosynthesis is essential for a successful life-history strategy. But, strong solar radiation in late spring enhances the risk of photodamage, particularly before photosynthesis is fully functional. We compared the photoprotective strategy of five alpine forbs: one geophyte not particularly specialised in subnival life (Crocus albiflorus) and four wintergreens differing in their degree of adaptation to subnival life, from least to most specialised: Gentiana acaulis, Geum montanum, Homogyne alpina and Soldanella alpina. We used distance to the edge of snow patches as a proxy to study time-dependent changes after melting. We postulated that the photoprotective response of snowbed specialists would be stronger than of more-generalist alpine meadow species. F /F was relatively low across wintergreens and even lower in the geophyte C. albiflorus. This species also had the largest xanthophyll-cycle pool and lowest tocopherol and flavonoid glycoside contents. After snow melting, all the species progressively activated ETR, but particularly the intermediate snowbed species G. acaulis and G. montanum. The photoprotective responses after snowmelt were idiosyncratic: G. montanum rapidly accumulated xanthophyll-cycle pigments, tocopherol and flavonoid glycosides; while S. alpina showed the largest increase in plastochromanol-8 and chlorophyll contents and the greatest changes in optical properties. Climate warming scenarios might shift the snowmelt date and consequently alter the effectiveness of photoprotection mechanisms, potentially changing the fitness outcome of the different strategies adopted by alpine forbs.
高山生态系统的融雪带来了充足的水分,加上高于冰点的温度,启动了植物的生长。在这种情况下,光合作用的快速激活对于成功的生活史策略至关重要。但是,春末强烈的太阳辐射增加了光损伤的风险,尤其是在光合作用尚未完全发挥作用之前。我们比较了五种高山草本植物的光保护策略:一种不太专门适应亚冰雪生境的球茎植物(白花紫堇)和四种适应程度不同的冬季常绿植物,从最不适应到最适应:獐牙菜、火绒草、高山火绒草和高山堇菜。我们使用距离雪斑边缘的距离作为研究融雪后时间依赖性变化的替代指标。我们假设,雪床专家的光保护反应会强于更具一般性的高山草甸物种。冬季常绿植物的 F/F 相对较低,球茎植物白花紫堇的 F/F 甚至更低。该物种还具有最大的叶黄素循环库,以及最低的生育酚和类黄酮糖苷含量。融雪后,所有物种的 ETR 都逐渐激活,但特别是中间的雪床物种獐牙菜和火绒草。融雪后的光保护反应是独特的:火绒草迅速积累叶黄素循环色素、生育酚和类黄酮糖苷;而高山堇菜表现出最大的质体色醇-8和叶绿素含量增加,以及最大的光学性质变化。气候变暖的情景可能会改变融雪日期,从而改变光保护机制的有效性,这可能会改变高山草本植物采用的不同策略的适应性结果。