Gugger Simona, Kesselring Halil, Stöcklin Jürg, Hamann Elena
Institute of Botany, Department of Environmental Sciences, Section Plant Ecology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland.
Institute of Botany, Department of Environmental Sciences, Section Plant Ecology, University of Basel, Schönbeinstrasse 6, CH-4056 Basel, Switzerland
Ann Bot. 2015 Nov;116(6):953-62. doi: 10.1093/aob/mcv155. Epub 2015 Sep 30.
Recent global changes, particularly warming and drought, have had worldwide repercussions on the timing of flowering events for many plant species. Phenological shifts have also been reported in alpine environments, where short growing seasons and low temperatures make reproduction particularly challenging, requiring fine-tuning to environmental cues. However, it remains unclear if species from such habitats, with their specific adaptations, harbour the same potential for phenological plasticity as species from less demanding habitats.
Fourteen congeneric species pairs originating from mid and high elevation were reciprocally transplanted to common gardens at 1050 and 2000 m a.s.l. that mimic prospective climates and natural field conditions. A drought treatment was implemented to assess the combined effects of temperature and precipitation changes on the onset and duration of reproductive phenophases. A phenotypic plasticity index was calculated to evaluate if mid- and high-elevation species harbour the same potential for plasticity in reproductive phenology.
Transplantations resulted in considerable shifts in reproductive phenology, with highly advanced initiation and shortened phenophases at the lower (and warmer) site for both mid- and high-elevation species. Drought stress amplified these responses and induced even further advances and shortening of phenophases, a response consistent with an 'escape strategy'. The observed phenological shifts were generally smaller in number of days for high-elevation species and resulted in a smaller phenotypic plasticity index, relative to their mid-elevation congeners.
While mid- and high-elevation species seem to adequately shift their reproductive phenology to track ongoing climate changes, high-elevation species were less capable of doing so and appeared more genetically constrained to their specific adaptations to an extreme environment (i.e. a short, cold growing season).
近期的全球变化，尤其是变暖和干旱，已在全球范围内对许多植物物种的开花时间产生了影响。在高山环境中也有物候变化的报道，那里生长季节短且温度低，使得繁殖特别具有挑战性，需要对环境线索进行精细调整。然而，尚不清楚来自此类栖息地的物种，凭借其特定的适应性，是否具有与来自要求较低栖息地的物种相同的物候可塑性潜力。
将源自中高海拔的14对同属物种对相互移栽到海拔1050米和2000米的模拟未来气候和自然田间条件的共同花园中。实施干旱处理以评估温度和降水变化对生殖物候期开始和持续时间的综合影响。计算表型可塑性指数，以评估中高海拔物种在生殖物候方面是否具有相同的可塑性潜力。
移栽导致生殖物候发生了相当大变化，中高海拔物种在较低（且较温暖）的地点都出现了高度提前的起始时间和缩短的物候期。干旱胁迫放大了这些反应，并导致物候期进一步提前和缩短，这一反应与“逃避策略”一致。相对于中海拔同属物种，高海拔物种观察到的物候变化天数通常较少，导致表型可塑性指数较小。
虽然中高海拔物种似乎能充分改变其生殖物候以追踪当前的气候变化，但高海拔物种在这方面的能力较弱，并且似乎在遗传上更受其对极端环境（即短暂寒冷的生长季节）的特定适应的限制。
