Museo delle Scienze, Via Calepina 14, Trento, Italy.
Ann Bot. 2012 Jul;110(1):155-64. doi: 10.1093/aob/mcs097. Epub 2012 May 17.
Despite the considerable number of studies on the impacts of climate change on alpine plants, there have been few attempts to investigate its effect on regeneration. Recruitment from seeds is a key event in the life-history of plants, affecting their spread and evolution and seasonal changes in climate will inevitably affect recruitment success. Here, an investigation was made of how climate change will affect the timing and the level of germination in eight alpine species of the glacier foreland.
Using a novel approach which considered the altitudinal variation of temperature as a surrogate for future climate scenarios, seeds were exposed to 12 different cycles of simulated seasonal temperatures in the laboratory, derived from measurements at the soil surface at the study site.
Under present climatic conditions, germination occurred in spring, in all but one species, after seeds had experienced autumn and winter seasons. However, autumn warming resulted in a significant increase in germination in all but two species. In contrast, seed germination was less sensitive to changes in spring and/or winter temperatures, which affected only three species.
Climate warming will lead to a shift from spring to autumn emergence but the extent of this change across species will be driven by seed dormancy status. Ungerminated seeds at the end of autumn will be exposed to shorter winter seasons and lower spring temperatures in a future, warmer climate, but these changes will only have a minor impact on germination. The extent to which climate change will be detrimental to regeneration from seed is less likely to be due to a significant negative effect on germination per se, but rather to seedling emergence in seasons that the species are not adapted to experience. Emergence in autumn could have major implications for species currently adapted to emerge in spring.
尽管已有相当数量的研究探讨了气候变化对高山植物的影响，但很少有研究尝试调查其对繁殖的影响。种子繁殖是植物生活史中的一个关键事件，影响着它们的传播和进化，而季节性气候变化不可避免地会影响繁殖的成功。在这里，我们研究了气候变化将如何影响八种冰川前缘高山物种的萌发时间和萌发水平。
本研究采用了一种新方法，该方法将温度的海拔变化视为未来气候情景的替代物，将种子在实验室中暴露于 12 个不同的模拟季节性温度循环中，这些温度循环来自于研究地点土壤表面的测量。
在当前气候条件下，除了一种外，所有物种的种子在经历了秋季和冬季后，都在春季萌发。然而，秋季变暖导致除了两种外的所有物种的萌发显著增加。相比之下，种子萌发对春季和/或冬季温度变化的敏感性较低，这只影响了三个物种。
气候变暖将导致萌发从春季向秋季转变，但这种变化在物种间的程度将取决于种子休眠状态。在未来更温暖的气候中，秋季末未萌发的种子将经历更短的冬季和更低的春季温度，但这些变化对萌发的影响很小。气候变化对种子繁殖的不利影响程度不太可能是由于对萌发本身产生重大负面影响，而是由于物种不适应的季节出现幼苗萌发。秋季的萌发可能对目前适应在春季萌发的物种产生重大影响。
