Drought increases the freezing resistance of high-elevation plants of the Central Chilean Andes
Drought increases the freezing resistance of high-elevation plants of the Central Chilean Andes
复制标题
干旱增强了智利中部安第斯山脉高海拔植物的抗冻能力
作者：
Ángela Sierra;Claudia Reyes;L. Cavieres
严寒和夏季干旱塑造了地中海高海拔栖息地的植物生命。因此，气候变化对这些物种的植物生存的影响可能与梅西奇山脉的影响大不相同。我们暴露了12个高山物种的实验灌溉和变暖在智利中部的安第斯山脉，以评估灌溉是否会降低抗冻性，灌溉影响抗冻性时，植物暴露于变暖，并评估灌溉和温度在控制植物抗冻性的相对重要性。抗冻性被确定为产生50%光灭活的冷冻温度[致死温度（LT50）]和凝固点（FP）。在7个12高安第斯物种，LT 50干旱暴露的植物平均3.5 K低于灌溉植物。相比之下，大多数物种在FP上没有表现出差异。变暖改变了灌溉对LT50的影响。根据不同的物种，变暖被发现有（1）没有影响，（2）增加，或（3）减少灌溉对LT50的影响。然而，灌溉对LT50的影响大小大于变暖的几乎所有物种。灌溉对FP的影响略有改变变暖，有时不同意与LT50的反应。我们的数据表明，干旱增加了高安第斯植物物种的抗冻性作为一般植物的反应。虽然抗冻性的增加取决于物种特异性的性状，我们的研究结果表明，温暖和潮湿的生长季节，由于气候变化将严重威胁植物的生存和持久性，这些和其他高山物种在干旱山区。
Freezing temperatures and summer droughts shape plant life in Mediterranean high-elevation habitats. Thus, the impacts of climate change on plant survival for these species could be quite different to those from mesic mountains. We exposed 12 alpine species to experimental irrigation and warming in the Central Chilean Andes to assess whether irrigation decreases freezing resistance, irrigation influences freezing resistance when plants are exposed to warming, and to assess the relative importance of irrigation and temperature in controlling plant freezing resistance. Freezing resistance was determined as the freezing temperature that produced 50 % photoinactivation [lethal temperature (LT50)] and the freezing point (FP). In seven out of 12 high-Andean species, LT50 of drought-exposed plants was on average 3.5 K lower than that of irrigated plants. In contrast, most species did not show differences in FP. Warming changed the effect of irrigation on LT50. Depending on species, warming was found to have (1) no effect, (2) to increase, or (3) to decrease the irrigation effect on LT50. However, the effect size of irrigation on LT50 was greater than that of warming for almost all species. The effect of irrigation on FP was slightly changed by warming and was sometimes in disagreement with LT50 responses. Our data show that drought increases the freezing resistance of high-Andean plant species as a general plant response. Although freezing resistance increases depended on species-specific traits, our results show that warmer and moister growing seasons due to climate change will seriously threaten plant survival and persistence of these and other alpine species in dry mountains.