In alpine plants, the temporal variation in the concentrations of non-structural carbohydrates (NSC) is closely related to the growth phenology, which is largely controlled by annual variations in temperature. However, in alpine areas of Mediterranean-type climate regions, plants growing at low elevations are also exposed to seasonal drought. Given the influence of drought on growth phenology and gas exchange, we hypothesize that the seasonal dynamics of growth and NSC concentrations in alpine plants of Mediterranean biomes is co-controlled by elevational gradients of temperature and soil moisture. If so, the end of the growing season and the maximum NSC concentrations at lower elevations should coincide with the occurrence of drought. We characterized the seasonal dynamics of photosynthesis capacity, growth and NSC concentrations, in an alpine plant species of the Andes of central Chile (Phacelia secunda Gmel.) at 1600 and 3600 m. We found that the length of the growing season was similar between elevations, but the timings differed. Whilst at 3600 m, the number of leaves and the mean leaf length progressively increased from December to February, at 1600 m, in contrast, they increased from the October to December. Likewise, maximum NSC concentrations at 3600 were observed at autumn along with growth cessation. Conversely, at 1600 m, the highest NSC concentration and the growth cessation were found towards mid-summer, and coincided with a drastic drop in both stomatal conductance and photosynthesis which were not observed at 3600 m. These results demonstrate that temperature alone does not control the growth phenology and the seasonal dynamics of NSC concentrations in alpine plants of Mediterranean biomes. Rather, summer drought also exerts a significant influence in the timing of the growing season and the NSC dynamics.

在高山植物中，非结构性碳水化合物（NSC）浓度的时间变化与生长物候密切相关，主要受温度的年度变化控制。然而，在地中海型气候区的高山地区，生长在低海拔地区的植物也面临季节性干旱。鉴于干旱对生长物候和气体交换的影响，我们假设地中海生物群落的高山植物生长的季节性动态和 NSC 浓度受温度和土壤湿度的海拔梯度共同控制。如果是这样，生长季节的结束和低海拔地区的最大 NSC 浓度应该与干旱的发生同时发生。我们描述了光合作用能力、生长和 NSC 浓度的季节性动态，(Phacelia secunda)Gmel.) 在 1600 和 3600 m。我们发现不同海拔的生长季节长度相似，但时间不同。而在 3600 m 处，叶片数和平均叶长从 12 月到 2 月逐渐增加，而在 1600 m 处，相反，它们从 10 月到 12 月增加。同样，在秋季观察到 3600 的最大 NSC 浓度以及生长停止。相反，在 1600 米处，最高 NSC 浓度和生长停止出现在夏季中期，同时气孔导度和光合作用急剧下降，而在 3600 米处未观察到。这些结果表明，单独的温度不能控制地中海生物群落高山植物中 NSC 浓度的生长物候和季节性动态。相当，