It is unclear whether the frequently observed increase in non-structural carbohydrates (NSC) in plants exposed to low temperatures or drought reflects a higher sensitivity of growth than photosynthesis in such conditions (i.e. sink limitation), or a prioritization of carbon (C) allocation to storage. Alpine areas in Mediterranean-type climate regions are characterized by precipitation increases and temperature decreases with elevation. Thus, alpine plants with wide elevational ranges in Mediterranean regions may be good models to examine these alternative hypotheses. We evaluated storage and growth during experimental darkness and re-illumination in individuals of the alpine plant Phacelia secunda from three elevations in the Andes of central Chile. We hypothesized that storage is prioritized regarding growth in plants of both low- and high elevations where drought and cold stress are greatest, respectively. We expected that decreases in NSC concentrations during darkness should be minimal and, more importantly, increases in NSC after re-illumination should be higher than increases in biomass. We found that darkness caused a significant decrease in NSC concentrations of both low- and high-elevation plants, but the magnitude of the decrease was lower in the latter. Re-illumination caused higher increase in NSC concentration than in biomass in both low- and high-elevation plants (1.5- and 1.9-fold, respectively). Our study shows that C allocation in Phacelia secunda reflects ecotypic differences among elevation provenances and suggests that low temperature, but not drought, favours C allocation to storage over growth after severe C limitation.

目前尚不清楚暴露于低温或干旱的植物中经常观察到的非结构性碳水化合物（NSC）的增加是否反映了在这种条件下（例如，水库限制）比光合作用更高的生长敏感性，或碳（C）分配的优先次序存放。地中海型气候区的高山地区的特点是降水增加，温度随海拔升高而降低。因此，地中海地区海拔范围宽广的高山植物可能是检验这些替代假设的良好模型。我们评估了高山植物Phacelia secunda个体在实验黑暗和重新照明过程中的储存和生长。来自智利中部安第斯山脉的三个海拔高度。我们假设在干旱和寒冷胁迫最严重的低海拔和高海拔植物的生长方面，都优先考虑存储。我们预计在黑暗中NSC浓度的降低应最小，更重要的是，重新照明后NSC的升高应高于生物量的升高。我们发现黑暗导致低海拔植物和高海拔植物的NSC浓度均显着下降，但后者的下降幅度较小。在低海拔和高海拔植物中，重新照明引起的NSC浓度增加幅度均高于生物量（分别为1.5倍和1.9倍）。我们的研究表明，Phacelia secunda中的碳分配 反映了高海拔种源之间的生态型差异，并表明低温（而不是干旱）有利于碳的分配，而在严重的碳限制后，碳的分配更倾向于存储。