Through the annual cycle of plant growth and dormancy, the winter season leads to profound metabolic changes allowing plants to undergo cold acclimation. In boreal environments, winter conditions are changing rapidly and are likely to cause damage to commercial wild lowbush blueberry. In this study, we addressed the level of frost hardiness and determined the role of environmental factors and nonstructural carbohydrates (NSCs) on frost hardiness. From autumn to spring, stem sections of Vaccinium angustifolium and Vaccinium myrtilloides were harvested each month in a commercial blueberry field to assess the relative electrolyte leakage and calculate the temperature at which 50% of the cells are lysed [LT₅₀ ( °C)], used as frost hardiness index. Stems were also collected to assess soluble carbohydrates and starch. Correlations, principal component analysis (PCA) and structural equation modeling (SEM) were used to determine how environmental factors and NSCs directly or indirectly influence the frost hardiness index. Frost hardiness reached its lowest level in December and January with LT₅₀ dropping below -60 °C. Seasonality of frost hardening was closely linked to photoperiod and temperature, generating clock-wise hysteretic loops that divide frost hardening into acclimation, from September to January, and deacclimation, from January to the end of May. Environmental factors such as photoperiod and temperature were more important in determining the level of frost hardiness during acclimation, with either direct or indirect effect through an influence on starch degradation, increasing soluble carbohydrate content. During deacclimation, soluble carbohydrates, especially raffinose, further induced a stronger direct regulation of frost hardiness. Direct biological regulation through raffinose defined the level of frost hardiness during deacclimation. However, the negative influence of temperature on raffinose concentration could increase vulnerability to winter warming events.

通过植物生长和休眠的年度循环，冬季导致了深刻的新陈代谢变化，使植物经受了冷驯化。在北方环境中，冬季条件瞬息万变，可能会破坏野生野生矮灌木蓝莓。在这项研究中，我们解决了霜冻抗性的水平，并确定了环境因素和非结构性碳水化合物（NSC）对霜冻抗性的作用。从秋天到春季，每个月在商业蓝莓田中收获越桔和越橘的茎干部分，以评估相对的电解质渗漏并计算50％的细胞被裂解的温度[LT ₅₀（°C）]，用作抗霜指数。还收集茎以评估可溶性碳水化合物和淀粉。使用相关性，主成分分析（PCA）和结构方程模型（SEM）来确定环境因素和NSC如何直接或间接影响防霜指数。霜冻强度在12月和1月达到最低水平，为LT ₅₀降至-60°C以下。霜冻硬化的季节性与光周期和温度密切相关，产生顺时针方向的磁滞回线，将霜冻硬化分为从9月到1月的驯化和从1月到5月底的无驯化。环境因素（例如光周期和温度）对于确定驯化过程中的霜冻坚硬程度更为重要，它通过影响淀粉降解或增加可溶性碳水化合物含量而具有直接或间接作用。在去适应过程中，可溶性碳水化合物（尤其是棉子糖）进一步诱导了更强的霜冻硬度直接调节。通过棉子糖进行的直接生物调节定义了去驯化过程中的霜冻坚韧性水平。然而，