There is increasing interest in expanding grapevine production into colder regions. Here, to identify reliable methods for evaluating cold hardiness, we analyzed tissue discoloration, electrolyte leakage (EL), triphenyl tetrazolium chloride (TTC) reduction, and exotherms in the buds and canes of ‘Campbell Early’ grapevines. In both tissues, we monitored exotherms during cooling to − 40 °C at a rate of − 2 °C/h and analyzed the other indices during 2-h exposure to various freezing temperatures. Evaluating tissue discoloration is a subjective method to score freezing injury; it is more time-consuming and requires larger amounts of sample material than other methods but offers the advantage that it can be used to estimate LT₅₀ (the temperature at which 50% injury occurs). EL analysis in buds and canes is another relatively rapid technique providing reproducible LT₅₀ values. However, our EL analysis of buds was limited by the small amounts of sample material. For TTC reduction analysis, the results were not reproducible for both buds and canes: at the same freezing temperature, buds and canes showed significant differences in TTC reduction levels, leading to erroneous LT₅₀ estimates. Finally, detection of low-temperature exotherms (LTEs), an indicator of intracellular ice formation (which causes fatal cell damage), through differential thermal analysis revealed LTEs in buds but seldom in canes, and those detected in buds exhibited much narrower peaks. Thus, exotherm and EL analyses are reliable methods for evaluating cold hardiness of grapevine buds and canes, respectively, and their combined application could be a useful strategy for assessing grapevine cultivars.

人们越来越有兴趣将葡萄种植扩大到较冷的地区。在这里，为了确定评估耐寒性的可靠方法，我们分析了组织变色、电解质泄漏 (EL)、氯化三苯基四唑 (TTC) 还原以及“Campbell Early”葡萄藤芽和藤茎中的放热现象。在这两种组织中，我们在以 − 2 °C/h 的速率冷却至 − 40 °C 期间监测放热，并在暴露于各种冷冻温度 2 小时期间分析其他指数。评估组织变色是一种对冷冻损伤评分的主观方法；它比其他方法更耗时，需要更多的样品材料，但具有可用于估计 LT _{50 的优势}（发生 50% 伤害时的温度）。芽和藤茎中的 EL 分析是另一种相对快速的技术，可提供可重现的 LT ₅₀值。然而，我们对芽的 EL 分析受到少量样品材料的限制。对于 TTC 降低分析，芽和藤茎的结果均不可重复：在相同的冷冻温度下，芽和藤茎的 TTC 降低水平存在显着差异，导致错误的 LT ₅₀估计。最后，通过差热分析检测低温放热 (LTE)，这是细胞内冰形成（导致致命的细胞损伤）的指标，显示 LTE 在芽中，但在藤茎中很少，并且在芽中检测到的峰更窄。因此，放热和 EL 分析分别是评估葡萄芽和藤茎抗寒性的可靠方法，它们的组合应用可能是评估葡萄品种的有用策略。