Model for grapevine bud cold hardiness and budbreak response: Data files

<br>Fundamental questions in bud dormancy remain, including what temperatures fulfill dormancy requirements (i.e. chill accumulation). Recent studies demonstrate freezing temperatures promote chill accumulation and cold hardiness influences time to budbreak—the phenotype used for dormancy evaluations. Here we evaluated bud cold hardiness and budbreak responses of grapevines (<i>Vitis </i>hybrids) throughout chill accumulation under three treatments: constant (5 °C), fluctuating (−3.5 to 6.5 °C daily), and field conditions (Madison, Wisconsin, USA). Chill treatments experiencing lower temperatures promoted greater gains in cold hardiness (field&gt;fluctuating&gt;constant). All treatments decreased observed time to budbreak with increased chill accumulation. However, perceived treatment effectiveness changed when time to budbreak was adjusted to remove cold acclimation effects. Among three classic chill models (North Carolina, Utah, and Dynamic), none was able to correctly describe adjusted time to budbreak responses to chill accumulation. Thus, a new model is proposed that expands the range of chill accumulation temperatures to include freezing temperatures and enhances chill accumulation under fluctuating temperature conditions. Most importantly, our analysis demonstrates that adjustments for uneven acclimation change the perceived effectiveness of chill treatments. Therefore, future work in bud dormancy would benefit from simultaneously evaluating cold hardiness.

芽休眠（bud dormancy）领域仍存在诸多基础科学问题尚未解决，例如何种温度可满足植物的休眠需求，即需冷量积累（chill accumulation）。近期研究证实，冻结温度可促进需冷量积累，而抗寒性（cold hardiness）会影响芽萌发（budbreak）所需时间——该表型（phenotype）正是芽休眠评价的常用指标。本研究针对葡萄属（<i>Vitis</i>）杂交品种，在三种处理条件下全程监测其需冷量积累过程中的芽抗寒性与芽萌发响应：恒定温度处理（5 ℃）、每日波动温度处理（-3.5 ℃至6.5 ℃）以及田间自然条件处理（美国威斯康星州麦迪逊市）。需冷量处理的温度越低，植株抗寒性提升幅度越大，表现为田间处理＞波动温度处理＞恒定温度处理。所有处理组中，随着需冷量积累的增加，观测到的芽萌发所需时间均有所缩短。然而，当对芽萌发时间进行校正以排除冷驯化（cold acclimation）的影响后，各处理的评估效果发生了变化。当前主流的三种经典需冷量模型分别为北卡罗来纳模型（North Carolina model）、犹他模型（Utah model）与动态模型（Dynamic model），但无一可准确描述校正后的芽萌发时间对需冷量积累的响应。据此，本研究提出一种全新的需冷量模型，该模型将需冷量积累的温度范围拓展至冻结温度区间，并优化了波动温度条件下的需冷量积累计算方式。尤为重要的是，本研究的分析结果表明，针对不均一冷驯化的校正会改变需冷量处理的评估效果。因此，未来开展芽休眠相关研究时，同步评估抗寒性将有助于提升研究可靠性。