Abstract

Variable winter temperatures cause a year-to-year discrepancy in the phenology of deciduous trees. This implies that an intrinsic ‘winter clock’ synchronizes bloom with the progression of winter to spring. The carbohydrate–temperature (C–T) model established a mechanistic association between carbohydrate metabolism in dormant trees and hourly winter temperatures. Using historical winter temperature and bloom times of Prunus dulcis (Mill.) D. A. Webb (almond), Malus domestica L. (apple), Pistachia vera L. (pistachio) and Juglans regia L. (walnut) in California and Washington states, we parametrized species-specific metabolic parameters to the C–T model. There was a sound fit between actual and projected bloom dates with a deviation (root mean square error) of 4–7 days in all species. The parameterized model enabled us to study how the observed variability in soluble carbohydrate concentrations at senescence (SC₀) could affect bloom time. The C–T model projected that low SC₀ could advance, while high SC₀ possibly delays, the bloom of the early blooming almond trees. In contrast, high SC₀ would advance the bloom of apple, pistachio and walnut trees. These novel projections suggest that after experimental validation, SC₀ could guide post-harvest farming applications that affect fall carbohydrate accumulation to mediate the effects of climate shifts.

中文翻译：

---

关闭开花时钟——衰老时的糖分水平是否决定了树木对冬季温度的反应？

摘要

多变的冬季温度导致落叶树物候的逐年差异。这意味着内在的“冬季时钟”使开花与冬季到春季的进程同步。碳水化合物-温度 (C-T) 模型建立了休眠树木中碳水化合物代谢与冬季每小时温度之间的机制关联。使用Prunus dulcis (Mill.) DA Webb (杏仁)、Malus domestica L. (苹果)、Pistachia vera L. (开心果) 和Juglans regia L. 的历史冬季温度和开花时间。（核桃）在加利福尼亚州和华盛顿州，我们将物种特异性代谢参数参数化为 C-T 模型。所有物种的实际开花日期和预计开花日期之间存在良好的拟合，偏差（均方根误差）为 4-7 天。参数化模型使我们能够研究在衰老 (SC ₀ ) 时观察到的可溶性碳水化合物浓度的变化如何影响开花时间。C-T 模型预测低 SC ₀可能会提前，而高 SC ₀可能会延迟早期开花的杏树的开花。相比之下，高 SC ₀会促进苹果、开心果和核桃树的开花。这些新颖的预测表明，经过实验验证，SC ₀ 可以指导影响秋季碳水化合物积累的收获后农业应用，以调解气候变化的影响。