Winter rest and chilling accumulation play a crucial role in regulating the leaf-out and flowering of extratropical woody plants. Still, there is a lack of understanding regarding the potential rest condition of overwintered immature cones of coniferous trees and how the dormancy of different organ types responds to environmental cues. To address this gap, we conducted a unique experimental design using 8–10-year-old potted adult trees. We examined the rest condition in leaf buds, flower buds, and overwintered immature nuts (cones) simultaneously, and we summarized our findings with process-based models. Our results revealed that overwintered nuts, too, exhibit a rest condition and a chilling requirement similar to those of leaf and flower buds. The effects of photoperiod on rest break were minor in general, so that we did not include photoperiod in our process-based models. The upper limit of an effective chilling temperature was lower for the nuts (<13 °C) than for the flower and leaf buds (<17 °C). During the quiescence period after rest completion, a low forcing temperature of 10 °C enabled ontogenetic development in the nuts and the flower buds but not in the leaf buds. Despite these differences, our models predicted an almost identical change rate for the spring phenology under climate warming in the three organ types. Organ-specific phenological responses provide valuable insights into the impact of environmental factors on plant growth and development.

中文翻译：

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亚热带香榧树对寒冷和强迫的器官特异性休息和静止

冬季休息和积冷对调节温带木本植物的落叶和开花起着至关重要的作用。尽管如此，对于越冬的针叶树未成熟球果的潜在休息条件以及不同器官类型的休眠如何响应环境线索仍缺乏了解。为了解决这一差距，我们使用 8-10 年树龄的盆栽成年树进行了独特的实验设计。我们同时检查了叶芽、花芽和越冬未成熟坚果（球果）的静止状态，并用基于过程的模型总结了我们的发现。我们的结果表明，越冬坚果也表现出与叶和花蕾类似的休息条件和冷藏要求。一般来说，光周期对休息时间的影响很小，因此我们在基于过程的模型中没有包括光周期。坚果的有效冷却温度上限 (<13 °C) 低于花和叶芽 (<17 °C)。在休眠完成后的静止期，10°C的低强制温度使坚果和花芽能够个体发育，但叶芽却不能。尽管存在这些差异，我们的模型预测气候变暖下三种器官类型的春季物候变化率几乎相同。器官特异性物候反应为了解环境因素对植物生长和发育的影响提供了宝贵的见解。