Premise Leaf phenology is an essential developmental process in trees and an important component in understanding climate change. However, little is known about the regulation of leaf phenology in tropical trees. Methods To understand the regulation by temperature of leaf phenology in tropical trees, we performed daily observations of leaf production under rainfall‐independent conditions using saplings of Shorea leprosula and Neobalanocarpus heimii, both species of Dipterocarpaceae, a dominant tree family of Southeast Asia. We analyzed the time‐series data obtained using empirical dynamic modeling (EDM) and conducted growth chamber experiments. Results Leaf production by dipterocarps fluctuated in the absence of fluctuation in rainfall, and the peaks of leaf production were more frequent than those of day length, suggesting that leaf production cannot be fully explained by these environmental factors, although they have been proposed as regulators of leaf phenology in dipterocarps. Instead, EDM suggested a causal relationship between temperature and leaf production in dipterocarps. Leaf production by N. heimii saplings in chambers significantly increased when temperature was increased after long‐term low‐temperature treatment. This increase in leaf production was observed even when only nighttime temperature was elevated, suggesting that the effect of temperature on development is not mediated by photosynthesis. Conclusions Because seasonal variation in temperature in the tropics is small, effects on leaf phenology have been overlooked. However, our results suggest that temperature is a regulator of leaf phenology in dipterocarps. This information will contribute to better understanding of the effects of climate change in the tropics.

中文翻译：

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温度是赤道东南亚龙脑香科叶片生产的调节剂

前提 叶物候学是树木的重要发育过程，也是了解气候变化的重要组成部分。然而，对热带树木叶片物候的调节知之甚少。方法为了了解热带树木叶片物候温度的调节，我们在不依赖降雨的条件下使用 Shorea leprosula 和 Neobalanocarpus heimii 的树苗进行叶片生产的日常观察，这两种植物都是东南亚的优势树科龙脑香科。我们分析了使用经验动态模型 (EDM) 获得的时间序列数据并进行了生长室实验。结果 龙脑香的叶片产量在降雨量无波动的情况下有波动，叶片产量峰值比日长峰值更频繁，表明这些环境因素不能完全解释叶片的产生，尽管它们已被提议作为龙脑香植物叶片物候的调节剂。相反，EDM 表明温度与龙脑香的叶片产量之间存在因果关系。长期低温处理后，当温度升高时，N. heimii树苗在室内的叶片产量显着增加。即使仅在夜间温度升高时也观察到叶片产量的增加，这表明温度对发育的影响不是由光合作用介导的。结论 由于热带地区温度的季节性变化很小，因此忽略了对叶片物候的影响。然而，我们的结果表明温度是龙脑香植物叶片物候的调节器。