Wang Fucheng, Liu Yiming, Hänninen Heikki, Zheng Jinbin, Zhao Yu, Chang Wenwen, Wu Jiasheng, Zhang Rui
National Key Laboratory of Forest Food Resources Development and Utilization, Zhejiang A&F University, Hangzhou 311300, China.
Provincial Key Laboratory for Non-wood Forest and Quality Control and Utilization of Its Products, Zhejiang A&F University, Hangzhou 311300, China.
For Res (Fayettev). 2025 Apr 9;5:e007. doi: 10.48130/forres-0025-0007. eCollection 2025.
Climate warming has substantially delayed the autumn phenology of trees over recent decades. As the primary focus of previous studies on autumn phenology has been on temperate tree species, the environmental regulation of leaf senescence in subtropical trees under distinct climatic conditions remains poorly understood. To address this gap, using climate chambers, we experimentally examined the effects of air temperature, photoperiod, and soil moisture on leaf senescence and dormancy depth in seedlings of four subtropical tree species. Our results showed that low temperature served as the primary environmental cue driving leaf senescence in all four species, whereas photoperiod and soil moisture had no significant effect on senescence under low-temperature conditions. However, under high-temperature conditions, both drought and short photoperiod accelerated leaf senescence. This suggests that during warm autumns in subtropical regions when the typical senescence trigger (low temperature) is absent, drought and photoperiod are alternative cues to ensure senescence occurs before the onset of winter. Furthermore, we found that leaf senescence and dormancy induction were not closely linked processes. Overall, our experimental results reveal the dominant role of air temperature and its interactions with alternative cues (photoperiod and soil moisture) in regulating autumn leaf senescence in subtropical trees, which challenges the common assumption for a majority of temperate tree species that the primary driver of leaf senescence is short photoperiod. These findings provide valuable insights into the ways trees adapt to subtropical environments.
近几十年来，气候变暖已显著推迟了树木的秋季物候。由于先前关于秋季物候的研究主要集中在温带树种上，对于不同气候条件下亚热带树木叶片衰老的环境调控仍知之甚少。为了填补这一空白，我们利用气候箱，通过实验研究了气温、光周期和土壤湿度对四种亚热带树种幼苗叶片衰老和休眠深度的影响。我们的结果表明，低温是驱动所有这四个树种叶片衰老的主要环境信号，而在低温条件下，光周期和土壤湿度对衰老没有显著影响。然而，在高温条件下，干旱和短光周期都会加速叶片衰老。这表明，在亚热带地区温暖的秋季，当典型的衰老触发因素（低温）不存在时，干旱和光周期是确保衰老在冬季来临之前发生的替代信号。此外，我们发现叶片衰老和休眠诱导并非紧密相连的过程。总体而言，我们的实验结果揭示了气温及其与替代信号（光周期和土壤湿度）的相互作用在调节亚热带树木秋季叶片衰老中的主导作用，这对大多数温带树种的常见假设提出了挑战，即叶片衰老的主要驱动因素是短光周期。这些发现为树木适应亚热带环境的方式提供了有价值的见解。
