Photoperiod and temperature as dominant environmental drivers triggering secondary growth resumption in Northern Hemisphere conifers
Photoperiod and temperature as dominant environmental drivers triggering secondary growth resumption in Northern Hemisphere conifers
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DOI：
10.1073/pnas.2007058117
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发表时间：
2020-08-25
影响因子：
11.1
通讯作者：
Ziaco, Emanuele
中科院分区：
文献类型：
--
作者：
Huang, Jian-Guo;Ma, Qianqian;Ziaco, Emanuele
木材形成每年消耗约 15% 的人为二氧化碳排放量，在地球上的长期碳封存中发挥着关键作用。然而，驱动木材形成开始的外源因素和潜在的细胞机制仍然知之甚少，这阻碍了对全球变暖下陆地森林生产力和碳预算的有效评估。在这里，我们使用了北半球（北纬 23 至 67 度）21 个针叶树种的每周木质部组织形成（木材形成）的大量独特数据集，定量证明了北半球针叶树木材形成的开始主要由光周期和年平均温度 (MAT) 驱动，其次是春季强迫、冬季寒冷和水分可用性。光周期与 MAT 相互作用，在调节次生分生组织生长的开始中起主导作用，这与它在影响初级分生组织春季物候中尚未量化的作用相反。外源因素与木材形成之间的独特关系有助于预测森林生态系统如何响应和适应气候变暖，并可以更好地理解植被与气候之间由物候介导的反馈。我们的研究量化了主要环境驱动因素的作用，以便将其纳入最先进的地球系统模型（ESM5）中，从而对整个陆地生物群落的生物地球化学循环的长期和高分辨率观测提供改进的评估。
Wood formation consumes around 15% of the anthropogenic CO2 emissions per year and plays a critical role in long-term sequestration of carbon on Earth. However, the exogenous factors driving wood formation onset and the underlying cellular mechanisms are still poorly understood and quantified, and this hampers an effective assessment of terrestrial forest productivity and carbon budget under global warming. Here, we used an extensive collection of unique datasets of weekly xylem tissue formation (wood formation) from 21 coniferous species across the Northern Hemisphere (latitudes 23 to 67 degrees N) to present a quantitative demonstration that the onset of wood formation in Northern Hemisphere conifers is primarily driven by photoperiod and mean annual temperature (MAT), and only secondarily by spring forcing, winter chilling, and moisture availability. Photoperiod interacts with MAT and plays the dominant role in regulating the onset of secondary meristem growth, contrary to its as-yet-unquantified role in affecting the springtime phenology of primary meristems. The unique relationships between exogenous factors and wood formation could help to predict how forest ecosystems respond and adapt to climate warming and could provide a better understanding of the feedback occurring between vegetation and climate that is mediated by phenology. Our study quantifies the role of major environmental drivers for incorporation into state-of-the-art Earth system models (ESM5), thereby providing an improved assessment of long-term and high-resolution observations of biogeochemical cycles across terrestrial biomes.