Research Highlights: This study emphasized the importance of multi-parameter analyses along ecological gradients for a more holistic understanding of the complex mechanism of tree-ring formation. Background and Objectives: The analysis of climatic signals from cell anatomical features measured along series of tree-rings provides mechanistic details on how environmental drivers rule tree-ring formation. However, the processes of cell development might not be independent, limiting the interpretation of the cell-based climatic signal. In this study, we investigated the variability, intercorrelations and climatic drivers of wood anatomical parameters, resulting from consequent cell developmental processes. Materials and Methods: The study was performed on thin cross-sections from wood cores sampled at ~1.3 m stem height from mature trees of Pinus sylvestris L. growing at five sampling sites along an ecological gradient from cold and wet to hot and dry within continental Southern Siberia. Tracheid number per radial file, their diameters and wall thicknesses were measured along the radial direction from microphotographs for five trees per site. These parameters were then averaged at each site for earlywood and latewood over the last 50 tree rings to build site chronologies. Their correlations among themselves and with 21-day moving climatic series were calculated. Results: Our findings showed that wood formation was not simply the result of environmentally driven independent subprocesses of cell division, enlargement and wall deposition. These processes appear to be interconnected within each zone of the ring, as well as between earlywood and latewood. However, earlywood parameters tend to have more distinctive climatic responses and lower intercorrelations. On the other hand, there are clear indications that the mechanisms of cell division and enlargement share similar climatic drivers and are more sensitive to water limitation than the process of wall deposition. Conclusions: Indications were provided that (i) earlywood formation left a legacy on latewood formation, (ii) cell division and enlargement shared more similar drivers between each other than with wall deposition, and (iii) the mechanism of cell division and enlargement along the gradient switch from water to heat limitations at different thresholds than wall deposition.

中文翻译：

---

西伯利亚南苏格兰松木质部细胞发育过程中不同干旱敏感性的证据

研究重点：这项研究强调了沿着生态梯度进行多参数分析的重要性，以便更全面地了解树木年轮形成的复杂机制。背景与目的：对沿一系列树木年轮测量的细胞解剖特征的气候信号进行分析，提供了有关环境驱动因素如何控制树木年轮形成的机制细节。但是，细胞发育的过程可能不是独立的，从而限制了基于细胞的气候信号的解释。在这项研究中，我们调查了由随后的细胞发育过程引起的木材解剖参数的变异性，相互关系和气候驱动因素。材料和方法：这项研究是在从西伯利亚南部大陆上从冷，湿到热，干的生态梯度在五个采样点生长的樟子松成熟树木的茎干高约1.3 m的木芯上进行的薄截面横截面上进行的。从每个地点五棵树的显微照片沿径向测量每个径向锉的气管数量，其直径和壁厚。然后，在每个站点上对最近50个树环上的早木和晚木进行平均，以建立站点年表。计算了它们之间以及与21天移动气候序列之间的相关性。结果：我们的发现表明，木材的形成不仅仅是环境独立的细胞分裂，扩大和壁沉积的子过程的结果。这些过程似乎在环的每个区域内以及早木和晚木之间相互关联。但是，早木参数往往具有更独特的气候响应和较低的相互关系。另一方面，有明确的迹象表明，细胞分裂和扩大的机制具有相似的气候驱动因素，并且比壁沉积过程对水分限制更为敏感。结论： 提供了以下指示：（i）早木形成留下了晚木形成的遗产；（ii）细胞分裂和扩大彼此之间比壁沉积具有更多相似的驱动力；（iii）沿梯度开关的细胞分裂和扩大的机制从水到热量的限制与壁沉积的阈值不同。