Couplings in cell differentiation kinetics mitigate air temperature influence on conifer wood anatomy
Couplings in cell differentiation kinetics mitigate air temperature influence on conifer wood anatomy
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DOI：
10.1111/pce.13464
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发表时间：
2019-04-01
影响因子：
7.3
通讯作者：
Frank, David C.
中科院分区：
文献类型：
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作者：
Cuny, Henri E.;Fonti, Patrick;Frank, David C.
针叶树具有典型的解剖学年轮结构，其特征是由大而薄壁的早材管胞向窄而厚壁的晚材管胞过渡。然而，很少有人知道这种特征性的结构是如何在不同的环境条件下保持的，因为它对确保树液上升和机械支持起着至关重要的作用。在这项研究中，我们监测了两种温带针叶树种（即，欧洲云杉Picea abies（L.）喀斯特和落叶落叶松（Larix decidua Mill.）跨越800到2,200 m a的8摄氏度温度梯度。S.L.在中欧调查空气温度对木材细胞形成的速率和持续时间的影响。结果表明，对较冷的网站，形成管胞补偿分化率下降（细胞扩大和壁增厚）的延长持续时间，除了最后一个细胞的晚材在壁增厚阶段。这种补偿允许针叶树减轻空气温度对最终年轮结构的影响，对木质部对不同环境条件的功能和弹性具有重要意义。晚材细胞加厚补偿的消失也可能解释了最大晚材密度对气候的敏感性。
Conifer trees possess a typical anatomical tree-ring structure characterized by a transition from large and thin-walled earlywood tracheids to narrow and thick-walled latewood tracheids. However, little is known on how this characteristic structure is maintained across contrasting environmental conditions, due to its crucial role to ensure sap ascent and mechanical support. In this study, we monitored weekly wood cell formation for up to 7 years in two temperate conifer species (i.e., Picea abies (L.) Karst and Larix decidua Mill.) across an 8 degrees C thermal gradient from 800 to 2,200 m a. s.l. in central Europe to investigate the impact of air temperature on rate and duration of wood cell formation. Results indicated that towards colder sites, forming tracheids compensate a decreased rate of differentiation (cell enlarging and wall thickening) by an extended duration, except for the last cells of the latewood in the wall-thickening phase. This compensation allows conifer trees to mitigate the influence of air temperature on the final tree-ring structure, with important implications for the functioning and resilience of the xylem to varying environmental conditions. The disappearing compensation in the thickening latewood cells might also explain the higher climatic sensitivity usually found in maximum latewood density.