Institute of Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
Laboratory for Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Testing and Research, St. Gallen, 9014, Switzerland.
Plant Cell Environ. 2018 Jan;41(1):245-260. doi: 10.1111/pce.13091. Epub 2017 Nov 21.
Parenchyma represents a critically important living tissue in the sapwood of the secondary xylem of woody angiosperms. Considering various interactions between parenchyma and water transporting vessels, we hypothesize a structure-function relationship between both cell types. Through a generalized additive mixed model approach based on 2,332 woody angiosperm species derived from the literature, we explored the relationship between the proportion and spatial distribution of ray and axial parenchyma and vessel size, while controlling for maximum plant height and a range of climatic factors. When factoring in maximum plant height, we found that with increasing mean annual temperatures, mean vessel diameter showed a positive correlation with axial parenchyma proportion and arrangement, but not for ray parenchyma. Species with a high axial parenchyma tissue fraction tend to have wide vessels, with most of the parenchyma packed around vessels, whereas species with small diameter vessels show a reduced amount of axial parenchyma that is not directly connected to vessels. This finding provides evidence for independent functions of axial parenchyma and ray parenchyma in large vesselled species and further supports a strong role for axial parenchyma in long-distance xylem water transport.
木质部是木本被子植物次生木质部边材中一种极为重要的有生命力的组织。考虑到薄壁组织与输水导管之间的各种相互作用，我们假设这两种细胞类型之间存在结构-功能关系。通过基于文献中 2332 种木本被子植物的广义加性混合模型方法，我们探讨了射线薄壁组织和轴向薄壁组织的比例和空间分布与导管大小之间的关系，同时控制了最大植物高度和一系列气候因素。当考虑最大植物高度时，我们发现随着年平均温度的升高，平均导管直径与轴向薄壁组织的比例和排列呈正相关，但与射线薄壁组织无关。具有高轴向薄壁组织分数的物种往往具有较宽的导管，大部分薄壁组织围绕着导管排列，而直径较小的导管的物种则具有较少的轴向薄壁组织，而且这些薄壁组织与导管没有直接连接。这一发现为大导管物种中轴向薄壁组织和射线薄壁组织的独立功能提供了证据，并进一步支持了轴向薄壁组织在长距离木质部水分运输中的重要作用。
