Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany.
Tree Physiol. 2013 Jul;33(7):684-94. doi: 10.1093/treephys/tpt050.
Various structure-function relationships regarding drought-induced cavitation resistance of secondary xylem have been postulated. These hypotheses were tested on wood of 10 Prunus species showing a range in P50 (i.e., the pressure corresponding to 50% loss of hydraulic conductivity) from -3.54 to -6.27 MPa. Hydraulically relevant wood characters were quantified using light and electron microscopy. A phylogenetic tree was constructed to investigate evolutionary correlations using a phylogenetically independent contrast (PIC) analysis. Vessel-grouping characters were found to be most informative in explaining interspecific variation in P50, with cavitation-resistant species showing more solitary vessels than less resistant species. Co-evolution between vessel-grouping indices and P50 was reported. P50 was weakly correlated with the shape of the intervessel pit aperture, but not with the total intervessel pit membrane area per vessel. A negative correlation was found between P50 and intervessel pit membrane thickness, but this relationship was not supported by the PIC analysis. Cavitation resistance has co-evolved with vessel grouping within Prunus and was mainly influenced by the spatial distribution of the vessel network.
已经提出了关于次生木质部干旱诱导空化阻力的各种结构-功能关系。这些假设在 10 种李属树种的木材上进行了测试，这些树种的 P50（即水力传导率损失 50%时对应的压力）范围为-3.54 至-6.27 MPa。使用光镜和电子显微镜定量了与水力相关的木材特性。构建了一个系统发育树，使用系统发育独立对比（PIC）分析来研究进化相关性。发现导管群集特征在解释 P50 的种间变异方面最具信息量，抗空化的物种比抗性较低的物种具有更多的孤立导管。报告了导管群集指数与 P50 之间的共同进化。P50 与导管间纹孔开口的形状呈弱相关，但与每个导管的导管间纹孔膜总面积无关。发现 P50 与导管间纹孔膜厚度之间存在负相关，但 PIC 分析不支持这种关系。在李属中，抗空化性与导管群集共同进化，主要受导管网络空间分布的影响。
