College of Forestry, Northwest A&F University, Yangling, Shaanxi, 712100, China.
Plant Cell Environ. 2010 Jul;33(7):1059-69. doi: 10.1111/j.1365-3040.2010.02127.x. Epub 2010 Mar 1.
The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel-size distributions. Measurements were done on seed-grown, 4-month-old aspen (Populus tremuloides Michx) grown in a greenhouse. VCs of stem segments were measured using a centrifuge technique and by a staining technique that allowed a VC to be constructed based on vessel diameter size-classes (D). Vessel-based VCs were also fitted to Weibull cumulative distribution functions (CDF), which provided best-fit values of Weibull CDF constants (c and b) and P(50) = the tension causing 50% loss of hydraulic conductivity. We show that P(50) = 6.166D(-0.3134) (R(2) = 0.995) and that b and 1/c are both linear functions of D with R(2) > 0.95. The results are discussed in terms of models of VCs based on vessel D size-classes and in terms of concepts such as the 'pit area hypothesis' and vessel pathway redundancy.
本研究的目的是量化物种内易空化性与血管直径之间的关系。我们测量了白杨茎的脆弱性曲线（VC：水力传导率损失百分比与张力的关系），并测量了血管大小分布。测量工作是在温室中种植的 4 个月大的白杨（Populus tremuloides Michx）上进行的。使用离心技术和染色技术测量茎段的 VC，染色技术允许根据血管直径大小类别（D）构建 VC。基于血管的 VC 也拟合了威布尔累积分布函数（CDF），提供了威布尔 CDF 常数（c 和 b）和 P（50）的最佳拟合值，P（50）是导致水力传导率损失 50%的张力。我们表明，P（50）= 6.166D（-0.3134）（R²= 0.995），b 和 1/c 都是 D 的线性函数，R²> 0.95。结果根据基于血管 D 大小类别的 VC 模型进行了讨论，并根据“坑面积假说”和血管途径冗余等概念进行了讨论。
