Department of Botany and Plant Sciences, University of California, Riverside, CA, USA.
USDA-ARS, US Salinity Laboratory, Riverside, CA, USA.
Tree Physiol. 2019 Aug 1;39(8):1438-1445. doi: 10.1093/treephys/tpz036.
Morphological traits of the plant vascular system such as xylem vessel diameter have been implicated in many physiological processes including resistance to drought-induced xylem cavitation and vessel occlusion during infection with vascular wilt diseases. In both events, xylem vessels lose function because they become filled with air or tyloses and gels. Xylem cavitation has been well studied, whereas vessel occlusion remains purely descriptive even though it is a critical response to wounding injuries and compartmentalization of vascular pathogens. The timing of vessel occlusion is a key determinant to a successful compartmentalization of pathogens within the plant vascular system and we hypothesized that xylem vessel diameter is the driving variable. Using a dye injection method coupled with automated image analysis, we parameterized a model to investigate how xylem vessel diameter affects the speed of vessel occlusion in Vitis vinifera L. cv. Cabernet Sauvignon in response to wounding. Our dataset contains observations from 6,646 vessels at five kinetic points following stem pruning, over a time course of 1 week. Using this approach we provide evidence that the diameter of vessels is a key determinant of the timing of their occlusion. We discuss how these findings impact resistance to vascular wilt diseases in perennial woody hosts.
植物维管系统的形态特征，如木质部导管直径，与许多生理过程相关，包括对干旱引起的木质部空化和维管束萎蔫病感染期间导管阻塞的抗性。在这两种情况下，木质部导管都会因为充满空气、侵填体或凝胶而丧失功能。木质部空化已经得到了很好的研究，而导管阻塞仍然只是描述性的，尽管它是对创伤损伤和维管束病原体分隔的关键反应。导管阻塞的时间是病原体在植物维管系统中成功分隔的关键决定因素，我们假设木质部导管直径是驱动变量。我们使用染料注射方法结合自动化图像分析，参数化了一个模型，以研究木质部导管直径如何影响葡萄品种赤霞珠（Vitis vinifera L. cv. Cabernet Sauvignon）对创伤的响应中导管阻塞的速度。我们的数据集包含了茎修剪后 5 个动力学点的 6646 个导管的观察结果，时间跨度为 1 周。通过这种方法，我们提供了证据表明，导管的直径是导管阻塞时间的关键决定因素。我们讨论了这些发现如何影响多年生木本宿主对维管束萎蔫病的抗性。
