Musso C, Ganthaler A, Mayr S
Department of Botany, University of Innsbruck, Innsbruck, Austria.
Plant Biol (Stuttg). 2025 Sep 3. doi: 10.1111/plb.70088.
Shrubs are perennial, multi-stemmed woody plants whose adaptation to stress factors allows them to colonise extreme habitats, including high elevations. Accordingly, shrubs are one of the most important growth forms in mountain regions, but their hydraulic properties are poorly understood. We conducted a literature search on the water use strategies of mountain shrubs, focusing on their main hydraulic traits related to water uptake, transport and release, as well as hydraulic limitations in summer and winter. In addition, the leaf cuticular conductance was measured in selected Alpine species. A total of 104 publications were found, mainly from North America, Europe and Asia, and a few from Africa and South America, with snow and steppe habitats strongly underrepresented. The dataset revealed a wide range of specific hydraulic conductivity (k; 0.8-25.8 × 10 ms MPa), with highest values in tundra shrubs, and of the water potential at 50% conductivity loss (Ψ; -11.8 to -0.29 MPa), with lowest values in steppe and temperate dry summer species. Deep-rooted shrubs from arid environments had access to more reliable water sources, while others relied on shallow but nutrient-rich soil water. No clear trend was observed along elevation or precipitation gradients, suggesting a wide range of hydraulic strategies to achieve a balanced water status. Shrub species from arid regions have to withstand low water potentials during the dry season, whereas temperate shrubs experience frost drought and freeze-thaw-induced embolism in winter. The literature review revealed major gaps in the geographic distribution of available studies, and in our knowledge of root characteristics, recovery from embolism, and water storage capacity.
灌木是多年生、多茎的木本植物，它们对压力因素的适应能力使它们能够在包括高海拔地区在内的极端栖息地定居。因此，灌木是山区最重要的生长形式之一，但人们对它们的水力特性了解甚少。我们对山区灌木的水分利用策略进行了文献检索，重点关注它们与水分吸收、运输和释放相关的主要水力特征，以及夏季和冬季的水力限制。此外，还对选定的高山物种的叶片角质层导度进行了测量。共发现104篇出版物，主要来自北美、欧洲和亚洲，少数来自非洲和南美洲，其中雪和草原栖息地的研究严重不足。数据集显示了广泛的比水力导率（k；0.8 - 25.8×10 ms MPa），苔原灌木中的值最高，以及在导水率损失50%时的水势（Ψ；-11.8至-0.29 MPa），草原和温带夏季干燥物种中的值最低。来自干旱环境的深根灌木能够获取更可靠的水源，而其他灌木则依赖浅层但营养丰富的土壤水分。沿海拔或降水梯度未观察到明显趋势，这表明存在广泛的水力策略以实现水分平衡状态。干旱地区的灌木物种在旱季必须承受低水势，而温带灌木在冬季会经历霜冻干旱和冻融诱导的栓塞。文献综述揭示了现有研究在地理分布、我们对根系特征、栓塞恢复和储水能力的了解方面存在重大差距。
