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Water potential gradient, root conduit size and root xylem hydraulic conductivity determine the extent of hydraulic redistribution in temperate trees
Functional Ecology ( IF 5.2 ) Pub Date : 2020-01-08 , DOI: 10.1111/1365-2435.13508
Benjamin D. Hafner 1, 2 , Benjamin D. Hesse 1 , Taryn L. Bauerle 2 , Thorsten E. E. Grams 1
Affiliation  

Hydraulic redistribution (HR) of soil water through plant roots is widely described; however its extent, especially in temperate trees, remains unclear. Here, we quantified HR of five temperate tree species. We hypothesized that both, HR within a plant and into the soil increase with higher water‐potential gradients, larger root conduit diameters and root‐xylem hydraulic conductivities as HR driving factors. Saplings of conifer (Picea abies, Pseudotsuga menziesii), diffuse‐porous (Acer pseudoplatanus) and ring‐porous species (Castanea sativa, Quercus robur) were planted in split‐root systems, where one plant had its roots split between two pots with different water‐potential gradients (0.23–4.20 MPa). We quantified HR via deuterium labelling. Species redistributed 0.39 ± 0.14 ml of water overnight (0.08 ± 0.01 ml/g root mass). Higher pre‐dawn water‐potential gradients, hydraulic conductivities and larger conduits significantly increased HR quantity. Hydraulic conductivity was the most important driving factor on HR amounts, within the plants (0.03 ± 0.01 ml/g) and into the soil (0.06 ± 0.01 ml/g). Additional factors as soil‐root contact should be considered, especially when calculating water transfer into the soil. Nevertheless, trees maintaining high‐xylem hydraulic conductivity showed higher HR amounts, potentially making them valuable ‘silvicultural tools’ to improve plant water status. A free Plain Language Summary can be found within the Supporting Information of this article.

中文翻译:

水势梯度、根导管大小和根木质部水力传导率决定了温带树木中水力再分配的程度

土壤水分通过植物根系的水力再分配 (HR) 被广泛描述;然而,它的范围,特别是在温带树木中,仍不清楚。在这里,我们量化了五种温带树种的 HR。我们假设植物内和土壤中的 HR 都随着更高的水势梯度、更大的根导管直径和根 - 木质部水力传导率作为 HR 驱动因素而增加。将针叶树(Picea abies、Pseudotsuga menziesii)、散孔树(Acer pseudoplatanus)和环孔树(Castanea sativa、Quercus robur)的树苗种植在分根系统中,其中一株植物的根分在两个不同的盆中。水势梯度 (0.23–4.20 MPa)。我们通过氘标记量化 HR。物种重新分配 0.39 ± 0.14 毫升水过夜(0.08 ± 0.01 毫升/克根质量)。更高的黎明前水势梯度、水力传导率和更大的管道显着增加了 HR 数量。在植物内 (0.03 ± 0.01 ml/g) 和土壤中 (0.06 ± 0.01 ml/g),水力传导率是 HR 量的最重要驱动因素。还应考虑土壤-根系接触等其他因素,尤其是在计算向土壤中转移的水分时。尽管如此,保持高木质部水力传导率的树木显示出更高的 HR 量,这可能使它们成为改善植物水分状况的宝贵“造林工具”。可以在本文的支持信息中找到免费的普通语言摘要。在植物内 (0.03 ± 0.01 ml/g) 和进入土壤 (0.06 ± 0.01 ml/g)。还应考虑土壤-根系接触等其他因素,尤其是在计算向土壤中转移的水分时。尽管如此,保持高木质部水力传导率的树木显示出更高的 HR 量,这可能使它们成为改善植物水分状况的宝贵“造林工具”。可以在本文的支持信息中找到免费的普通语言摘要。植物内 (0.03 ± 0.01 ml/g) 和土壤中 (0.06 ± 0.01 ml/g)。还应考虑土壤-根系接触等其他因素,尤其是在计算向土壤中转移的水分时。尽管如此,保持高木质部水力传导率的树木显示出更高的 HR 量,这可能使它们成为改善植物水分状况的宝贵“造林工具”。可以在本文的支持信息中找到免费的普通语言摘要。
更新日期:2020-01-08
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