A standardization method to disentangle environmental information from axial trends of xylem anatomical traits
| Autor: | Silvia Lechthaler, Giai Petit, Francesco Pirotti, Tarryn L. Turnbull, Mark A. Adams, Tommaso Anfodillo, Ylenia Gelmini |
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| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
0301 basic medicine Victoria Physiology Climate Acacia Plant Science Biology Environment Hydraulic resistance 01 natural sciences Trees 03 medical and health sciences Hydraulic conductivity Species Specificity Xylem Botany Hydraulic diameter aridity hydraulic conductivity hydraulic diameter tree height vessel nearest-neighbour distance xylem tree height fungi food and beverages Water biology.organism_classification Apex (geometry) hydraulic diameter 030104 developmental biology aridity vessel nearest-neighbour distance New South Wales Axial distance hydraulic conductivity 010606 plant biology & botany Woody plant |
| Zdroj: | Tree physiology. 39(3) |
| ISSN: | 1758-4469 |
| Popis: | Anatomical traits such as xylem conduit diameter and vessel connectivity are fundamental characteristics of the hydraulic architecture of vascular plants. Stem xylem conduits are narrow at the stem apex, and this confers resistance to embolisms that might otherwise be induced by large, negative water potentials at the top of tall trees. Below the apex, conduits progressively widen and this characteristic minimizes effects of path length on total hydraulic resistance. While interconnections among xylem vessels have been noted for decades, their role(s) are not fully clarified. For example, we do not know if they allow water to bypass embolized vessels, or increase the risk of spread of embolisms, or how their arrangement varies within a tree. Here we demonstrate the benefit of removing the independent effect of stem length on assessment of effects of external (e.g., climatic) factors on such xylem traits. We measured the hydraulic diameter (Dh) and vessel conductivity index (VCI) along the stem of 21 shrubs/trees of similar height (1.19 < H < 5.45 m) belonging to seven Acacia species, across a wide aridity gradient in Australia. All trees showed similar scaling exponents of Dh (b = 0.33) and VCI (b = 0.53) vs axial distance from the apex (L), thus conforming with general patterns in woody plants. After de-trending for L, neither Dh (P = 0.21) nor VCI (P = 0.109) differed across the aridity gradient. We found that across a wide gradient of aridity, climate had no effect on xylem anatomy of Acacia spp, which was instead dictated by axial distances from stem apices. We argue that the use of standardization procedures to filter out intrinsic patterns of vascular traits is an essential step in assessing climate-driven modifications of xylem architecture. |
| Databáze: | OpenAIRE |
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