Weak link or strong foundation? Vulnerability of fine root networks and stems to xylem embolism.

Autor: Harrison Day BL; School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia.; School of the Environment, Yale University, New Haven, CT, 06520, USA., Brodersen CR; School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia.; School of the Environment, Yale University, New Haven, CT, 06520, USA., Brodribb TJ; School of Natural Sciences, University of Tasmania, Private Bag 55, Hobart, TAS, 7001, Australia.
Jazyk: angličtina
Zdroj: The New phytologist [New Phytol] 2024 Nov; Vol. 244 (4), pp. 1288-1302. Date of Electronic Publication: 2024 Sep 12.
DOI: 10.1111/nph.20115
Abstrakt: Resolving the position of roots in the whole-plant hierarchy of drought-induced xylem embolism resistance is fundamental for predicting when species become isolated from soil water resources. Published research generally suggests that roots are the most vulnerable organ of the plant vascular system, although estimates vary significantly. However, our knowledge of root embolism excludes the fine roots (< 2 mm diameter) that form the bulk of total absorptive surface area of the root network for water and nutrient uptake. We measured fine root and stem xylem vulnerability in 10 vascular plant species from the major land plant clades (five angiosperms, three conifers, a fern and lycophyte), using standardised in situ methods (Optical Methods and MicroCT). Mean fine root embolism resistance across the network matched or exceeded stems in all study species. In six of these species (one fern, one lycophyte, three conifers and one angiosperm), fine roots were significantly more embolism resistant than stems. No clear relationship was found between root xylem conduit diameter and vulnerability. These results provide insight into the resistance of the plant hydraulic pathway at the site of water and nutrient uptake, and challenge the long-standing assumption that fine roots are more vulnerable than stems.
(© 2024 The Author(s). New Phytologist © 2024 New Phytologist Foundation.)
Databáze: MEDLINE
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