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Stem water transport and freeze-thaw xylem embolism in conifers and angiosperms in a Tasmanian treeline heath


Field, TS and Brodribb, TJ, Stem water transport and freeze-thaw xylem embolism in conifers and angiosperms in a Tasmanian treeline heath, Oecologia , 127, (3) pp. 314-320. ISSN 0029-8549 (2001) [Refereed Article]

DOI: doi:10.1007/s004420000603


The effect of freezing on stem xylem hydraulic conductivity and leaf chlorophyll a fluorescence was measured in 12 tree and shrub species from a treeline heath in Tasmania, Australia. Reduction in stem hydraulic conductivity after a single freeze-thaw cycle was minimal in conifers and the vessel-less angiosperm species Tasmannia lanceolata (Winteraceae), whereas mean loss of conductivity in vessel-forming angiosperms fell in the range 17-83%. A positive linear relationship was observed between percentage loss of hydraulic conductivity by freeze-thaw and the average conduit diameter across all 12 species. This supports the hypothesis that large-diameter vascular conduits have a greater likelihood of freeze-thaw cavitation because larger bubbles are produced, which are more likely to expand under tension. Leaf frost tolerances, as measured by a 50% loss of maximum PSII quantum yield, varied from -6 to -13°C, indicating that these species were more frost-sensitive than plants from northern hemisphere temperate forest and treeline communities. There was no evidence of a relationship between frost tolerance of leaves and the resilience of stem water transport to freezing, suggesting that low temperature survival and the resistance of stem water transport to freezing are independently evolving traits. The results of this study bear on the ecological importance of stem freezing in the southern hemisphere treeline zones.

Item Details

Item Type:Refereed Article
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the environmental sciences
UTAS Author:Brodribb, TJ (Professor Tim Brodribb)
ID Code:47886
Year Published:2001
Web of Science® Times Cited:87
Deposited By:Plant Science
Deposited On:2007-12-04
Last Modified:2011-11-23

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