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The impact of vessel size on vulnerability curves: data and models for within‐species variability in saplings of aspen, Populus tremuloides Michx
Author(s) -
CAI JING,
TYREE MELVIN T.
Publication year - 2010
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2010.02127.x
Subject(s) - weibull distribution , hydraulic conductivity , dimensionless quantity , soil science , materials science , mathematics , environmental science , statistics , mechanics , physics , soil water
The objective of this study was to quantify the relationship between vulnerability to cavitation and vessel diameter within a species. We measured vulnerability curves (VCs: percentage loss hydraulic conductivity versus tension) in aspen stems and measured vessel‐size distributions. Measurements were done on seed‐grown, 4‐month‐old aspen ( Populus tremuloides Michx) grown in a greenhouse. VCs of stem segments were measured using a centrifuge technique and by a staining technique that allowed a VC to be constructed based on vessel diameter size‐classes ( D ). Vessel‐based VCs were also fitted to Weibull cumulative distribution functions (CDF), which provided best‐fit values of Weibull CDF constants ( c and b ) and P 50 = the tension causing 50% loss of hydraulic conductivity. We show that P 50 = 6.166D −0.3134 ( R 2 = 0.995) and that b and 1/c are both linear functions of D with R 2 > 0.95. The results are discussed in terms of models of VCs based on vessel D size‐classes and in terms of concepts such as the ‘pit area hypothesis’ and vessel pathway redundancy.