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Evaluation of centrifugal methods for measuring xylem cavitation in conifers, diffuse‐ and ring‐porous angiosperms
Author(s) -
Li Yangyang,
Sperry John S.,
Taneda Haruhiko,
Bush Susan E.,
Hacke Uwe G.
Publication year - 2008
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2007.02272.x
Subject(s) - hydraulic conductivity , conductivity , cavitation , xylem , porosity , materials science , drop (telecommunication) , pressure drop , analytical chemistry (journal) , composite material , chemistry , mechanics , soil science , chromatography , botany , geology , biology , physics , soil water , telecommunications , computer science
Summary• A centrifugal method is used to measure ‘vulnerability curves’ which show the loss of hydraulic conductivity in xylem by cavitation. Until recently, conductivity was measured between bouts of centrifugation using a gravity‐induced head. Now, conductivity can be measured during centrifugation. This ‘spin’ method is faster than the ‘gravity’ technique, but correspondence between the two has not been evaluated. • The two methods were compared on the same stem segments for two conifer, four diffuse‐porous, and four ring‐porous species. • Only 17 of 60 conductivity measurements differed, with differences in the order of 10%. When different, the spin method gave higher conductivities at the beginning of the curve and lower at the end. Pressure at 50% loss of conductivity, and mean cavitation pressure, were the same in 14 of 20 comparisons. When different, the spin method averaged 0.32 MPa less negative. Ring‐porous species showed a precipitous initial drop in conductivity by both techniques. This striking pattern was confirmed by the air‐injection method and native embolism measurements. • Close correspondence inspires confidence in both methods, each of which has unique advantages. The observation that ring‐porous species operate at only a fraction of their potential conductivity at midday demands further study.