A new paper by Sebastian Pfaustch was just published in Annals of Botany, which included John Drake as the third author. Get the paper here. There is currently a controversy regarding the anatomical and physiological characteristics of trees that allow them to efficiently transport water from the soil to their leaves, while also minimizing the chance of hydraulic failure from xylem cavitation. A portion of this controversy stems from the fact that most hydraulic research is done at the scales of cells, tissues, or organs, often separately. Very few studies have taken a whole-organismal approach with large trees and studied how hydraulic traits co-vary along the stems of large trees. Pfaustch et al. heavily instrumented three Eucalyptus grandis trees with sapflow probes and stem psychrometers and collected physiological data for a month, and then felled the trees and measured a wide range of anatomical traits with light and electron microscopy. Pfaustch et al. may have set a record with the number of sapflow probes installed on an individual tree, with 52 heat-ratio method probes. The study revealed complex and synchronized covariation among traits and tradeoff with increasing height in these trees. In particular, the anatomical traits of xylem vessels and pit membranes co-varied to increase efficiency and apical dominance in water transport in ways that are likely to minimize cavitation. That is, coherent trait variation may minimize the strength of the trade-off between efficient water transport and resistance to xylem caviation.
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Drake lab
Tree ecophysiology at SUNY-ESF Archives
October 2022
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