The roles of conduit redundancy and connectivity in xylem hydraulic functions
DOMEC, Jean‐christophe
Interactions Sol Plante Atmosphère [UMR ISPA]
Nicholas School of the Environment
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Interactions Sol Plante Atmosphère [UMR ISPA]
Nicholas School of the Environment
Language
en
Article de revue
This item was published in
New Phytologist. 2021-06-02p. 1-12
Wiley
English Abstract
Wood anatomical traits shape a xylem segment's hydraulic efficiency and resistance to embolism spread due to declining water potential. It has been known for decades that variations in conduit connectivity play a role in ...Read more >
Wood anatomical traits shape a xylem segment's hydraulic efficiency and resistance to embolism spread due to declining water potential. It has been known for decades that variations in conduit connectivity play a role in altering xylem hydraulics. However, evaluating the precise effect of conduit connectivity has been elusive. The objective here is to establish an analytical linkage between conduit connectivity and grouping and tissue-scale hydraulics. It is hypothesized that an increase in conduit connectivity brings improved resistance to embolism spread due to increased hydraulic pathway redundancy. However, an increase in conduit connectivity could also reduce resistance due to increased speed of embolism spread with respect to pressure. We elaborate on this trade-off using graph theory, percolation theory and computational modeling of xylem. The results are validated using anatomical measurements of Acer branch xylem. Considering only species with vessels, increases in connectivity improve resistance to embolism spread without negatively affecting hydraulic conductivity. The often measured grouping index fails to capture the totality of the effect of conduit connectivity on xylem hydraulics. Variations in xylem network characteristics, such as conduit connectivity, might explain why hypothesized trends among woody species, such as the 'safety-efficiency' trade-off hypothesis, are weaker than expected.Read less <
English Keywords
Acer (maples)
connectivity
embolism spread
grouping
hydraulic conductance
xylem
Origin
Hal imported