10.5061/DRYAD.HM482
Richards, Anna E.
Macquarie University
Wright, Ian J.
Macquarie University
Lenz, Tanja I.
Macquarie University
Zanne, Amy E.
George Washington University
Missouri Botanical Garden
Data from: Sapwood capacitance is greater in evergreen sclerophyll species
growing in high compared to low rainfall environments
Dryad
dataset
2013
pre-dawn water potential
cumulative water release
Wood density
plant hydraulic strategies
midday water potential
stem water storage
2013-10-01T20:25:13Z
2013-10-01T20:25:13Z
en
https://doi.org/10.1111/1365-2435.12193
91511 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
1. The capacitative release of water from sapwood allows photosynthesis to
continue for longer into dry periods, both diurnally and seasonally.
However, costs of high capacitance include increased vulnerability to
xylem cavitation. The degree of reliance on stored water is predicted to
differ among environments as a result of this trade off 2. Xylem water
potential and sapwood capacitance were measured on 32 evergreen
sclerophyll shrub and tree species in eastern Australia, sampled from four
sites contrasting in soil nutrients and rainfall. 3. Capacitance
calculated over species’ typical shoot water potential operating range was
3-fold higher for species from high compared to low rainfall sites, and
1.5-fold higher for species from high compared to low nutrient sites. 4.
To determine whether these site differences were related to extrinsic
(e.g. water availability) or intrinsic (e.g. species anatomical
construction) factors, we calculated capacitance at two common operating
ranges; i.e. the mean range in water potential observed for low rainfall
species (ΔΨlow rain) and the mean range for high rainfall species (ΔΨhigh
rain). While no difference was seen between low and high rainfall species
in release of stored water across ΔΨhigh rain, across ΔΨlow rain the high
rainfall species released 38% more stored water than low rainfall species.
Presumably these differences reflect underlying differences in anatomy,
such as wood density, which was lower in high rainfall species. 5. These
results accord with predictions that (i) species from wetter sites exhibit
less negative stem water potentials and high sapwood capacitance, enabling
them to maintain function under variable conditions characterized by many
short, dry periods; while (ii) species from low rainfall sites have wood
anatomies conferring tolerance to very low water potentials, with low
sapwood capacitance, enabling them to survive longer through unpredictable
and extended periods of low rainfall. The finding that the degree to which
species rely on stem-stored water varies with site rainfall suggests that
changes in drought regimes (e.g. incidence, duration and severity) under
future climates could differentially affect species according to the
capacitance properties of their woody tissues.
Sapwood water potential, relative water content and cumulative water
released from sapwood samples of 32 plant species measured in a
thermocouple psychrometer and their wood
densities.Richards_FuncEcol_DRYAD.xlsx