Tree Physiology Advance Access originally published online on March 27, 2009
Tree Physiology 2009 29(6):765-775; doi:10.1093/treephys/tpp018
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Intraspecific differences in drought tolerance and acclimation in hydraulics of Ligustrum vulgare and Viburnum lantana
1 Institut für Botanik, Universität Innsbruck, Sternwartestr. 15, A-6020 Innsbruck, Austria
2 Corresponding author (barbara.beikircher{at}uibk.ac.at)
| Abstract |
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An adequate general drought tolerance and the ability to acclimate to changing hydraulic conditions are important features for long-lived woody plants. In this study, we compared hydraulic safety (water potential at 50% loss of conductivity,
50), hydraulic efficiency (specific conductivity, ks), xylem anatomy (mean tracheid diameter, dmean, mean hydraulic diameter, dh, conduit wall thickness, t, conduit wall reinforcement, (t/b)h2) and stomatal conductance, gs, of forest plants as well as irrigated and drought-treated garden plants of Ligustrum vulgare L. and Viburnum lantana L. Forest plants of L. vulgare and V. lantana were significantly less resistant to drought-induced cavitation (
50 at –2.82 ± 0.13 MPa and –2.79 ± 0.17 MPa) than drought-treated garden plants (– 4.58 ± 0.26 MPa and –3.57 ± 0.15 MPa). When previously irrigated garden plants were subjected to drought, a significant decrease in dmean and dh and an increase in t and (t/b)h2 were observed in L. vulgare. In contrast, in V. lantana conduit diameters increased significantly but no change in t and (t/b)h2 was found. Stomatal closure occurred at similar water potentials (
sc) in forest plants and drought-treated garden plants, leading to higher safety margins (
sc –
50) of the latter (L. vulgare 1.63 MPa and V. lantana 0.43 MPa). These plants also showed higher gs at moderate
, more abrupt stomatal closure and lower cuticular conductivity. Data indicate that the development of drought-tolerant xylem as well as stomatal regulation play an important role in drought acclimation, whereby structural and physiological responses to drought are species-specific and depend on the plants hydraulic strategy.
Keywords: embolism, hydraulic efficiency, hydraulic safety, phenotypic plasticity, stomatal conductance, vulnerability, xylem anatomy
Received October 3, 2008; Accepted March 5, 2009