Biologia Plantarum

, Volume 49, Issue 4, pp 551–559

Contribution of physiological and morphological adjustments to drought resistance in two Mediterranean tree species

Article

DOI: 10.1007/s10535-005-0049-y

Cite this article as:
Serrano, L. & Penuelas, J. Biol Plant (2005) 49: 551. doi:10.1007/s10535-005-0049-y

Abstract

Plant water potential (ψ), its components, and gas exchange data of two Mediterranean co-occurring woody species (Quercus ilex L. and Phillyrea latifolia L.) were measured in response to seasonal changes in water availability over two consecutive years. The relative contribution of physiological and morphological adjustments to drought resistance was assessed through Principal Component Analyses. There were large adjustments in stomatal conductance (∼36 % of accounted variance). Net photosynthetic rate and water use efficiency were closely tuned to water availability and accounted for ∼17 % of variance. The slope of the water potential vs. relative water content (dψ/dRWC0) below zero pressure potential increased as a result of seasonal and ontogenic increases in apoplastic water fraction and accounted for ∼20 % variance. This tolerance mechanism was accompanied by an increased range of positive pressure potential, suggesting a functional role of sclerophylly in these Mediterranean evergreens. Similarly, changes in the slope of dψ/dRWC in the range of positive pressure potential (∼13 % of accounted variance) were associated to variations in cell wall elasticity and resulted in lower RWC at zero pressure potential. When considering the species studied separately, the results indicated the primary role of stomatal regulation in the drought resistance of Qilex, while increased apoplastic water fraction had a major contribution in the drought resistance of P. latifolia.

Additional key words

drought stressPhillyrea latifolianet photosynthetic rateplant and tissue-water relationsQuercus ilexstomatal conductancewater potential

Abbreviations

AWF

apoplastic water fraction

dψ/dRWC

slope of the water potential vs. relative water content above zero pressure potential

dψ/dRWC0

slope of the water potential vs. relative water content below zero pressure potential

E

transpiration rate

gs

stomatal conductance

HE

hydraulic efficiency

PN

net photosynthetic rate

RWC0

relative water content at zero pressure potential

WUE

water use efficiency

Δψ

diurnal amplitude of leaf water potential

ψmd

midday leaf water potential

ψpd

predawn leaf water potential

ɛ

bulk modulus of elasticity

100 - π0)

range of positive pressure potential

Copyright information

© Institute of Experimental Botany, Academy of Sciences of the Czech Republic, Praha 2005

Authors and Affiliations

  1. 1.Departament d’Enginyeria Agroalimentaria i BiotecnologiaUniversitat Politecnica de CatalunyaBarcelonaSpain
  2. 2.Unitat d’Ecofisiologia CSIC-CEAB-CREAFUniversitat Autonoma de BarcelonaBellaterra, BarcelonaSpain