title: Water stress and recovery in the performance of two Eucalyptus globulus clones: physiological and biochemical profiles.
abstract: Eucalyptus plantations are among the most productive forest stands in Portugal and Spain, being mostly used for pulp production and, more recently, as an energy crop. However, the region's Mediterranean climate, with characteristic severe summer drought, negatively affects eucalypt growth and increases mortality. Although the physiological response to water shortage is well characterized for this species, evidence about the plants' recovery ability remains scarce. In order to assess the physiological and biochemical response of Eucalyptus globulus during the recovery phase, two genotypes (AL-18 and AL-10) were submitted to a 3-week water stress period at two different intensities (18 and 25% of field capacity), followed by 1 week of rewatering. Recovery was assessed 1 day and 1 week after rehydration. Drought reduced height, biomass, water potential, NPQ and gas exchange in both genotypes. Contrarily, the levels of pigments, chlorophyll fluorescence parameters (F(v) /F(m) and (φPSII)), MDA and ABA increased. During recovery, the physiological and biochemical profile of stressed plants showed a similar trend: they experienced reversion of altered traits (MDA, ABA, E, g(s), pigments), while other parameters did not recover ((φPSII), NPQ). Furthermore, an overcompensation of CO(2) assimilation was achieved 1 week after rehydration, which was accompanied by greater growth and re-establishment of oxidative balance. Both genotypes were tolerant to the tested conditions, although clonal differences were found. AL-10 was more productive and showed a more rapid and dynamic response to rehydration (namely in carotenoid content, (φPSII) and NPQ) compared to clone AL-18.
authors.affiliation: Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Barbara
authors.initials: B
authors.lastname: Correia
authors.forename: Marta
authors.initials: M
authors.lastname: Pintó-Marijuan
authors.forename: Lucinda
authors.initials: L
authors.lastname: Neves
authors.forename: Ricard
authors.initials: R
authors.lastname: Brossa
authors.forename: Maria Celeste
authors.initials: MC
authors.lastname: Dias
authors.forename: Armando
authors.initials: A
authors.lastname: Costa
authors.forename: Bruno B
authors.initials: BB
authors.lastname: Castro
authors.forename: Clara
authors.initials: C
authors.lastname: Araújo
authors.forename: Conceição
authors.initials: C
authors.lastname: Santos
authors.forename: Maria Manuela
authors.initials: MM
authors.lastname: Chaves
authors.forename: Glória
authors.initials: G
authors.lastname: Pinto
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology*; D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism; D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D055864:Droughts; D005052:Eucalyptus / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005838:Genotype; D008315:Malondialdehyde / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010858:Pigmentation / Q000235:genetics / Q000502:physiology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D013045:Species Specificity; D013053:Spectrophotometry; D013312:Stress, Physiological / Q000502:physiology*; D053719:Tandem Mass Spectrometry; D013997:Time Factors; D014867:Water / Q000378:metabolism / Q000502:physiology*
chemical_list: D045332:Photosystem II Protein Complex; D014867:Water; D002734:Chlorophyll; D002245:Carbon Dioxide; D002338:Carotenoids; D008315:Malondialdehyde; D000040:Abscisic Acid