Physiologia Plantarum 150: 580–592. 2014 © 2013 Scandinavian Plant Physiology Society, ISSN 0031-9317 Water stress and recovery in the performance of two Eucalyptus globulus clones: physiological and biochemical profiles Barbara Correia a , Marta Pint ´ o-Marijuan b,c , Lucinda Neves d,e , Ricard Brossa c , Maria Celeste Dias a , Armando Costa a , Bruno B. Castro a , Clara Ara ´ ujo e , Conceic ¸˜ ao Santos a , Maria Manuela Chaves b and Gl ´ oria Pinto a,∗ a Department of Biology & CESAM – Centre for Environmental and Marine Studies, University of Aveiro, Campus Universit ´ ario de Santiago, 3810-193 Aveiro, Portugal b Molecular Ecophysiology Lab., ITQB (Instituto de Tecnologia Qu´ ımica e Biol ´ ogica), 2780-901 Oeiras, Portugal c Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, 08028 Barcelona, Spain d Institute of Experimental and Technological Biology (IBET), 2781-901 Oeiras, Portugal e Altri Florestal SA, Quinta do Furadouro, 2510-582 Olho Marinho, Portugal Correspondence *Corresponding author, e-mail: gpinto@ua.pt Received 26 August 2013; revised 9 September 2013 doi:10.1111/ppl.12110 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 φ PSII ), 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 (φ PSII , 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, φ PSII and NPQ) compared to clone AL-18. Abbreviations – 1-day Rec, 1-day recovery; 1-week Rec, 1-week recovery; ABA, abscisic acid; HPLC MS/MS, high-performance liquid chromatography tandem mass spectrometry; Max Stress, maximum stress; MDA, malondialdehyde; MRM, multiple reaction monitoring; NPQ, non-photochemical quenching; PCA, principal components analysis; PPFD, photosynthetic photon flux density; PSII, photosystem II; PTFE, polytetrafluoroethylene; RWC, relative water content; TBA, thiobarbituric acid; TCA, trichloroacetic acid; VPD, vapor pressure deficit; WS, water stressed; WW, well-watered. 580 Physiol. Plant. 150, 2014