title: Hydrogen peroxide is involved in the acclimation of the Mediterranean shrub, Cistus albidus L., to summer drought.
abstract: This study evaluated the possible role of hydrogen peroxide (H(2)O(2)) in the acclimation of a Mediterranean shrub, Cistus albidus L., to summer drought growing under Mediterranean field conditions. For this purpose, changes in H(2)O(2) concentrations and localization throughout a year were analysed. H(2)O(2) changes in response to environmental conditions in parallel with changes in abscisic acid (ABA) and oxidative stress markers, together with lignin accumulation, xylem and sclerenchyma differentiation, and leaf area were also investigated. During the summer drought, leaf H(2)O(2) concentrations increased 11-fold, reaching values of 10 micromol g(-1) dry weight (DW). This increase occurred mainly in mesophyll cell walls, xylem vessels, and sclerenchyma cells in the differentiation stage. An increase in ABA levels preceded that of H(2)O(2), but both peaked at the same time in conditions of prolonged stress. C. albidus plants tolerated high concentrations of H(2)O(2) because of its localization in the apoplast of mesophyll cells, xylem vessels, and in differentiating sclerenchyma cells. The increase in ABA, and consequently of H(2)O(2), in plants subjected to drought stress might induce a 3.5-fold increase in ascorbic acid (AA), which maintained and even decreased its oxidative status, thus protecting plants from oxidative damage. After recovery from drought following late-summer and autumn rainfall, a decrease in ABA, H(2)O(2), and AA to their basal levels (approximately 60 pmol g(-1) DW, approximately 1 micromol g(-1) DW, and approximately 20 micromol g(-1) DW) was observed.
authors.affiliation: Departament de Biologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Avinguda Diagonal 645, 08028 Barcelona, Spain. tanajubany@ub.edu
authors.forename: Tana
authors.initials: T
authors.lastname: Jubany-Marí
authors.forename: Sergi
authors.initials: S
authors.lastname: Munné-Bosch
authors.forename: Marta
authors.initials: M
authors.lastname: López-Carbonell
authors.forename: Leonor
authors.initials: L
authors.lastname: Alegre
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000064:Acclimatization; D029758:Cistus / Q000502:physiology*; D055864:Droughts; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism; D019083:Mediterranean Region; D018384:Oxidative Stress; D018515:Plant Leaves / Q000378:metabolism; D012621:Seasons; D052584:Xylem / Q000378:metabolism
chemical_list: D000040:Abscisic Acid; D008031:Lignin; D006861:Hydrogen Peroxide