title: Reversibility of cold- and light-stress tolerance and accompanying changes of metabolite and antioxidant levels in the two high mountain plant species Soldanella alpina and Ranunculus glacialis.
abstract: Two high mountain plants Soldanella alpina (L.) and Ranunculus glacialis (L.) were transferred from their natural environment to two different growth conditions (22 degrees C and 6 degrees C) at low elevation in order to investigate the possibility of de-acclimation to light and cold and the importance of antioxidants and metabolite levels. The results were compared with the lowland crop plant Pisum sativum (L.) as a control. Leaves of R. glacialis grown for 3 weeks at 22 degrees C were more sensitive to light-stress (defined as damage to photosynthesis, reduction of catalase activity (EC 1.11.1.6) and bleaching of chlorophyll) than leaves collected in high mountains or grown at 6 degrees C. Light-stress tolerance of S. alpina leaves was not markedly changed. Therefore, acclimation is reversible in R. glacialis leaves, but constitutive or long-lasting in S. alpina leaves. The different growth conditions induced significant changes in non-photochemical fluorescence quenching (qN) and the contents of antioxidants and xanthophyll cycle pigments. These changes did not correlate with light-stress tolerance, questioning their role for light- and cold-acclimation of both alpine species. However, ascorbate contents remained very high in leaves of S. alpina under all growth conditions (12-19% of total soluble carbon). In cold-acclimated leaves of R. glacialis, malate represented one of the most abundant compounds of total soluble carbon (22%). Malate contents declined significantly in de-acclimated leaves, suggesting a possible involvement of malate, or malate metabolism, in light-stress tolerance. Leaves of the lowland plant P. sativum were more sensitive to light-stress than the alpine species, and contained only low amounts of malate and ascorbate.
authors.affiliation: Unité Mixte de Recherche 5019 (Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Université Joseph Fourier), Département de Biologie Moléculaire et Structurale, Grenoble, France. peter.streb@eco.u-psud.fr
authors.forename: P
authors.initials: P
authors.lastname: Streb
authors.forename: S
authors.initials: S
authors.lastname: Aubert
authors.forename: E
authors.initials: E
authors.lastname: Gout
authors.forename: R
authors.initials: R
authors.lastname: Bligny
mesh_terms: D000064:Acclimatization; D000531:Altitude; D000975:Antioxidants / Q000378:metabolism*; D002338:Carotenoids / Q000378:metabolism; D003080:Cold Temperature; D008027:Light; D018515:Plant Leaves / Q000502:physiology; D029623:Primulaceae / Q000502:physiology*; D031947:Ranunculus / Q000502:physiology*
chemical_list: D000975:Antioxidants; D002338:Carotenoids