Role of reactive oxygen species-generating enzymes and hydrogen peroxide during cadmium, mercury and osmotic stresses in barley root tip

• Published in: Planta Vol. 231; no. 2; pp. 221 - 231
• Main Authors: Tamás, Ladislav, Mistrík, Igor, Huttová, Jana, Halušková, L'ubica, Valentovičová, Katarína, Zelinová, Veronika
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.01.2010; Springer Nature B.V
• Subjects: Agriculture; Barley; Biomedical and Life Sciences; Cadmium; Cadmium - toxicity; Dehydration; Ecology; Enzyme Activation - drug effects; Enzymes; Extracellular Space - drug effects; Extracellular Space - enzymology; Forestry; Gene Expression Regulation, Plant - drug effects; Hordeum - drug effects; Hordeum - enzymology; Hordeum - genetics; Hydrogen peroxide; Hydrogen Peroxide - metabolism; Hydrogen Peroxide - toxicity; Life Sciences; Mercury; Mercury - toxicity; Meristem - drug effects; Meristem - genetics; Meristem - growth & development; Meristem - metabolism; Models, Biological; Original Article; Osmotic Pressure - drug effects; Oxidases; Oxidative stress; Plant roots; Plant Sciences; Plants; Polyethylene Glycols - toxicity; Reactive oxygen species; Reactive Oxygen Species - metabolism; Root tips; Stress, Physiological - drug effects; Superoxides - metabolism; Time Factors; Water stress; Dehydrins; Aquaporins; NADPH oxidase; Superoxide dismutase; Oxalate oxidase; Peroxidase; Root growth inhibition; Water stress
• ISSN: 0032-0935; 1432-2048
• DOI: 10.1007/s00425-009-1042-z

The effect of cadmium (Cd) on the expression and activity of NADPH oxidase, peroxidase and oxalate oxidase as well as on the expression of aquaporins and dehydrins was studied in barley root tip. The root tip represented intact apical part of the barley root containing the root cap, meristems and elongation zone. Except stress induced by Cd, barley root tips were analysed after their exposure to phytotoxic concentration of mercury (Hg)-, hydrogen peroxide (H2O2)- or polyethylene glycol (PEG)-induced water stress in order to compare the Cd-induced changes with changes induced by these other stress factors. Cd, Hg, H2O2 and with some exceptions also PEG treatments caused similar alterations in the gene expression of reactive oxygen species (ROS)-generating and water deficiency-related genes, and in the activity of ROS-generating enzymes. These evidences support our opinion that ROS accumulation and water imbalance are the common symptoms of these stress factors and that the elevated production of H2O2 plays, probably as a signal molecule, a key role in the induction of plant responses to abiotic stresses in barley root tip. On the other hand, H2O2 at permanent high concentration is probably the main toxic factor during stress conditions.