Role of reactive oxygen species-generating enzymes and hydrogen peroxide during cadmium, mercury and osmotic stresses in barley root tip.
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.
Tamás
Ladislav
L
Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 14, 84523 Bratislava, Slovak Republic. Ladislav.Tamas@savba.sk
Mistrík
Igor
I
Huttová
Jana
J
Halusková
L'ubica
L
Valentovicová
Katarína
K
Zelinová
Veronika
V
D002104:Cadmium / Q000633:toxicity*; D003681:Dehydration; D004789:Enzyme Activation / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000201:enzymology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D001467:Hordeum / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000633:toxicity; D008628:Mercury / Q000633:toxicity*; D018519:Meristem / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008954:Models, Biological; D009997:Osmotic Pressure / Q000187:drug effects; D011092:Polyethylene Glycols / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013312:Stress, Physiological / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors
D017382:Reactive Oxygen Species; D002104:Cadmium; D013481:Superoxides; D011092:Polyethylene Glycols; D006861:Hydrogen Peroxide; D008628:Mercury