Superoxide production induced by short-term exposure of barley roots to cadmium, auxin, alloxan and sodium dodecyl sulfate.
Abiotic stress-induced superoxide generation depending on its localization, level, duration and presumably also on the action of other signals may lead to different stress responses. The purpose of this study was to analyze the alterations in superoxide generation and morphogenesis following short-term Cd, IAA and alloxan treatments, during stress and recovery period in barley root tips. At low Cd concentration the transient accumulation of superoxide in the epidermal cells was accompanied by root growth inhibition and radial expansion of cortical cells in the elongation zone of root tips. These morphological changes were very similar to the externally applied IAA-induced responses. However, the role of superoxide generated in the epidermal cells by low concentration of Cd and IAA is probably alone not sufficient for the induction of these processes. SDS as an activator of NOX activity caused a strong accumulation of superoxide in the epidermal cells along the whole root apex but without any changes in root morphology and growth. On the other hand, higher Cd concentrations as well as alloxan stimulated the generation of superoxide in the cortical tissue of the elongation zone of root tip, which was accompanied by the induction of cell death. Our results suggest that enhanced superoxide generation, depending on its localization, level, duration and presumably also on the action of other signals, may lead to altered root morphology (15 μM Cd or IAA), root growth inhibition (alloxan), transient root growth cessation (30 μM Cd) or to the death of cells/root at higher (60 μM) Cd concentrations.
Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, 84523 Bratislava, Slovak Republic.
L'ubica
L
Liptáková
Beáta
B
Bočová
Jana
J
Huttová
Igor
I
Mistrík
Ladislav
L
Tamás
D000496:Alloxan / Q000494:pharmacology*; D002104:Cadmium / Q000494:pharmacology*; D016923:Cell Death; D004789:Enzyme Activation; D001467:Hordeum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D007210:Indoleacetic Acids / Q000494:pharmacology*; D019255:NADPH Oxidases / Q000378:metabolism; D059828:Plant Cells / Q000187:drug effects / Q000378:metabolism; D019441:Plant Epidermis / Q000187:drug effects / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology*; D013312:Stress, Physiological; D013481:Superoxides / Q000378:metabolism*; D013997:Time Factors
D007210:Indoleacetic Acids; D002104:Cadmium; D013481:Superoxides; D012967:Sodium Dodecyl Sulfate; D000496:Alloxan; D019255:NADPH Oxidases