Induction of heat resistance of wheat coleoptiles by salicylic and succinic acids: Connection of the effect with the generation and neutralization of reactive oxygen species

The influence of salicylic (SaA) and succinic (SuA) acids on the generation of active oxygen forms (AOFs) and the heat resistance of wheat (Triticum aestivum L.) coleoptiles has been studied. The treatment of coleoptiles with 10 microM SaA or SuA results in the accumulation of hydrogen peroxide and enhanced formation of a superoxide anion radical. This effect is partially suppressed by both alpha-naphthol (the NADPH oxidase inhibitor) and salicylhydroxamic acid (peroxidase inhibitor). SaA and SuA cause an increase in the activity of antioxidant enzymes, such as superoxide dismutase, catalase, and soluble peroxidase, and improve the heat resistance ofcoleoptiles. Antioxidant ionol and compounds, which inhibit the NADPH oxidase and peroxidase, significantly reduce the positive influence of SaA and SuA on the heat resistance of wheat coleoptiles. AOFs are considered to be intermediates for heat resistance induction in coleoptiles, treated with SaA and SuA; enhanced AOF generation can be caused by an increased activity of the NADPH oxidase and peroxidase.