SUMMARY. The mechanisms of influence of exogenous nitrogen oxide (NO) on heat resistance of wheat coleoptiles have been studied. The treatment of plant cells with nitrogen oxide donor (sodium nitroprusside) resulted in the increase of superoxide anion-radical (О2•–) generation already after 10 minutes. The inhibitor of protein biosynthesis cycloheximide did not inhibit the О2•– generation by coleoptiles caused with the NO donor whereas the inhibitor of phosphatidic acid formation (butanol-1) partially inhibited it. The treatment of coleoptiles with the calcium ionophore (А23187) or activator of inositol cycle (inositol) compensated the suppression of butanol-1 effect on NO-dependent О2•– formation. Butanol-1 has also leveled the induction of coleoptiles heat resistance caused by the NO donor, whereas calcium ionophore and inositol almost completely removed the butanol-1 effect. The possible mechanisms of participation of reactive oxygen species, phosphatidic acid and calcium ions in the realization of NO physiological effects are discussed.
Keywords: Triticum aestivum L., nitrogen oxide (NO), reactive oxygen species, NADPH oxidase, phosphatidic acid, calcium, heat resistance
