Participation of Hydrogen Sulfide in Induction of Antioxidant System in Roots of Wheat Plantlets and Their Heat Resistance by Salicylic Acid

The possible role of hydrogen sulfide as a signal mediator in the induction of heat resistance of wheat (Triticum aestivumL.) plantlets by salicylic acid (SA) has been studied. The treatment of plantlets with SA (1 and 10 mu M) or a hydrogen sulfide donor (NaHS, 0.1 and 0.25 mM) increased their resistance to damaging heating (10 min at 45 degrees C). Under the influence of SA, a transient increase in the hydrogen sulfide content occurred in roots with the maximum effect in 2-3 h after the start of treatment. The treatment of roots with SA increased the activity of superoxide dismutase (SOD), catalase, and guaiacol peroxidase in them. Under the influence of the hydrogen sulfide donor NaHS, the activity of SOD and catalase increased significantly. Also, the treatment of roots with SA and NaHS reduced the effect of the accumulation of the product of lipid peroxidation, malondialdehyde, which is caused by heating. The inhibitors of hydrogen sulfide synthesis, hydroxylamine and potassium pyruvate, partially eliminated the effects of the increase in the activity of antioxidant enzymes and the development of heat resistance caused by SA. At the same time, the combined treatment of intact plantlets with 10 mu M SA and 0.1 mM NaHS contributed to the additional increase in the activity of antioxidant enzymes and increased plantlet survival after heating. It is concluded that hydrogen sulfide participates in the implementation of the protective influence of SA on wheat plantlets under heat stress.