Stress-Protective Responses of Wheat and Rye Seedlings Whose Chilling Resistance Was Induced with a Donor of Hydrogen Sulfide

The effect of sodium hydrosulfide (NaHS) as a donor of hydrogen sulfide on the resistance to subzero temperatures was investigated in the seedlings of winter wheat (Triticum aestivum L.) and rye (Secale cereale L.). Treatment of nonhardened seedlings with NaHS at concentrations of 0.1 and 0.5 mM improved their survival after freezing at –5°С. Exposure to NaHS at the same concentrations also improved the survival of wheat and rye seedlings hardened at 2–4°С after their freezing at –9°С. Under the effect of the hydrogen sulfide donor, the seedlings of both species at normal temperature (20–22°С) and upon cold hardening accumulated more sugars and proline. After sodium hydrosulfide treatment, the content of anthocyanins rose only in wheat seedlings. The donor of hydrogen sulfide also induced a rise in the activity of catalase and guaiacol peroxidase in the seedlings of both species at normal and hardening temperatures, while the activity of superoxide dismutase remained essentially the same. Under the effect of NaHS, both species accumulated less malonic dialdehyde caused by cryogenic stress. The contribution of different components of stress-protective systems to chilling resistance induced by hydrogen sulfide and hardening is discussed in relation to plant species.