Аннотация:A comparative evaluation of the protective effect of humic substances (HS) derived from coal and peat towards the seedlings of common wheat Triticum aestivum L. under water deficiency conditions. Experiments have shown that HS were able to reduce in part the inhibition of wheat seedlings under water deficit caused by hyperosmotic solution of PEG-6000. The protective effect of HS was shown to enhance when the content of phenolic fragments increases; the latter might indicate the antioxidant activity of HS was the main mechanism of the protective activity of HS under water deficiency conditions.