It is shown that aqueous extracts from bird cherry tree Padus avium L., aspen Populus tremula L., and celandine Chelidonium majus L., effectivily suppress the germination of Puccinia triticina Eriks uredospores. Fungitoxic activity of the extracts is supposed to be determined by high content of phenolic compounds and high peroxidase activity in the leaves of these plants. Fungitoxic activity of the extracts from the leaves, inflorescences, roots, and stems of siberian cowparsnip Heracleum sibiricum L., was also correlated with the content of phenolic compounds in these organs. Treatment of healthy wheat Triticum aestivum L., cv. Lyubava, with the extracts from common comfrey Symphytum officinale L., cowparsnip Heracleum sibiricum L., and giant knotweed Reynoutria sashalinensis (F. Schmitt) Nakai, stimulated the photosynthetic activity in treated leaves.

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Spraying of wheat seedlings with aqueous preparations of CGA 245704 (BION) caused a slight decrease in chlorophyll content accompanied by the stable increase in the rate of O₂ evolution per chlorophyll. Stimulant effect of BION on photosynthetic activity depended on both the ai concentration and number of treatments. Biophysical methods based on the registration of slow fluorescence induction and thermoluminescence of wheat leaves revealed the stimulation of photosystem II activity and the increase in the rate of electron transport between the photosystems in treated plants. It is also shown that BION itself can show a partial fungitoxic activity because it slowed down the germination of Erysiphe graminis f.sp. tritici fungi. This is obviously the reason for partial protective effect of BION when it was applied after the inoculation of wheat seedlings with the pathogen.