Abstract
The influence of stress factors on a plant may lead to worse functioning of the plant and the loss of its crop. The effect of Aulacorthum solani feeding on Trollius europaeus with regard to active compounds in the leaves was investigated in the study. The antioxidant activity of the leaves, the material on which the insects fed, was compared with that of the material that was not infested by the aphids. Stress level was evaluated on the basis of such physiological parameters as chlorophyll fluorescence and photosynthesis activity. An increase of 34.5% in the content of polyphenolic compounds, as compared to control, was demonstrated in the material exposed to the biotic stress caused by aphids. The content of phenolic acids was 28% higher while that of flavonoids rose by 25%. The increase in polyphenolic compounds augmented the antioxidant activity of the material.