EN
Polyphenoloxidase (PPO) plays an important role in plant resistance to insects, and in the detoxication of phenolic compounds taken in the nutrient components. Activity of PPO was examined in the ears of spring wheat and triticale. Extraction of enzymatic protein was carried out from acetone powder with the use of 0.05M phosphoric buffer of pH 7.4. The cultivars of spring wheat have possessed higher activity of PPO than cultivars of triticale. Feeding of the grain aphid has reduced this enzyme activity in the all analysed species and cultivars.