SUMMARY
The influence of microelements (B, Zn, Cu, Co, Mn) on the peroxidase and polyphenol oxidase activity in eggplant leaves and fruit was studied. Activity of the enzymes under the study varies in different phases of plant vegetation. It can be explained by the fact that eggplant bears the technically, physiologically mature and crude fruit as well as buds and blossoms together. In both the control and microelement group with the increase of the peroxidases activity the polyphenol oxidase activity decreases. Compared to the control group the polyphenol oxidase activity increased the most in the phase of vegetation of 4–5 leaves, after treatment with boron and then with cobalt. Boron and zinc have similar action on the enzyme activity. Under the action of boron the polyphenol oxidases activity especially increases in the phase of vegetation of 4–5 leaves and in the later phase decreases. The peroxidase activity changes accordingly. After pre-sowing treatment of eggplant seeds with zinc the peroxidase activity decreases in leaves (in their early phase of vegetable) and fruit. It reaches its maximum in leaves in the fruit bearing period. Under the influence of copper and cobalt the peroxidase activity in fruit increases. In leaves it increases in the late phase of vegetation. The Mn influence on the activity of polyphenol oxidase is less in the early phase of vegetation then in the late phase. In eggplants with the increase of polyphenol oxidase activity the peroxidase activity decreases