INFLUENCE OF Polystigma rubrum (Pers.) D.C ATTACK ON SOME BIOCHEMICAL PARAMETERS IN DIFFERENT PLUM CULTIVARS

The aim of this study is to evaluate the effects of the influence of Polystigma rubrum attack on some enzymes (catalase, peroxidase and polyphenol oxydase) activity from healthy and attacked leaves of the following plum cultivars with different degrees of resistance to diseases attack: Poroabe and Vinete romaneúti (sensitive cultivars), Renclod violet and Grase romaneúti (middle-resistant cultivars) and Renclod verde (resistant cultivar), during the year 2008. The pathogen Polystigma rubrum determined a peroxidase activity variation in all plum cultivars according to these phenophases registering a growth of its in the initial attack phase and a decrease in the intermediate and final phases, in the attcked leveas. The peroxidase activity was higher in healthy leaves comparatively with the attacked leaves. The evolution of catalase activity depending on the attack evolution but can established modifications from one cultivars to another. Analyzing the dynamic of polyphenol oxydase activity we observed that Polystigma rubrum produced some variations of this enzyme activity in all plum cultivars and recorded significant increases in the attacked leaves in the initial phase and terminal phase of attack of this fungus. In generally, it can not established a correlation between oxidoreductases activity and the degree of resistance of the plum cultivars to attack of Polystigma rubrum.