ANALYSIS OF THE GENETIC SPECIALIZATION OF MELAMPSORA LARICI-POPULINA WITH RAPD MARKERS Chemical constituents from fallen leaves of Populus alba × P. berolinensis Early Selection of Poplar Clones Resistant to Coryneum populinum in Vitro Culture Studies on the Antipyreiic and Analgesic Constituents of Leaves of Populus tomentosa Carr HISTOPATHOLOGY STUDIES ON INTERACTION OF POPLARS AND LEAF RUST WITH DIFFERENT COMPATIBILITIES Dynamic Changes of Active Oxygen and Related Enzymes of the Host in Interaction between the Poplar and Melampsora larici-populina CYTOLOGICAL STUDIES ON THE HOST-PATHOGEN RELATIONSHIP IN THE COURSE OF POPLAR LEAF INFECTION BY MELAMPSORA LARICI-POPULINA Role of Cell Wall Degrading Enzymes in Interaction of Poplar and Melampsora laricipopulina Poplar rust resistance study