(1) It was not found that Melampsora rust on poplars had an alternate host in Shanghai. The overwinter uredinia may be one of the preliminary infection sources.

(2) The occurance of Melampsora rust on poplars in Shanghai was studied. The sprouting and infestation of uredinia and telia of the pathogen were tested.

(3) The conclusions showed that:1, There were significantly differences on the variation amplitude of ROS in the different poplar varieties (species) after inoculated with Melampsora larici-populina Kleb.

(4) This thesis mainly from the following aspects to do research makes a breakthrough in the Molecular marker research on Chinese Melampsora larici-populina.

(5) Poplar is an important ecological and commercial forest tree species. Leaf rust is a major leaf disease, which is caused by Melampsora larici-populina Kleb.