POST INFECTIONAL BIOCHEMICAL CHANGES IN SOME VARIETIES OF MULBERRY (MORUS SPP.) DUE TO ROOT ROT DISEASE CAUSED BY MACROPHOMINA PHASEOHNA

摘要

The post infectional biochemical changes in some varieties of mulberry leaves due to the infection of Macrophomina phaseolina root rot at field level under natural epiphytotic conditions was evaluated. In the present study the leaf samples from 5 yearold mulberry plants of the varieties V-1, S-36, S-13, K-2 and RFS-175 showing typical symptoms of M. phaseolina infection under field conditions on the 60th day after pruning were collected and analyzed for various biochemical parameters. The amount ofleaf moisture, total chlorophyll, total nitrogen, crude protein, total carbohydrate, total phenol, zinc, iron, calcium contents and nitrate reductase activity were estimated in the healthy and diseased leaves. There was a drastic reduction in various biochemical parameters in the leaf samples of the diseased plants. Among the parameters analyzed the maximum reduction was found in nitrate reductase (94.19 %) followed by total carbohydrate content (91.65 %) in leaves of infected plants than the healthy plants in variety V-1 and S-36, respectively. A significant increase in total phenol content was recorded in the diseased plants indicating the triggering of plant defense mechanism against the pathogen. These post infectional biochemical changes were brought out by the interference of pathogen in host metabolism during the process of pathogenesis.