HISTOPATHOLOGICAL CHANGES IN RESPONSE TO Ceratocystis manginecans IN MANGO (Mangifera indica)

摘要

Ceratocystis manginecans is a destructive systemic fungus and a major cause of mango sudden decline. Heavy losses to the mango industry in Pakistan are due to this disease. This study was designed to evaluate the histological changes in mango seedlings inoculated with C. manginecans. The pathogenic fungus was inoculated to indigenous mango germplasm of Punjab, Azad Jammu and Kashmir. After one week of inoculation, plants started showing disease symptoms including gum exudation, wilting of leaves, discoloration of stem, and bark splitting. Discolored bark from diseased plants was peeled off and internal symptoms were studied and confirmed for C. manginecans infection. Diseased stems were transversely sliced and fixed in formaline acetic alcohol (FAA), double stained and examined under compound microscope. The epidermal tissues were found to be collapsed due to sclertization of xylem vessels, fungal hyphal growth, production of phenolics and tyloses. Deposition of phenolics and formation of tyloses in turns leads to the obstruction of water and minerals uptake, therefore, plants start wilting and then decline.