SURFACE ULTRASTRUCTURE OF THE UREDINIAL STAGE OF CEROTELIUM-FICI AND ITS INFECTION PROCESS ON MULBERRY

Surface morphology of uredinia and urediniospores of Cerotelium fici ( Cast.) Arth., and its infection process in mulberry (Mol us alba L.) h ave been described using the scanning electron microscope. The uredini a of C. fici are paraphysate and bear pedicellate urediniospores. The surface morphology of urediniospore is similar to most of the rust fun gi which have pedicellate urediniospores. The infection process of C. fici on mulberry leaves differs from other rust fungi in not forming a ppressoria over the stomates. Further, the germ tube of the urediniosp ore crosses over the stomata, and sometimes forms an appressorium clos e to the stoma rather than forming over it. Thus, the present study in dicates that the formation of appressoria by C. fici on mulberry leave s is not site specific but an independent, specialized and inherent me chanism required by C. fici to penetrate the mulberry leaf cuticle and epidermis.