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Cytology and Histology

Histological Development of Sphacelotheca reiliana on Zea mays. C. A. Matyac, Former graduate research assistant, Department of Plant Pathology, University of Minnesota, St. Paul 55108, Present address: Department of Plant Pathology, North Carolina State University, Raleigh 27650; Phytopathology 75:924-929. Accepted for publication 24 March 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/Phyto-75-924.

Shoot apices of corn seedlings infected by Sphacelotheca reiliana are colonized in the first 6 wk after planting. This results in sorus development in mature plants in place of ears and tassels. A young sorus has a peridium consisting of a dense layer of hyphae beneath a two- to three-cell layer of host tissue. Beneath the peridium, hyphae grow abundantly between and within columns of highly vascularized host tissue. As the sorus matures the hyphae form aggregates of intercalary teliospores within a gelatinous matrix. Newly formed teliospores are covered with small rounded processes which continue to elongate as the spore enlarges, and a second group of processes begin to develop as the spore reaches maturity. Partitioning hyphae grow between the teliospore aggregates throughout their development. As the sorus emerges, the peridium deliquesces, exposing a mass of teliospores enmeshed in vascular strands of the host.