| Abstract: | Sphacelotheca reiliana, the causal organism of sorghum head smut, develops only in actively growing host meristematic tissue. Three types of mycelium are found in a developing sorus. A thin parasitizing mycelium was intercellular with haustoria. A large, reproductive mycelium produced teliospores from the centers of the intervascular regions. The peridium consisted of a partially segmented, non-reproductive mycelium surrounded by a thin layer of host cells. The distribution of mycelium in the apical meristem determined the type of sorus produced. This mycelium was carried by the elongating cells to regions in the floral primordium at the initiation of the host reproductive cycle. Wide-spread colonization of the host apical meristem at the beginning of elongation and differentiation of the floral primordium resulted in the formation of a smooth sorus. ... |
|---|