Scanning Electron Microscopy on the Perithecial Development of Phyllactinia corylea on Mulberry-II. Sexual Stage

Development of perithecia of Phyllactinia corylea (Pers.) Karst. on mulberry (Morus spp.) leaves was examined by scanning electron microscopy. Two short specialized structures, antheridium and ascogonium, emerged from two separate hyphae, were fused with each other and developed into an egg-shaped perithecial primordia. These primordia later developed into globose immature perithecia, which covered with protruded wall cells with clear margins. A large number of hyphae emerged from near the base of globose perithecia, which radiated on the leaf surface and thus helped the perithecia to fix to the surface. Specific characteristic penicillate cells and acicular appendages originated from the immature perithecia. The penicillate cells developed with apical sterigma-like projections from the wall cells of the upper part of immature perithecia, whereas the acicular appendages originated from the shrunken wall cells at the perithecial equatorial planes. On maturation of perithecia, the acicular appendages bent down and pushed the perithecia above the substrate and thus helped them to liberate out. The sterigma-like projections were covered with paste-like granular substance, which help the dispersed perithecia to attach to mulberry leaves and branches