An Electron Microscope Study of the Outer Layers of Barley Leaves Infected with Rhynchosporium secalis

Abstract

An electron microscopic examination was made of barley leaves before and after infection by R. secalis. Ruthenium red was used as an electron-opaque stain for pectic material. In uninfected leaves the adaxial surface consisted of wax, cuticle, pectic and inner and outer layer of the epidermal cell wall. Following penetration, infecting hyphae grew between the pectic layer and outer layer of the epidermal wall. The pectic and cuticular layers remained largely intact in leaf lesions until conidia were produced, whereas the cell wall was degraded and replaced by hyphae.