Ultra-structures of the hypertrophied leaf-tissue of Plantago major L. infected with Puccinia miscanthi MIURA were studied under the electron-microscope.
Although the tips of hyphae were recognized in the region of the central vacuole of the suscept cell, the hyphae were always sorrounded and separeted from the suscept cytop lasm by a invaginated cell membrane. Nuclei, endoplasmic reticula, chloroplasts and mitochondria were found in the cytoplasmic areas of the suscept cells. Swollen, contacted and/or vacuous mitochondria were not found but developed cristae mitochondriales were observed in the mitochondria. Starch grains, osmiophilic granules and lamellar structures were recognized but grana structures were not recognized in every chloroplast.