Microscopic Observations on Fungi Associated with Cotton Boll-Rot Fibers

SUMMARY

Cotton boll-rot fibers were examined microscopically to determine the manner in which fungi grow on them. Cellulose decomposing boll-rot fungi wound around the fibers, paralleling closely the helical structure of the secondary wall; non-cellulose decomposers did not wind. Cellulose decomposers penetrated through the secondary walls and grew in the lumens; non-cellulose decomposers did not. Some fungi formed spores in the lumens. Mounting fibers in NaOH solutions made fungi easier to see, as did differential staining with Niagara Sky Blue 6B or mounting in cuprien. The cuprien caused swelling of the cellulose or its complete solution without visibly attacking the fungus.