Production of extracellular fibers by tobacco leaf epidermal protoplasts.

Protoplasts prepared from the upper epidermis of tobacco (Nicotiana tabacum L.) leaves produce tubular structures which are highly fluorescent in the presence of Calcofluor white. The presence of Ca(2+) in the incubation medium appears to be necessary for the production of these fibers. A commercial cellulase preparation destroyed these structures and inhibited their production.