A refined technique to apply electrical currents to callus cultures.

A simple, inexpensive technique is described which can be used to pass small electrical currents of a few microamperes through callus cultures under sterile conditions without contaminating the tissue or the medium with electrode products. Application of 1 or 2 microamperes currents of either polarity stimulated growth as well as shoot regeneration in tobacco (Nicotiana tabacum var. virginica) callus cultures, indicating that these effects are due to the electrical fields set up by the exogenous currents, rather than by electrode products.