Glucose Catabolism in Normal and Autonomous Tobacco Tissue Cultures.

Callus tissue derivedI from the stem1pith of Nicotia(nia tabacumt L. cv. \Visconsin no. 38 invariably requiires a mediumii containiing an auxin and a kinin or the naturally occurring equivalent of these for growth in vitro (e.g. 2, 7). In recent vears. however, strains which have lost their requirement for one or both of these plant growth regulators have appeared spontaneously in culture. One of these, a strain derived from normal tobacco callus but now completely autonomous for kinins and auxins, has been described previously (5) and its ability to synthesize auxin-like and kinetin-like materials noted (4, 14). Strains with drastically reduced requirements for exogenously supplied growth substances are valuable since they provide a convenient means to investigate niormal and neoplastic growth in plant tissues and to assess the role played by kinilns and auxins in growth processes. Consequently. a study of the growth control mechanisms associated with the appearance of autonomy in plant tissues has been initiated; the work reported here is one aspect of that study.