Induction and Selection of Atrazine Resistance Variants from Tobacco Cell Cultures
Photomixotrophic cell cultures of Nicotiana tabacum L. (var. Wisconsin 38) were obtained by repeated selection of cell cultures initially established from hypocotyl expiants. Attempts to induce photomixotrophic cell cultures of N. tabacum L. var. Ky 14 were not successful. Calli derived from Wisconsin 38 hypocotyls regularly produced a greening response and were used for optimizing the growth conditions for photoautotrophic and photomixotrophic cultures. Two light intensities (67 and 7.6 μE/M2 sec) and 4 sucrose concentrations (0, 0.5, 1, and 2%) were tested for optimizing chlorophyll synthesis and callus growth rate. Calli growing on media containing 0.5% sucrose gave better chlorophyll synthesis and chlorophyll a/b ratios at high light intensity than did other treatments.