OPTIMAL CONDITIONS FOR CELL SUSPENSION CULTURES OF THLASPI CAERULESCENS AND BRASSICA NAPUS

Thlaspi caerulescens (Brassicaceae), known as a Zn hyper accumulator, is able to accumulate and tolerate Zn, Ni, Cu, and Cd at high concentrations in its biomass. We are examining the feasibility of using cell suspensions of T. caerulescens and B. napus to study the effect of selected heavy metals on growth and nutrient uptake. Callus was initiated by culturing seedlings on basal medium containing MS salts supplemented with MS or B5 vitamins, 1, 2, 5, or 10 mg 2,4-D/liter, and 0.7% Phytagar. Cell suspensions were initiated by transferring calli to liquid basal medium containing MS or B5 vitamins, and 1 or 2 mg 2,4-D/liter, and were incubated on a gyratory shaker at 120 rpm. Growth of suspensions inoculated at 0.2, 0.4, or 0.6 g/25 ml was monitored for 13 days. Optimal conditions required to initiate and maintain suspension cultures of T. caerulescens and B. napus include MS medium supplemented with B5 vitamins and 1 mg 2,4-D/liter, an inoculation density of 0.4 g/25 ml, and a 2-week subculture schedule.