NI TOXICITY ON CARNATION (DYANTHUS-CARIOPHYLLUS L CV CORRIDA) CELL-CULTURES - SELECTION OF NI TOLERANT LINES AND EFFECTS OF CA AND MG

In Dyanthus cariophyllus L. cv. Corrida, Ni toxicity was evaluated on callus growth and on the ability of cell suspensions to form colonies in Murashige and Skoog agarized medium supplemented with 4.5 mu M 2,4- dichlorophenoxyacetic acid, and 0.44 mu M 6-benzylaminopurine. Ni conc entrations higher than 0.1 and 0.01 mM were very toxic for callus and suspension cell cultures, respectively. Carnation cell lines were sele cted for resistance to Ni by stepwise exposure to increasing Ni concen trations. Callus cultures were obtained from Ni tolerant cells in susp ension and were grown in MS agarized medium. Exclusion mechanisms for Ni uptake were not found in tolerant callus. Mg but not Ca was able to ameliorate Ni toxicity in non-selected callus even if Ni cellular con centration was increased.