Increase Helianthus annuus L. Tolerance and Accumulation of Cadmium In Vitro and it's Expression in Intact Plants

Abstract

An experiment was carried out to study cadmium tolerance at the tissue culture and whole plant levels of Helianthus annuus. Callus was initiated and maintained on Murashige and Skoog medium (MS) supplemented with 0.2 mg.L-1 Kinetin (KIN), 0.4 mg.L-1 Naphthalene acetic acid (NAA) and 0.5 mg.L-1 2,4- dichlorophenoxy acetic acid (2,4-D) using hypocotyls explants for callus induction. Different concentrations of cadmium were added directly to the culture medium as a contaminants. Selected tolerant cell lines were subjected to regeneration. The concentration of cadmium accumulated in callus tissues recorded 18 ppm at 2.0 mg.L-1 of Cd. The study included the effect of the cytokinin Benzyl adenine (BA) and the auxin NAA on the number of regenerated shoots percentage from tolerant callus to Cd. Results exhibited that 71% of callus tolerant to Cd, when the combination of 1.0 mg.L-1 BA and 0.5 mg.L-1 NAA was supplemented to the medium. The effect of NAA on rooting of shoots showed that the concentration 2.0 mg.L-1 of NAA gave rooting percentage mounted to 66%. The study also included measurement of plant height and fresh weight. Maximum Cd accumulation reached 12.2 ppm in the shoots. Tolerance to Cd seems to express in the plant shoots according to the current study.