In vitro selection and plant regeneration of copper-tolerant plants from leaf explants of Nicotiana tabacum L. cv. 'Xanthi'

Abstract

Copper tolerance of Nicotiana tabacum L. var. Xanthi in vitro was achieved through plant regeneration from leaf explants on Murashige and Skoog's (MS) medium supplemented with 0.5 mg/l BA, 0.1-0.25 mg/l IAA and 60 μm Cu. Tolerant organogenic calli showed more vigorous growth in medium containing 60 μm Cu than the non-tolerant calli. Standard growth parameters such as fresh and dry weight of organogenic callus, growth tolerance index (GTI), enzyme activity (peroxidase and catalase) and copper accumulation were used as indicators of copper tolerance. The activities of peroxidase and catalase as well as estimation of protein, total amino acid and chlorophyll were greater in tolerant calli than non-tolerant ones. The GTI in the 4 weeks after the beginning of treatments yielded significant differences among the tolerant and non-tolerant organogenic callus cultures. The accumulation of copper in the tolerant calli increased significantly with an increase in copper concentration in the medium. Shoot bud regeneration was achieved in both tolerant and non-tolerant organogenic calli on MS medium containing 0.5 mg/l BA and 0.1 mg/l IAA. The tolerant regenerated shoots were rooted on half-strength basal MS medium with 60 μm Cu for selection of tolerant clones. This study may help in the selection and characterization of Cu-tolerant lines of N. tabacum cv. 'Xanthi' for building conservation strategies and also for phytoremediation programmes. © 2007 The Authors.