EFFECTS OF GENOTYPE AND EXPLANT DURING IN-VITRO RESPONSE TO CADMIUM STRESS AND VARIATION IN PROTEIN AND PROLINE CONTENTS IN LINSEED

The effects of genotype and explants in influencing in vitro growth in the presence and absence of a selection pressure, viz. the heavy meta l cadmium were studied. The response to callus-induction and organogen esis by different explants of three Indian cultivars of linseed (Limum usitatissimum) viz. Garima, Gaurav, and Kiran was investigated. Of th e explants, hypocotyl gave the best in vitro response. Among the culti vars under control conditions (O Cd), Gaurav and Garima fared much bet ter in callusing response compared to Kiran, but Garima and Kiran show ed higher organogenetic potential. However, in the presence of Cd (100 mu M) callusing was not appreciably affected in any of the cultivars, but organogenesis was highly inhibited in both Garima and Gaurav; Kir an appeared to be least affected by the presence of Cd. Genotype, expl ant, and genotype-explant interactions had highly significant effects on both callusing and organogenesis, but cadmium treatment had a great er effect on organogenesis. To estimate the stress responses due to ca dmium treatment, the total protein and proline content in callus lines of the three cultivars was also studied. Both parameters showed an in crease due to cadmium, but the genotypic differences in the three cult ivars remained unchanged. (C) 1997 Annals of Botany Company.