Enhancemant of Sesbania rostrata Capability for Cadmium and Lead Tolerance by Tissue Culture

Abstract

Several experiments were carried out to study cadmium and lead tolerance at the tissue culture or whole plant levels of Sesbania rostrata. Callus was induced and maintained on Murashige and Skooge, 1962 medium (MS) supplemented with 0.3 mg/l Kinetin and 2 mg/l 2,4- dichloro  phenoxy acetic acid (2,4-D). Using cotyledons as the source for callus induction. Different concentration of cadmium and lead directly or gradually were added to the culture medium as contaminants. Selected tolerant cell lines were subjected to regeneration. Callus showed better tolerance to gradual exposure than direct addition. The concentration of cadmium and lead recorded to 27 and 24 ppm when 1.0 and 2.0 mg/ of cadmium and lead respectively. The study included the effect of  cytokinins (benzyl adenine) and auxin (Naphthalene acetic acid) in the regeneration of shoot from callus tolerant to pollutants reached 78 and 76%  for Callus tolerant to  lead and cadmium respectively, when the combination of 0.7 mg/l benzyl adenine and 0.2 mg /l  naphthalene acetic acid was supplemented to the medium. The effect of auxin (indole butyric acid) on rooting of shoots was studied. The concentration 0.7 mg/l gave highest percentage of rooting amounted to 70 and 66% in the medium supplement with lead and cadmium respectively. The study was also included effect of pollutants on plant height and fresh weights shoot fresh weight was superior at the concentration 1.0 and 2.0 ppm of cadmium and lead recording 8.7 and 7.5 g respectively. Maximum cadmium accumulation reached 12.5 ppm in shoot while, 10.5ppm for lead was in roots.