In vivo and in vitro Studies on Heavy Metals Tolerance in Sesbania grandiflora L.

In an attempt to enhance heavy metal tolerance in tissue cultures and intact plant of S. grandiflora. Several experiments were carried out.Callus was induced on otyledon explants and maintained on MS medium supplemented with (0.5) mg/l BA and (2) mg/l 2,4-D.Heavy metals (Cd, Co, Cu, Cr and Zn) were added to the culture medium at different concentrations as contamination agents.Results showed that callus fresh weight decreased with increasing heavy metals concentrations in cultural medium.In order to asses these heavy metals on seed germination,  seeds were  sown in soil contaminated with different concentrations of heavy metals for 3 weeks.Result showed that germination percentage and plant height increased over time. However a reduction occurred in these parameters with increasing of heavy metals level.Atomic Absorption Spectrophotometer 5000 was used for  analysis of samples taken from whole plants and callus cultures.Levels of metals accumulated in callus were (0.001, 0.011, 0.012  and 0.013%) at (0.0, 0.05, 0.075 and 0.1) mg/l Cd respectively, (0.001, 0.008, 0.016 and 0.006%) at (0.0, 0.1, 0.25 and 0.5) mg/l Co respectively, (0.001, 0.020,    0.034 and 0.015%) at (0.0, 0.075, 0.2 and 0.5) mg/l Cu respectively, (0.001, 0.013,  0.012 and 0.010%) at   (0.0, 0.25, 0.4 and 0.5) mg/l Cr respectively and (0.027, 0.051,0.059 and 0.056%) at (0.0 , 0.75, 1.0 and 1.5) mg/l Zn respectively.Levels  of metals  accumulated  in  whole  plant  were  (0.08,  0.55,  1.11, 0.83 and 0.44%) at (0.0, 1.0, 2.0, 3.0 and 4.0) mg/Kg soil Cd respectively, (0.11, 0.22,0.55,  0.47  and  0.44%)   at  (0.0,  15.0,   30.0  45.0  and   60.0)  mg/Kg   soil     Co respectively, (0.01, 0.10, 0.57, 0.58 and 0.72%) at (0.0, 25.0, 50.0, 75.0 and 100.0) mg/Kg soil Cu respectively, (0.08, 0.80, 1.28, 1.31 and 0.88%) at (0.0, 25.0,   50.0, 75.0 and 100.0) mg/Kg soil Cr respectively and (0.06, 1.11, 1.20, 1.83 and 2.22%) at (0.0,  100.0, 200.0, 300.0 and 400.0) mg/Kg soil  Zn respectively.