EFFECT OF PB AND NION ROOT DEVELOPMENT AND BIOMASS PRODUCTION OF BLACK GRAM (Vignamungo L.): OVERCOMING THROUGH EXOGENOUS NITROGEN APPLICATION

ABSTRACT:Soil contamination with potentially toxic elements in agricultural lands, is responsible for limiting the crop productivity and food chain. This study was conducted to evaluate effect of Pb and Ni on rood development and biomass production in Black gram (Vignamungo) L. seedlings. As biomass is the criteria for cultivation of urd crop in this region due to scarcity of fodder during summer. The straw of this crop is mixed with green forage for fed to the livestock. Three concentration viz. 10, 50 and 100 µM of Pb and Ni were applied. These concentrations significantly ( < 0.05%) affected root development and biomass production of black gram as compare to control.Pb and Ni at 10 µM/L concentration resulted in less significant effect on primary roots and remains same, while 100 µM/L concentration of Pb and Ni showed more toxic effect and reduced rate increased to 54, 62% and 35 & 40% over control in 100 µM/L concentration. Tertiary roots are more affected then primary and secondary roots. In biomass, the decline rate at 100 µM/L was 58, 65% and 52, 59% in root dry weight and shoot dry weight compared to control.However, the addition of nitrogen (5 mM) somehow minimized the effect of these heavy metals. Nitrogen increased the root development and biomass content of metal treated plants. Nickel showed more toxic effects than lead. This study suggest that cultivation of Vignamungo in toxic soils, should be avoided or appropriate control measures be adopted to maintain heavy metal content of the soil below the threshold level.For this, nitrogen may be use as a good detoxifier.