Assessment of Cadmium & Chromium Stress on Growth, Physiology and Metal Uptake Using Mirabilis jalapa

Abstract

Phytoextraction potential of Mirabilis jalapa, with tuberous root having high ecological adoptability was studied in the present work . Different levels of cadmium and chromium stress on growth, physiology and metal uptake were studied using pot experiments. The experiment comprised of 5 dosages of cadmium and chromium with different test concentrations (TC) viz, TC1(0), TC2(25), TC3(50), TC4(75) and TC5(100) ppm, for the period of 45 days. Growth, physiological parameters and metal accumulation were estimated at 15 days intervals in root and shoot of Mirabilis jalapa. The shoot biomass of Mirabilis jalapa shown no significant reduction in both cadmium and chromium treatments of soil whereas, root biomass and physiological parameters like chlorophyll a, chlorophyll b and carotenoids were significantly reduced and shown inhibitory effect. The maximum uptake of cadmium by root and shoot was 36.2mg/kg and 48.62mg/kg in TC4 soils on day 45. The maximum uptake of chromium by root and shoot was 34.8mg/kg and 23.5mg/kg in TC4 soils on day 45. There is no inhibitory effect shown on metal uptake as it increased with increasing the dosage of heavy metals in soils. Bioconcentration factor (BCF) and Translocation factor (TF) were >1 in cadmium contaminated soils, where as in chromium contaminated soils BCF>1 but TF<1. Over all the present study can be concluded that Mirabilis jalapa could be promising accumulator and most suitable for the remediation of cadmium and chromium contaminated soils.