Root uptake/foliar uptake in a natural ecosystem

Abstract

The leaves of native tree species (sylva) and their associated soil samples were collected from Western Ghats, India, and analyzed to comprehend the mechanism of radionuclide uptake. For comparison, prominent tree species of the region, Elaeocarpus oblongus and Michelia nilagirica (tall trees), Vaccinium neilgherrense and Viburnum hebanthum (short trees), Lasianthus coffeoiaes and Hedyotis stylosa (bushes), and Cymbidium aloifolium (an orchid), were sampled, and the concentration of radionuclides in the plant and soil was measured using a gamma-ray spectrometer and an alpha counter selected for analysis. The activity concentration ratio (CR) of radionuclides in the plants from the underlying soil was calculated and found to vary widely within plants and between plants. CR values indicate the variation of radionuclide accumulation in various species, while E. oblongus, Evodia roxburghiana, and C. aloifolium exhibited preferential uptake of radionuclides. The dust particles trapped in the root system of C. aloifolium could be used as a bioindicator to monitor fallout radionuclides in the Western Ghats.