Root Growth Responses of Anagallis arvensis of the Tropical Agroecosystem to Coal Smoke Pollution

Abstract

The effect of coal smoke pollution on the root length, root biomass and net primary productivity of Anagallis arvensis growing in association with wheat cropland was studied at monthly intervals with collections from four selected sites situated at 0.5, 2, 4 and 20 Km leeward from a thermal power plant complex. The degree of loss in the root growth increased significantly with decrease in distance from the source of pollution. The trend of loss in the root length was similar in the first (seedling stage) and the second (flowering stage) collections; the adverse effect of pollutants was almost constant up to 4 km at old stage from the pollution source in the third collection (post-flowering stage), compared with the population at site 'D' situated at 20 km leeward from the source of pollution. Root biomass suffered considerably at seedling stage up to 4 Km. The trend of loss was almost similar at flowering and post-flowering stages of growth. Root biomass and net primary productivity showed a maximum loss (-45.8 to -74% and -53.8 to -76.9% respectively) at flowering stage. This correlates to high coal consumption and greater release of gaseous pollutants from the power plant during that period. The percent loss in the root growth of A. arvensis showed a linear relationship with the distance of the site from the source of pollution at any given stage. Root biomass exhibited a relatively greater degree of dependence (59 to 76%) on distance than the root length (38 to 58%).