Ecology, Environment and Conservation Paper

ECO-TOXICOLOGICAL IMPACT OF ATMOSPHERIC LEAD ON ROADSIDE PERENNIAL PLANTS AND RAGI SEEDLINGS IN PETRI PLATECULTURE UNDER CONTROLLED CONDITIONS

Sabita Barik, Alaka Sahu and A. K. Panigrahi

Abstract

Higher accumulation of lead in perennial old plant leaves were observed. Young plants eithershowed noresidual lead or the amount of lead if present was insignificant. No residual lead was observed in smallherbs present on both the sides of the road. Significant decrease in total chlorophyll and phaeophytincontent was recorded in plant leaves situated on the roadsides of the ghat area when compared to plantscollected from deep inside the forest area far away from freeways / highways. Insignificant decrease or nochange in carotenoid content was recorded in plant leaves collected from the plants available on the roadsidesof the ghat area. Change in leaf colour and heavy surface deposition was noted in exposed leaves of theplants. Residual lead level was untraceable in control plant leaves. Initial increment in photosynthetic ratewas observed at LC00 (MAC) of lead nitrate in petriplate culture compared to control valuefollowed bydepletion of photosynthetic rate in higher lead nitrate concentrations in petriplate culture. Tissue respirationand photosynthesis rate significantly declined in lead exposed seedlings in petriplate cultureexperimentsdepleting the productivity of the exposed seedlings when compared to control seedlings. The GPP valuedecreased in all exposed seedlings indicating the impact of the toxicant. Notable but insignificant amountof residual lead was noted in lead nitrate exposed 6day old seedlings in petriplate culture. The observedobservation in all parameters studied relates to residual lead accumulation in the seedlings which might have impacted different physiological activity in the exposed ragi seedlings.