PHYTOREMEDIATION POTENTIAL OF CATHARANTHUS ROSEUS L. AND EFFECTS OF LEAD (Pb) TOXICITY ON ITS MORPHO-ANATOMICAL FEATURES

Abstract

This research work was conducted to explore some morpho-anatomical features of periwinkle (Catharanthusroseus L.) that are affected by lead toxicity. Pb pollution is a common problem in Lahore and its surroundings. Untreated industrial waste is disposed in the rivers and canals which causes high levels of Pb in waters and soils in Pakistan. An economically and medicinally important plant species was exposed to different concentrations of Pb (NO3)2 and various morphoanatomical parameters were checked in order to observe the accumulation and the extent of toxicity of this heavy metal in treated plants. The parameters included root, shoot and leaf anatomies, chlorophyll estimation, and changes in structures of tissues. Atomic Absorption Spetroscopy was also done to observe the estimated amounts of metal accumulated in different tissues of treated plants. Results showed that the applications of higher concentrations of Pb caused reduction in sizes of cells, especially in the vascular tissues of roots and stems; this was an indication that Pb was accumulated in the treated plants. It was also observed that the accumulation of this metal was higher in roots than the aerial parts. Hence, the treated plant species appeared to be affected by exposure to higher concentrations of Pb without any considerable harm to its anatomy and physiology. Periwinkle, a medicinally and ornamentally important plant, can be a potential accumulator of Pb and can be used in excluding toxic metals from the contaminated soils although further research is required in this regard.