Physiological and Biochemical Responses of Calotropis procera to Traffic Related Cadmium Pollution along Roadside

摘要

The vehicles as a source of metal pollution have tremendous adverse effects on flora and fauna. Automobiles have recently increased the concentration of metal pollutants in urban areas and along the highway. This study determined the concentration of cadmium (Cd) released from the transport sector and its negative effects on Calotropis procera L. were determined along two major roads with diverse traffic volume i.e., Faisalabad to Gojra Motorway (M-4) and Gojra-Jhang Road (GJR) Punjab, Pakistan. Significant inhibitory changes were noted in the photosynthetic and transpiration rates of C. procera leaves along roads. Similarly, chlorophyll a, b, total chlorophyll and carotenoids were also significantly lower. Whereas, hydrogen peroxide, malondialdehyde, and total phenolic contents exhibited a stimulatory response. The Cd concentration (2.26 ± 0.40) in leaves of C. procera and soil (5.19 ± 0.30) remained higher along Gojra-Jhang road compared to Faisalabad-Gojra motorway. The Cd concentration was positively correlated indicative of having a strong contribution of vehicular traffic load. The correlation of different physiological and biochemical characteristics of plant with traffic load was significant that suggested the direct impact of vehicle exhaust on C. procera and showed the high tendency of plants to survive under metal-contaminated environment along roads.