Effect of auto exhaust emission on the phenology of Cassia siamea and Peltophorum pterocarpum growing in different areas of Karachi

Abstract

The response of plant species to different seasons and environmental pollutants is of important interest to researchers. Observations were made on Cassia siamea and Peltophorum pterocarpum plants growing in the polluted and other less polluted areas of Karachi. The phenology of C. siamea and P.pterocarpum was significantly (p highly affected by pollutants at Gulshan-e-Iqbal, Nazimabad, Shahrah-e-Faisal and M.A. Jinnah Road as compared to Karachi University Campus. Leaflet length of C. siamea was found lowest in July- September at M.A. Jinnah Road as compared to Shahrah-e-Faisal, Nazimabad, Gulshan-e-Iqbal and University Campus. Leaflet width and area of C. siamea were significantly (p March at the highly polluted sites of M.A. Jinnah Road. Leaflet length, width and area of P. pterocarpum were found lowest in October-December at M.A. Jinnah Road as compared to other areas of city and University Campus. Leave dry weight of the two species was found lowest at M.A. Jinnah Road as compared to Shahrah-e-Faisal, Nazimabad, Gulshan-e-Iqbal and University Campus. Leaf dry weight of C. siamea and P. pterocarpum was significantly (p comparatively less affected to automobile pollution of the city as compared to C. siamea. It is therefore, suggested that P. pterocarpum should be given more preference for further plantation in the city, particularly along the busy roads. Keeping such record of phenological data would be helpful in understanding the current trend of environment impact on plant growth.