Full Length Research Paper

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

Muhammad Shafiq¹, M. Zafar Iqbal¹, Mohammad Athar²* and Manzar Qayyum³

¹Department of Botany, University of Karachi, Karachi- 75270, Pakistan.

²California Department of Food and Agriculture, 3288 Meadowview Road, Sacramento, CA 95832, USA.

³Infinity Engineering and Technology Corporation, Research, Development and Extension Division, 4810 Black Rock Drive, Sacramento, CA 95835, USA.

*Corresponding author. E-mail: ATariq@cdfa.ca.gov. Tel: 916-262-0855. Fax: 916-262-2059.

Accepted 13 January, 2009

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<0.05) affected in the polluted environment of Karachi. Plants were 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<0.05) reduced in January-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<0.05) reduced in January-March and July-September, respectively at M.A. Jinnah Road than to other less polluted sites of the city. P. pterocarpum was found 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.

Key words: Autoexhaust emission, phenology, roadside plants, Cassia siamea, Peltophorum pterocarpum, urban pollution, Karachi, Pakistan.