Influence of Automobile Pollution on Growth of Albizia Lebbeck (L.) Bth

Automobile exhaust emission are an important feature of urban environment contamination due to movement of high traffic density and are widely believed to have detrimental effects on plant growth. The effects of automobile exhaust emission on the germination and early seedling growth performance of Albizia lebbeck (L.) Bth. was observed. The auto emission showed negative effects on seedling height, leaf area, total plant fresh weight, total plant dry weight, root dry weight, stem dry weight, leaf dry weight, root/shoot ratio for fresh weight and root/shoot ratio for dry weight of A. lebbeck. Auto emission showed significantly (p<0.05) toxic effects on seedling growth of A. lebbeck growing in polluted sites (Tariq Road, Bahadurabad, Khalid Bin Waleed Road, Gulshan-e-Iqbal Gulshan-e-Iqbal) of city as compared to Karachi University Campus (Cleaner site). The seeds of A. lebbeck collected from the Karachi University campus, which is considered as control site showed better percentage of seed germination and seedling growth as compared to the seeds of the same species collected from the different polluted areas of the city. A high percentage of decrease in seed germination was found for the seeds collected from the Tariq Road, followed by Bahadurabad, Khalid Bin Waleed Road and Gulshan-e-Iqbal Gulshan-e-Iqbal as compared to control. Seedling length was also highly decreased for seeds of same species collected from Tariq Road as compared to control. High percentage of decrease in seedling dry weight was found for seeds of same species collected from Tariq Road, Bahadurabad, Khalid Bin Waleed Road, and Gulshan-e-Iqbal as compared to control. Root growth of A. lebbeck was significantly decreased in the polluted seedlings as compared to control. According to tolerance test it was observed that seedling growth of A. lebbeck showed lowest percentage of tolerance in samples collected from Tariq Road, followed by Bahadurabad, Khalid Bin Waleed Road and Gulshan-e- Iqbal Gulshan-e-Iqbal as compared to University Campus