Traffic density, climatic conditions and seasonal growth of Samanea saman (Jacq.) Merr. on different polluted roads of Karachi city

摘要

A study was conducted during July 2008 to May 2009 to investigate the effects of traffic density and climatic conditions on the growth of Samanea saman (Jacq.) Merr., growing along different polluted roads of Karachi. Reduction in growth parameters such as leaf area, leaf fresh and dry weight, pods length, breadth, weight, seed length, breadth, weight and number of seeds per pod of S. saman were recorded at University Campus, University road, Board office road, Shaheed-e-millat road and Shahrah-e-Faisal during different seasons of the year. Some visual observations as canopy, fruit, seed production and leaf color were also recorded periodically which showed variation at different sites. Results indicated that S. saman at control site are growing as fast as they are given the favorable resources such as climatic factors which includes heat index, chill, humidity, temperature and wind speed available to them but road-side pollution stressed the growth. Climatic conditions were comparatively different on the city roads as compared to University Campus. The automobiles density has significantly (p0.05) reduced the leaf area of S. saman at Shahrah-e-Faisal in summer season. This might be that during summer, growth was already slow, therefore the effects of pollutants on plants were more pronounced. These findings demonstrated that traffic density and harsh climatic conditions showed poor appearance and reduction in the reproductive parts and biomass of S. saman.