Effect of particulate pollution on rate of transpiration in Shorea robusta at Lalpahari forest

The effect of stone dust deposition on the rate of transpiration in Shorea robusta was studied in three principal seasons in a polluted forest in comparison to an almost non-polluted forest. The extent of particulate pollution was determined by measuring suspended particulate matter in the air and dust fall on leaf surface. Macroscopic and microscopic leaf injury symptoms were studied. Scanning electron microscopic examination of leaf surfaces revealed a number of foliar anomalies. Qualitative determination of rate of transpiration in field condition was done by ‘cobalt chloride method’. It was found that transpiration was diminished as a result of foliar dust deposition which not only caused blockage of stomatal aperture but also physical damage to the leaf surface. Thus, particulate air pollution can be considered as one of the external factors regulating the rate of transpiration in plants.