RISK EVALUATION OF BRICK KILN SMOKE TO KIDNEY BEAN (PHASEOLUS VULGARIS)

In view of global change caused by green house gases, bean plants (Phaseolus vulgaris L.) were exposed to brick kiln smoke in close chambers under laboratory conditions. Brick kiln smoke was produced by firing bituminous coal and furnace oil. The duration of smoke exposure was 4, 8 and 12 hours on daily basis which lasted until crop maturity. Additional control plants were grown in ambient air for evaluating the 'brick kiln smoke effect on plants. A significant reduction in mean length of shoot and roots of plants exposed to smoke for 8 and 12 hours compared with the control were observed. The pollution effects were directly proportional to the intensity of the exposure. The average pore areas of stomata from plants treated for 8 and 12 hours were significantly smaller compared with control plants. The continued uptake of the gaseous pollutants through leaf stomata eventually resulted in cellular damage, which was manifested through effects on growth and the foliar characteristics. Microscopic studies of stomata revealed that a longer duration of smoke exposure resulted in deformation and destruction of stomatal shape. A critical look on the experimental data revealed that the epidermis on adaxial surface was more affected as compared with one present on abaxial surface.