The problem of impact of air pollutants on vegetation is quite complex. Our knowledge on the impact of air pollutants on different plant species comes largely from the morphological and physiological investigations. The effects of pollutants on different tropical plants have conceived relatively little attention than the tropical animals. The observations recorded in the present study on the extent of circumference of shoot axis, cortex area, pith, xylem area, fibre length, and the number of stomata/field of Abutilon indicum G.Don, Croton sparsiflorus Morong and Cassia occidentalis Linn. has clearly indicated that air pollutants emitted from the clay industry and automobile exhaust exercised a decisive influence on the above parameters. A statistical analysis of the data obtained from the study showed a significant reduction in circumference of shoot axis and xylem area of the plants. But cortex and pith areas did not show any significant variation between the control and the polluted samples.

air pollutant, particulate matter, shoot axis, vessels, stomata