Abstract: Air Pollution Tolerance Index (APTI) is used by landscapers to select plant species tolerant to air pollution. To develop the usefulness of plants as bioindicators requires an appropriate selection of plant species which entail an utmost importance for a particular situation. Four physiological and biochemical parameters including leaf relative water content (RWC), ascorbic acid (AA) content, total leaf chlorophyll (TCh) and leaf extract pH were used to develop an APTI. The present study was designed to categorise trees commonly used as roadside plantations, as sensitive or resistant based on their air pollution tolerance index (APTI) values. The study area selected for the same was the educational hub of Gujarat State i.e. Vidyanagar. The seasonal variations in the APTI values of the selected tree species were studied. From the present study the order of tolerance of the selected tree species was Cassia renigera>Cassia fistula> Delonix regia>Azadirachta indica >Samanea saman >Ficus religiosa >Albizzia amara >Peltophorum pterocarpum>Lagerstroemia indica>Pongamia pinnata. It could be also noted that the tree species belonging to Cesalpinaceae family showed greater tolerance to air pollution as compared to other trees. The results of such studies are handy for future town planning.
Keywords: Air Pollution Tolerance Index, Relative Water Content, Ascorbic Acid, pH, tolerance, bioinidicators