The Effects of Atmospheric Nitrogen Dioxide and Sulphur Dioxide on the Biochemical Factors of Plant Tolerance

Abstract

Abstract Atmospheric nitrogen dioxide (NO2) and sulphur dioxide (SO2) enter leaves through stomata and follow the same diffusion pathways as carbon dioxide (CO2). During the exposure of these pollutants the plants experience changes in the levels of their biochemical constituents (such as, ascorbic acid, chlorophyll, leaf extract pH, and relative water content). Biochemical and Physiological changes in plant leaves are studied and quantified using air pollution tolerance index (APTI) formula. A plant with high APTI can be used as a tolerant, while a plant with a low APTI can be used as a crucial bio-monitor to track the level of air pollution. In the present study, APTI of 15 plants species were calculated. The leaves of the selected plants were sampled from six different locations in Punjab India. Simultaneously air quality data was collected from central pollution control board (CPCB) online monitoring portal. Among 15 species collected from Jalandhar, Amritsar, and Ludhiana, the Ficus religiosa has the highest APTI values (144.6, 176.7, and 280 respectively). Similarly in Sector 22, Sector 25 and Sector 53 of Chandigarh, Ficus benghalensis has been reported to have the highest APTI values. Moreover, the present study correlates the APTI and the concentration of gaseous air pollutants (SO2 and NO2) in the atmosphere. The APTI of the studied plant species has been found to have a negative correlation with SO2 but no significant correlation has been found with NO2. The current study provides pollutant-specific information and insights that can potentially contribute in improvement in the APTI formula.