Biochemical changes in some deciduous tree species around Talcher thermal power station, Odisha, India

The present study was conducted to evaluate biochemical traits in leaves to assess the air pollution impact on plants caused by thermal power plant emissions. Ten species of deciduous trees were selected from study sites in different seasons. pH, chlorophyll, phenols, total soluble sugar content and proline content in fresh leaf was analyzed. The leaf wash pH content reveals moderately acidic (4.5-5.0) to highly acidic (3.5-4.5) range. Significant differences (p < 0.01) were observed in chlorophyll content according to the seasons and sites. Maximum reduction in chlorophyll was noticed at 2.5 km and 5.0 km west from the power plant. Greater reduction in chloropohyll 'b' than chlorophyll 'a' was noticed. An increase in total soluble sugars and phenols was observed at sites closer to thermal power plant in comparison to control. Highest concentration of total phenols was found in summer season in Dalbergia sissoo (1.52%), Butea monosperma (1.12%), Mangifera indica (1.2%), Tectona grandis (1.26%) and Acacia leucophloea (1.16%) at 2.5 km north from the source. Highest concentration of soluble sugar was found in Dalbergia sissoo (7.75%) during winter season. There was about 10-20 fold increase in proline content of leaves in comparison to the control.