Biochemical and Physiological response of Brassica juncea and Nephrolepis exaltata in Mercury spiked soil

The current study sought to investigate the variations in the physiological functions such as Photosynthetic rate, Stomata conductance, Transpiration rate, Total Chlorophyll and the significant role of enzymatic and non-enzymatic antioxidants in eliminating the Reactive Oxygen Species (ROS) generated in response to varying concentration of mercury viz., 0 , 2.5, 5, 10 and 20 mg kg-1 in Indian mustard (Brassica juncea) and fern (Nephrolepis exaltata). Results revealed a 17.3 and 10.4 per cent reduction in chlorophyll content of Indian Mustard and Boston Fern between the 20 mg kg-1 treated plants and the control suggesting reduction in photosynthetic rate of the plant Albeit these parameters were affected, plants tolerated 20 mg kg-1 without any visual phytotoxicity symptoms. Gaseous parameters were inversely proportional to the mercury concentration whereas oxidative stress indicators and antioxidant enzymes exhibited a positive correlation. An average increase of 38 per cent Proline was observed in both plants. In B.juncea and N.exaltata, Average catalase activity and peroxidase activity ascended from 2.35 to 5.12 min-1 g-1 and 3.26 to 6.80 min-1 g-1, and 0.23 to 1.17 min-1 g-1 and 0.30 to 1.27 min-1 g-1, respectively which assures the phytoremediation potential of these plants in mercury contaminated soils.