DESICCATION- INDUCED CHANGES IN LIPID PEROXIDATION SUPEROXIDE LEVEL AND CELL MEMBRANE H+ATPASE ACTIVITY IN FORKED FERN ?DICRANOPTERIS LINEARIS (BURM.F.) UNDERW.

Desiccating environments pose physiological challenges to plants, especially those experiencing them on recurring basis. Many desiccation-tolerant organisms are known to withstand loss of body water in response to seasonal dehydration events through adaptations that facilitate their survival in the dry state followed by recurring back upon favourable conditions. Free radical-induced non-enzymatic peroxidation leads to damage membranes, enzymes and nucleic acids and it is likely to be the major causes of injury during desiccation of plants. Protective mechanisms to scavenge the peroxidatively-produced free radicals and peroxides have evolved within plants, keeping these reactive molecules to minimum. The extent of drought tolerance varies from species to species. The formation of superoxide radical (O2??), hydroxyl radical (OH?), hydrogen peroxide (H2O2) and singlet oxygen (1O2) are common physiological events noticed with desiccation. In this juncture, the objective of this study is to analyze the desiccation stress induced features from 2nd day to 10th day of the terrestrial forked fern ?Dicranopteris linearis. The hydrogen peroxide (H2O2) and superoxide radical (O2??), showed a remarkable increase in the treated groups when compared to control revealing its role as signaling cascade. Peroxidation of membrane lipids is a sensitive diagnostic index of oxidative stress. Lipid peroxidation levels in the analysis showed an initial rise and subsequently decreased at par with the control indicating the active anti-oxidative machinery operating in the plant. The H+ATPase in the plasma membrane showed an increased activity throughout the treatment period. The enhanced H+ATPase may be due to the plant?s adaptation in maintaining transportation normal in cells. Abrupt changes in the lipid peroxidation levels due dehydration rehydration treatments may also induce the increase in the plasmalemma H+ATPase activity. Thus, the present results indicate the oxidative stress happened in the plant due to induced ROSs synthesis. Maintenance of lipid peroxidation and increased membrane bound H+ATPase activity throws light into the desiccation adaptation of the plant.