Fluoride toxicity triggered oxidative stress and the activation of antioxidative defence responses in Spirodela polyrhiza L. Schleiden

ABSTRACT The present study was designed to assess the fluoride mediated antioxidant defence responses in Spirodela polyrhiza, grown under hydroponic conditions. The plants of S. polyrhiza were exposed to different fluoride concentrations (0, 5, 10, 15, 20, 25, 50？ppm) for the time period 24, 72, 120 and 168？h. Fluoride was observed to be readily accumulated by S. polyrhiza at all the exposure periods. Increased accumulation of fluoride triggered the oxidative stress that was quite evident from enhanced electrolyte leakage, proline, anthocyanin and phenolic content To counterbalance the stress, plant responded by the alterations in the activities of antioxidative enzymes (SOD, CAT, APOX, POD, GR), that was also supposed to confer tolerance ability to plant. Moreover, SEM-EDX, CLSM and FT-IR studies were also performed to confirm oxidative damage. Hence, it can be elucidated that this plant can act as an efficient fluoride accumulator and antioxidant defence system minimized fluoride toxicity