Nickel toxicity induced antioxidant enzyme and phenylalanine ammonia-lyase activities in Jatropha curcas L. cotyledons

Abstract

Jatropha curcas L. embryos were germinated and grown in vitro under nickel concentrations of 100, 200, 400 and 800 μmol to observe the effects of high nickel concentrations on seedling growth. Observed biological makers included biomass, and the activities of Superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and phenylalanine ammonia-lyase (PAL) in the cotyledons. The fresh weight of cotyledons in all the tested nickel concentrations was lower than that of the control, but dry weight of cotyledons increased with increasing nickel concentrations up to 200 μmol. SOD activity increased significantly up to 400 μmol and then decreased at 800 μmol nickel. POD activities were induced remarkably at 100 and 200 μmol, but the activity decreased with increasing nickel concentrations. Similarly, a negative link between CAT activity and nickel concentrations was observed in this experiment. PAL activity had a positive correlation to nickel concentrations, and the highest activity was found at 400 μmol nickel. Electrophoresis analysis suggested that a significant correlation between nickel concentrations and isoenzyme patterns of SOD and POD was observed, and these results were consistent with the changes of the activity assayed in solutions.