The effect of different concentrations of salicylic acid on protective enzyme activities of pepper (Capsicum annuum L.) plants.

The objective of this study was to investigate the effects of different concentration (0, 0.1, 0.7, 1.5, 3, 6 and 9 mM) of SA on antioxidant enzymes in Capsicum annuum L. plants. Enzyme activities of peroxidase, polyphenol oxidase, ascorbate peroxidase, catalase and glutathione reductase were measured. The plants were grown in pots vermiculite. Before applying the salicylic acid treatments, plants filled with were irrigated with based nutrient solution (Hoagland solution) for 5 weeks. After 5 weeks, plants were sprayed with different concentrations (0, 0.1, 1.5, 3, 6 and 9 mM) of salicylic acid. Data were analyzed using SPSS software and means were compared by Duncan test. In each experiment 4 replicats were used. Concentrations of 1.5, 3, 6 and 9 mM of SA caused significant increase in polyphenol oxidase and peroxidase enzyme activities in treated leaves. Concentrations of 0.7, 1.5 ad 3 mM of SA decreased in (catalase, ascorbate peroxidase and glutathione reductase) activities, but concentrations of 6 and 9 Mm of SA increased enzyme activities. Different concentrations of salicylic acid had different effects on enzyme activities in Capsicum annuum L.