The effect of different concentrations of salicylic acid on the pigments content, rutin and quercetin in pepper (Capsicum annuum

Salicylic acid is an antioxidant which has been used in recent years to increases the resistance of plants to deal with stresses. In this study different concentrations (0.1, 1.5, 3, 6 and 9 mM) of salicylic acid were investigated on the quantity of fresh and dry weight, chlorophyll, carotenoid, malon di aldehyde, flavonoids, rutin and quercetin in pepper (Capsicum annuum). After 5 weeks, plants were treated with different concentrations (zero, 0.1, 1.5, 3, 6 and 9 mM) of salicylic acid. The results showed that concentrations of 0.7, 1.5 and 3 mM of SA increased fresh and dry weight, chlorophyll a, b, total and carotenoid content, but concentrations 6 and 9 mM of SA decreased fresh and dry weight, chlorophyll a, b, total and carotenoid content. Concentrations of 1.5 and 3 mM of SA decreased malon dialdehyd and other aldehyde content, but concentrations 6 and 9 mM of SA increased malon dialdehyd and other aldehyde content. Concentrations of 0.1, 0.7, 1.5 and 3 mM SA caused significant increase in total flavonoids in treated leaf. The results showed that under our experimental conditions different concentrations (0.7, 1.5 and 3mM) of salicylic acid increased rutin and quercetin content. In general, according to the results, treatment of salicylic acid in low concentrations has positive effects and high concentrations has negative effects on the growth of the pepper plant.