Improved productivity and quality associated with salicylic acid application in greenhouse pepper

Previous studies have shown that salicylic acid (SA) plays a role in the response of plants to diverse conditions. Therefore, a factorial experiment block design was conducted to investigate the effects of foliar spray of salicylic acid (10⁻⁶ and 10⁻⁴ M) on fruit productivity and quality of pepper grown in a moderately salt-stressed greenhouse. SA application at low concentration (10⁻⁶ M) positively increased the foliage fresh and dry weight, fruit number, average fruit weight, fruit yield, vitamin C, carotenoids content, cuticle thickness of fruit pericarip and translocation of sugars from leaves to fruits. It was found that SA treatment (10⁻⁶ M) caused a reduction in peroxidase and increasing of invertase activities of pepper leaves and fruits. According to these results it is expected that, SA treatment regulated sugar contents (translocation from source to sink) and antioxidants and thus reduced stress-induced inhibition of plant growth.