Salinity stress alleviation by use of silicon in Ocimum basilicum L.: an approach based on enhancing antioxidant responses

Basil (Ocimum basilicum L.) is one of the valuable medicinal plants. Negative effects of NaCl stress on plants have been reported and silicon may alleviate these negative effects through promoting antioxidant system. This study was conducted to investigate the effects of silicon as elicitor and NaCl as salinity stress on some morphological, biochemical, and antioxidant parameters in basil plant. The plants were pretreated with silicon (0, 0.5, and 1.50 mM) and submitted to NaCl stress (0, 50 and 100 mM). Results showed that NaCl stress decreased dry and fresh weight of shoot and root, cholorophyll and carbohydrate content, but carotenoid, hydrogen peroxide (H2O2) content, superoxide dismutase (SOD) and catalase (CAT) activity increased (p<0.05). Silicon also increased dry and fresh weight of shoot and root, carotenoid, chlorophyll and carbohydrate content, CAT and SOD activity but H2O2 content decreased (p<0.05). Based on these results, silicon especially 1.50 mM concentration is recommended for protection of basil under NaCl stress.