Silicon Stimulates Physiochemical Properties of Coriander (Coriandrum sativum L.) to Improve Growth and Yield under Salt Stress

Silicon (Si) has a principal role in mitigating the adverse effects of salt stress on plant growth; however, its effects on physiochemical properties of medicinal plants under salinity is still unknown. This study investigated the effect of Si and salinity on growth, chlorophyll and water content, the antioxidant capacity of coriander (Coriandrum sativum L.) leaves as factorial in a randomized complete block design (RCBD). Foliar application of ۵۰, ۱۰۰, and ۲۰۰ mg/L Si and ۵۰, ۱۰۰, and ۲۰۰ mM NaCl were applied on ۴-leaf plants. The results revealed reduced growth by representing lower shoot and root dry weight through progressing the salinity. ۱۰۰ and ۲۰۰ mg/L Si represented a greater role in alleviating the salinity stress on growth properties. Salinity significantly reduced chlorophyll (Chl) and relative water content (RWC), but they were improved by Si spraying. Total phenol content (TPC) and total flavonoid content (TFC) significantly increased up to ۱۰۰ mM NaCl and then decreased at ۲۰۰ mM NaCl. Salinity led to increases in catalase (CAT) and superoxide dismutase (SOD) activity, but higher Si concentration reduced them. ۱۰۰ mg/L Si and ۱۰۰ mM NaCl was the best treatment for obtaining the optimum essential oil (EO) percentage and yield. Finally, ۱۰۰ mg/L Si can be suggested to promote the plant growth and yield by changing physiochemical characteristics under medium or severe salinity.

Keywords:

essential oil yield , foliar-applied silicon , Phenolic content , Salinity