The Combined Influence of Zinc and Epibrassinolide Increase Tolerance to Salt Stress in Brassica napus L.

Abstract

The separate foliar application of zinc (Zn) and epibrassinolide (EBL) have widely proved tolerance to several abiotic stresses, but their combined effect exposed to oxidative stress is an untouched area of investigation. In order to evaluate the physiological mechanism of salt stress tolerance, a pot experiment was conducted. The results revealed that chlorophyll content, efficiency of photosystem ΙΙ, total leaf area, total biomass, membrane stability index and relative water content decreased under 100 mM NaCl concentration whereas, the foliar application of Zn and EBL alone and in combination increased these parameters. In addition, an increase in accumulation of osmoprotectants and antioxidant enzymes activity was noted under stressed conditions, which was more pronounced in rapeseed plants (Brassica napus L.) treated with combined application of Zn and EBL. Salt stress increased H₂O₂ and MDA content, while the exogenous application of Zn and EBL decreased these oxidative stress markers. It is concluded that Zinc and EBL reduced toxic effect of salinity, while its combined application showed an additive effect and significantly enhanced salt tolerance.