Interactive Effects of Salinity and ZnO Nanoparticles on Physiological and Molecular Parameters of Rapeseed (Brassica napus L.)

Salinity is considered as the main factor limiting the yield of crops in arid and semi-arid regions. There are still many uncertainties about the nanotechnology and its potential applications, as well as doubts about its efficacy and safety in the long term. The aim of this study was to examine the alleviative effects of ZnO NPs (nanoparticles) (0, 20 and 80 mgL−1) on toxicity damage caused by NaCl (0, 50 and 100 mM) at physiological and molecular parameters in Rapeseed. Rapeseed plants were treated at the rosette stage by different levels of salinity and ZnO NPs based on a completely randomized design (CRD) with three replications. At the physiological level, salinity stress significantly increased root ion leakage and decreased relative water content (RWC), stomata density and Hill reaction while application of ZnO NPs improved Hill reaction, and reduced ion leakage. At the molecular level, salinity stress significantly reduced the expression of ARP, MYC and SKRD2 genes compared to non-stressed plants while MPK4 gene expression increased under a high level of NaCl imposition. Foliar spraying of ZnO NPs considerably decreased the expression of MYC, MPK4, and SKRD2 genes and increased the expression of the ARP gene. It can be concluded that ZnO NPs had the ability to reduce the toxicity created under salinity stress at the optimal concentration (20 mgL−1) in rapeseed and could play an important role in increasing the resistance of rapeseed plants to salinity stress.