Effect of the foliar application of zinc oxide nanoparticles on some biochemical and physiological parameters of Trigonella foenum-graecum under salinity stress

Salinity stress is one of the environmental factors that has many negative effects on the biochemical and physiological processes of the plants. In addition, according to previous reports, nanoparticles have both negative and positive effects on different plant species. The present research evaluated the interaction effects of zinc oxide (ZnO) nanoparticles and salinity stress on two cultivars of Trigonella foenum-graecum. To this end, four levels of salinity and three levels of ZnO nanoparticles were used, followed by measuring some biochemical parameters, trigonelline, antioxidant enzymes, and some elements such as Na, K, Ca, Zn, and Fe. Based on the results, increasing salinity concentration led to a significant increase in proline and malondialdehyde in both cultivars and significantly increased protein while reducing sugar in cv. Mashhadian. At a high concentration of salinity, polyphenol oxidase, peroxidase, lipoxygenase, and phenylalanine ammonia lyase significantly increased in both cultivars. In addition, an increase in salinity concentration increased Na concentration, while it decreased K and Ca concentrations in the shoot and root in both cultivars. Overall, the interaction effects of nanoparticles and salinity stress varied due to different salinity and nanoparticle concentrations, as well as the cultivar type.