Foliar application of graphene oxide, Fe, and Zn on Artemisia dracunculus L. under salinity

Abstract

Salinity is an abiotic stressor that greatly influences crop growth and yield. Scientists are always exploring diverse methods to combat salinity depression. Here, we conducted a greenhouse experiment to study the effects of NaCl salinity (0, 50, and 100 mM) under the foliar spray with zinc-oxide, nano zinc-oxide, iron-chelate, magnetized-Fe, and graphene-oxide on tarragon. The results revealed that the treatment with foliar spray of graphene showed the highest K+/Na+. Salinity of 50 and 100 mM × all foliar applications increased superoxide dismutase activity, whereas 100 mM NaCl raised the malondialdehyde content to its highest level. All salinity levels × Zn foliar spray improved the catalase activity. The foliar spray and salinity experiment exposed to Zn-treated plants attained the highest contents of essential oils. Proline and total phenolics showed the greatest amounts with 50 and 100 mM of NaCl, respectively. The GC/MS analysis revealed 38 compounds in the oil of Artemisia dracunculus L. as estragole (81-91.8 %) was the most dominant constituent. The highest amounts of estragole were found at 50 and 100 mM NaCl foliar sprayed with ZnO. Cis-Ocimene (0.1-6.4 %) was another major constituent with a high variation between the treatments. The highest cis-ocimene content was recorded at 100 mM NaCl × foliar Fe-chelated and in the graphene treatment. Overall, salinity adversely affected the physiological responses of tarragon; however, foliar spray with both forms of Fe and Zn partially ameliorated the adverse salinity effects.