Changes in some physiological traits and mucilage yield of sour tea (Hibiscus sabdariffa L.) under foliar application of magnesium and iron oxide nanoparticles

In order to investigate the effect of magnesium oxide (MgO) and iron oxide (Fe2O3) nanoparticles (NPs) on physiological traits and the yield of sour tea (Hibiscus sabdariffa L.), a factorial experiment was conducted in a randomized complete block design (RCBD) with four replications in 2018. MgO and Fe2O3 were used in concentrations of 0.01% and 0.03% as foliar application. The results showed NPS improved chlorophyll (Chl) content and index. The highest total chlorophyll was obtained in plants treated with 0.01% of MgO and 0.0.3% of Fe2O3. Catalase (CAT) and peroxidase (POX) activities significantly increased with NPs, in which all combined concentrations of NPs had greater enzymes activities compared to control. The seed weight in plants treated with 0.03% of MgO and 0.01% of Fe2O3 was higher compared to non-NPs treatment. The highest mucilage yield was found at 0.01% of MgO and 0.03% of Fe2O3. Total flavonoid content (TFC) in plants treated with 0.01% of MgO and 0.01% of Fe2O3 was higher than other experimental treatments. The treatment including 0.01% of MgO and non Fe2O3 had lower anthocyanin content compared to other combined levels of NPs. Carotenoid increased with medium concentrations of NPs, but decreased with high level of NPs (0.03%). Protein concentration at all combinations of 0.1% and 0.3% NPs was higher than other experimental treatments. According tour results, we suggest the use of 0.01% of MgO and 0.03% of Fe2O3 for improving the physiological properties of sour tea.