Physiological role of iron chelators and/or arginine for improving yield and active constituents of roselle sepals

Abstract

Background and Objective: Roselle (Hibiscus sabdariffa L.) plants are grown in Africa, South east Asia, Central America, it is known as Karkadeh (Egypt). Many active constituents present in Roselle have potential health benefits and support its medicinal uses. The target of this investigation was to evaluate the physiological function of ferric ethylenediaminetetraacetic acid-iron chelators (Fe-EDTA) or hemin and/or arginine for improving yield and nutritional value of sepals of roselle plant grown under the reclaimed sandy soil. Materials and Methods: A field experiment was conducted in 2016 and 2017 summer successive seasons at the experimental farm, National Research Centre, Al Nubaria District El-Beheira Governorate, Egypt. The foliar application separately or in combination with arginine (at 50 g LG 1), Fe-EDTA (50 and mg LG 1) and/or hemin at (50 and 100 mg LG 1 of treatments were practiced twice at 45 and 60 days after planting. Results: Foliar treatment of Fe-EDTA, hemin and arginine alone or mixture of them with different concentrations, significantly increased all yield parameters, non-photosynthetic pigments as anthocyanin, lycopene and β-carotene, flavonoids, radical scavenging activity as 1,1-diphenyl-2-picrylhydrazyl (DPPH), as well as all sugar fractions, total soluble sugars, total carbohydrates, macro and microelements of roselle plants as compared with control (untreated) plants. It also showed that most treatments decreased significantly in total acidity and sodium (Na) contents of roselle sepals, when compared with untreated plant. Conclusion: Foliar application with arginine, Fe-EDTA and/or hemin separately or in a combination of roselle plants could be increase all active constituents as compared with untreated plants grown under new reclaimed sandy soil.