Effect of Zinc and Boron foliar application on leaf chemical composition of Moringa oleifera and on yield and characters of its seed oil

Abstract

Extracted oils from plants make up an important part of human life wellbeing all over the world, especially oils containing polyunsaturated acids, such as oleic, linoleic and palmitoleic acids. In Egypt, vegetable oils are produced from multiple sources such as: cotton, soybeans and sunflower. Unfortunately, all these sources do not fulfill consumer requirements. So it is important to find alternate sources of edible oils. Therefore, this study aimed to evaluate the chemical composition of three-year-old Moringa oleifera trees and their seed oil characterization as affected using foliar application with zinc (Z) and boron (B). Treatments included two doses of solo-foliar application of Zinc (Zn1 & Zn2) or Boron (B1 & B2) and four combinations between the two doses of Zn and B (Zn1B1, Zn1B2, Zn2B1 and Zn2B2) compared to untreated control. Chemical composition of Moringa oleifera leaves, i.e. N, P, K, Zn, B, Protein (%) and vitamin C including physical and chemical characters of Moringa oleifera oil, i.e. oil yield (%), specific gravity, refractive index, acid number, saponification number, ester number and free fatty acids were evaluated. The obtained results reflected that all foliar application treatments improved Moringa oleifera chemical composition in leaf samples, not to mention seed oil physical and chemical characters compared to the untreated control.