Interaction of iron and zinc fortification and late-season water deficit on yield and fatty acid composition of Dragon's Head (Lallemantia iberica L.)

Abstract

Dragon's head (Lallemantia iberica) is a rich source of alpha-linolenic acid, linoleic acid, essential oil, protein, and mucilage. Therefore, the aim of this study was to evaluate the effects of foliar application of three different concentrations of Fe and Zn (control, 4, and 8 g lit−1) at two different developmental stages (vegetative stage (VS) and reproductive stage (RS)) on the quantity and quality of dragon's head seed yield and fatty acid composition in two crop seasons (2018 and 2019) under two environments (normal irrigation as control (NI) and post-anthesis water deficit (WD). In NI, average yields of seed, oil, and protein were 1155, 340, and 183 kg ha−1, respectively, and in the WD, they were 879, 283, and 148 kg ha−1, respectively. By applying Zn and Fe, the mean values of seed, oil, and protein yields in the NI were 1425, 478, and 264 kg ha−1, while in the WD, they were 1011, 354, and 200 kg ha−1, respectively. Furthermore, the application of WD resulted in a significant increase in zinc concentration, protein percentage, and saturated fatty acid percentage in seeds. Unlike WD, iron and zinc treatments decreased the percentage of saturated fatty acids and increased the percentage of unsaturated fatty acids. The number of capsules per plant had the most positive indirect effect on grain yield. The results showed that foliar spraying of Fe and Zn could effectively mitigate the adverse effects of WD on the quality and quantity of seed and oil yield dragon's head.