Abstract
This work aims to study the effect of foliar spraying of three anti-transpirants i.e., A(1): tryptophan (Tri), A(2): potassium silicate (KS), A(3): chitosan (Chi) as well as A(0) : control (Tap water) under three irrigation regimes, I-1 : 2400, I-2 : 3600, and I-3 : 4800 m(3) ha(-1) on the quality and production of faba bean crop and its nutrient contents. The study was carried out during two successive winter seasons of 2018/2019 and 2019/2020. Drought stress affected the average performance of all studied traits as it reduced seed yield and traits, as a result of the decrease in chlorophyll related to photosynthesis, protein, carbohydrates, total phenols, amino acids, macronutrients (N, P, and K), micronutrient contents (Fe, Mn, and Zn) and their absorption. The single foliar spraying of faba bean with tryptophan 75 ppm, potassium silicate at 100 ppm, or chitosan at 750 ppm significantly increased all studied traits and reduced the drought stress compared to control under different irrigation systems. We recommended using a foliar spray of chitosan (750 ppm) on faba bean plants under an irrigation level of 4800 m(3) led to an improvement in the physiological properties of the plant, i.e., plant height, the number of branches/plants, and the number of plants, pods plant(-1), the number of seed pods(-1), the weight of 100 seeds and seed yield ha(-1) increased with relative increase about 42.29, 89.47, 28.85, 75.91, 24.43, and 306.48% compared to control. The quality properties also improved, as the total chlorophyll, protein, carbohydrates, total phenols, and amino acids were higher than the control with a relative increase of 63.83, 29.58, 27.72, 37.54, and 64.19%. Additionally, an increase in the contents and uptake of macronutrients (N, P, and K), and micronutrients (Fe, Mn, Zn) and their absorption. The increase was estimated with 29.41, 75.00, 16.56, 431.17, 630.48, 72.68%, 22.37, 35.69, 42.33, 397.63, 452.58, and 485.94% about the control. This was followed by potassium silicate (100 ppm), then tryptophan (75 ppm) compared to the control, which recorded the minimum values in plant traits. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.