Abstract
Two field experiments were conducted at the Experimental Farm of Faculty of Agriculture, Zagazig University during two consecutive winter seasons of 2106/2017 and 2017/2018. Aiming to study the effect of foliar application (eight treatments) with salicylic acid (SA), ascorbic acid (Vit.C), thiamin (Vit. Bi) and their combinations between them as well as control (sprayed with tap water) on growth, yield and volatile and fixed oil production as well as chemical constituents of black cumin plant. These compounds were chosen because their effect on the growth was previously reported in animal models as well as in vitro. Plants were sprayed three times at 30, 45 and 60 days after sowing. Foliar spray of Nigella sativa plants with (SA+Vit.C+Vit.B-1) at 100 mg/l of each increased plant growth parameters (plant height, branch number/plant and total dry weight), total chlorophyll in leaf tissues, yield components (capsule number/plant, seed yield/plant, seed yield/fad.), oil production(volatile and fixed oils %, volatile and fixed oils yield/plant and volatile and fixed oils yield/fad.) and chemical constituents (N, P, K and total carbohydrates percentages in seeds) compared to control and the other ones under study, in most cases. The main compounds of N. sativa seeds volatile oil as detected by GC/MS were pcymene (50.40-50.52%), alpha-Thujene (8.47-8.59%), Thymoquinone (7.14-7.26%), Longifolene (3.61-3.73%), beta-Pinene (3.09-3.21%), Terpinen-4-ol (2.42-2.52%), and Carvacral (2.28-2.40%) which increased due to the effect of treatments. SA+Vit.C+Vit.B treatment resulted in higher values of yield components and main constituents of volatile oil compared with the control and other treatments, thus it seems to be recommended treatments.