Journal of Medicinal Botany 2019, 3: 8-14 doi: 10.25081/jmb.2019.v3.5281 https://updatepublishing.com/journal/index.php/jmb/ 8 J Med Bot • 2019 • Vol 3 INTRODUCTION Ocimum basilicum L., called sweet basil or basil in English and rehan in Arabic, is one of the most important aromatic and medicinal plant species in the genus Ocimum of the family Lamiaceae [16, 21, 26]. It is chosen to be the subject of our present investigation because of its economic importance as an ornamental, spice, culinary and medicinal herb. Basil grow well in Egypt, the cultivated area is about 1091 feddans (one feddan = 4200 m 2 ) produced about 1951 tons fresh herb per year and yielded about 29.363 tons essential oil [6]. Basil herb contains 0.5-1.5% essential oil of varying composition, out of which linalool as the main component [20]. The essential oil, obtained by steam distillation from the fresh herb, is used in perfumery, in making incense and in the food industry [9]. The market for basil oil is dominated by European and Egyptian production [22]. Therefore, increasing productivity of basil plant from fresh herb and essential oil per unit area is highly recommended to meet the demand of human needs and exportation. In this respect, the use of natural and safety growth promoting substances for enhancing plant growth and increasing productivity of aromatic plants from fresh herb and volatile oil is highly recommended. Stigmasterol is considered as one of the mostly free or conjugated sterols that play essential functions in plant growth and metabolism. [18]. It promoted assimilation of C 14 in leaves and successive translocation of the assimilate into rice panicles [17]. Brassinolides are found in plants with lot of roles in plant growth and development [11]. It has been found that Brassinosteroid enhanced the development of cell walls and thereby speed up the growth cycle [10,25]. In this concern, [1,2,3] reported that sitosterol had a stimulatory effect on growth, yield, photosynthetic pigments and some chemical composition of wheat and maize plants. Also, [5] stated that stigmasterol had a promotive effect on growth, yield and structure of rice plants. Likewise, [23] found that stigmasterol induced promotive effect on vegetative growth, anatomical structure and yield components as well as seed quality of soybean plant. In this connection, [13] stated that increasing stigmasterol concentration up to 200 ppm significantly increased sesame growth, seed yield and number of capsules/plant as well as 1000 seed weight and seed oil percentage. Similar results were also reported by [19] on Egyptian lupine plant. They stated that stigmasterol at concentration of 40 or 80 ppm induced significant promotive effects on lupine plant height and most Enhancement of growth and increased productivity of fresh herb and aromatic oil in basil plant by foliar application with stigmasterol Ahmed A. El-Tantawy 1 , Samah N. Azoz 2 * 1 Ornamental Horticulture Department, Faculty of Agriculture, Cairo University, Giza, Egypt, 2 Department of Agricultural Botany, Faculty of Agriculture, Cairo University, Giza, Egypt. ABSTRACT The present study was conducted through the two growing seasons of 2017 and 2018 to disclose the impact of foliar application with different concentrations of stigmasterol (0, 25, 50, 75 and 100 ppm) on vegetative growth characters, yield of fresh herb/plant, anatomical structures of vegetative organs (main stem and leaves) and percentage and constituents of aromatic oil of basil plant. The obtained results indicated that stigmasterol application had a enhancing effect on growth and productivity as well as on the percentage and composition of volatile oil of basil plant and the maximum promotion was detected at 100 ppm stigmasterol. Such treatment induced favorable changes in the anatomical structures of vegetative organs. Keywords: Ocimum basilicum L., Growth, Anatomy, Volatile oil, Stigmasterol. Copyright: © The authors. This article is open access and licensed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted, use, distribution and reproduction in any medium, or format for any purpose, even commercially provided the work is properly cited. Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. Research Article Received: January 14, 2019 Accepted: March 01, 2019 Published: March 05, 2019 *Corresponding Author: Samah N. Azoz Email: samah.ali@agr.cu.edu.eg samahnageeb@gmail.com ISSN: 2521-3903