Impact of Foliar Application of Some Growth Stimulants on the Vegetative Growth and the Essential Oil Characters of Ocimum Basilicum Var. Thyrsiflorum (L.)

This study aimed to investigate the effect of foliar application by synthetic and natural growth stimulants (salicylic acid (SA), selenium (SE) and orange peel extract (OPE)), on vegetative growth, oil production and the total phenolic content of Ocimum basilicum thyrsiflorum L. essential oil. A pot experiment was carried out and the treatments of foliar application ((SA) at (0.5, 1 and 1.5 mm), (SE) at (6, 8, and 10 mg /L), and OPE at (600, 800, 1000 mg/L) and the control treatment (spray with distilled water)) stared 60 days after sowing date. Plant shoot was cut each 45 days intervals, then plant growth and biochemical traits were estimated. It was noticed that plant treated with SA, SE at high concentration and OPE at medium concentration showed the highest vegetative growth values, and essential oil production. The total phenolic content and photosynthetic pigments exhibited greater development due to increase in vegetative growth characters and increase in volatile oil chemical characters of Ocimum basilicum. In respect to chlorophyll a, b and carotenoids in plant green leaves recorded the highest values with the high level of synthetic promoters and medium concentration of natural one (OPE) at the third cut.