Integrative effects of biostimulants and salinity on vegetables: Contribution of bioumik and Lithovit®-urea50 to improve salt-tolerance of tomato
¹Lebanese University, Faculty of Agriculture, Department of Plant Production, Beirut, Lebanon
²University of Forestry, Faculty of Agronomy, Department of Agronomy, 10 Kliment Ohridski blvd, BG1797 Sofia, Bulgaria
³National Research Center, Department of Vegetable Researches, Dokki, Cairo, Egypt
⁴King Faisal University, College of Agricultural and Food Sciences, Department of Arid Land Agriculture, P.O. Box 400, Al Ahsa 31982, Kingdom of Saudi Arabia
The separate and combined effect of lithovit-urea50 and bioumik was tested on salt-stressed tomato crops. Salinity was induced using three different NaCl solutions (2, 4 and 8 dS m-1). Under the salinity effect, all aspects of plant growth were inhibited. Total chlorophyll and carotenoids reduced from mg g-1 FW and 1.1 mg g-1 FW at 2 dS m-1 to reach 1.01 mg g-1 FW and 0.66 mg g-1 FW at 8 dS m-1 in control plants. Plants treated by the combination of both products had the highest chlorophyll and carotenoids content with 2.24 mg g-1 FW and 1.34 mg g‑1 FW, 1.88 mg g-1 FW and 1.05 mg g-1 FW, and 1.39 mg g-1 FW and 0.86 mg g-1 FW respectively at 2, 4 and 8 dS m-1. Treating plants by this combination maximized flower number, fruit weight, yield and fruit diameter at 2 dS m-1 (17 flowers, 47.93 g, 431.1 g plant-1 and 3.23 cm respectively) and 4 dS m-1 (15flowers, 36.45 g, 291.85 g plant-1 and 2.8 cm respectively). The separate application of bioumik minimized cell electrolyte leakage at 2 dS m-1 (8.82%) compared to control (11.43%). Additionally, plants treated by lithovit-urea and bioumik had the highest relative water content with 107.3%, 96.5% and 91.2% respectively at 2, 4 and 8 dS m-1. N, Ca and Mg in roots were significantly the highest at 2 dS m-1 (4.5%, 2.6% and 0.5% respectively), at 4 dS m-1 (3.74%, 2.49% and 0.48% respectively) and at 8 dS m-1 (3.21%, 2.61% and 0.32% respectively). K content in roots was maximized following the separate application of bioumik with 3.21% at 2 dS m-1 and 2.55% at 8 dS m-1. Conclusively, lithovit-urea and bioumik helped plants in tolerating salt-stress with an optimal effect obtained after their combination.