Integrative effects of biostimulants and salinity on vegetables: Contribution of bioumik and Lithovit®-urea50 to improve salt-tolerance of tomato

Y.N. Sassine¹, T.K. Sajyan¹²*, A. El Zarzour¹, A.M.R. Abdelmawgoud³, M. Germanos¹ and S.M. Alturki⁴

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
*Correspondence: tony.sajyan@st.ul.edu.lb

Abstract:

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.

Key words:

biostimulants, growth, physiology, salinity, small scale fertilizers, tomato