Alleviating the adverse effects of salinity stress on tomato crop (Solanum lycopersicum) using nano-fertilizer as foliar application

Salinity is a major abiotic stress which affects tomato growth through reduced water uptake and ion imbalances, which may result in toxicity or deficiency symptoms. This study reports the effect of nano-fertilizer (Lithovit-standard) on vegetative and reproductive growth of salt-stressed tomato plants. Nano-fertilizer consisting of 79.19% CaCO(3) and 4.62% MgCO(3)% was applied through foliar spraying in three concentrations: N1: 0.5 g L(-1), N2: 0.75 g L(-1), and N3: 1 g L(-1). Control and treated plants were irrigated by saline water with 5 salinity levels: S1: 2 dS m(-1), S2: 4 dS m(-1), S3: 6 dS m(-1), S4: 8 dS m-1, and S5: 10 dS m(-1). Exogenously applied nano-fertilizer counteracted the salt-induced adverse effects on plants. It improved plant height of salt-stressed plants compared to the control with a maximum effect at N2. Similarly, it increased leaf number and stem diameter in salt-stressed plants regardless of the application dose. Flowering characteristics were also improved by nano-fertilizer application under all salinity levels; average number of clusters and flowering capacity in N2/S2 (3.5 and 17), N2/S3 (3.1 and 15), N2/S4 (3.4 and 15) and N2/S5 (2.9 and 11) were higher than those in N0/S2 (2.2 and 12), N0/S3 (2.5 and 12), N0/S4 (2.1 and 10), N0/S5 (2 and 9). The product application induced amelioration in reproductive parameters; fruit set was improved in all treatments especially in N1/S1 (65%) compared to the control N0/S1 (26%). Although it did not enhance fruit diameter or individual weight of fruit (g), it did increase yields (g plant(-1)) due to the production of a higher number of fruits for all salinity levels with best yields obtained at N1 (N1/S1 (90 g), N1/S2 (110 g), N1/S3 (115 g), N1/S4 (100 g) and N1/S5 (55 g) and N2 (N2/S1 (100 g), N2/S2 (108 g), N2/S3 (122 g), N2/S4 (105 g) and N2/S5 (50 g) compared to control (N0/S1 (65 g), N0/S2 (75 g), N0/S3 (70 g), N0/S4 (25 g), N0/S5 (30 g). Consequently, salt tolerance of tomato was ameliorated by nano-fertilizer application.