2.1. Seeds and seedling growth
Seeds of the tomato ( Lycopersicon esculentum Mill) cultivar G.S. were procured from the Ministry of Agriculture, Egypt, and used in this study. The seeds were sown in plastic pots, each with a 20-cm diameter and containing a soil mixture composed of sand (1.5 kg/pot) and 1% slow-releasing NPK (12: 4: 6) fertilizer, at approximately 250 mL of NPK suspension (8 g L-1) per week. All of the pots were placed on a bench in an environmentally controlled greenhouse at 30 ± 5 _C with 68e80% RH and watered as required.