Influence of Plant Growth Promoting Rhizo Bacteria on Tomato Response to Salt Stress Using N¹⁵ Technique

Pot experiments were conducted in experimental greenhouse at Nuclear Research Center. Atomic Energy Authority, Egypt, during the two growing seasons of 2017 and 2018 for studying the effect of salinity and Rhizobacteria on improving tomato plants growth and its productivity in the saline soil of Ras-Sudr, South Sinai Provence. In the first season (2017), three salt treatments were used as follows: 1) Crude soil of Ras-Sudr (9 kg /pot), 2) 75% crud soil mixture of Ras-Sudr +25% sand, 3) 50% crude soil of Ras-Sudr + 50% sand. In the second season (2018), four saline treatments were used as follows: 1) Crude sandy soil (9 kg /pot); 2) 8900-gram sand was mixed with 100 gram of crud Ras Sudr soil to develop 9 kg /pot; 3) 8800-gram sand was mixed with 200-gram crud Ras Sudr soil to develop 9 kg/pot; and 4) 8700- gram sand was mixed with 300 gram of crude Ras Sudr soil to develop 9 kg / po. Rhizobacteria treatments were as follows: In the first season (2017) 1) (control) pots did not treated with Rhizobacteria; 2) Asperillum sp. ; 2) Azotobatersp; and 3) a mixture from Azosprillum sp.⁺ Azotobater sp. In the second season (2018), Rhizobacteria treatments were:1) (control) pots without Rhizobacteria; and 2) a mixture from Azosprillum sp.⁺ Azotobater sp. Pots prepared by weighing nine kilogram of soil / pot and then water holding capacity for pot was estimated to measure irrigation water per pot. Seedlings of tomato hybrid "Anfoway" were used, transplanting in pots (one seedling / pot) was carried out at 12^nd March, 2017 and at 26^th February, 2018 in the first and second seasons, respectively. At 27 days after transplanting. nitrogen was added with irrigation water every 15 days interval at the rate of 300 kg form of ammonium sulphate as tracer technique (N¹⁵) isotope aiming to determine and evaluating nitrogen utilized as affected by plant growth promoting Rhizobacteria applied (P G R P) in a saline media (Ras Sudr soil). In this respect, the total quantity of nitrogen was divided and applied in ten times along the tomato growth season through the two growing seasons. Ammonium sulphate was used as a source of nitrogen having a %10 atom excess to fertilizer tomato plants as tracer technique. The ammonium sulphate N¹⁵ 10% atom excess was diluted to be 2% atom excess in fertilizer rate after dilution of ammonium sulphate by ordinary ammonium sulphate