Effects of Six Strains of Potassium Releasing Bacteria on Growth and Potassium Uptake of Tomato Plant

Potassium availability in soil is an important criterion for plant growth and yield production. In this study the ability of six strains of potassium releasing bacteria including Lysinibacillus fusiformis (JK1) and five strains of Bacillus megaterium (JK2، JK3، JK4، JK5 and Jk6) On growth and potassium uptake of tomato plants was investigated in a sandy loam soil with 70 mg kg-1 available-K. An experiment based on completely randomized design with four replications was conducted under greenhouse conditions. Treatments consisted of six strains of bacteria، K- fertilizer treatment (+K and -bacteria) and control (- K and - bacterial). The results showed that the effect of six bacterial strains inoculum on dry weight of shoot and root in treatment of bacteria was significant (P<0. 05). The highest amounts of dry weights shoot and root were accounted for JK4 and JK5 which in comparsion with the non-bacterial control showed 23. 97 and 52. 23% increments، respectively، while their difference with other strains were not significant. The highest concentration and content of potassium in shoot was calculated for K treated and non-bacterial plants that was significantly different from other treatments (P<0. 01)، which compared to the non-bacterial control showed 69. 88 and 88. 06 % increase، respectively. Among the strains tested here the highest concentration of shoot potassium was belong to the strains JK5 (17. 10 mg g-1) and JK6 (17. 10 mg g-1) that compared to the non-bacterial control showed 32. 04 % increase and showed no significant difference with JK1. Also the highest content of shoot potassium was obtained with strain JK6 that compared to the non-bacterial control showed 59. 28 % increase and showed no significant difference with JK5 and JK1. The highest concentration and content of root potassium was related to K treated and non-bacterial plants that showed significant difference with other strains. Among the strains tested the highest concentration and content of root K was related to strain JK4.