Effect of Plant Growth Promoting Rhizobacteria and Rhizofungus on the Growth of Hairy Basil (Ocimum basilicum L.f. var. citratum Back.)

Abstract

In this study, plant growth promoting rhizobacteria (PGPR) and plant growth promoting fungi (PGPF) were isolated from soil adhered to the roots of herbs. PGPR and PGPF isolates were selected for producing microbial inoculant as a starter culture for bio-fertilizer production. The screening of PGPR and PGPF was performed using the spread plate technique on the selected medium. Total plant growth promoting microorganisms (PGPM) were composed of 72 isolates, nitrogen-fixing microorganisms: 39 isolates, phosphate-solubilizing: 11 isolates, and potassium-solubilizing: 22 isolates. Two bacterial isolates, S-K7-2 and S-P7-1, had the highest plant growth promoting abilities, and a fungus isolate, Di-K7-2, was able to produce the greatest amount of IAA, which was 45.17 μg IAA equivalent/ml. The isolates were tested on hairy basil seed germination. Treatment using microbial cell dissolved in sterile distilled water had the greatest potential for stimulating the growth of seed and presented 145.26% of GI, followed by 82.87% where the treatment was with IAA standard. The study of the effect of PGPR and PGPF on hairy basil growth found that the highest biomass was shown in treatment 3, peat supplemented bacteria (S-K7-2, S-P7-1), which indicated that rhizobacteria immobilized on peat was able to enhance the growth of hairy basil and had better potential for promoting plant development compared with chemical fertilizer treatment.