Synergism bioassay of selected indigenous halotolerant phosphorizobacteria from rice rhizosphere on saline soil ecosystem

Abstract

The research was conducted to study the activity and synergism of indigenous halotolerant phosphorizobacteria. Three selected isolates (K5, TR-C2, CLR-A) isolated from different saline soil ecosystem were tested to find out the synergism of each isolate and its ability in P solubilizing. The experiment was arranged as randomize complete design, consisted of seven treatments and provided with four replications. Synergism test was carried out using filter paper disc method. The filter paper disc (d = 5 mm) were soaked in each suspension of selected isolates and stick onto NA plate media directly for single isolate treatments (B, C, D), while combined isolate treatments (E, F, G) were spread first against another isolate according to its treatments. Each treatments were incubated for 72 h at 30°C then inhibition zone was observed. The solubilizing index was tested by sticking soaked filter paper disc on supplemented Pikovskaya agar plate and incubated for 72 h at 30°C. Liquid inoculants were prepared by inoculating of each selected bacteria into 40 ml modified Pikovskaya media supplemented with 0,09 g.L−1 NaCl (EC = 4 dS.m−1), shaken at 100 rpm for five days. Inoculants were centrifuge at 7500 rpm for 10 minutes, 2.5 ml of supernatant were taken and P-available were observed using Bray II method. The experiment result showed that K5, TR-C2 and CLR-A isolates were compatible to grow in consortium condition. K5 isolate showed the highest P solubilizing activity but not significantly different when combined with TR-C2 isolate.