Journal of Pure and Applied MicrobiologyVol. 9 No. 4

Biochemical Attributes of Efficient PGPR Bioinoculants and their Effect on Growth of Dalbergia sissoo (Roxb.).

Shahid A. Padder1, Z. A. Bhat2, Shakeela Sofi1 and Maheen Mukhtar1

1 Department of agricultural microbiology SKUAST-K, Srinager 2 Department of soil science SKUAST-K, Srinager

Received on 04 September 2015 and accepted on 01 November 2015

 

ABSTRACT

Biochemical characterization of Bacillus and Pseudomonas bioinoculants was done on the basis of phosphate solubilisation and indole-3-acetic acid production (IAA). It was observed that Bacillus isolate SD25 produced the highest solubilization zone (11mm) and solubilisation index (2.89) whileas; lowest solubilization zone was reported to be produced by Bacillus isolate SD4 and Bacillus isolate SD64 (2.5mm) but the lowest solubilisation index was reported in Bacillus isolate SD4 (1.26). Indole-3-acetic acid production (?g mL-1) by the Pseudomonas and Bacillus isolates was observed at two levels of tryptophan (0.05 and 0.1g tryptophan L-1 ?g mL-1) and it was observed that maximum IAA was produced by Pseudomonas isolate SD2 (54.34 ?g mL-1 at 0.1 g tryptophan L-1) while minimum by Bacillus isolate SD65 (7.17 ?g mL-1 at 0.1 g tryptophan L-1). In the same way the IAA production at 0.05 g tryptophan L-1 was highest and lowest levels produced by Pseudomonas isolate SD2 (32.368 ?g mL-1 ) and by Bacillus isolate SD65 (3.981 ?g mL-1) respectively. However it was observed that some isolates at both the levels of tryptophan did not produce IAA (SD64, SD66) and it was further observed that Psudomonas isolate SD47 produced IAA at 0.1 g tryptophan L-1 but not at 0.05 g tryptophan L-1 . The isolates were further mixed together to form a consortium named as ?Rhizobacterial Consortium? or RC in a solution whose effect on plant growth was observed using different concentrations of the solution (0.2%, 0.5%, 1%, 2%, 5% 10% and 15%) in the form of seed treatment and inoculation into poly bags at fifteen days interval. Seed germination rate and growth parameters of seedlings were recorded, such as shoot and root length, the shoot and root dry and fresh weight. The effect of rhizobacterial consortia concentration on leaf pigments (Chlorophyll a, chlorophyll b and caeotenoid) was determined and it was found that contents of chlorophyll and carotenoids were highest (44.49, 14.54 and 36.29 mg mL-1 respectively) in 5% treatment and lowest 34.65, 10.32 and 24.34 mg mL-1 respectively) in control treatment.

Keywords : Pseudomonas, Bacillus, Dalbergia sissoo, Isolate, RC.