Improvement in bioavailability of tricalcium phosphate to Cymbopogon martinii var. motia by rhizobacteria, AMF and Azospirillum inoculation

Abstract

The interactive effects of phosphate solubilizing bacteria, N2 fixing bacteria and arbuscular mycorrhizal fungi (AMF) were studied in a low phosphate alkaline soil amended with tricalcium insoluble source of inorganic phosphate on the growth of an aromatic grass palmarosa (Cymbopogon martinii). The microbial inocula consisted of the AM fungus Glomus aggregatum, phosphate solubilizing rhizobacteria Bacillus polymyxa and N2 fixing bacteria Azospirillum brasilense. These rhizobacteria behaved as "mycorrhiza helper" and enhanced root colonization by G. aggregatum in presence of tricalcium phosphate at the rate of 200 mg kg(-1) soil (P1 level). Dual inoculation of G. aggregatum and B. polymyxa yielded 21.5 g plant dry weight (biomass), while it was 21.7 g in B. polymyxa and A. brasilense inoculated plants as compared to 14.9 g of control at the same level. Phosphate content was maximum (0.167%) in the combined treatment of G. aggregatum, B. polymyxa and A. brasilense at P1 level, however acid phosphatase activity was recorded to be 4.75 pmol mg(-1) min(-1) in G. aggregatum, B. polymyxa and A. brasilense treatment at P0 level. This study indicates that all microbes inoculated together help in the uptake of tricalcium phosphate which is otherwise not used by the plants and their addition at 200 mg kg(-1) of soil gave higher productivity to palmarosa plants.

Alleviation of Salt Stress in Legumes by Co-inoculation with Pseudomonas and Rhizobium

“…In the rhizosphere, a synergism between various bacterial genera such as Bacillus , Pseudomonas , Arthrobacter , and Rhizobium has been shown to promote plant growth of various plants such as peanut, corn, soybean, and maize (Dey et al 2004 ;Ratti et al 2001 ). Available reports indicate improved yield of legumes health, and nodulation when co-inoculated with PGPB, compared to inoculation with Rhizobium alone (Valverde et al 2005 ;Egamberdieva et al 2010 ;Yadegari and Rahmani 2010 ).…”

Effects of organic and biological fertilizers on fruit yield and essential oil of sweet fennel (Foeniculum vulgare var. dulce)

“…It has been reported that application of mycorrhizae, vermicompost and their combination increased anethole and decreased limonene contents of fennel essential oil (Darzi et al, 2009). In addition, Ratti et al (2001) stated that phosphate solubilizing bacterium of Bacillus polymyxa increased the zhranyvl content and decreased the several components of essential oil in Cymbopogon martinii. Phosphate solubilizing bacterium such as Pseudomonas sp.…”

Diversity of Cold Tolerant Phosphate Solubilizing Microorganisms from North Western Himalayas

“…Much research focuses on bacteria and fungi, which live in association with higher plants. Some bacterial inoculants can enhance root colonization by mycorrhizal fungi (Ratti et al 2001). Although many authors report a growth-promoting effect of phosphorus solubilizing microorganisms (PSM) (Narula et al 2000;Sundara et al 2002), results in the field are highly variable (Gyaneshwar et al 2002).…”