Bio-solubilization of Rock Phosphate and Plant Growth Promotion by Aspergillus niger TMPS1 i in Ultisol and Vertisol

摘要

The effectiveness of the phosphate solubilizing fungus Aspergillus n/ger strain TMPS1 isolated from the rhizospheric soil of mangrove was evaluated for wheat grown on Ultisol and Vertisol soil types under greenhouse conditions using the phosphorus-32(32P) isotope dilution technique. The fungus was identified using 18S ribosomal ribonucleic acid (18S rRNA). Two low grade Indian rock phosphates (RP)from Lalitpur (LRP) and Purulia (PRP) were used as phosphorus (P)sources. Plants were grown for six weeks. In both soils dry mat-yield and P uptake of wheat increased significantly with fungus ulation and rock phosphate fertilizer addition compared with the ertilized control and un-inoculated RP fertilizer treatments. This demonstrates solubilization of the RPs by fungus which increases the relative contribution to plant P uptake. The relative contribution to plant P uptake from the RPs was comparatively higher in Ultisol than in Vertisol, implying higher solubilization of the RPs by fungus in the former.Phosphate derived from the LRP was greater than from PRP in fungus inoculated treatments in both soil types. This demonstrates the potential of Aspergillus niger strain TMPS1 isolate as a phosphate solubilizer in Ultisols and Vertisols. Further, the advantages were n of using 32P to distinguish the contributions of bio-available soil P and P from RPs to P nutrition in plant-microbe interac-