Effects onGlomus mosseaeRoot Colonization byPaenibacillus polymyxaandPaenibacillus brasilensisStrains as Related to Soil P-Availability in Winter Wheat

摘要

Greenhouse experiments were conducted to assess the effects of inoculating winter wheat (Triticum aestivum) with plant growth promoting rhizobacteria (PGPR) of the genusPaenibacillusunder phosphate P-limited soil conditions in the presence or absence of the arbuscular mycorrhizal fungus (AMF)Glomus mosseae. FourP. polymyxastrains and oneP. brasilensisstrain were compared at two cell concentrations (106and 108 cells g−1seeds) of inoculation, and surface sterilized AMF spores were added to pots. Mycorrhizal root colonization, plant growth, and plant uptake of phosphorus were analyzed. Bacterial phosphate solubilization was examined separatelyin vitro. MostP. polymyxastrains, isolated from wheat, had dramatic effectsper seon root growth and root P-content. No treatment gave significant effect on shoot growth. AMF root colonization levels and total plant uptake of P were much stimulated by the addition of mostP. polymyxastrains. The AM fungus alone and theP. brasilensis, alone or in combination with the fungus, did not affect total plant P-levels. Our results indicate that practical application of inoculation with plant host-specific rhizobacteria (i.e.,P. polymyxa) could positively influence uptake of phosphorus in P-deficient soils by wheat plants, provided that suitable AM fungi (e.g.,G. mosseae) are present.