Publication Date:
2013-11-29
Description:
In a greenhouse experiment, Medicago sativa was grown in iron-rich soil colonized with iron-reducing bacteria (IRB) and/or Glomus mosseae (GM) under different inorganic phosphorus levels, which was to understand the effects of IRB and GM on the activation and turnover of the Fe(III)-fixed phosphorus. The results showed that at the both P rates, dual-inoculation treatment stimulated the hyphal growth and increased the shoot P content. IRB could accelerate mycorrhizal colonization, and showed a positive effect on plant biomass and P uptake at both P levels. Compared to sole-IRB or GM treatment, the dual inoculation treatment increased the soil available P content at both P rates ( p 〈 0.05), which was in the following order: the dual IRB+GM 〉 the sole IRB 〉 the sole GM 〉 control for soil SMP content at low P rate, whilst the dual IRB+GM 〉 the sole IRB ≈ the sole GM 〉 control treatment at high P rate. Compared with the IRB treatment, the GM treatment significantly decreased the soil available P content and the MBP content at low P rate, but made no difference at high P rates. The soil MBC in dual-inoculation treatment was greatest under the high P level, while the highest soil MBC was the sole-GM treatment under the low P level. The sole GM treatment showed significantly ( p 〈 0.05) higher soil MBC than that of sole IRB at low P rate ( p 〈 0.05), while there was no significant differences between sole IRB and sole GM at high P rate. Our results suggested that the interaction between GM and IRB had synergetic effect on the mobilization of Fe(III)-fixed P and their relationship could be regulated by the turnover of MBP. The fact that plants acquired more P via mycorrhizal pathway in the GM-IRB system suggested that the three symbiont of plant-GM-IRB had great ecological and functional significance for P activity in tropical and subtropical soil.
Print ISSN:
1436-8730
Electronic ISSN:
1522-2624
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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