Impact of Mycorrhizal Inoculation on the Development of Intsia bijuga Grown on Soil under Exotic Species Casuarina equisetifolia Plantation

Abstract

Installation of exotic species often influences the functioning of the soil microbial population and the development of indigenous plants. The objective of this study was to determine the influence of ectomycorrhizal inoculation on soil microorganisms and the development of the native plant Intsia bijuga grown on soils collected under exotic plantation of Casuarina equisetifolia. Two isolates of Pisolithus, Pis02 and PisE, were used to inoculate Intsia bijuga seedlings. After six months growth in a greenhouse, different parameters of plant development were evaluated: total biomass, mycorrhizal rate and chemical properties of leaves. For the rhizosphere soil, chemical and microbiological analyses were performed and enzyme activities were evaluated. The results showed that the inoculation of both ectomycorrhizal isolates caused a significant increase in phosphorus content in plant leaves and assimilable phosphorus content in soil cultures. In addition, the aboveground biomass of Intsia bijuga, the nitrogen content of leaves, the total microbial activity and the carbon content of the soil cultures were significantly higher with Pis02 inoculation. However the intensity of the acid phosphatase and the numbers of solubilizing tricalcium phosphate microorganisms and actinomycetes were significantly reduced. This study highlighted the importance of mycorrhizae in the establishment of native plants in soils under exotic plantation.