Effects of inoculation with arbuscular mycorrhizal fungi on AlPO4 uptake by Poncirus trifoliata.

With sand culture in greenhouse, this paper studied the effects of inoculation with arbuscular mycorrhizal (AM) fungi Glomus mosseae and G. versiforme on the utilization of insoluble phosphate AIPO₄ (AI-P) by trifoliate orange (Poncirus trifoliate) seedlings. The results indicated that inoculation with AM fungi notably increased the dry matter, P content, and P adsorption rate of P. trifoliate. The contribution of mycorrhiza, P uptake by plant and AM fungi, and the contribution of AM fungi in P uptake by P. trifoliata increased greatly with increasing AI-P level in the medium. Inoculation with AM fungi greatly increased the excretion of phosphatase, especially acid- and neutral phosphatase, from plant root and hyphae, but the excretion amount decreased with increasing AI-P level. The contribution of the fungi in P uptake by P. trifoliata was significantly positively correlated with the amounts of acid-, neutral-, alkaline-, and total phosphatase. [ABSTRACT FROM AUTHOR]