Evaluating Effectiveness of Four Inoculation Methods with Arbuscular Mycorrhizal Fungi on Trifoliate Orange Seedlings

Citrus plants are highly dependent on arbuscular mycorrhizal fungi (AMF). However, mycorrhizal colonization of citrus is relatively low in field. Mycorrhization of seedlings becomes a feasible tool to elevate the colonization. The present experiment was conducted to evaluate the effectiveness of four inoculation methods with Glomus mosseae on trifoliate orange [Poncirus trifoliata (L.) Raf.] seedlings. At the time of seedlings transplant, the mycorrhizal inoculum was respectively placed as one layer, two layers and core and mixed with the growth substrates. After 152 days of the inoculation, root colonization ranged from 46-65%, and the one-layer mycorrhizal inoculation exhibited the highest mycorrhizal colonization of trifoliate orange. In general, all the mycorrhizal treatments except two-layer inoculation significantly improved some traits of growth and root system architecture (RSA) in addition to marked increase in leaf chlorophyll and soluble sugar concentrations of leaf and root. It suggests that AM symbiosis induced soluble sugar accumulation to sustain growth of both AMF and roots through increasing leaf chlorophyll concentration. The one-layer mycorrhizal inoculation is the best for mycorrhization of trifoliate orange. (C) 2012 Friends Science Publishers