Invasive Species Compendium

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Abstract

Effect of colonization with arbuscular mycorrhizal fungi on phosphorus utilization of macadamia seedlings under water stress.

Abstract

The effects of arbuscular mycorrhizal fungi (AMF) inoculation on drought tolerance in macadamia seedlings with cluster roots, were studied based on seasonal drought and congenital low phosphorus soil in Yunnan tropical regions, providing a theoretical basis for domestication and cultivation of alien species. An experiment of potted macadamia seedlings with inoculated Native-AMF and Glomus mosseae under well-watered or water stress condition was conducted to determine the growth, AMF colonization, acid phosphatase activity, secretion of citric and phosphorus utilization, etc. The colonization rate of N-AM treatment on seedlings with cluster roots and without cluster roots were significantly higher than that of under G-AM treatment, and it would reach the maximum under well-watered condition. Compared with control, the plant with AMF had higher dry biomass in shoots and roots in both treatments, and it would perform best in well-watered condition. There was a significant positive correlation between AMF colonization rate and number of cluster roots. The water stress significantly inhibited the production of cluster roots, but the inoculation promoted cluster roots number. Macadamia seedlings had high total phosphorus content in roots, stems and leaves after inoculated with AMF, which enhanced the root ability to activate, absorb and transform phosphorus. The phosphorus content in three treatments turned out to be CK < G-AM < N-AM under both water conditions. Although both AM and cluster roots had effect on phosphorus absorption of macadamia seedlings, AM seemed more helpful to roots for phosphorus absorption, even if there was a water stress. The two AMF could establish symbiotic relationship with macadamia seedlings. It's found that the treatment with N-AM showed significant advantages that treatment with G-AM, possibly due to its strong inoculation ability in macadamia roots, or AMF's positive feedback on the exotic species of macadamia.