title: Direct and indirect effects of glomalin, mycorrhizal hyphae, and roots on aggregate stability in rhizosphere of trifoliate orange.
abstract: To test direct and indirect effects of glomalin, mycorrhizal hyphae, and roots on aggregate stability, perspex pots separated by 37-μm nylon mesh in the middle were used to form root-free hyphae and root/hyphae chambers, where trifoliate orange (Poncirus trifoliata) seedlings were colonized by Funneliformis mosseae or Paraglomus occultum in the root/hyphae chamber. Both fungal species induced significantly higher plant growth, root total length, easily-extractable glomalin-related soil protein (EE-GRSP) and total GRSP (T-GRSP), and mean weight diameter (an aggregate stability indicator). The Pearson correlation showed that root colonization or soil hyphal length significantly positively correlated with EE-GRSP, difficultly-extractable GRSP (DE-GRSP), T-GRSP, and water-stable aggregates in 2.00-4.00, 0.50-1.00, and 0.25-0.50 mm size fractions. The path analysis indicated that in the root/hyphae chamber, aggregate stability derived from a direct effect of root colonization, EE-GRSP or DE-GRSP. Meanwhile, the direct effect was stronger by EE-GRSP or DE-GRSP than by mycorrhizal colonization. In the root-free hyphae chamber, mycorrhizal-mediated aggregate stability was due to total effect but not direct effect of soil hyphal length, EE-GRSP and T-GRSP. Our results suggest that GRSP among these tested factors may be the primary contributor to aggregate stability in the citrus rhizosphere.
authors: College of Horticulture and Gardening/Institute of Root Biology, Yangtze University, Jingzhou, Hubei 434025, China.
authors: Qiang-Sheng
authors: QS
authors: Wu
authors: College of Horticulture and Gardening/Institute of Root Biology, Yangtze University, Jingzhou, Hubei 434025, China.
authors: Ming-Qin
authors: MQ
authors: Cao
authors: College of Horticulture and Gardening/Institute of Root Biology, Yangtze University, Jingzhou, Hubei 434025, China.
authors: Ying-Ning
authors: YN
authors: Zou
authors: 1] Key Laboratory of Plant Nutrition and Nutrient Cycling, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China [2] School of Plant Biology, University of Western Australia, Crawley, WA 6009, Australia.
authors: Xin-hua
authors: XH
authors: He
mesh_terms: D005656:Fungal Proteins / Q000378:metabolism*; D055137:Glomeromycota / Q000302:isolation & purification / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D025301:Hyphae / Q000378:metabolism; D038821:Mycorrhizae / Q000378:metabolism; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology; D032104:Poncirus / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology; D058441:Rhizosphere; D036226:Seedlings / Q000254:growth & development / Q000378:metabolism / Q000382:microbiology
chemical_list: D005656:Fungal Proteins; D006023:Glycoproteins; C573268:glomalin