Effectiveness of autochthonous bacterium and mycorrhizal fungus on Trifolium growth, symbiotic development and soil enzymatic activities in Zn contaminated soil

• Published in: Journal of applied microbiology 2006-03, Vol.100 (3), p.587-598
• Main Authors: Vivas, A, Barea, J.M, Biró, B, Azcón, R
• Format: Article
• Language: English
• Subjects: Absorption; Bacteria; beta-Glucosidase - chemistry; Biological and medical sciences; Biomass; Brevibacterium - physiology; cadmium; copper; enzyme activity; Fundamental and applied biological sciences. Psychology; G. mosseae interaction; Glomus mosseae; host plants; indole acetic acid; Indoleacetic Acids - analysis; inoculum; iron; Metals, Heavy - pharmacokinetics; Microbiology; molybdenum; mycelium; Mycelium - physiology; Mycorrhizae - physiology; mycorrhizal fungi; Oxidoreductases - chemistry; Phosphoric Monoester Hydrolases - chemistry; Plant Growth Regulators - analysis; plant nutrition; Plant Roots - chemistry; Plant Roots - growth & development; Plant Shoots - chemistry; Plant Shoots - growth & development; polluted soils; rhizosphere; root growth; Soil Microbiology; Soil Pollutants - toxicity; Symbiosis - physiology; Trifolium; Trifolium - chemistry; Trifolium - growth & development; Trifolium - microbiology; vesicular arbuscular mycorrhizae; zinc; Zinc - toxicity; Zn contamination
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/j.1365-2672.2005.02804.x

This study investigates how autochthonous micro-organisms [bacterium and/or arbuscular mycorrhizal (AM) fungi] affected plant tolerance to Zn contamination. Zinc-adapted and -nonadapted Glomus mosseae strains protected the host plant against the detrimental effect of Zn (600 [mu]g g[superscript [-]1]). Zn-adapted bacteria increased root growth and N, P nutrition in plants colonized by adapted G. mosseae and decreased the specific absorption rate (SAR) of Cd, Cu, Mo or Fe in plants colonized by Zn-nonadapted G. mosseae. Symbiotic structures (nodule number and extraradical mycelium) were best developed in plants colonized by those Zn-adapted isolates that were the most effective in increasing plant Zn tolerance. The bacterium also increased the quantity and quality (metabolic characteristics) of mycorrhizal colonization, with the highest improvement for arbuscular vitality and activity. Inocula also enhanced soil enzymatic activities (dehydrogenase, [beta]-glucosidase and phosphatase) and indol acetic acid (IAA) accumulation, particularly in the rhizosphere of plants inoculated with Zn-adapted isolates. Glomus mosseae strains have a different inherent potential for improving plant growth and nutrition in Zn-contaminated soil. The bacterium increased the potential of mycorrhizal mycelium as inoculum. Mycorrhizal performance, particularly that of the autochthonous strain, was increased by the bacterium and both contributed to better plant growth and establishment in Zn-contaminated soils.