大气O3浓度升高对2种基因型矮菜豆根际微生物的影响

在模拟的大气臭氧浓度升高环境中,用磷脂脂肪酸方法（PLFA）分析大气臭氧浓度升高和接种丛枝菌根（AM）真菌对臭氧敏感性不同的2种基因型矮菜豆（臭氧敏感性：S156;臭氧耐受性：R123）根际和菌丝际微生物量及群落结构的影响,旨在明确大气臭氧浓度变化对植物根际微生物的影响,为全面评价臭氧浓度升高对土壤-植物生态系统的影响...

Effect of Elevated O3 on Rhizosphere Microorganisms of Two Genotypes of Snap Bean

In open top chamber (OTC), elevated atmospheric ozone was simulated to investigate effects of elevated O₃ or/and arbuscular mycorrhizae (AM) inoculation on microbial biomass and microbial community structure (MCR) in rhizosphere and hyphosphere of two genotypes (O₃-sensitive: S156; O₃-tolerant: R123) of snap bean by phospholipid fatty acids (PLFA) method. The objective was to clarify the effect of elevated ozone on rhizosphere microorganism and provide evidence for evaluating the influence of elevated ozone on soil-plant system. The result showed that mycorrhizal colonization rates in two genotypes presented significantly different responses to elevated O₃. Relative to ambient O₃, mycorrhizal colonization rate of S156 plant decreased at both 50 nL·L^-1and 80 nL·L^-1 O₃, but it only decreased at 80 nL·L^-1 O₃ in R123 plant. Biomass of actinomycetes in rhizosphere and Gram-positive bacteria in hyphosphere showed more sensitive to the treatments than others. Actinomycete biomass was significantly affected by plant genotypes, O₃×AM and O₃×AM×genotype, and Gram-positive bacterial biomass was affected O₃, AM and AM×genotype. In S156 plant, AM inoculation and elevated O₃ affected alone MCR in rhizosphere, and their interaction showed greater effect on MCR than single factor. But elevated O₃ only altered MCR in hyphosphere of mycorrhizal plant. In R123 plant, elevated O₃ and AM inoculation altered alone MCR in rhizosphere, but their interaction was slight effect on MCR. MCR in hyphosphere was only affected by 80 nL·L^-1 O₃. The conclusion of this study was that elevated O₃ and AM inoculation can alter alone microbial biomass and community in rhizosphere and hyphosphere, but their interaction depended on sensitivity of host plant to ozone.