Lodewyckx C, Mergeay M, Vangronsveld J, Clijsters H, Van der Lelie D
Department SBG, Environmental Biology, Limburgs Universitair Centrum, Universitaire Campus, B-3590 Diepenbeek, Belgium.
Int J Phytoremediation. 2002;4(2):101-15. doi: 10.1080/15226510208500076.
We investigated bacterial populations associated with the Zn hyperaccumulator Thlaspi caerulescens subsp. calaminaria grown in a soil collected from an abandoned Zn-Pb mine and smelter in Plombières, Belgium. The bacterial population of the nonrhizospheric soil consisted of typical soil bacteria, some exhibiting multiple heavy-metal resistance characteristics that often are associated with polluted substrates: 7.8% and 4% of the population survived in the presence of elevated levels of Zn (1 mM) and Cd (0.8 mM), respectively. For the bacterial population isolated from the rhizosphere, the comparable survival rates were 88 and 78%. This observation indicates a selective enrichment of the metal-resistant strains due to an increased availability of the metals in soils near the roots compared with nonrhizospheric soil. The endophytic inhabitants of the roots and shoots were isolated, identified, and characterized. Although similar endophytic species were isolated from both compartments, those from the rhizoplane and roots showed lower resistance to Zn and Cd than the endophytic bacteria isolated from the shoots. In addition, root endophytic bacteria had additional requirements. Contrary to the rootresiding inhabitants, the shoot represented a niche rich in metal-resistant bacteria and even seemed to contain species that were exclusively abundant there. These differences in the characteristics of the bacterial microflora associated with T. caerulescens might possibly reflect altered metal speciation in the different soils and plant compartments studied.
我们研究了与锌超积累植物天蓝遏蓝菜亚种卡氏天蓝遏蓝菜相关的细菌种群，该植物生长在从比利时普隆比耶尔一个废弃的锌铅矿和冶炼厂采集的土壤中。非根际土壤中的细菌种群由典型的土壤细菌组成，其中一些表现出多种重金属抗性特征，这些特征通常与受污染的基质有关：分别有7.8%和4%的种群在锌（1 mM）和镉（0.8 mM）含量升高的情况下存活。对于从根际分离的细菌种群，相应的存活率分别为88%和78%。这一观察结果表明，与非根际土壤相比，由于根际附近土壤中金属的有效性增加，金属抗性菌株出现了选择性富集。对根和茎中的内生菌进行了分离、鉴定和表征。虽然从这两个部位分离出了相似的内生菌种，但从根际和根中分离出的内生菌对锌和镉的抗性低于从茎中分离出的内生细菌。此外，根内生细菌还有其他需求。与根内的细菌不同，茎代表了一个富含金属抗性细菌的生态位，甚至似乎含有仅在那里大量存在的物种。与卡氏天蓝遏蓝菜相关的细菌微生物群落特征的这些差异可能反映了所研究的不同土壤和植物部位中金属形态的变化。
