Department of Soil Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
Department of Horticulture Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran.
Environ Geochem Health. 2020 Aug;42(8):2535-2545. doi: 10.1007/s10653-019-00422-3. Epub 2019 Oct 3.
The objective of this research was to determine the combined effects of ethylenediaminetetraacetic acid (EDTA) and plant growth-promoting rhizobacteria (PGPR) on the phytostabilization of Cd, Pb, and Zn by corn and chemical fractionation of these elements in soil. Three heavy metal-resistant bacteria (P18, P15, and P19) were selected. All strains, belonging to the fluorescent pseudomonads, exhibited plant growth-promoting properties, including phosphorus solubilization and production of siderophore, indole acetic acid, and 1-aminocyclopropane-1-carboxylic acid deaminase. Applying EDTA individually or in combination with bacterial strains (P18 and P15) significantly increased shoot biomass. The highest dry shoot biomass was recorded in the combined treatment of EDTA and P15-inoculated pots. Application of EDTA in PGPR-inoculated pots increased concentrations of heavy metals in corn shoots and roots compared to the control. The highest concentration of Zn in corn root and shoot was observed in P15 + EDTA treatment, which were 2.0-fold and 1.3-fold higher than those in the untreated soil. Results of chemical speciation showed that the co-application of EDTA and fluorescent pseudomonads strains increased the bioavailability of Zn, Pb, and Cd by their redistribution from less soluble fractions to water-soluble forms. It was concluded that bacterial inoculation could improve the efficiency of EDTA in phytostabilization of heavy metals from multi-metal contaminated soils.
本研究旨在确定乙二胺四乙酸(EDTA)和植物促生根际细菌(PGPR)联合作用对玉米对 Cd、Pb 和 Zn 的植物稳定化效果,以及这些元素在土壤中的化学形态。选择了三株重金属抗性细菌(P18、P15 和 P19)。所有菌株均属于荧光假单胞菌,具有植物促生特性,包括磷溶解、铁载体、吲哚乙酸和 1-氨基环丙烷-1-羧酸脱氨酶的产生。单独或结合菌株(P18 和 P15)施用 EDTA 可显著增加地上生物量。在 EDTA 和 P15 接种盆的联合处理中记录到最高的干地上生物量。与对照相比,EDTA 在 PGPR 接种盆中的应用增加了玉米地上和地下部分重金属的浓度。在 P15+EDTA 处理中,玉米根和地上部的 Zn 浓度最高,分别比未处理土壤高 2 倍和 1.3 倍。化学形态分析结果表明,EDTA 和荧光假单胞菌菌株的共同应用通过将 Zn、Pb 和 Cd 从较难溶解的部分重新分配到水溶性形式,增加了它们的生物有效性。结论是,细菌接种可以提高 EDTA 在多金属污染土壤中植物稳定重金属的效率。