Abstract：
Plant growth regulators (PGR) and plant growth-promoting bacteria (PGPB) have the potential in phytoremediation of heavy metals (HMs) contaminated soils. However, their sole application may not yield the optimal results, thus necessitating the combined application. The present study aimed to enhance the phytoremediation efficiency of Sedum alfredii Hance (S. alfredii) in acidic and alkaline soils through the combination of PGR (Brassinolide, BR) and PGPB (Pseudomonas fluorescens, P. fluorescens). The combination of BR and P. fluorescens (BRB treatment) effectively increased the removal efficiency of S. alfredii for Cd, Pb, and Zn by 355.2 and 155.3 %, 470.1 and 128.9 %, and 408.4 and 209.6 %, in acidic and alkaline soils, respectively. Moreover, BRB treatment led to a substantial increase in photosynthetic pigments contents and antioxidant enzymes activities, resulting in a remarkable increase in biomass (86.71 and 47.22 %) and dry mass (101.49 and 42.29 %) of plants grown in acidic and alkaline soils, respectively. Similarly, BRB treatment significantly elevated the Cd (109.4 and 71.36 %), Pb (174.9 and 48.03 %), and Zn levels (142.8 and 104.3 %) in S. alfredii shoots, along with cumulative accumulation of Cd (122.7 and 79.47 %), Pb (183.8 and 60.49 %), and Zn (150.7 and 117.9 %), respectively. In addition, the BRB treatment lowered the soil pH and DTPA-HMs contents, while augmenting soil enzymatic activities, thereby contributing soil microecology and facilitating the HMs absorption and translocation by S. alfredii to over-ground tissues. Furthermore, the evaluation of microbial community structure in phyllosphere and rhizosphere after remediation revealed the shift in microbial abundance. The combined treatment altered the principal effects on S. alfredii HMs accumulation from bacterial diversity to the soil HMs availability. In summary, our findings demonstrated that synergistic application of BR and P. fluorescens represents a viable approach to strengthen the phytoextraction efficacy of S. alfredii in varying soils.
摘要：
植物生长调节剂（PGR）和植物生长促进细菌（PGPB）在重金属（HM）污染土壤的植物修复中具有潜力。然而,它们的单独应用可能不会产生最佳结果，因此需要联合应用。本研究旨在提高仙草的植物修复效率(S.alfredii）通过PGR（油菜素内酯，BR)和PGPB(荧光假单胞菌，P.荧光素）。BR和荧光假单胞菌(BRB处理)的组合有效地提高了大黄沙丁草对Cd的去除效率,Pb,锌分别为355.2和155.3％，470.1和128.9%，408.4和209.6%，在酸性和碱性土壤中，分别。此外，BRB处理导致光合色素含量和抗氧化酶活性大幅增加，导致在酸性和碱性土壤中生长的植物的生物量（86.71和47.22％）和干重（101.49和42.29％）显着增加，分别。同样，BRB处理显着升高了Cd（109.4和71.36％），铅（174.9和48.03%），和锌水平（142.8和104.3％）在S.alfredii芽，随着Cd的累积积累(122.7和79.47%)，铅（183.8和60.49%），和锌(150.7和117.9%)，分别。此外,BRB处理降低了土壤pH值和DTPA-HMs含量，在增强土壤酶活性的同时，从而促进土壤微生态，并促进HMs的吸收和转移。此外，修复后对叶际和根际微生物群落结构的评估揭示了微生物丰度的变化。联合处理改变了从细菌多样性到土壤HMs可用性对S.alfrediiHMs积累的主要影响。总之,我们的研究结果表明，协同应用BR和荧光假单胞菌代表了一种可行的方法，以加强植物提取的效率在不同的土壤。
