Abstract
Petroleum hydrocarbon pollutants in soil are challenging to biodegrade, negatively impacting plant growth as well as the metabolic activity and community structure of soil microorganisms. Microorganisms immobilized by seed carriers can synergistically contribute to the remediation of petroleum hydrocarbon-contaminated soil. We prepared a rape seed carrier with immobilized microorganism by seed coating (with a mixture of diatomaceous earth and bentonite as fillers) and microbial immobilization. A pot experiment was conducted with the following treatments: control (CK, neither seeds nor microorganisms added), bare rapeseed (T1), rapeseed coated with diatomaceous earth and bentonite (T2), free-living Pseudomonas aeruginosa added (T3), rapeseed coated with diatomaceous earth and bentonite plus free-living P. aeruginosa (T4), and rapeseed coated with diatomaceous earth and bentonite immobilized with P. aeruginosa (T5). We measured rape seed growth, rhizosphere microbial community structure, and petroleum hydrocarbon removal efficiency. The results showed that 1) There were no significant difference in seed germination rate among T1, T2, T4, and T5 treatments. Compared to T1, leaf length, root length, biomass, and soluble protein content of rape seed significantly increased in T4 and T5 treatments, while T2 treatment showed no significant effect. Leaf width, stem length, chlorophyll content, and superoxide dismutase activity of rape seed in T2, T4, and T5 treatments were significantly higher than T1, while malondialdehyde content was signi-ficantly lower. 2) Compared to CK, the removal rate of petroleum hydrocarbon in the T1, T2, T3, T4, and T5 treatments increased by 0.8, 1.6, 0.5, 1.8, and 2.2 times, respectively. The T5 treatment achieved the highest petro-leum hydrocarbon removal rate of 54.0%. Soil dehydrogenase activity in all treatments increased significantly, with a positive correlation with the petroleum hydrocarbon removal rate (r=0.893). 3) The T5 treatment had the highest soil microbial α diversity and the abundances of Chloroflexi and Acidobacteria. In conclusion, seed carriers with immobilized microorganisms could regulate plant growth, modify the structures of microbial communities, enhance the biological activity of soil enzymes, thereby improving petroleum hydrocarbon removal efficiency. This provides a novel environmentally friendly approach for the joint remediation of petroleum hydrocarbon-polluted soil by plants and microorganisms.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call