石油污染盐碱土壤棉花根际微生物与石油烃降解关系

Correlation between rhizosphere microbial community of Gossypium spp. and petroleum hydrocarbon degradation in the petroleum contaminated saline-alkali soil

【目的】探讨棉花(Gossypium spp.)生长对石油烃(TPH)污染盐碱土壤微生物群落结构的影响,揭示根际微生物与TPH降解的相关关系。【方法】利用磷脂脂肪酸(PLFA)方法解析根际土壤活性微生物群落随棉花生长的动态变化特征。【结果】根际土壤先后出现了21种PLFAs,包括:饱和脂肪酸(SAT),标识除放线菌之外的细菌;甲基支链末端型饱和脂肪酸(TBSAT),标识除放线菌之外的革兰氏阳性(G+)细菌;标识真菌的多不饱和脂肪酸(PUFA);标识放线菌的甲基支链中间型饱和脂肪酸(MBSAT);标识革兰氏阴性(G-)细菌的单不饱和脂肪酸(MONO)和环丙基脂肪酸(CYCLO)。棉花根际与未栽种棉花的对照(CK)相比,根际土壤微生物PLFAs种类在苗期、蕾期、吐絮期分别增加了100%、83.3%、20.0%,生物量分别增加了53.9%、6.60倍和60.7%;土壤TPH降解率分别提高13.0%、28.0%和30.6%。相关性分析表明:根际土壤TPH降解与根际土壤微生物总生物量具有低度正相关关系(|r|=0.5),但与a14:0、a16:0、i15:0标记的G+细菌生物量高度正相关(|r|≥0.8)。【结论】棉花生长对石油污染盐碱土壤活性微生物群落结构具有显著(P<0.05)的影响,且加速了土壤TPH的降解。该结果将为今后更好地开展石油污染盐碱土壤的生物修复技术研究提供理论依据。

[Objective] Open out the correlation between rhizosphere microbial community of Gossypium spp. and petroleum hydrocarbon（TPH） degradation in the petroleum contaminated saline-alkali soil. [Methods] Phospholipid fatty acid（PLFA） analysis method in different growing periods（seeding, bud and boll opening season） of Gossypium spp. was used to evaluate the microbial community diversity in the soil. [Results] It was found 21 kinds of PLFAs in the soil, including bacteria（except actinomycetes） biomarkers of saturated fatty acids（SAT）, fungi species biomarkers of polyunsaturated fatty acid（PUFA）, actinomycetes biomarkers of middle branched saturated fatty acids（MBSAT）, Gram positive（G＋） bacteria（except actinomycetes） biomarkers of terminal branched saturated fatty acids（TBSAT）, Gram negative bacteria（G-） biomarkers of monounsaturated fatty acids（MONO） and Cyclopropyl fatty acids（CYCLO）. There are significant differences on microbial diversity in the rizosphere soil between the Gossypium spp. and without cotton（CK）, the differences were also observed in the different growth periods. Compared with the CK, the microbial diversity increased by 100%, 83.3%, and 20.0% and biomass of soil microbes increased by 53.9%, 6.60 times, and 60.5% for seedling, bud and boll opening periods, respectively. In addition, when Gossypium spp. was grown in the petroleum contaminated saline-alkali soil, the degradation rates of total petroleum hydrocarbon（TPH） in the rhizosphere soils increased by 13.0%, 28.0% and 30.6% in seedling, bud and boll opening periods, respectively. Correlation analysis（Spearman method） was used to determine the correlation between the soil microbial community and the TPH degradation. Although the total soil microbial biomass had a low correlation with TPH degradation with a correlation coefficient ｜r｜=0.5, whereas i15：0, a14：0, a16：0 had a high positive correlation with the correlation coefficient ｜r｜≥0.8. [Conclusion] The study indicate that the structure and the biomass of the soil microbial community have significant changed（P0.05） and the TPH degradation have improved in the rhizospheres soils of Gossypium spp.. The planting of Gossypium spp. can effectively improve TPH contaminated saline-alkali soil, and the results have a great reference value in application of TPH contaminated saline-alkali soil.