| 摘要: |
| 【目的】探讨水稻土中微生物Fe(Ⅲ)还原过程与磷酸盐质量浓度之间的关系。【方法】以6种不同来源（吉林永吉、黑龙江东宁、天津宝坻、天津塘沽、四川邛崃和江西南昌）的水稻土为材料，对水稻土浸提液和泥浆进行厌氧培养试验，向培养体系中添加磷酸盐后，使土壤浸提液中磷酸盐质量浓度分别为30.97，61.94，123.88，247.66和 371.64 mg/L，泥浆培养体系中最终磷含量分别为52，103，206，413和619 mg/kg，均以不添加磷酸盐为对照，测定培养期间土壤浸提液和泥浆中Fe(Ⅱ)、有效磷含量的变化。【结果】在土壤浸提液培养试验中，添加30.97 mg/L的磷酸盐对微生物Fe(Ⅲ)还原过程有明显促进作用，而高质量浓度（371.64 mg/L）磷酸盐对Fe(Ⅲ)还原具有明显抑制作用；采自江西南昌和四川邛崃的水稻土浸提液中Fe(Ⅲ)还原比较迅速，而采自吉林永吉和天津塘沽的土壤浸提液中Fe(Ⅲ)还原较为缓慢；采自天津宝坻和四川邛崃的土壤浸提液中Fe(Ⅲ)还原微生物对磷酸盐质量浓度的适应范围较大，采自江西南昌、吉林永吉、黑龙江东宁的酸性水稻土浸提液中Fe(Ⅲ)还原微生物对磷酸盐质量浓度变化比较敏感；有效磷质量浓度在不同pH值的土样中表现出不同的变化趋势，采自江西南昌、吉林永吉、黑龙江东宁的酸性土壤浸提液体系中有效磷质量浓度没有明显改变，而采自天津宝坻、四川邛崃、天津塘沽的石灰性土壤浸提液体系中有效磷质量浓度在培养初期呈降低趋势。在泥浆厌氧培养试验中，磷酸盐对Fe(Ⅲ)还原的影响程度与土壤浸提液的培养试验相比明显减弱，通过Fe(Ⅲ)还原特征参数可以看出，不同磷酸盐处理间仍然存在一定的显著性差异。在酸性水稻土中，被固持的有效磷随Fe(Ⅲ)还原过程的进行被不断释放，有效磷的增加幅度与Fe(Ⅲ)还原能力的排序一致；在碱性水稻土中，加入的磷酸盐在培养前期被大量固定，有效磷含量均明显降低。【结论】厌氧环境中的微生物Fe(Ⅲ)还原过程与磷酸盐质量浓度相互影响，高质量浓度磷酸盐对Fe(Ⅲ)还原均具有明显的抑制作用。磷酸盐对Fe(Ⅲ)还原的影响与pH值有关，在酸性条件下，随着Fe(Ⅲ)被微生物还原成Fe(Ⅱ)，被吸附的磷得以释放，有效磷质量浓度增加；在碱性条件下，有效磷质量浓度随Fe(Ⅲ)被还原而降低。 |
| 关键词: 微生物Fe(Ⅲ)还原 磷酸盐 水稻土 厌氧培养 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金面上项目（41171204） |
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| Relationship between microbial Fe(Ⅲ) reduction process and phosphate mass concentration |
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ZHOU Xing,QU Dong
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| Abstract: |
| 【Objective】The experiment was carried out to study the relationship between microbial Fe(Ⅲ) reduction process and phosphate mass concentration.【Method】The slurry and bacterial suspension from six paddy soils (Yongji,Jilin,Dongning,Heilongjiang,Baodi,Tianjin,Tanggu,Tianjin,Qionglai,Sichuan and Nanchang,Jiangxi) were added to different concentrations of phosphate before being incubated under anaerobic conditions.The mass concentrations of phosphate were 30.97,61.94,123.88,247.66 and 371.64 mg/L in bacterial suspension incubation,and the final phosphate contents were 52,103,206,413 and 619 mg/kg in slurry anaerobic incubation,respectively.The case without addition of phosphate was used as control (CK).The mass concentrations of Fe(Ⅱ) and available phosphorus were measured regularly during the incubation.【Result】Adding 30.97 mg/L phosphorus had significant promoting effect on microbial Fe(Ⅲ) reduction in bacterial suspension incubation,but high mass concentrations of phosphate (371.64 mg/L) had inhibitory effect on Fe(Ⅲ) reduction.Fe(Ⅲ) was reduced fast in soils from Nanchang and Qionglai,but slowly in soils from Yongji and Tanggu.Microorganisms from Baodi and Qionglai adapted a wide range of phosphate concentration,but they were more sensitive to change of phosphate concentration in acid bacterial suspension system (Nanchang,Yongji and Dongni).The mass concentration of available phosphorus varied differently in soils with different pH:no significant change in acid bacterial suspension system,but it declined at the beginning of alkaline incubation system (Baodi,Qionglai and Tanggu).Phosphate had less influence on Fe(Ⅲ) reduction in slurry anaerobic incubation than that in bacterial suspension incubation,which was confirmed from the dynamics fitting parameters of Fe(Ⅲ) reduction.The immobilized available phosphorus was released as Fe(Ⅲ) was reduced in acid paddy soils,and the order of available phosphorus increment was consistent with the maximum Fe(Ⅱ) accumulation. In alkaline paddy soils,however,phosphate was immobilized at the beginning of incubation,and available phosphorus decreased significantly.【Conclusion】Mutual effect between the microbial Fe(Ⅲ) reduction and phosphate existed in anaerobic environment.High concentrations of phosphate had significant inhibitory effect on Fe(Ⅲ) reduction.The effect of Fe(Ⅲ) reduction on phosphate was related to pH.As Fe(Ⅲ) was reduced to Fe(Ⅱ) by microorganisms,available phosphorus mass concentration increased with the release of adsorbed phosphate in acidic conditions.Available phosphorus mass concentration decreased as Fe(Ⅲ) was reduced in alkaline conditions. |
| Key words: microbial Fe(Ⅲ) reduction phosphate paddy soil anaerobic incubation |
