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为探讨Cd污染胁迫与洞庭湖湿地土壤微生物学特性之间的内在关系,通过野外土样采集和室内模拟胁迫相结合的方法,研究Cd污染胁迫对洞庭湖湿地土壤微生物数量和微生物活性的影响。结果表明,当Cd胁迫浓度为3 mg kg~(-1)时对洞庭湖湿地土壤细菌、微生物总数及土壤微生物生物量碳(SMBC)刺激作用显著,当Cd胁迫浓度为6 mg kg~(-1)时对真菌有显著的刺激作用,而对细菌、放线菌、微生物总数及微生物生物量氮(SMBN)均表现出抑制作用,且随Cd胁迫浓度的进一步增加对细菌、真菌、放线菌、微生物总数及SMBC、SMBN的抑制作用增强;土壤脲酶、蔗糖酶、过氧化氢酶、磷酸酶和脱氢酶活性随Cd胁迫浓度的增加而降低;土壤基础呼吸(SBR)与代谢墒(qCO_2)随Cd胁迫浓度的增加呈上升趋势。放线菌、SMBC、SMBN、土壤脲酶活性、蔗糖酶活性、过氧化氢酶活性、磷酸酶活性、脱氢酶活性、SBR及qCO_2与Cd胁迫浓度相关显著或极显著;Cd胁迫条件下脱氢酶活性的变异系数最大为50.0%,表明脱氢酶活性的变化对Cd胁迫反映最为敏感,可作为洞庭湖湿地Cd污染土壤质量评价的灵敏指标。
In order to investigate the relationship between Cd pollution and soil microbiological characteristics in Dongting Lake wetland, the effects of Cd pollution on soil microbial population and microbial activity in the Dongting Lake wetland were studied by field sampling combined with simulated indoor stress. The results showed that when Cd concentration was 3 mg kg ~ (-1), the effect of stimulating bacteria, microbial population and soil microbial biomass carbon (SMBC) in soil of Dongting Lake wetland was significant. When the Cd stress concentration was 6 mg kg ~ (-1) 1) had significant stimulating effects on the fungi, but showed an inhibitory effect on the bacteria, actinomycetes, the total number of microbes and the microbial biomass nitrogen (SMBN), and inhibited the growth of bacteria, fungi and bacteria with the further increase of Cd stress concentration The activity of soil urease, sucrase, catalase, phosphatase and dehydrogenase decreased with the increase of Cd stress concentration. Soil basal respiration (SBR) and metabolic entropy qCO_2) increased with the increase of Cd stress concentration. Actinomycetes, SMBC, SMBN, soil urease activity, invertase activity, catalase activity, phosphatase activity, dehydrogenase activity, SBR and qCO 2 were significantly or extremely significantly correlated with Cd stress concentration. Under Cd stress, The coefficient of variation of enzyme activity was up to 50.0%, which indicated that the change of dehydrogenase activity was the most sensitive to Cd stress and could be used as sensitive index to evaluate Cd pollution soil quality in Dongting Lake wetland.