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微生物电子传递体系(ETS)活性是反映微生物活性的一个重要指标。为了解湿地环境中微生物活性的特征,探讨湿地植物根际土壤微生物活性对湿地生态系统物质循环的影响,以白洋淀湿地典型植物芦苇为研究对象,分析了不同水位条件下芦苇根际土壤微生物ETS活性的季节变化规律。结果表明,根际土壤ETS活性季节变化明显,呈现先上升后下降的趋势。ETS活性在夏季较高,8月前后出现最大值,淹水区、水陆交错区和台地的最大值分别为0.08 mg O_2/(g·h)、0.084 mg O_2/(g·h)、0.13 mg O_2/(g·h),随后逐步下降;在冬季较低,淹水区、水陆交错区和台地的最小值分别为0.027mg O_2/(g·h)、0.037 mg O_2/(g·h)、0.045 mg O_2/(g·h),出现在12月前后,最大值约为最小值的3倍。相关性分析指出其活性变化与气温变化呈显著正相关(p<0.01)。不同水位条件下ETS活性从大到小依次为台地、水陆交错区、淹水区。其中,台地区和水陆交错区根际土壤ETS活性与淹水区相比均存在显著差异(p<0.01),其活性分别为淹水区的1.8倍和1.2倍。芦苇根际沉积物TN、NH+4及NO_3~-质量比呈现相似的季节变化趋势。最大值出现在6月1日,淹水区、水陆交错区、台地区TN质量比峰值的范围在2.8~3.4 mg/g,NH_4~+质量比峰值的范围在72.0~78.3μg/g,NO_3~-质量比峰值的范围在20.0~28.5μg/g;最小值出现在9—10月,淹水区、水陆交错区、台地区质量比最低值的范围在0.6~1.6 mg/g,NH+4质量比最低值的范围在8.1~15.0μg/g,NO_3~-质量比最低值的范围在5.1~9.7μg/g。其中,水陆交错区ETS活性与土壤中TN和NH+4质量比的相关性极其显著(p<0.01),淹水区ETS活性与土壤中NH_4~+质量比相关性极其显著(p<0.01),其他条件下ETS活性与土壤中氮素质量比均无显著相关性。由此可见,湿地植物根际土壤ETS活性不仅受到水位和气温变化的影响,还可能与土壤中TN和NH+4含量相关。因此,在评价湿地土壤质量变化时,除考虑土壤微生物量等敏感指标外,还应获得环境因素等其他信息,为正确快速评价土壤微生物群落和土壤质量变化提供参考。
Microbial electron transport system (ETS) activity is an important indicator of microbial activity. In order to understand the characteristics of microbial activity in wetland environment and to explore the effect of rhizospheric soil microbial activity on wetland ecosystem material circulation in wetland plants, the ETS activity of rhizosphere soil microbial biomass under different water level conditions The seasonal variation. The results showed that the seasonal variation of ETS activity in rhizosphere soils showed a trend of rising and then declining. The maximum value of ETS activity was found in summer and around August, and the maximum values of flooding zone, land-water interlacing zone and platform were 0.08 mg O_2 / (g · h), 0.084 mg O_2 / (g · h), 0.13 mg O_2 / (g · h), and then decreased gradually. In the winter, the minimum value was 0.027mg O_2 / (g · h) and 0.037 mg O_2 / (g · h) in the flooded area, , 0.045 mg O 2 / (g · h), appeared in December before and after the maximum value is about 3 times the minimum. Correlation analysis indicated that there was a significant positive correlation between changes of activity and temperature (p <0.01). Under different water conditions ETS activity from descending order of platform, land and water interlaced area, flooded area. Among them, the ETS activity in rhizosphere soils in the Taiwan area and the land-water intercourse area were significantly different from those in the flooded area (p <0.01), and their activities were 1.8 times and 1.2 times that of the flooded area respectively. The TN, NH + 4 and NO 3 - - mass ratio of rhizosphere sediments showed a similar seasonal trend. The maximum value appeared on June 1, the range of peak value of TN mass ratio was 2.8-3.4 mg / g, and the peak value of NH 4 + mass ratio was 72.0-78.3 μg / g in flooded area, water-land interlaced area and Taiwan area, NO 3 ~ - mass ratio peaks ranged from 20.0 to 28.5 μg / g, and the minimum appeared from September to October. The mass ratio of flooding zone, water-land interlacing zone and station area ranged from 0.6 to 1.6 mg / g, NH + 4 in the range of 8.1 ~ 15.0μg / g and the lowest NO_3 ~ - mass ratio ranged from 5.1μg / g to 9.7μg / g. Among them, the correlation between ETS activity and the mass ratio of TN and NH + 4 in soil was extremely significant (p <0.01), and the correlation between ETS activity in flooded area and NH 4 + mass ratio in soil was extremely significant (p <0.01) Under other conditions, there was no significant correlation between ETS activity and soil N content. Thus, the ETS activities of rhizospheric soil in wetland plants are not only affected by the changes of water level and temperature, but also with the contents of TN and NH + 4 in soil. Therefore, in evaluating wetland soil quality changes, besides the sensitive indicators such as soil microbial biomass, other information such as environmental factors should also be obtained to provide a reference for the correct and rapid assessment of soil microbial community and soil quality changes.