Measurement of dehydrogenase activity in acid soils rich in organic matter
Measurement of dehydrogenase activity in acid soils rich in organic matter
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DOI：
10.1016/s0038-0717(98)00010-8
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发表时间：
1998-08-01
影响因子：
9.7
通讯作者：
Leiros, C
中科院分区：
文献类型：
--
作者：
Camina, F;Trasar-Cepeda, C;Leiros, C
脱氢酶活性可以被认为是土壤微生物氧化活性的一个很好的指标。II通常是通过测量被微生物活性还原的人工电子受体的量来确定的，例如具有红色还原形式的可溶性四氮唑盐（福马甲酸），可以在用合适的溶剂提取后用比色法测定。在早期对加利西亚（西班牙西北部）富含酸性有机物的森林土壤的研究中，测量到的脱氢酶活性很低，与显示高生物活性的呼吸活动数据不同。为了研究这些低脱氢酶活性是否由于甲醛的吸附而被低估，我们研究了6种土壤与碘化四氮唑甲醛（INTF）的相互作用。同时，比较了甲醇和1:1二甲甲酰胺-乙醇（dmf -乙醇）两种萃取剂对INTF的萃取能力。结果表明，土壤对INTF的吸附强度与土壤碳含量密切相关，因此每种土壤对脱氢酶活性的低估程度不同。1:1的dmf -乙醇混合物比甲醇更有效地提取INTF，从而提高脱氢酶活性的估计。采用含有土壤的参比标准，对每种土壤分别建立校正曲线，可实现对INTF吸附效应的校正。这些标准是在测定脱氢酶活性的相同条件下，将不同浓度的INTF与土壤混合而成的。因此，建议使用dmf -乙醇和含有土壤的参考标准来测定脱氢酶活性，至少在与本文研究的性质相似的土壤中是这样。1998爱思唯尔科学有限公司版权所有。
Dehydrogenase activity can be considered to be a good measure of microbial oxidative activity in soils. II is usually determined by measuring the amount of an artificial electron acceptor reduced by microbial activity, such as a soluble tetrazolium salt with a red colored reduced form (a formazan) that can be determined colorimetrically following extraction with a suitable solvent. In an earlier study of acid organic-matter rich forest soils of Galicia (N.W. Spain), measured dehydrogenase activities were low, at variance with respiratory activity data indicating high biological activity. To investigate the possibility that these low dehydrogenase activities were underestimated due to adsorption of the formazan, we have studied the interaction of six soils with iodonitotetrazolium formazan (INTF). At the same time, the capacities of two extractants, methanol and 1:1 dimethylformamide-ethanol (DMF-ethanol), to extract INTF were compared. The results show that INTF is adsorbed by the soils studied with an intensity that closely correlates with soil carbon content, and that dehydrogenase activity is thus underestimated to a different degree for each soil. A mixture of 1:1 DMF-ethanol was more effective than methanol in extracting INTF, thereby improving estimates of dehydrogenase activity. Correction for the effects of INTF adsorption could be achieved by using reference standards containing soil to construct a separate calibration curve for each soil. These standards were prepared by incorporating different concentrations of INTF with the soil under the same conditions used for determination of the dehydrogenase activity. The use of DMF-ethanol and reference standards containing soil is thus recommended for determination of dehydrogenase activity, at least in soils with similar properties to those studied here. (C) 1998 Elsevier Science Ltd. All rights reserved.