微孔板荧光法对土壤糖酶活性的测定研究

应用荧光共轭物质作为底物，将96微孔板和荧光检测法结合进行稻-麦轮作系统CO₂倍增条件(FACE)下土壤两种糖酶(木聚糖酶和纤维素酶)活性的测定，探讨了微孔板结合荧光法测定糖酶活性的可行性。结果表明，此种方法可以灵敏的检测到土壤稀释液中的糖酶活性，测定结果重现性较好(变异系数最大为4.879%)。与传统的分光光度法相比，是一种准确、快速、简便的土壤糖酶活性测定方法。CO₂倍增条件下土壤木聚糖酶活性高于自然条件，且在小麦的拔节期，抽穗期和成熟期及水稻的抽穗期和成熟期显著高于对照(P<0.05)，CO₂浓度升高提高作物的生长代谢水平，进而影响微生物活性造成土壤木聚糖酶活性提高。纤维素酶活性在CO₂倍增条件下未发生显著变化，说明土壤纤维素酶在短时期内对CO₂增加的响应不显著。

A Microplate Fluorimetric Assay for Sacchariase Activity Measurement

With the fluorescent compound conjugates substrates, soil xylanase and cellulose in a free-air carbon dioxide enrichment (FACE) experiment were measured on the base of 96 microplate and fluorescence detection, aiming at testing its feasibility in sacchariase activity measurement. The results show that sacchariase activity can be tested and the data exhibit better repeatability（coefficient of variability≤4.879%）. Compared with spectrophotometric assay, this method allows a large number of soil samples and/or enzymes to be analyzed in a short time accurately and conveniently. Soil xylanase activity tends to be greater at elevated CO2 which significantly increases in jointing, heading and ripening stages of wheat and in heading and ripening stages of rice (P<0.05), and the crop metabolizes rapidly under FACE condition and soil microorganisms are affected, which causes elevation of xylanase acitivy. Compared with ambient CO2, soil cellulose activity decreased slightly under elevated CO2 but there was no significant difference between treatments, indicating the cellulose activity was not influenced intensively in a short time.