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选取长白山针叶林与阔叶林A层土壤,以0.25~12.5 mmol L~(-1)不同终浓度2,2’-连氮-双(3-乙基苯并噻唑-6-磺酸)(ABTS)为底物,考察漆酶氧化产物在0~32、0~54和0~95 min吸光值线性变化率,并藉此获得3个不同时间段线性拟合漆酶活力值;以一级反应动力学方程拟合最大吸光值增幅及相应平均反应时间,计算吸光值平均变化率,并藉此获得非线性拟合漆酶活力值。当ABTS浓度为7.5 mmol L~(-1)时,反应体系吸光值增幅和酶活最大。阔叶林反应体系吸光值增量显著大于针叶林,前者在0~300 min持续增加,且不同算法间漆酶活力差异不显著;后者仅在0~21 min显著变化,且非线性拟合漆酶活力值显著高于线性拟合。非线性拟合测算的漆酶活力变异系数整体上低于线性拟合。因此,森林土壤漆酶活力测定应重视酶底物浓度、反应时间、算法和林分条件变化带来的显著影响。
The soil of A layer in coniferous forest and broadleaf forest of Changbai Mountain was selected and treated with different concentrations of 2,2’-azinobis (3-ethylbenzothiazole-6-sulfonic acid) (ABTS) as substrates, the linear change rate of absorbance of laccase oxidation products at 0-32, 0-54 and 0-95 min was investigated. The laccase activity of laccase was linearly adjusted in three different time periods. The kinetic equation of level reaction fitted the increase of maximum absorbance value and the corresponding average reaction time, and calculated the average rate of change of absorbance, and obtained the value of nonlinear fitting laccase activity. When the concentration of ABTS was 7.5 mmol L -1, the increase of absorbance and the activity of enzyme in the reaction system were the highest. The increment of absorbance of broad-leaved forest reaction system was significantly larger than that of coniferous forest. The former increased continuously from 0 to 300 min and the laccase activity was not significantly different among different algorithms. The latter only changed significantly from 0 to 21 min, Co-laccase activity was significantly higher than the linear fit. The coefficient of variability of laccase activity measured by non-linear fit was lower than the linear fit as a whole. Therefore, the determination of laccase activity in forest soil should pay attention to the significant influence of enzyme substrate concentration, reaction time, algorithm and change of stand conditions.