模拟氮沉降对兴安落叶松林腐殖质层微生物数量及酶活性的影响

EFFECTS OF SIMULATED NITROGEN DEPOSITION ON MICROBIAL QUANTITY AND ENZYME ACTIVITIES OF HUMUS LAYER IN Larix gmelinii FOREST

对NH2Cl、KNO3和NH4NO33种氮肥设置低、中、高3个施氮水平,施加于兴安落叶松林(Larix gmelinii)样地。用常规的微生物计数及酶测定法分析了模拟大气氮沉降增加对兴安落叶松腐殖质微生物及酶活性的影响。结果表明施加NH4Cl、KNO3和NH4NO33种氮肥下,细菌数量随施氮水平的增加而显著提高;中氮水平l的NH4C和KNO3分别使放线菌数量提高;中氮水平的KNO3和NH4NO3使真菌数量增加。施加3种氮肥下,脲酶活性随着施氮水平的增加而提高;施加NH4Cl促进过氧化氢酶活性,但随氮水平提高而促进作用降低。高氮水平的KNO3和中氮水平的NH4NO3使过氧化氢酶活性提高;施加3种氮肥的实验结果均表明,低水平的氮肥可使蔗糖酶活性提高,而高水平的氮肥使蔗糖酶活性降低。

Three kinds of nitrogen( NH4 CL,KNO3and NH4NO3) at 3 different levels,low,intermediate and high,were applied in larix gmelinii forest sample in Daxinganling of Inner Mongolia. The effect of simulated nitrogen deposition on the humus microbial quantity and enzyme activities was analyzed by using the traditional method of microbial count and Enzyme assay. The results showed that the number of bacteria increased significantly with the increase of nitrogen level in the application of,and. The number of actinomyces increased with respective application of intermediate level of and. The number of fungi also increased with application of intermediate level of and. The enzyme activity of urease rose with the increasing application of three kinds of nitrogen. Applyingboosted the catalase activity at first,but such effect decreased as the increase of nitrogen level; the catalase activity increased respectively at high level ofand intermediate level of. The activity of invertase increased at low level,and decreased at high level of application of three kinds of nitrogen.