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作 者 ：邓仁菊^{1, 2};杨万勤¹;吴福忠¹

期 刊 ：应用生态学报 2009年 20卷 05期 页码：1026-1031

关键词：冷杉；

摘 要 ：为了了解季节性冻融对亚高山森林生态系统过程的影响，2006年10月—2007年10月，采用凋落物分解袋法，研究了冻融和非冻融处理下岷江冷杉和白桦凋落物的酶活性动态.结果表明：凋落物的酶活性均具有明显的月变化，但活性高峰与酶类有关;季节性冻融显著影响了冷杉和白桦凋落物分解过程中的转化酶、纤维素酶、脲酶和脱氢酶活性(P＜0.05).冻融处理使冷杉凋落物分解过程中的转化酶、纤维素酶和脲酶活性在生长季节内分别增加了66.1%、14.8%和76.3%，但脱氢酶活性降低了18.4%;冻融处理使白桦凋落物分解过程中的转化酶活性增加了39.4%，但脲酶、纤维素酶和脱氢酶活性分别降低了18.2%、28.7%和15.6%.冻融处理对两种凋落物的过氧化物酶和多酚氧化酶活性影响不显著.说明季节性冻融对亚高山森林凋落物分解过程具有不同程度的影响，其影响程度与凋落物种类和分解阶段有关.

Abstract:To understand the effects of seasonal freeze-thaw on the ecological processes of subalpine forest ecosystem, the enzyme activities in Abies faxoniana and Betula platyphylla litters under freeze-thaw were measured from October 2006 to October 2007 by the method of litter bags. There was an obvious monthly change in the enzyme activities, but the peak time varied with enzymes. Compared to the control, freeze-thaw had significant effects on the activities of invertase, urease, cellulase, and dehydrogenase in the litters (P＜005). Over a growth season, the invertase, cellulase, and urease activities in fir litter increased by 661%, 148%, and 763%, respectively while dehydrogenase activity decreased by 184%, and the invertase activity in birch litter increased by 394% while the urease, cellulase and dehydrogenase activities decreased by 182%, 287% and 156%, respectively. As for the activities of peroxidase and polyphenol oxidase in fir and birch litters, they were less affected by freeze-thaw. All of these revealed that seasonal freez
e-thaw had definite effects on the litter decomposition of subalpine forest, which closely related to the kind of litter and its decomposition stage.

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