亚热带森林凋落物层土壤酶活性的季节动态

Enzyme activities in litter, fragmentation and humus layers of subtropical forests

凋落物分解是森林生态系统养分循环中至关重要的过程。凋落物的分解与凋落物中的分解酶的活性直接相关。本研究调查了亚热带常绿阔叶林与针叶林中与土壤碳氮元素循环有关的β-糖苷酶(β-glucosidase)、内切纤维素酶(endocellulase)和几丁质酶(chitobiase)活性的季节变化规律。结果表明:在两个群落中,3种土壤酶活性与温度之间都有一定相关性,最高值均出现在温度较高的七月份;阔叶林中三种酶的活性在各个季节中大小顺序都为未分解凋落物层(L)>半分解层(F)>腐殖质层(H),而针叶林中则是半分解层(F)>未分解凋落物层(L)>腐殖质层(H);在每个取样时间点β-糖苷酶和几丁质酶的活性最高值都在阔叶林L层,显著高于针叶林L层,而内切纤维素酶的活性最高值是在针叶林H层。两林型下酶活性动态的差异,可能是导致两林型下凋落物层残存量差别的一个重要原因。

The aim of the study was to investigate enzyme activities in different layers in Huangshan forests floors. Hence, activities of chitobiase, endocdlulase and β-glucosidase were investigated in litter （L）, fragmentation （F） and humus （H） layers collected seasonal periods from the broadleaf fore, st and coniferous forest. The results show that chitobiase, endocellulase and β-glucosidase activities were ranked in order L〉 F 〉 H under broadleaf forest, but in order F 〉 L 〉 H in conifouse forest. On a seasonal scale, the highest activities of all enzymes were observed in July both under broadleaf forest and coniferous forest. In general enzymes activities values were significantly higher in layer of L than of H and F layers under broadleaf forest, but under coniferous forest the values were higher in layer of F than of L and H layers in all sampling times. The different enzyme dynamics may be one of the important reasons of the different litter quantity between broadleaf forest and coniferous forest.