中文摘要：

为了认识林窗大小对凋落叶分解过程中微生物生物量的影响，以42年生的马尾松人工林7种不同大小林窗（G1：100m2、G2：225m2、G3：400m2、G4：625m2、G5：900m2、G6：1225m2、G7：1600m2）为研究对象，分析红椿凋落叶分解过程中微生物生物量碳（MBC）、氮（MBN）及其比值（MBC／MBN）随林窗面积和分解时间（30、90和180d）的动态变化，并对比这些指标在林窗中心和边缘的差异。结果显示：（1）林窗大小极显著影响了红椿凋落叶分解过程中的MBN，对MBC和MBC／MBN也有显著影响。总体上，中小型林窗（G1～G5）的微生物生物量较高。（2）各林窗中央与边缘间MBC、MBN、MBC／MBN虽有所差异，但并不显著。（3）分解时间对凋落叶中的MBC、MBN、MBC／MBN都有着极显著影响，在分解90d时，MBC和MBC／MBN最高，MBN最低。（4）MBC与温度、含水量极显著相关，MBN、MBC／MBN与温度的相关性也极显著。研究表明，林窗形成后温度和水分的改变显著影响了红椿凋落叶分解过程中的微生物生物量；其中，中小型（G1一G5）林窗能显著增加微生物生物量；MBC与MBN随分解时间的变化表现出相反的变化趋势。

英文摘要：

To understand the effects of forest gap on microbial biomass in the process of leaf litter decomposition, seven gap sizes （GI： 100 m2, G2：225 m2, G3：400 m2, G4：625 m2, GS： 900 m2, G6：1225 m2, G7：1600 m2） were created in a 42-year-old Pinus massoniana planta- tion, and uncut pure stand was used as a control. We investigated the dynamics of microbial bio- mass C （MBC）, N （MBN） and MBC/MBN in the process of leaf litter decomposition of Toona ciliata after 30, 90, and 180 days of incubation, and compared the differences of such parame- ters between the center and edge of the gaps. Our results showed that ： （ 1 ） the gap size signifi- cantly affected MBN, MBC and MBC/MBN. Overall, the microbial biomass in small and moder- ate forest gaps （G1-GS） was higher than that in large forest gaps. （2） There was no significantdifference in MBC, MBN and MBC/MBN between the center and the edge of each size of gap. （3） Decomposition time exhibited very significant effects on MBC, MBN and MBC/MBN. After 90 days of incubation, MBC and MBC/MBN were the highest, whereas MBN was the lowest. （4） MBC showed a very close correlation with both temperature and water content, while MBN and MBC/MBN were related to temperature significantly. Taken together, our results indicated that the alteration of soil temperature and moisture due to the formation of forest gaps significantly af- fected the microbial biomass in the process of T. ciliata litter decomposition, the small and mod- crate gaps （ G 1 - G5 ） could showed an opposite trend to significantly increase microbial MBN along with decomposition biomass, and the variation of MBC time.