中文摘要：

主导的树崽分解上的 understory 植物垃圾的效果很好没特别在半干旱的森林里被记录。在这研究，我们使用了一个缩影实验检验二 understory 种(Artemisia scoparia 和 Setaria viridis ) 的效果集体损失和蒙古的松的 N 版本上的垃圾(Pinus sylvestris var。mongolica ) 在 Keerqin 沙的陆地的垃圾，东北中国，并且从分解垃圾的化学质量识别了影响机制。四崽联合被建立：蒙古的松的一个单一经营和在每种的相等的集体比例的蒙古的松和一或二 understory 种的三混合物。全部的 C，全部的 N，木质素，纤维素和多酚集中，和松垃圾的集体损失在天被分析 84 孵化和 182。松垃圾的化学不仅随着分解的阶段变化了，而且被 understory 种类的存在强烈也在分解期间影响。两 understory 种在 84 点支持了松垃圾的集体损失 ? 天，当仅仅二 understory 种的同时的存在支持了松的集体损失时，在 182 点乱丢东西 ? 天。松垃圾的集体损失否定地在全部潜伏期期间与崽联合的 C/N， lignin/N 和 polyphenol/N 的起始的比率被相关；在 182 点 ? 天它否定地在 84 点与多酚集中和 C/N 的比率和崽联合的 polyphenol/N 被相关 ? 孵化的天。松垃圾的氮版本面对 understory 种类被支持。在 84 点的氮版本 ? 天否定地与起始的 N 集中被相关；在 182 点 ? 天它否定地与崽联合的起始的多酚集中被相关并且断然在 84 点与崽联合的木质素集中相关 ? 孵化的天。我们的结果建议 understory 种类的存在在能对松垃圾的随后的分解施加强烈影响的松垃圾的化学部件引起实质的变化。

英文摘要：

The effects of understory plant litter on domi- nant tree litter decomposition are not well documented especially in semi-arid forests. In this study, we used a microcosm experiment to examine the effects of two understory species （Artemisia scoparia and Setaria viridis） litter on the mass loss and N release of Mongolian pine （Pinus sylvestris var. mongolica） litter in Keerqin Sandy Lands, northeast China, and identified the influencing mechanism from the chemical quality of decomposing litter. Four litter combinations were set up： one monocul- ture of Mongolian pine and three mixtures of Mongolian pine and one or two understory species in equal mass proportions of each species. Total C, total N, lignin, cel- lulose and polyphenol concentrations, and mass loss of pine litter were analyzed at days 84 and 182 of incubation.The chemistry of pine litter not only changed with the stages of decomposition, but was also strongly influenced by the presence of understory species during decomposition. Both understory species promoted mass loss of pine litter at 84 days, while only the simultaneous presence of two understory species promoted mass loss of pine litter at 182 days. Mass loss of pine litter was negatively correlated with initial ratios of C/N, lignin/N and polyphenol/N of litter combinations during the entire incubation period; at 182 days it was negatively correlated with polyphenol concentration and ratios of C/N and polyphenol/N of litter combinations at 84 days of incubation. Nitrogen release of pine litter was promoted in the presence of understory species. Nitrogen release at 84 days was negatively correlated with initial N concentration; at 182 days it was negatively correlated with initial polyphenol concentration of litter combinations and positively correlated with lignin concentration of litter com- binations at 84 days of incubation. Our results suggest that the presence ofunderstory species causes substantial changes in chemical components of pine litter that can exert strong influences on