中文摘要：

植物根流出物包含包括葡萄糖的各种各样的器官、无机的部件，柠檬性并且草酸酸。这些部件影响微生物引起的根围和 microfaunal 活动，而是机制充分不被知道。从降级的草地生态系统担心低土壤碳(C) 内容的研究是稀罕的，尽管有需要恢复的草地的全球分发。都，这些为碳隐遁有一个高潜力，与由于 overutilization 的一个减少的碳内容。很快分解的一个流出物部件将增加土壤呼吸和 CO2 排放，当减少本国的土壤碳的分解的一个部件能减少 CO2 排放并且实际上帮助扣押时在土壤的碳。因此，在根围活动，柠檬性的酸，葡萄糖和草酸酸( 0.6 g C/kg 干燥土壤)完成调查根流出物从位于 Naiman 的三 biotopes (草地，固定沙丘和活动沙丘)被加到土壤， Horqin 沙的土地，内部蒙古，中国)并且和控制使遭到了到一个24天的孵化实验。土壤也为一般土壤性质被分析。结果证明没有流出物增加的那全部的呼吸在草地土壤是最高的，在固定沙丘中间、在活动沙丘土壤最低。然而，本国的土壤碳的比例使矿物化，反映最高，在活动沙丘，土壤在那里发现了的低 C/N 比率是。CO2-C 排出物和另外的变量上的流出物效果在 biotopes，而是全部的呼吸之间有点不同(从增加的底层包括那) 显著地与控制相比在所有联合被增加除了活动沙丘土壤的草酸酸增加，它从本国的土壤减少了 CO2-C 排出物碳。由在草地和固定沙丘土壤的流出物增加的 pH 的小却统计上重要的增加被观察，但是从酸增加有主要减少到活动沙丘土壤。相反，电的电导率在草地减少了并且修理了沙丘土壤并且在活动沙丘增加了。因此，影响的根流出物的分离部件不同地玷污环境条件，并且对在有低碳内容的土壤的根流出物的回答能在正常土壤不同于那些。结果显示一个潜力因为，例如，到减少分解的酸根流出物

英文摘要：

Plant root exudates contain various organic and inorganic components that include glucose, citric and oxalic acid. These components affect rhizosphere microbial and microfaunal activities, but the mechanisms are not fully known. Studies concerned from degraded grassland ecosystems with low soil carbon（C） contents are rare, in spite of the global distribution of grasslands in need of restoration. All these have a high potential for carbon sequestration, with a reduced carbon content due to overutilization. An exudate component that rapidly decomposes will increase soil respiration and CO2 emission, while a component that reduces decomposition of native soil carbon can reduce CO2 emission and actually help sequestering carbon in soil. Therefore, to investigate root exudate effects on rhizosphere activity, citric acid, glucose and oxalic acid（0.6 g C/kg dry soil） were added to soils from three biotopes（grassland, fixed dune and mobile dune） located in Naiman, Horqin Sandy Land, Inner Mongolia, China） and subjected to a 24-day incubation experiment together with a control. The soils were also analyzed for general soil properties. The results show that total respiration without exudate addition was highest in grassland soil, intermediate in fixed dune and lowest in mobile dune soil. However, the proportion of native soil carbon mineralized was highest in mobile dune soil, reflecting the low C/N ratio found there. The exudate effects on CO2-C emissions and other variables differed somewhat between biotopes, but total respiration（including that from the added substrates） was significantly increased in all combinations compared with the control, except for oxalic acid addition to mobile dune soil, which reduced CO2-C emissions from native soil carbon. A small but statistically significant increase in pH by the exudate additions in grassland and fixed dune soil was observed, but there was a major decrease from acid additions to mobile dune soil. In contrast, electrical conductivity decreased in grassland