中文摘要：

【目的】Bt棉已在我国种植广泛。而温室气体（CO2和O3）浓度升高会进一步改变植物的化学成分,从而通过凋落物可能会引起土壤动物（甲螨）种群数量的变化。【方法】本文应用开顶式气室（OTC）,研究了CO2和O3浓度升高下转Bt棉花凋落物对土壤甲螨种群数量的影响。【结果】研究结果发现,不同取样时间对甲螨种群数量有显著影响,甲螨种群数量的最高值出现在7月份的采样中。CO2浓度升高通过棉花凋落物显著降低了甲螨的种群数量。O3浓度升高通过棉花凋落物降低了常规棉凋落物中的甲螨种群数量,对转Bt作物凋落物中甲螨种群数量无显著影响。【结论】不同温室气体（CO2和O3）浓度升高对土壤甲螨作用不同,其中CO2浓度升高通过棉花凋落物可以显著降低土壤动物的种群数量,而O3浓度升高作用较小。转Bt作物可以缓冲温室气体（CO2和O3）浓度升高通过作物凋落物对土壤动物（甲螨）的影响。

英文摘要：

[Objectives] Transgenic Bt cotton was modified to express a gene derived from the bacterium Bacillus thuringiensis （Bt） to combat lepidopteran pests. Elevated CO2 and O3 are expected to further alter the chemical composition of cotton, and may thus affect the role that soil fauna plays in the decomposition of Bt plants. [Methods] A three month litterbag field study, consisting of eight treatments using leaves from Bt cotton and near-isolines of non-Bt cotton grown under normal control, OTC control, elevated O3 and CO2 levels, was conducted to investigate the abundance of soil Acari that developed on the decaying leaf materials. [Results] The abundance of Acari was significantly impacted by sampling times. Acari abundance was highest in July and significantly decreased in elevated CO2 treatments. Moreover, only the common Simian3 significantly decreased in elevated CO2 levels. Acari abundance was significantly reduced in Bt cotton litter in the OTC control but not in the normal control, elevated CO2 and O3 treatments. [Conclusion] Soil fauna were not affected by elevated O3 cotton litter but cotton litter grown under elevated CO2 levels could significantly reduce the abundance of Acari compared to those found under the normal control, OTC control and elevated O3 treatments.