【摘要】 植物是影响沉积物反硝化作用的重要因素之一,国内外已有不少研究探讨了植物对河口或湖泊沉积物反硝化速率的影响,但关于植物类型对自然沟渠沉积物反硝化速率及其相应功能基因的影响研究不多.因此,本文以7种常见沟渠植物为研究对象,通过室内盆栽试验,利用改进的乙炔抑制法和实时荧光定量PCR技术研究了不同植物对自然沟渠沉积物反硝化速率和相应功能基因（nirS和nirK）拷贝数的影响.结果表明,培养至第180 d时,不同植物生长条件下沉积物反硝化速率在2.85～13.20μg·m^-2·h^-1之间,不同植物间反硝化速率差异显著,且大型挺水植物>浮水植物>小型挺水植物.不同植物之间沉积物中nirS基因拷贝数在2.70×10⁸～5.02×10⁸ copies·g^-1之间,nirK基因拷贝数在3.97×10⁵～6.91×10⁵ copies·g^-1之间,与培养初期相比,培养180 d后沉积物中nirK、nirS基因拷贝数明显增多.7种植物中,美人蕉沉积物中的反硝化功能基因拷贝数较高,狐尾藻较低,整体来看,基因拷贝数大小顺序为:挺水植物>浮水植物.nirS基因拷贝数与NO^-₃-N含量、TN含量及反硝化速率之间均呈显著性的正相关关系（p<0.05）,但nirK基因拷贝数与沉积物碳氮含量及反硝化速率之间相关性不显著.更多还原

【Abstract】 The influence of plant on the denitrification of sediment in the estuary or lake have been reported by many studies. However, the effects of plant species on the denitrification of sediment and function genes in the natural ditches is still not clear. Here, we explored the effects of seven ditch plants on denitrification and functional genes（nirS, nirK） in ditch sediment via pot experiments by using the chloramphenicol-amended acetylene inhibition procedure and real time-PCR. The results show that the denitrification rates of the sediment under different plant species ranged from 2.85 μg·m^-2·h^-1 to 13.2 μg·m^-2·h^-1 after 180 days. The denitrification rates were as follows: Macrophytes> floating plants> small emerged plants, and there was a significant difference among different plant species. The gene abundances of nirS ranged from 2.70×10⁸ copies·g^-1 to 5.02×10⁸ copies·g^-1, and the gene abundances of nirK ranged 3.97×10⁵ copies·g^-1 to 6.91×10⁵ copies·g^-1. Furthermore, the gene abandunces of nirK and nirS increased significantly after 180 days of incubation. The denitrification functional gene copies was the highesin the sediment of Canna indica, while the lowest in Myriophyllum spicatum. The gene abundances of emerged plants were higher than that of floating plants. Moreover, pearson correlation analysis showed that there was a significant positive correlation between nirS and NO^-₃-N content, TN content, and denitrification rate（p<0.05）, but the correlation between nirK and sediment physicochemical properties, denitrification rate were not significant.更多还原