青藏高原农田土壤氨氧化古菌和细菌数量与活性及对氨氧化过程的贡献  

Quantity and activity of ammonia-oxidizing archaea and bacteria and their contribution to ammonia oxidation in farmland soil of Qinghai-Tibet Plateau

作　　者：寇涌苹 张晓瑛 赵文强 汤娜 KOU Yongping;ZHANG Xiaoying;ZHAO Wenqiang;TANG Na(Chengdu Institute of Biology,Chinese Academy of Science,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院成都生物研究所,成都610041 [2]中国科学院大学,北京100049

出　　处：《应用与环境生物学报》2022年第4期883-889,共7页Chinese Journal of Applied and Environmental Biology

基　　金：第二次青藏高原综合科学考察研究项目(2019QZKK0303);中国科学院青年创新促进会项目(2021371)资助。

摘　　要：氨氧化过程是硝化过程的第一步,也是限速步骤,主要由氨氧化古菌(AOA)和氨氧化细菌(AOB)参与完成,但是关于土壤中AOA和AOB的活性及对氨氧化作用的相对贡献尚不清楚,AOA和AOB数量与氨氧化速率之间是否存在相关关系仍然存在争议.采用荧光定量PCR并结合乙炔(C_(2)H_(2))和1-辛炔抑制法对青藏高原林芝、拉孜、桑珠孜和桑日地区小麦、青稞、油菜土壤中AOA和AOB的数量与活性进行定量测定.结果表明:在所有土壤样品中,AOB数量[每克干土中拷贝数为(2.34±0.84)×10^(5)-(2.65±1.07)×10^(6)]均显著高于AOA数量[每克干土中拷贝数为(0.20±0.10)×10^(4)-(4.02±0.39)×10^(4));土壤pH是影响AOB数量的关键因素,土壤总磷和铵态氮是影响AOA数量的关键因素.拉孜(2.42±0.73 mg kg^(-1) d^(-1))和桑珠孜(3.24±1.15 mg kg^(-1) d^(-1))所有农田作物土壤中氨氧化速率均显著高于林芝(1.17±0.43 mg kg^(-1) d^(-1))和桑日(0.88±0.57 mg kg^(-1) d^(-1)),并且拉孜和桑珠孜农田土壤中氨氧化速率由AOB主导,林芝和桑日农田土壤中氨氧化速率由AOA主导.4个地区均是小麦和油菜土壤中氨氧化速率显著高于青稞土壤,但AOA和AOB活性与农作物类型无关.土壤氮磷比是影响AOA活性的主要因素,而土壤pH和总碳是影响AOB活性的主要因素.此外,AOA和AOB数量与总的氨氧化速率及AOA、AOB活性均无相关关系.总的来说,本研究表明AOA和AOB在青藏高原农田土壤氨氧化中均起到重要作用,并且通过氨氧化微生物amoA基因数量推测AOA和AOB活性以及二者对氨氧化作用的相对贡献不可行,需要通过直接测定AOA和AOB活性才能准确衡量,上述结果对于理解青藏高原农田生态系统氨氮去除过程以及减缓硝酸盐流失、降低温室气体氧化亚氮排放具有重要意义.(图1表4参44)Ammonia oxidation, the first and rate-limiting step of nitrification, is mainly performed by ammoniaoxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB). However, the activities of AOA and AOB in soil and their relative contribution to ammonia oxidation are unclear, and whether there is a significant correlation between the quantity of AOA and AOB and the ammonia oxidation rate is also controversial. In this study,quantitative PCR combined with acetylene(CH) and 1-octyne inhibition methods were used to determine the quantity and activity of AOA and AOB in wheat, highland barley, and oilseed rape soils in Nyingchi, Lhatse,Sangzhuzi, and Sangri counties on the Qinghai-Tibet Plateau. The results showed that the quantity of AOB((2.34± 0.84) ×10^(5)-(2.65 ± 1.07) ×10^(6) copies gdry soil) was significantly higher than that of AOA((0.20 ± 0.10) ×10^(4)-(4.02 ± 0.39) ×10^(4) copies gdry soil) in all the soil samples. Soil pH was the key factor affecting the quantity of AOB, and the total phosphorus and ammonium nitrogen in soil were the key factors affecting the quantity of AOA. The rates of ammonia oxidation in the farmland soils of Lhatse(2.42 ± 0.73 mg kg^(-1) d^(-1)) and Sangzhuzi(3.24± 1.15 mg kg^(-1) d^(-1)) were significantly higher than those in the soils of Nyingchi(1.17 ± 0.43 mg kg^(-1) d^(-1)) and Sangri counties(0.88 ± 0.57 mg kg^(-1) d^(-1)). The rates of ammonia oxidation in the farmland soils of Lhatse and Sangzhuzi were dominated by AOB, while those in the farmland soils of Nyingchi and Sangri counties were dominated by AOA. For crops, the ammonia oxidation rates of wheat and oilseed rape soils in all four regions were significantly higher than those of highland barley soil, whereas the activity of AOA and AOB was not influenced by crops. The ratio of nitrogen to phosphorus was the key factor influencing AOA activity, whereas soil pH and total carbon were the main factors influencing AOB activity. Additionally, the quantities of AOA and AOB were not significantly correlated with the to

关 键 词：氨氧化速率 氨氧化细菌 氨氧化古菌 农田土壤 青藏高原 

分 类 号：S154.3[农业科学—土壤学]