Gut-Associated Denitrification and In Vivo Emission of Nitrous Oxide by the Earthworm Families Megascolecidae and Lumbricidae in New Zealand
Gut-Associated Denitrification and In Vivo Emission of Nitrous Oxide by the Earthworm Families Megascolecidae and Lumbricidae in New Zealand
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新西兰蚯蚓科巨蚓科和蚓科的肠道相关反硝化和一氧化二氮体内排放
DOI：
10.1128/aem.00304-09
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发表时间：
2009
影响因子：
4.4
通讯作者：
H. Drake
中科院分区：
文献类型：
--
作者：
Pia K. Wüst;M. Horn;G. Henderson;P. Janssen;B. Rehm;H. Drake
摘要以前的研究已经证明了欧洲蚯蚓的能力属于家庭蚯蚓排放温室气体一氧化二氮（N2O），活动主要归因于激活摄入的土壤净化剂。为了将信息库扩展到南半球的蚯蚓，研究了新西兰四种蚯蚓的肠道相关反硝化作用。蚯蚓和Aporrectodea rosea（引进种蚯蚓）排放N2O，而排放的N2O的Octolopyruscyaneum（引进种蚯蚓）和排放的N2O的多孔刺刺蛾（本地种巨鞘蛾）是可变的，可以忽略不计，分别。蚯蚓暴露于亚硝酸盐或硝酸盐和乙炔显着增加了N2O的排放量，暗示反硝化作为N2O的主要来源，并表明蚯蚓排放二氮（N2），除了N2O。当补充亚硝酸盐时，消化道显示出产生N2O的高能力，并且消化道内容物含有大量的碳水化合物和指示发酵的有机酸（例如，琥珀酸盐、乙酸盐和甲酸盐），其可以用作反硝化的还原剂来源。nosZ编码用于反硝化的末端氧化还原酶的一部分。nosZ序列在L. rubellus和O.多孔菌与从土壤中回收的那些相似并且与未培养的土壤细菌和土壤中常见的属的序列远缘（即，慢生根瘤菌属、固氮菌属、红曲霉属、红曲霉属、假单胞菌属、寡养菌属和中华根瘤菌属）。这些发现（i）表明排放N2O和N2的能力是蚯蚓的一般特征，不受地理限制，（ii）表明属于不同蚯蚓科的物种（即，Megascolecidae和Lumbricidae）可能没有平等的能力，排放N2O，和（iii）也证实了以前的研究结果，这种能力在消化道反硝化。
ABSTRACT Previous studies have documented the capacity of European earthworms belonging to the family Lumbricidae to emit the greenhouse gas nitrous oxide (N2O), an activity attributed primarily to the activation of ingested soil denitrifiers. To extend the information base to earthworms in the Southern Hemisphere, four species of earthworms in New Zealand were examined for gut-associated denitrification. Lumbricus rubellus and Aporrectodea rosea (introduced species of Lumbricidae) emitted N2O, whereas emission of N2O by Octolasion cyaneum (an introduced species of Lumbricidae) and emission of N2O by Octochaetus multiporus (a native species of Megascolecidae) were variable and negligible, respectively. Exposing earthworms to nitrite or nitrate and acetylene significantly increased the amount of N2O emitted, implicating denitrification as the primary source of N2O and indicating that earthworms emitted dinitrogen (N2) in addition to N2O. The alimentary canal displayed a high capacity to produce N2O when it was supplemented with nitrite, and alimentary canal contents contained large amounts of carbohydrates and organic acids indicative of fermentation (e.g., succinate, acetate, and formate) that could serve as sources of reductant for denitrification. nosZ encodes a portion of the terminal oxidoreductase used in denitrification. The nosZ sequences detected in the alimentary canals of L. rubellus and O. multiporus were similar to those retrieved from soil and were distantly related to sequences of uncultured soil bacteria and genera common in soils (i.e., Bradyrhizobium, Azospirillum, Rhodopseudomonas, Rhodospirillum, Pseudomonas, Oligotropha, and Sinorhizobium). These findings (i) suggest that the capacity to emit N2O and N2 is a general trait of earthworms and not geographically restricted, (ii) indicate that species belonging to different earthworm families (i.e., Megascolecidae and Lumbricidae) may not have equal capacities to emit N2O, and (iii) also corroborate previous findings that link this capacity to denitrification in the alimentary canal.