Liu Dongyan, Tago Kanako, Hayatsu Masahito, Tokida Takeshi, Sakai Hidemitsu, Nakamura Hirofumi, Usui Yasuhiro, Hasegawa Toshihiro, Asakawa Susumu
Soil Biology and Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University.
Microbes Environ. 2016 Sep 29;31(3):349-56. doi: 10.1264/jsme2.ME16066. Epub 2016 Sep 7.
Elevated concentrations of atmospheric CO2 ([CO2]) enhance the production and emission of methane in paddy fields. In the present study, the effects of elevated [CO2], elevated temperature (ET), and no nitrogen fertilization (LN) on methanogenic archaeal and methane-oxidizing bacterial community structures in a free-air CO2 enrichment (FACE) experimental paddy field were investigated by PCR-DGGE and real-time quantitative PCR. Soil samples were collected from the upper and lower soil layers at the rice panicle initiation (PI) and mid-ripening (MR) stages. The composition of the methanogenic archaeal community in the upper and lower soil layers was not markedly affected by the elevated [CO2], ET, or LN condition. The abundance of the methanogenic archaeal community in the upper and lower soil layers was also not affected by elevated [CO2] or ET, but was significantly increased at the rice PI stage and significantly decreased by LN in the lower soil layer. In contrast, the composition of the methane-oxidizing bacterial community was affected by rice-growing stages in the upper soil layer. The abundance of methane-oxidizing bacteria was significantly decreased by elevated [CO2] and LN in both soil layers at the rice MR stage and by ET in the upper soil layer. The ratio of mcrA/pmoA genes correlated with methane emission from ambient and FACE paddy plots at the PI stage. These results indicate that the decrease observed in the abundance of methane-oxidizing bacteria was related to increased methane emission from the paddy field under the elevated [CO2], ET, and LN conditions.
大气中二氧化碳浓度（[CO₂]）升高会增加稻田甲烷的产生和排放。在本研究中，通过PCR-DGGE和实时定量PCR，研究了在开放式空气CO₂浓度增高（FACE）试验稻田中，[CO₂]升高、温度升高（ET）和不施氮肥（LN）对产甲烷古菌和甲烷氧化细菌群落结构的影响。在水稻幼穗分化期（PI）和灌浆中期（MR），从上下两层土壤采集土壤样本。上下两层土壤中产甲烷古菌群落的组成，并未受到[CO₂]升高、ET或LN条件的显著影响。上下两层土壤中产甲烷古菌群落的丰度，也未受到[CO₂]升高或ET的影响，但在水稻PI期显著增加，在下层土壤中受LN影响显著降低。相反，上层土壤中甲烷氧化细菌群落的组成受水稻生育期的影响。在水稻MR期，两层土壤中甲烷氧化细菌的丰度均因[CO₂]升高和LN而显著降低，在上层土壤中因ET而显著降低。mcrA/pmoA基因的比率与PI期常规和FACE试验稻田的甲烷排放相关。这些结果表明，观察到的甲烷氧化细菌丰度下降，与[CO₂]升高、ET和LN条件下稻田甲烷排放增加有关。
