UV-B辐射增强对元阳哈尼梯田稻田CH_4排放规律的影响  

Effect of enhanced UV-B radiation on CH_4 emission from paddy field in Yuanyang Hani Terraces

作　　者：徐渭渭[1] 何永美[1] 湛方栋[1] 祖艳群[1] 李元[1] 

机构地区：[1]云南农业大学资源与环境学院,昆明650201

出　　处：《生态学报》2015年第5期1329-1336,共8页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31060083;41205113)

摘　　要：在大田条件下,原位种植传统水稻品种白脚老粳,采用静态箱-气相色谱法研究了UV-B(ultraviolet-B)辐射增强(7.5 kJ m-2d-1)对元阳哈尼梯田海拔1600 m处稻田CH4排放量的影响,同时观测UV-B辐射增强对水稻生长的影响。结果表明:(1)UV-B辐射增强显著降低了水稻植株分蘖末期、拔节孕穗期、抽穗扬花期、成熟期地上部和地下部生物量(P<0.05)。(2)UV-B辐射改变了稻田CH4的季节和日排放(成熟期)规律:对照组在拔节孕穗期出现1个排放峰,处理组在拔节孕穗期和成熟期出现2个排放峰;与对照相比,UV-B辐射增强改变了水稻成熟期CH4日排放第2个峰值出现的时间。(3)处理组CH4的季节排放通量与箱内温度的季节变化有显著的正相关性(R=0.789,P<0.05)。(4)UV-B辐射增强在分蘖末期、拔节孕穗期、成熟期都极显著提高了CH4的累计排放量(P<0.01),分别提高了47.2%,293.8%和74.4%。总之,UV-B辐射增强促进了元阳哈尼梯田传统水稻田CH4的排放。The destruction of ozonosphere and the global warming have been widely concerned by governments and peoples all over the world. Increase of UV-B（ ultraviolet-B） radiation on Earth＇s surface due to ozone layer depletion can decrease the growth and alter the chemical composition of litter fall of plant,and consequently change the microbial community composition,structure and activity in soil. Methane is an important greenhouse gas and has a global warming potential of 25 compared to CO2 over a 100-year period. Its rank is second only to CO2 in the atmosphere and its concentration in the Earth＇s atmosphere in 2010 was 1. 808 × 10^-6μL /L,up from 0.7 × 10^-6μL /L in 1750. In addition to abiogenic production of methane,there are biogenic methane as well. Biogenic methane produced by the process of methanogenesis usually occurred under highly anaerobic conditions,for example,in the guts of humans and other animals,especially ruminants,and in landfill,artificial and natural wetlands,etc. As a kind of wetland,flooded paddy can generate a lot of methane during plant growth and are considered to be one of the major anthropogenic sources of methane,especially the year-round flooded paddy field. Up to now,quite a few researches demonstrated that methane can be largely produced from plant tissues under the influence of UV（ ultraviolet） radiation due to the generation of ROS（ reactive oxygen species）. ROS was suggested to be apotential free-radical mechanism which can produce CH4 from plant polysaccharides under aerobic condition. Though the significant effects of UV-B radiation on methane emission from rice paddy field have been studied,the effects of UV-B radiation on the methane emission from year-round flooded paddy field are rarely studied. In this paper,Yuanyang Hani Terraces which is a typical year-round flooded paddy field in Yunnan,Southwestern China,was chosen to investigate the dynamics of methane emission under enhanced UV-B radiation. Field experiment was conducted to investigate methane emissi

关 键 词：UV-B辐射 元阳哈尼梯田 稻田 CH4排放 

分 类 号：S511.22[农业科学—作物学]