作物茎秆和叶片排放N_(2)O和CH_(4)的研究

Study on N_(2)O and CH_(4)Emission from Stems and Leaves of Crops

以东北主要作物大豆、玉米和高粱为研究对象,首次同步考察了新鲜离体植物茎秆和叶片的N_(2)O和CH_(4)排放。结果表明:3种植物茎秆均能排放N_(2)O,玉米茎秆排放量最大,为13.587μL/L;3种植物叶片的N_(2)O排放较少,但42 h时大豆叶片的N_(2)O排放出现高峰,浓度达33.913μL/L。3种植物茎秆的CH_(4)排放表现出最初有排放之后吸收,3 h时玉米、大豆和高粱的CH_(4)浓度分别为2.113、2.341和2.355μL/L;植物叶片CH_(4)排放不明显,呈波浪起伏的变化规律。从N_(2)O和CH_(4)排放通量看,大豆叶片N_(2)O通量最高,达210.970 ng/(g·h);玉米叶片CH_(4)通量为0.148 ng/(g·h),其他茎叶均为吸收CH_(4)。研究结果不仅为植物叶片本身既能排放N_(2)O又能排放CH_(4)在植物中可能具有普遍性提供了试验依据,而且找出了植物排放N_(2)O和CH_(4)的新的排放部位——茎秆。

Taking the main crops in Northeast China,including soybeans,corn and sorghum as the research objects,the N_(2)O and CH_(4)emissions from the stems and leaves of soybean,maize and sorghum were investigated simultaneously for the first time.The results showed that all the stems of three plants could emit N_(2)O.Among them,the maize stems showed high N_(2)O emission,with concentration of 13.587μL/L.The N_(2)O emission from the leaves of the three plant species was lower,but the N_(2)O emission from soybean leaves peaked at 42 h,reaching 33.913μL/L.The CH_(4)emissions from the stems of three plants showed absorption after initial emissions,with CH_(4)concentrations of 2.113,2.341 and 2.355μL/L for corn,soybean and sorghum at 3 hours,respectively;the CH_(4)emissions from plant leaves were not obvious,and showed a fluctuating law.From the perspective of N_(2)O and CH_(4)emission fluxes,soybean leaves had the highest N_(2)O flux,reaching 210.970 ng/(g·h);the CH_(4)flux of corn leaves was 0.148 ng/(g·h),while other stems and leaves absorbed CH_(4).The research results not only provide experimental basis for the universality of plant leaves emitting both N_(2)O and CH_(4),but also identify a new emission site for N_(2)O and CH_(4)in plants-the stem.