CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR inc. and LI-COR, 820) from Aug. to Oct. of 1999, A...CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000,and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profites showed that the verticat distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10μmol·mol^-1, but had a significant change in July, with a difference of 60μmol·mol^-1, In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8μmol·mol^-1. The calculated total storage ( Δ C/Δ t) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.展开更多
牧场表层由枯死植物残体、死亡根系等组成的草甸层的存在减少了施入的仔鸡废弃物与土壤的接触,因此增加了废弃物中磷随径流进入水体的可能性。本实验选用牧场原状土柱在实验室进行恒温(25oC)控湿模拟培养56天,研究牧场施用仔鸡废弃物(5 ...牧场表层由枯死植物残体、死亡根系等组成的草甸层的存在减少了施入的仔鸡废弃物与土壤的接触,因此增加了废弃物中磷随径流进入水体的可能性。本实验选用牧场原状土柱在实验室进行恒温(25oC)控湿模拟培养56天,研究牧场施用仔鸡废弃物(5 T hm-2)后,草甸层及土壤表层中水溶性磷的动态变化及草甸层存在与否对其含量的影响。结果表明:培养56天后,有草甸层处理土壤表层与草甸层中水溶性磷含量要明显高于无草甸层处理土壤表层中水溶性磷的含量(39:20 kg hm-2)。因此,生长良好的牧场因草甸层的存在如表施仔鸡废弃物可在草场表层留存有大量可溶性磷,如遇降雨引起径流则可导致附近地表水体的磷污染。图2表2参11。展开更多
棕色固氮菌固氮酶钼铁蛋白结晶,经酒石酸解离后得到一个含钢铁小分子组分,与棕色固氮菌突变株uw_(45)无细胞提取液的重组比活为6.8nM Mo natom^(-1) min^(-1)。它是由二种物质组成的混合物,其分子量分别为2100和1850道尔顿,分子量为210...棕色固氮菌固氮酶钼铁蛋白结晶,经酒石酸解离后得到一个含钢铁小分子组分,与棕色固氮菌突变株uw_(45)无细胞提取液的重组比活为6.8nM Mo natom^(-1) min^(-1)。它是由二种物质组成的混合物,其分子量分别为2100和1850道尔顿,分子量为2100道尔顿的成分含钼铁。酒石酸处理后的沉淀,再用N—甲基甲酰胺抽提得到的含钼铁组分具有恢复突变株uw_(45)乙炔还原活性的能力。经纸层析鉴定与用Shah法制备的铁钼辅因子相类似。由于Shah和Smith法制备的两种铁钼辅因子还原乙炔和氰化钾的比活不同,而且分子量也有大小,说明这两种铁钼辅因子结构可能不尽相同。展开更多
基金This study is supported by The Development Plan of State Key Fundamental Research of China (973) (contract No. 2002CB412502),by Knowledge Innovation Project of CAS (KZCX1-SW-01-03) and by Natural Science Foundation of China (30170167).
文摘CO2 concentrations at different heights in a broadleaved/Korean forest (with a mean height of 26 m) were measured with infrared gas analyzer IRGA (model 2250D, LI-COR inc. and LI-COR, 820) from Aug. to Oct. of 1999, Apr. to Jul. of 2000,and from Aug. 2002 to Sept. 2003. Based on the collected dada, the diurnal and seasonal dynamics of profiles and storage of carbon dioxide in the forest were analyzed. The diurnal CO2 profites showed that the verticat distribution of CO2 concentration were different for daytime and nighttime, and the CO2 concentration was highest close to forest floor, no matter at daytime and nighttime. The seasonal profiles of CO2 showed that stratification in the canopy was evident during growth season. CO2 concentrations at different heights (60 m to 2.5 m) had a little change in March, with a difference of 10μmol·mol^-1, but had a significant change in July, with a difference of 60μmol·mol^-1, In July, there also existed a greater gradient of CO2 concentrations at canopy (22, 26 and 32 m), with a difference of 8μmol·mol^-1. The calculated total storage ( Δ C/Δ t) of CO2 in the air column with height of 40 m beneath eddy covariance instrument was negative, and made a little contribution to NEE.
文摘牧场表层由枯死植物残体、死亡根系等组成的草甸层的存在减少了施入的仔鸡废弃物与土壤的接触,因此增加了废弃物中磷随径流进入水体的可能性。本实验选用牧场原状土柱在实验室进行恒温(25oC)控湿模拟培养56天,研究牧场施用仔鸡废弃物(5 T hm-2)后,草甸层及土壤表层中水溶性磷的动态变化及草甸层存在与否对其含量的影响。结果表明:培养56天后,有草甸层处理土壤表层与草甸层中水溶性磷含量要明显高于无草甸层处理土壤表层中水溶性磷的含量(39:20 kg hm-2)。因此,生长良好的牧场因草甸层的存在如表施仔鸡废弃物可在草场表层留存有大量可溶性磷,如遇降雨引起径流则可导致附近地表水体的磷污染。图2表2参11。
文摘棕色固氮菌固氮酶钼铁蛋白结晶,经酒石酸解离后得到一个含钢铁小分子组分,与棕色固氮菌突变株uw_(45)无细胞提取液的重组比活为6.8nM Mo natom^(-1) min^(-1)。它是由二种物质组成的混合物,其分子量分别为2100和1850道尔顿,分子量为2100道尔顿的成分含钼铁。酒石酸处理后的沉淀,再用N—甲基甲酰胺抽提得到的含钼铁组分具有恢复突变株uw_(45)乙炔还原活性的能力。经纸层析鉴定与用Shah法制备的铁钼辅因子相类似。由于Shah和Smith法制备的两种铁钼辅因子还原乙炔和氰化钾的比活不同,而且分子量也有大小,说明这两种铁钼辅因子结构可能不尽相同。
