[Objective] The study aimed to confirm difference of nitrogen uptake and used efficiency with different nitrogen use efficiency for grain output (NUEg) types of indica rice.[Method] 88 and 122 conventional indica rice...[Objective] The study aimed to confirm difference of nitrogen uptake and used efficiency with different nitrogen use efficiency for grain output (NUEg) types of indica rice.[Method] 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Dry matter weight (including root system, culm and sheath, leaves, panicle), nitrogen content of different organs, yield and its components were measured. The tested rice cultivars were classified into 6 types (i.e. A, B, C, D, E and F, A was the lowest, and F was the highest) based on their NUEg level by the MinSSw method.[Result](1)Difference of NUEg of the cultivars used in this study were very large; (2) No significant difference of N content at heading stage was observed among different NUEg types of indica rice. In the cultivars with higher NUEg, however, N content in leaf, stem-sheath and entire rice plant were lower at mature stage. (3)Cultivars with higher NUEg were characterized with lower N uptake before heading and at mature stage; (4) Cultivars with higher NUEg were characterized with higher N use efficiency in biomass production and harvest index. [Conclusion] The cultivars with higher NUEg showed lower N uptake and N content, while nitrogen use efficiency was higher.展开更多
Under the global value chain, a country extensively employs foreign intermediate inputs in manufacturing its export products, which may not employ entirely local technology. Science-based measurement of technology con...Under the global value chain, a country extensively employs foreign intermediate inputs in manufacturing its export products, which may not employ entirely local technology. Science-based measurement of technology content in and structure of exports should be conducted using production process data. Using world input-output tables(WIOTs) of 1995-2011, this paper developed a new method for measuring the export technology content of China and other major countries. Our research findings suggest that, since 1995, there has been some technology upgrade of Chinese exports. China's overall and sector-specific technology contents, and domestic technology contents and indexes all increased and demonstrated a weak convergence towards the average level of developed countries. Judging by the relative rankings of sector-specific technology levels, China is almost locked at the lowest level in the world, and cannot challenge the technological superiority of developed countries like the U.S. and Japan.展开更多
基金Supported by the National Natural Science Foundation of China(30270777,30471013)~~
文摘[Objective] The study aimed to confirm difference of nitrogen uptake and used efficiency with different nitrogen use efficiency for grain output (NUEg) types of indica rice.[Method] 88 and 122 conventional indica rice cultivars were solution-cultured in 2001 and 2002, respectively. Dry matter weight (including root system, culm and sheath, leaves, panicle), nitrogen content of different organs, yield and its components were measured. The tested rice cultivars were classified into 6 types (i.e. A, B, C, D, E and F, A was the lowest, and F was the highest) based on their NUEg level by the MinSSw method.[Result](1)Difference of NUEg of the cultivars used in this study were very large; (2) No significant difference of N content at heading stage was observed among different NUEg types of indica rice. In the cultivars with higher NUEg, however, N content in leaf, stem-sheath and entire rice plant were lower at mature stage. (3)Cultivars with higher NUEg were characterized with lower N uptake before heading and at mature stage; (4) Cultivars with higher NUEg were characterized with higher N use efficiency in biomass production and harvest index. [Conclusion] The cultivars with higher NUEg showed lower N uptake and N content, while nitrogen use efficiency was higher.
文摘Under the global value chain, a country extensively employs foreign intermediate inputs in manufacturing its export products, which may not employ entirely local technology. Science-based measurement of technology content in and structure of exports should be conducted using production process data. Using world input-output tables(WIOTs) of 1995-2011, this paper developed a new method for measuring the export technology content of China and other major countries. Our research findings suggest that, since 1995, there has been some technology upgrade of Chinese exports. China's overall and sector-specific technology contents, and domestic technology contents and indexes all increased and demonstrated a weak convergence towards the average level of developed countries. Judging by the relative rankings of sector-specific technology levels, China is almost locked at the lowest level in the world, and cannot challenge the technological superiority of developed countries like the U.S. and Japan.
