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The overexpression of algal glutamine synthetase (GS) gene DvGS2 in Arabidopsis thaliana resulted in higher plant biomass and better growth phenotype. The purpose of this study was to understand the biological mechanism for the improvement of growth phenotype of DvGS2-transgenic Arabidopsis. A series of molecular and biochemical investigation related to nitrogen and carbon metabolism in DvGS2-transgenic line was, respectively, conducted. Analysis of nitrogen use efficiency (NUE)-related gene expression and enzymatic activity revealed that the transcriptional level and enzymatic activity of genes encoding glutamate synthase, glutamate dehydrogenase and alanine aminotransferase were significantly up-regulated especially under low nitrate condition. The DvGS2-transgenic line showed higher total nitrogen content and lower carbon: nitrogen ratio than the wild type. Significant reduced concentration of leaf free ammonium, higher concentrations of total amino acids, individual amino acid (glutamine, methionine, alanine, asparagine) together with increased concentrations of glucose, fructose and starch, confirmed the higher efficiency of nitrogen and carbon assimilation. These improved metabolisms of nitrogen and carbon conferred the DvGS2-transgenic Arabidopsis more biomass, better growth phenotype and higher NUE compared with the wild type plant. [ABSTRACT FROM AUTHOR]

Development of rapid processes combining the preparation of porous structures with the control of their properties has remained a challenge. This is particularly true for applications of graphitized hierarchically porous carbon nanosheets (GHPCNs) predominantly focus on fields of energy storage and conversion materials, electronics, sensors, separation and detection. Here we report a one-step approach to transform commercial bakelite into three-dimensional high electrical conductivity GHPCNs using the high-repetition picosecond infrared laser scribing in nitrogen atmosphere. The GHPCNs with mesopores and macropores can be rapidly induced on bakelite plate by the transient laser heating due to thermal accumulation effect. Studies reveal that the in-plane topological defects of the bakelite-based GHPCNs flakes contain pentagon-heptagon structures. The local controllable laser patterning technique enables porous structures and shapes to be controlled in highly GHPCNs films with variable properties. The methodology developed here have great potential to stimulate both research and industrial interest in the development of bakelite-derived GHPCNs electronic and energy storage micro-devices. [ABSTRACT FROM AUTHOR]

This work mainly focuses on exploring carbon coated ε-MnO 2 (ε-MnO 2 /C) with 3D hierarchical structures for degradation of gaseous toluene under visible light. Influence of C-coating on surface adsorption, visible-light activity and photocatalytic activities of C-coated MnO 2 have been investigated. The results indicate that the C-coating behave as the adsorption and electron-transfer system, and the resulting C-coated ε-MnO 2 could extend the optical response from UV to visible light region, which can generate more electron − hole pairs. The photocatalyst ε-MnO 2 /0.45C exhibited excellent visible-light photocatalytic activities, with degradation rate of toluene up to 87.34% in 70 min, but no photocatalytic activity could be observed for the pure ε-MnO 2 . The PL spectra and photocurrent response results indicate that the composite structure can not only enhance the utilization of visible light but also consequently reduce electron (e − )-hole (h + ) pair recombination, which improve the photocatalytic efficiency of the composite photocatalyst. This work provides a facile and economic approach for fabricating photocatalysts with high efficiency for degradation of VOCs under visible light at room temperature. [ABSTRACT FROM AUTHOR]