The genetic transformation plays an important role in plant gene functional analysis and its geneticimprovement. However, only a limited number of maize germplasms can be routinely transformed. Themaize gene Wuschel-l...The genetic transformation plays an important role in plant gene functional analysis and its geneticimprovement. However, only a limited number of maize germplasms can be routinely transformed. Themaize gene Wuschel-like homeobox protein 2a (Wox2a) was shown to play a crucial role in promotingthe formation of embryonic cells and enhancing the efficiency of genetic transformation in maize. Thiscommentary discusses the mechanism by which the Wox2a gene contributes to the variation inembryogenic tissue culture response among different maize inbred lines. In addition, the frequency andintensity of Wox2a or Wus2/Bbm vector-induced somatic embryogenesis was also discussed. Theapplication of Wox2a in transformation of recalcitrant maize genotypes could well accelerate thedevelopment of maize genetic improvement.展开更多
A series of WO3/CeO2 （WOx/CeO2） catalysts were synthesized by wet impregnation of ammonium metatungstate on a CeO2 support. The resulting solid acid catalysts were characterized by X-ray diffraction （XRD）, UV-Vis ...A series of WO3/CeO2 （WOx/CeO2） catalysts were synthesized by wet impregnation of ammonium metatungstate on a CeO2 support. The resulting solid acid catalysts were characterized by X-ray diffraction （XRD）, UV-Vis spectroscopy （UV-Vis）, Raman spectroscopy （Raman）, in-situ Fourier transform infrared spectroscopy （in-situ FT-IR） of ammonia adsorption, NH3-TPD, H2 temperature- programmed reduction （H2-TPR）, NH3/NO oxidation and activity measurements for NOx reduction by NH3 （NH3-SCR）. The results show that polytungstate （WOx） species are the main species of tungsten oxide on the surface of ceria. The addition of tungsten oxide enhances the BriSnsted acidity of ceria catalysts remarkably and decreases the amount of surface oxygen on celia, with strong interaction between CeO2 and WOx. As a result, the N2 selectivity of NH3 oxidation and NH3-SCR at high temperatures （〉 300℃） is enhanced. Therefore, a wide working temperature window in which NOx conversion exceeds 80% （NOx conversion 〉 80%） from 200 to 450℃, is achieved over 10 wt.% WOx/CeO2 catalyst. A tentative model of the NH3-SCR reaction route on WOx/CeO2 catalysts is presented.展开更多
基金funded by the National Natural Science Foundation of China(32270378,31730008 to XSZ).
文摘The genetic transformation plays an important role in plant gene functional analysis and its geneticimprovement. However, only a limited number of maize germplasms can be routinely transformed. Themaize gene Wuschel-like homeobox protein 2a (Wox2a) was shown to play a crucial role in promotingthe formation of embryonic cells and enhancing the efficiency of genetic transformation in maize. Thiscommentary discusses the mechanism by which the Wox2a gene contributes to the variation inembryogenic tissue culture response among different maize inbred lines. In addition, the frequency andintensity of Wox2a or Wus2/Bbm vector-induced somatic embryogenesis was also discussed. Theapplication of Wox2a in transformation of recalcitrant maize genotypes could well accelerate thedevelopment of maize genetic improvement.
基金the Ministry of Science and Technology, PR China for financial support of Project 2010CB732304Science and Technology Department of Zhejiang Province Project 2011C31010
文摘A series of WO3/CeO2 （WOx/CeO2） catalysts were synthesized by wet impregnation of ammonium metatungstate on a CeO2 support. The resulting solid acid catalysts were characterized by X-ray diffraction （XRD）, UV-Vis spectroscopy （UV-Vis）, Raman spectroscopy （Raman）, in-situ Fourier transform infrared spectroscopy （in-situ FT-IR） of ammonia adsorption, NH3-TPD, H2 temperature- programmed reduction （H2-TPR）, NH3/NO oxidation and activity measurements for NOx reduction by NH3 （NH3-SCR）. The results show that polytungstate （WOx） species are the main species of tungsten oxide on the surface of ceria. The addition of tungsten oxide enhances the BriSnsted acidity of ceria catalysts remarkably and decreases the amount of surface oxygen on celia, with strong interaction between CeO2 and WOx. As a result, the N2 selectivity of NH3 oxidation and NH3-SCR at high temperatures （〉 300℃） is enhanced. Therefore, a wide working temperature window in which NOx conversion exceeds 80% （NOx conversion 〉 80%） from 200 to 450℃, is achieved over 10 wt.% WOx/CeO2 catalyst. A tentative model of the NH3-SCR reaction route on WOx/CeO2 catalysts is presented.
