Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content an...Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content and chloroplast structure little changed in the course of desiccation, therefore has been called homoiochlorophyllous desiccation-tolerant plants (HDTs). Another type of resurrection angiosperms that lost its chlorophyll dining desiccation is called poikilochlorophyllous desiccation-tolerant plants (PDTs). HDTs have been received more attention because of simplicity of protection mechanism which is much easy to the study and utilization of the desiccation tolerance of resurrection angiosperms. Recent advances in studies of photosynthesis of resurrection angiosperms indicate that photochemical activities are sensitive indicators for the study of physiological state of resurrection angiosperms during desiccation and rehydration. Photochemical activities of resurrection angiosperms are inhibited with loss of water similar to those of general plants, however, the magic thing is that they could reactivate rapidly during rehydration even losing more than 95% water. Up-regulations in xanthophyll cycle and antioxidative systems as well as preservation in integrity and stability of photosynthetic membranes during desiccation may be very important to desiccation tolerance of resurrection angiosperms. The fact that phosphate treatment in rehydration stage also strongly influences resurrection indicated importance of studies on rehydration stages of resurrection angiosperms.展开更多
[Objective] The aim was to research the influences of different formulations on oxidation resistance of PVDF hollow fiber membrane.[Method]The immersion precipitation phase inversion method was employed to make castin...[Objective] The aim was to research the influences of different formulations on oxidation resistance of PVDF hollow fiber membrane.[Method]The immersion precipitation phase inversion method was employed to make casting solution with different formulations into hollow fiber membrane.The membrane was immersed in 1% NaClO solution for testing its performance changes.[Result]The membrane made by materials with bigger molecular weight had better oxidation resistance performance;the surfactant tween-80 could increase water flux,but lead to lower rupture intension;Pore-forming agent PEG400 do better than PVP in the oxidation resistance of membrane.[Conclusion]This study will provide a good idea for the development of the PVDF membrane with high oxidation resistance.展开更多
By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechan...By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechanism of M. sieversii to changes of relative soil water content. According to the results, with the decrease of relative soil water content, MDA content in M. sieversii leaves increased by mem- brane lipid peroxidation. Cells resist water stress-induced membrane lipid peroxidation and clear the increased reactive oxygen species by improving soluble protein content and SOD, POD, CAT and APX activities. However, various enzymes were involved in the response to water stress under different moisture conditions. In addition, the results indicated that M. sieversii had a good adaptability to higher relative soil water contents.展开更多
Compact anodic films with high hardness and good corrosion resistance on magnesium alloys were prepared by a new constant voltage and arc-free anodizing process. The effects of anodizing parameters such as applied vol...Compact anodic films with high hardness and good corrosion resistance on magnesium alloys were prepared by a new constant voltage and arc-free anodizing process. The effects of anodizing parameters such as applied voltage and electrolyte temperature on the peak current density and the thickness of films were investigated. In addition, the morphologies and corrosion resistance of films were investigated by scanning electron microscopy and potentiodynamic polarization, respectively. The results show that the higher the applied voltage, the higher the peak current density and the thicker the films. However, too high applied voltage may result in breakdown of films and intense sparking which may deteriorate the properties of the anodic films and bring about unsafety. The new anodizing process can be applied in a wide range of temperature. The new anodic films have numbers of pores with the diameter of 0.55.0μm which do not transverse the entire film.展开更多
文摘Resurrection plants which are able to quickly reactivate after falling into a period of anabiosis caused by dehydration have been very rare among angiosperms, especially among dicotyledons whose chlorophyll content and chloroplast structure little changed in the course of desiccation, therefore has been called homoiochlorophyllous desiccation-tolerant plants (HDTs). Another type of resurrection angiosperms that lost its chlorophyll dining desiccation is called poikilochlorophyllous desiccation-tolerant plants (PDTs). HDTs have been received more attention because of simplicity of protection mechanism which is much easy to the study and utilization of the desiccation tolerance of resurrection angiosperms. Recent advances in studies of photosynthesis of resurrection angiosperms indicate that photochemical activities are sensitive indicators for the study of physiological state of resurrection angiosperms during desiccation and rehydration. Photochemical activities of resurrection angiosperms are inhibited with loss of water similar to those of general plants, however, the magic thing is that they could reactivate rapidly during rehydration even losing more than 95% water. Up-regulations in xanthophyll cycle and antioxidative systems as well as preservation in integrity and stability of photosynthetic membranes during desiccation may be very important to desiccation tolerance of resurrection angiosperms. The fact that phosphate treatment in rehydration stage also strongly influences resurrection indicated importance of studies on rehydration stages of resurrection angiosperms.
基金Supported by Sichuan Provincial International S&T Cooperation Program(No.2008HH0012)Cooperation Research Program of Sichuan University and Hitachi Company(No.07H372)~~
文摘[Objective] The aim was to research the influences of different formulations on oxidation resistance of PVDF hollow fiber membrane.[Method]The immersion precipitation phase inversion method was employed to make casting solution with different formulations into hollow fiber membrane.The membrane was immersed in 1% NaClO solution for testing its performance changes.[Result]The membrane made by materials with bigger molecular weight had better oxidation resistance performance;the surfactant tween-80 could increase water flux,but lead to lower rupture intension;Pore-forming agent PEG400 do better than PVP in the oxidation resistance of membrane.[Conclusion]This study will provide a good idea for the development of the PVDF membrane with high oxidation resistance.
基金Supported by Science and Technology Innovation Project of Ji'nan City "Identification of Stress-resistant Malus sieversii Germplasm Resources and Screening of Stressresistance Functional Genes"(201401125)~~
文摘By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechanism of M. sieversii to changes of relative soil water content. According to the results, with the decrease of relative soil water content, MDA content in M. sieversii leaves increased by mem- brane lipid peroxidation. Cells resist water stress-induced membrane lipid peroxidation and clear the increased reactive oxygen species by improving soluble protein content and SOD, POD, CAT and APX activities. However, various enzymes were involved in the response to water stress under different moisture conditions. In addition, the results indicated that M. sieversii had a good adaptability to higher relative soil water contents.
基金Project (2002107) supported by the Natural Science Foundation of Hunan Province project(2005-241) supported by theScience Project of Changsha
文摘Compact anodic films with high hardness and good corrosion resistance on magnesium alloys were prepared by a new constant voltage and arc-free anodizing process. The effects of anodizing parameters such as applied voltage and electrolyte temperature on the peak current density and the thickness of films were investigated. In addition, the morphologies and corrosion resistance of films were investigated by scanning electron microscopy and potentiodynamic polarization, respectively. The results show that the higher the applied voltage, the higher the peak current density and the thicker the films. However, too high applied voltage may result in breakdown of films and intense sparking which may deteriorate the properties of the anodic films and bring about unsafety. The new anodizing process can be applied in a wide range of temperature. The new anodic films have numbers of pores with the diameter of 0.55.0μm which do not transverse the entire film.
