The pollen tube pathway method of transformation has been reported to be successful in most crops, but less successfu in maizc. DNA can be transferred by cutting the stigma following pollination and applying the DNA s...The pollen tube pathway method of transformation has been reported to be successful in most crops, but less successfu in maizc. DNA can be transferred by cutting the stigma following pollination and applying the DNA solution in a suitable period DNA presumably reaches the ovary by flowing down the pollen tube and then integrates into the just fertilized but undivided zygotic cells. To provide the molecular evidence for this procedure, the plasmids pGBIRC carrying a CaMV35S promoter-PPT acetyle transferase （bar） gene-nos terminator genc fusion construct were used. Total 3 276 seeds were produced from the ears trcated with DNA. It was found that 35 scedlings were GUS assay positive, but less intense than that of the positive controls, of which 17 were PCR amplification positive. But, only 13 of the seeds from the plants treated with DNA containing the bar gene were found to be resistant compared with the negative control. Less than 1.07% of progeny seedlings tested cxpressed a herbicide positive reaction and polymerase chain reaction （PCR） with seedling DNA did detect the bar genc. Morphological variation was observed in six plants. We succeed in obtain PPT-resistant maize inbred lines via pollen tube pathway展开更多
Kanamycin was used to screen To seeds of the variety Dongnong 46 transformed by means of pollen-tube method. The results showed that 400 mg·L^-1 kanamycin could inhibit growth of non-transgenic plants, and 2 posi...Kanamycin was used to screen To seeds of the variety Dongnong 46 transformed by means of pollen-tube method. The results showed that 400 mg·L^-1 kanamycin could inhibit growth of non-transgenic plants, and 2 positive plants were gotten combined with Gus dyeing and PCR detection. It is proved that this method is economic and effective in preliminary screening the transgenic plants.展开更多
通过分析环核苷酸门控离子通道(cyclic nucleotide gated ion channels,CNGCs)蛋白结构、组织和细胞定位及CNGCs蛋白活性调节机制,对CNGCs蛋白在植物生长发育和胁迫响应中的作用进行全面综述。重点探讨了CNGCs蛋白调控植物花粉管生长的...通过分析环核苷酸门控离子通道(cyclic nucleotide gated ion channels,CNGCs)蛋白结构、组织和细胞定位及CNGCs蛋白活性调节机制,对CNGCs蛋白在植物生长发育和胁迫响应中的作用进行全面综述。重点探讨了CNGCs蛋白调控植物花粉管生长的机制,并对植物CNGCs蛋白未来的研究方向进行了展望,能够为深入理解CNGCs蛋白在植物中的作用机制提供理论参考。展开更多
Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w h...Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed.展开更多
In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on...In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on the elastic-plasticity theory, and under the consideration of the effect of tube size, material mechanical parameters, friction coefficient and loading paths, the external pressure plastic forming mechanical model of metal stator screw lining is established, to study the optimal loading path of metal stator lining tube hydroforming process. The results show that wall thickness reduction of the external pressure tube hydroforming(THF) is about 4%, and three evaluation criteria of metal stator screw lining forming quality are presented: fillet stick mold coefficient, thickness relative error and forming quality coefficient. The smaller the three criteria are, the better the forming quality is.Each indicator has a trend of increase with the loading rate reducing, and the adjustment laws of die arc transition zone equidistance profile curve are acquired for improving tube forming quality. Hence, the research results prove the feasibility of external pressure THF used for processing high-accuracy large length-to-diameter ratio metal stator screw lining, and provide theoretical basis for designing new kind of stator structure which has better performance and longer service life.展开更多
文摘The pollen tube pathway method of transformation has been reported to be successful in most crops, but less successfu in maizc. DNA can be transferred by cutting the stigma following pollination and applying the DNA solution in a suitable period DNA presumably reaches the ovary by flowing down the pollen tube and then integrates into the just fertilized but undivided zygotic cells. To provide the molecular evidence for this procedure, the plasmids pGBIRC carrying a CaMV35S promoter-PPT acetyle transferase （bar） gene-nos terminator genc fusion construct were used. Total 3 276 seeds were produced from the ears trcated with DNA. It was found that 35 scedlings were GUS assay positive, but less intense than that of the positive controls, of which 17 were PCR amplification positive. But, only 13 of the seeds from the plants treated with DNA containing the bar gene were found to be resistant compared with the negative control. Less than 1.07% of progeny seedlings tested cxpressed a herbicide positive reaction and polymerase chain reaction （PCR） with seedling DNA did detect the bar genc. Morphological variation was observed in six plants. We succeed in obtain PPT-resistant maize inbred lines via pollen tube pathway
文摘Kanamycin was used to screen To seeds of the variety Dongnong 46 transformed by means of pollen-tube method. The results showed that 400 mg·L^-1 kanamycin could inhibit growth of non-transgenic plants, and 2 positive plants were gotten combined with Gus dyeing and PCR detection. It is proved that this method is economic and effective in preliminary screening the transgenic plants.
文摘通过分析环核苷酸门控离子通道(cyclic nucleotide gated ion channels,CNGCs)蛋白结构、组织和细胞定位及CNGCs蛋白活性调节机制,对CNGCs蛋白在植物生长发育和胁迫响应中的作用进行全面综述。重点探讨了CNGCs蛋白调控植物花粉管生长的机制,并对植物CNGCs蛋白未来的研究方向进行了展望,能够为深入理解CNGCs蛋白在植物中的作用机制提供理论参考。
文摘Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed.
基金Project(51222406)supported by the National Natural Science Foundation of ChinaProject(NCET-12-1061)supported by the Funds for New Century Excellent Talents in University of China+1 种基金Project(12TD007)supported by the Scientific Research Innovation Team Program of Sichuan Colleges and Universities,ChinaProject(2014TD0025)supported by the Youth Scientific Research Innovation Team Program of Sichuan Province,China
文摘In order to meet the high temperature environment requirement of deep and superdeep well exploitation, a technology of large length-to-diameter ratio metal stator screw lining meshing with rotor is presented. Based on the elastic-plasticity theory, and under the consideration of the effect of tube size, material mechanical parameters, friction coefficient and loading paths, the external pressure plastic forming mechanical model of metal stator screw lining is established, to study the optimal loading path of metal stator lining tube hydroforming process. The results show that wall thickness reduction of the external pressure tube hydroforming(THF) is about 4%, and three evaluation criteria of metal stator screw lining forming quality are presented: fillet stick mold coefficient, thickness relative error and forming quality coefficient. The smaller the three criteria are, the better the forming quality is.Each indicator has a trend of increase with the loading rate reducing, and the adjustment laws of die arc transition zone equidistance profile curve are acquired for improving tube forming quality. Hence, the research results prove the feasibility of external pressure THF used for processing high-accuracy large length-to-diameter ratio metal stator screw lining, and provide theoretical basis for designing new kind of stator structure which has better performance and longer service life.
