With the development of economy and the improvement of science and technology in China, advanced construction technology such as modern seamless rail has gradually become one of the main development directions of rail...With the development of economy and the improvement of science and technology in China, advanced construction technology such as modern seamless rail has gradually become one of the main development directions of railway engineering construction in China. This paper summarizes the replacement technology of railway jointless track, analyzes and studies its corresponding replacement mode and locking technology according to relevant technical regulations, summarizes a complete set of technology and quality control standards, and completes the replacement of jointless track with quality and quantity, which has accumulated valuable experience for the replacement construction of jointless track of heavy haul railway and can also provide technical reference for similar heavy haul railway laying projects.展开更多
文摘【目的】小麦籽粒超氧化物歧化酶活性对小麦面粉色泽和营养品质具有重要影响,挖掘与小麦籽粒超氧化物歧化酶(superoxide dismutase,SOD)活性显著关联位点及候选基因,为揭示小麦籽粒SOD活性的遗传机理和小麦面粉色泽的遗传改良奠定基础。【方法】采用氮蓝四唑(nitro-blue tetrazolium,NBT)光化还原法对3个环境下种植的212份普通小麦品种(系)进行SOD活性检测,结合90K SNP芯片的16705个高质量SNP标记对小麦籽粒SOD活性进行全基因组关联分析(genome-wide association study,GWAS),并对稳定遗传的显著关联位点进行候选基因的挖掘。【结果】不同环境下,各小麦品种(系)间的SOD活性表现出丰富的表型变异,变异系数为4.34%—5.23%,相关系数介于0.60—0.90(P<0.001)。多态性信息含量(polymorphic information content,PIC)为0.24—0.29。全基因组连锁不平衡(linkage disequilibrium,LD)衰减距离为7 Mb。群体结构分析表明,供试材料可分为3个亚群。GWAS分析结果显示,共检测到29个与SOD活性显著关联位点(P≤0.001),分布在1A、1B、2A、2B、2D、3B、3D、4B、4D、5A、5B、5D、6A、6B、6D和7B染色体上,单个位点可解释5.47%—32.43%的表型变异,其中14个位点在2个及以上环境下均被检测到。9个显著关联位点在3个环境下被同时检测到,分布于1B、2B、4B、5A、5B、6B和6D染色体,贡献率为6.21%—16.62%。对稳定遗传的显著关联位点进行候选基因的挖掘,共挖掘TraesCS2B01G567600、TraesCS3D01G069900、TraesCS3D01G070200、TraesCS5B01G525700、TraesCS5B01G373700、TraesCS6A01G021400和TraesCS6D01G431500等7个SOD基因和TraesCS5A01G263500、TraesCS6B01G707800等2个与SOD活性相关的候选基因,候选基因的功能主要与抑制细胞活性氧积累及参与抗氧化剂再生过程有关。【结论】检测到与小麦籽粒SOD活性显著关联的29个SNP位点,共筛选出7个SOD基因和2个与SOD活性有关的候选基因。
文摘With the development of economy and the improvement of science and technology in China, advanced construction technology such as modern seamless rail has gradually become one of the main development directions of railway engineering construction in China. This paper summarizes the replacement technology of railway jointless track, analyzes and studies its corresponding replacement mode and locking technology according to relevant technical regulations, summarizes a complete set of technology and quality control standards, and completes the replacement of jointless track with quality and quantity, which has accumulated valuable experience for the replacement construction of jointless track of heavy haul railway and can also provide technical reference for similar heavy haul railway laying projects.
