This paper presents the structure and contents of a standardized layered classification system of digital geomorphology for China.This digital classification method combines landforms characteristics of morphology wit...This paper presents the structure and contents of a standardized layered classification system of digital geomorphology for China.This digital classification method combines landforms characteristics of morphology with genesis.A total of 15 categories of exogenic and endogenic forces are divided into two broad categories：morpho-genetic and morpho-structural landforms.Polygon patches are used to manage the morpho-genetic types,and solitary points,lines and polygons are used to manage the morpho-structural types.The classification method of digital morpho-genetic types can be divided into seven layers,i.e.basic morphology and altitude,genesis,sub-genesis,morphology,micro-morphology,slope and aspect,material and lithology.The method proposes combinations of matrix forms based on layered indicators.The attributes of every landform types are obtained from all or some of the seven layers.For the 15 forces categories,some classification indicators and calculation methods are presented for the basic morphology,the morphologic and sub-morphologic landforms of the morpho-genetic types.The solitary polygon,linear and point types of morpho-structural landforms are presented respectively.The layered classification method can meet the demands of scale-span geomorphologic mapping for the national primary scales from 1：500,000 to 1：1,000,000.The layers serve as classification indicators,and therefore can be added and reduced according to mapping demands,providing flexible expandability.展开更多
Salivary glands provide saliva to maintain oral health, and a loss of salivary gland function substantially decreases quality-of-life. Understanding the biological mechanisms that generate salivary glands during embry...Salivary glands provide saliva to maintain oral health, and a loss of salivary gland function substantially decreases quality-of-life. Understanding the biological mechanisms that generate salivary glands during embryonic development may identify novel ways to regenerate function or design artificial salivary glands. This review article summarizes current research on the process of branchingmorphogenesis of salivary glands, which creates gland structure during development. We highlight exciting new advances and opportunities in studies of cell-cell interactions, mechanical forces, growth factors, and gene expression patterns to improve our understanding of this important process.展开更多
80年代以来,以辣椒的子叶、胚轴、子叶节、茎尖和叶花盘为外植体进行离体培养,均诱导分化出了再生株(Fari et al,1981;Sripichitt et al,1987)。本试验在不同生长调节剂中离体培养三个辣椒品种的茎、叶,大部分能分化出再生株。 1 结果...80年代以来,以辣椒的子叶、胚轴、子叶节、茎尖和叶花盘为外植体进行离体培养,均诱导分化出了再生株(Fari et al,1981;Sripichitt et al,1987)。本试验在不同生长调节剂中离体培养三个辣椒品种的茎、叶,大部分能分化出再生株。 1 结果和分析 三个辣椒品种84—1、南京早椒、上海甜椒的茎、叶外植体在MS附加不同生长调节剂的培养基上,一周内多数外植体均在切断处发生膨大、隆起,然后逐渐扩展到外植体边缘形成愈伤组织,3—4周后分化出再生苗。 1.1 植物生长素与形态发生 三个辣椒品种的茎、叶外植体,在MS附加IAA(0.1、1mg/l)或NAA(o.1、1mg/l)的培养基上培养时,均较快地产生根和愈伤组织。但两种生长素在产生根的特征上有一定差异。含IAA培养基产生的根细而长,而含NAA培养基产生的根却粗而短。展开更多
基金Key Project of the National Natural Science Foundation of China, No.40871177 No.40830529 No.40971063
文摘This paper presents the structure and contents of a standardized layered classification system of digital geomorphology for China.This digital classification method combines landforms characteristics of morphology with genesis.A total of 15 categories of exogenic and endogenic forces are divided into two broad categories：morpho-genetic and morpho-structural landforms.Polygon patches are used to manage the morpho-genetic types,and solitary points,lines and polygons are used to manage the morpho-structural types.The classification method of digital morpho-genetic types can be divided into seven layers,i.e.basic morphology and altitude,genesis,sub-genesis,morphology,micro-morphology,slope and aspect,material and lithology.The method proposes combinations of matrix forms based on layered indicators.The attributes of every landform types are obtained from all or some of the seven layers.For the 15 forces categories,some classification indicators and calculation methods are presented for the basic morphology,the morphologic and sub-morphologic landforms of the morpho-genetic types.The solitary polygon,linear and point types of morpho-structural landforms are presented respectively.The layered classification method can meet the demands of scale-span geomorphologic mapping for the national primary scales from 1：500,000 to 1：1,000,000.The layers serve as classification indicators,and therefore can be added and reduced according to mapping demands,providing flexible expandability.
基金Supported by the Intramural Research Program of the National Institute of Dental and Craniofacial Research,NIH
文摘Salivary glands provide saliva to maintain oral health, and a loss of salivary gland function substantially decreases quality-of-life. Understanding the biological mechanisms that generate salivary glands during embryonic development may identify novel ways to regenerate function or design artificial salivary glands. This review article summarizes current research on the process of branchingmorphogenesis of salivary glands, which creates gland structure during development. We highlight exciting new advances and opportunities in studies of cell-cell interactions, mechanical forces, growth factors, and gene expression patterns to improve our understanding of this important process.
