中国主要河流鱼类分布及其种类多样性与流域特征的关系

对中国13条主要河流淡水鱼类分布进行的系统聚类分析结果表明,分异最小的是闽江与九龙江。瓯江与钱塘江、淮河与黄河、东北的水系分别较早聚为一类。相异系数在0.60～0.69时分为三类: 东北的水系、黄河到珠江间的水系和云南的元江。淡水鱼种类数与流域特征的相关和回归分析揭示了：鱼种数分别与河流流域面积、年平均流量呈显著或极显著的正相关,单位干流长和单位流域面积的鱼种类数分别与河流径流深、比降呈显著或极显著的正相关, 而与河流平均纬度呈显著负相关。主成分分析得到的第一和第二主成分分别综合反映了河流鱼种类数和相对种类数与河流特征值的关系。     

对虾病毒病病毒和细菌合并感染的病理特点和诊断价值

应用电镜超薄切片及光学石蜡切片和环氧树脂薄片技术,观察健康对照组、疾病始发组和濒临死亡组的草虾、中国对虾、日本对虾和长毛对虾的肝胰腺和中肠,结果在３组４种对虾中均检测到病毒,只在濒临死亡组的４种对虾中发现病毒与细菌的合并感染。合并感染的病毒有ＭＢＶ、球形病毒和淋巴样细胞核型杆状病毒。细菌以弧菌为主,其病理变化表现为器官和组织的保护层受损、溶解样坏死和凝固样坏死。仅以病毒和细菌合并感染作为养殖对虾病毒病早期诊断的指标是不够的,仅可作为辅助性诊断指标。但合并感染对评估对虾病毒病的预后以指导捕捞,却有一定意义。     

西双版纳勐养自然保护区植被的分布与生态特征

对西双版纳勐养自然保护区植被的类型进行了划分 ,包括人工和自然群落 ,共有7个大类、1 5个群系、2 4个群落类型分布 .对每个类型的主要组成种类、生态特征和分布现状进行了初步研究 .利用地理信息系统软件制取植被图并获得了各种植被类型的分布面积和分布格局特征 ,这一地区亚热带季风常绿阔叶林的分布面积和所占比例最大 ,达总面积的 41 .2 6 % ;而热带雨林面积不超过总面积的 1 0 % .依据地形、海拔、气候和现状植被分布的规律 ,在获得景观类型图的基础上 ,得到了可以反映这一地区在完全自然条件下植被可能分布的状况的还原植被图 ,为保护区的发展和植被的恢复提供了理论依据。     

播种密度和基肥条件对晚籼稻旱育秧苗某些生理特性的影响

研究了1995年晚季不同播种密度和不同基肥对华南稻区晚籼稻旱育秧苗某些生理特性的影响。结果表明,在2种播种密度和5种基肥构成的10个处理中,秧苗叶龄、苗高和假茎宽等均无明显差异。在播种量为125g m-2条件下,虽然秧苗的总生长量较低,但其干/鲜重比值仍较播种密度为65gm-2略高;不同处理间的功能叶叶绿素含量(a b)、白根数/株和根活力呈显著差异,其中以沤熟有机肥和高无机肥用量作基肥的处理效果明显优于低无机肥用量作基肥的处理。因此,在进行旱育秧苗床培肥中,应注意以施用有机肥为主,适当补充无机肥,才能获得根系发达、活力强的健壮旱秧,为移栽后的叶蘖早发打基础。     

动物数量性状选择的C语言程序

本文仅从实用角度出发,通过应用示例给出根据正态分布原理进行家畜数量性状选择的C语言程序,为实际选种提供方便。 Abstract:By using of instance,this paper gives C program about animal selection by the principle of normal distribution,Provides convenience for practice selection.     

Molecular and morphological characterization of monosomic additions in Beta vulgaris,carrying extra chromosomes of B. procumbens or B. patellaris

DNA fingerprinting with three repetitive DNA sequences (OPX2, PB6-4 and Sat-121) was carried out on a set of 10 monosomic additions of Beta procumbens and 75 anonymous B. patellaris-derived monosomic additions in B. vulgaris, for characterization of the alien chromosomes at the DNA level. The probes are Procumbentes-specific and distributed over all chromosomes. Morphological characteristics were also used for the classification of B. patellaris monosomic addition families and for comparison with the morphology of the addition families of B. procumbens.DNA fingerprinting revealed unique patterns for almost all individual addition chromosomes of B. procumbens. However, it was concluded that chromosomes 1 and 6 of B. procumbens may be identical with the only difference that the chromosome referred to as 6 carries a susceptible allele for beet cyst nematode (BCN) resistance. In contrast, it was concluded that the two addition types with chromosome 2 are carrying different chromosomes of B. procumbens, so that one of them was renumbered to become the new chromosome 6.DNA fingerprinting of 75 anonymous B. patellaris-derived monosomic additions facilitated the identification and characterization of the alien chromosomes and the grouping of these additions into nine different groups. Several of these groups could be divided in two sub-groups on the basis of small differences in banding patterns. The results of the DNA fingerprinting led to the conclusion that B. patellaris most likely is an allotetraploid. It was also deduced that the BCN gene(s) in this species are homozygous and located on chromosome 1, while the pair of homoeologous chromosomes does not carry such BCN gene(s). Because of the allotetraploid nature of B. patellaris, preferential association occurs between the two homologous chromosomes containing the allele(s) for BCN resistance. Each group of B. patellaris addition families united by DNA fingerprinting had comparable morphological characteristics. Some of these morphological traits appeared to be chromosome-specific and were very useful for primary classification of the addition families. However, the present study showed that these morphological traits are not adequate for the identification of all alien chromosomes without the aid of additional markers. Because of similarities observed between molecular characteristics or the effects on plant morphology of several chromosomes of B. procumbens and B. patellaris it was concluded that B. procumbens could have been involved in the evolutionary history of B. patellaris.     

沙地植物柄扁桃的生物学特性及引种栽培的研究

通过研究发现柄扁桃具有典型旱生植物的形态结构特征。同时,在生理特征上也与旱生环境相适应。因此,在沙区引种栽培柄扁桃是可行的。柄扁桃的繁殖主要采用播种法,利用沙藏催芽法处理种子,树苗当年可出圃造林。沙地造林采用植前造林法,将株高４０—１００ｃｍ的健壮苗在春季栽植于平缓的沙地、沙丘迎风坡下部或丘间地等风蚀轻、水分条件好的沙地。     

人T细胞系Jurkat表达特异性的C1q受体

采用酶联免疫吸附试验、流式细胞术、放射配体结合试验及蛋白质印迹等方法,首次证实了人Ｔ细胞系Jurkat表达特异性C1q受体,并对其特性进行了分析Jurkat可为C1q或抗人C1q受体抗体112识别,其对异硫氰酸荧光黄标记C1q的结合能被未标记C1q所抑制．在生理离子强度和温度条件下,Jurkat与 ¹²⁵I－C1q的结合呈持异、剂量依赖、可饱和及可逆性,每个细胞C1q结合位点数为1.1×10⁶,对C1q的K_a值为1.5×10⁷mol^-1,Hill系数为0.9643．Jurkat C1q受体识别C1q的胶原样区．该受体是分子量约70000的膜蛋白分子     

转基因的分子生物学特性

现代分子生物学研究中,转基因概念的出现越来越频繁,它渐渐被用来表示所有的用基因工程手段构建、导入高等真核生物细胞,并稳定地整合入受体基因组的外源DNA．文章较系统地总结了已见报道的转基因的结构类型、它在受体细胞内的遗传学行为、表达特性和影响因素及其相应的生物学效应;分析了转基因研究中尚待研究的问题,提出了系统地进行转基因本身的分子生物学特性研究的必要性.     

Blood Characteristics of the Crab-Eating Monkeys (Macaca fascicularis) in Bali Island,Indonesia: Implication of Water Deficiency in West Bali

Environmental effects on blood characteristics of macaques were examined by comparing serveral blood indices of the free-ranging crab-eating monkeys (Macaca fascicularis) in two distinct regions of Bali Island, Indonesia. The total plasma protein level and concentrations of' creatinine and sodium ion were higher with macaques of Teluk Terima in the west part of Bali Island (dry area) than those in the central Bali (wet area). Results indicated that water deficiency in the dry area significantly affects the blood characteristics of macaques.