三疣梭子蟹不同月龄形态性状的主成分分析

利用三疣梭子蟹(Portunus trituberculatus)在1-5月龄的生长数据, 对其全甲宽、甲宽、体长、体高、大螯长节长、大螯不动指长、第一步足长节长及体重8个性状进行主成分分析。结果表明: 1-3月龄各性状间相关系数均达到极显著水平(P<0.01), 4、5月龄部分性状间不显著(P>0.05)。各月龄三疣梭子蟹的主成分有所不同: 1月龄三疣梭子蟹的第一主成分为长度因子, 第二主成分为宽度因子; 2月龄三疣梭子蟹的第一主成分为宽度因子, 第二主成分为长度因子, 第三主成分为体重因子; 3月龄三疣梭子蟹的第一主成分为宽度因子; 4-5月龄三疣梭子蟹的第一主成分均为体重因子, 第二主成分均为长度因子。不同月龄三疣梭子蟹各性状的生长速率存在一定差异。1-3月龄形态性状的增长优先于体重, 4-5月龄体重增长优先于形态性状的增长。     

凡纳对虾形态性状对体重的影响效果分析

选择 6月龄凡纳对虾 176只 ,测定了体长、头胸甲长、胸宽、胸高、额剑上刺数、额剑下刺数、尾长和上市体重共 8个性状 ,采用相关分析和通径分析方法 ,剔除了与体长及头胸甲长有共线性的自变量尾长 ,计算了以形态性状为自变量对体重作依变量的相关系数、通径系数、决定系数及相关指数 ,定量地分析了形态性状对体重的影响效果。结果表明 ,凡纳对虾 5个形态性状与体重的相关系数达到极显著水平 (P<0 .0 1) ;通径分析揭示了多元分析中多个自变量与依变量的真实关系 ,体长、头胸甲长、胸宽、额剑下缘刺数目对体重的通经系数达到显著水平 ,它们是直接影响体重的重要指标 ,其中体长对体重的直接影响(0 .4 2 8* * )最大 ,是影响体重的最主要因素 ,其次为头胸甲长 (0 .2 90 * * )和胸宽 (0 .2 4 5 * * ) ,额剑下缘刺数对体重的直接影响(0 .0 70 * )较小 ;胸高与体重的相关程度很大 (0 .792 3) ,但它与额剑上缘刺数对体重的直接影响都非常小 ,主要通过其他性状间接影响活体重 ,是影响体重的次要因素 ,均被剔除 ;决定系数分析结果与通径分析结果有一致的变化趋势 ;所选形态性状与体重的复相关指数为 R2 =0 .92 13,说明影响体重的主要自变量指标已经找到 ;多元回归分析建立了体长 (X1 )、头胸甲长 (X2 )、胸宽(X3)、     

环境因子对凡纳滨对虾性别分化的影响

通过外部形态观察和组织学连续切片,探讨温度(251)℃、(291)℃和(331)℃、光照周期(6L∶18D、12L∶12D、18L∶6D和24L∶0D)、光照强度(800、3000和5000 lx)、盐度(10、20、30和40)和环境雌激素壬基酚(40、80和120g/L)对凡纳滨对虾仔虾性别分化的影响。结果表明:温度和光照对凡纳滨对虾性别比例无显著影响(P0.05),但显著地影响性分化时间;10、20和40盐度组以及120g/L的壬基酚处理组的凡纳滨对虾雌雄比分别为0.81∶1,0.67∶1,1.29∶1和1.24∶1,显著偏离1∶1的性别比例,且盐度和壬基酚处理也影响性腺分化时间。此外,凡纳滨对虾触鞭长与体长之比1.0时与其性腺及外部形态分化时期相一致,提示可以将触鞭长与体长之比1.0作为判定凡纳滨对虾性分化开始的指标。       

蝇蛆蛋白粉对凡纳滨对虾生长的影响

设计了4种实验饲料(ABCD)并进行了8周饲养试验来评定添加蝇蛆粉对凡纳滨对虾生长性能的影响.以实用饲料D作为对照组,ABC是在D的基础上,分别以5%,10%和15%的蝇蛆粉替代鱼粉.养殖试验结束后,分别计算体长、全长和背甲宽等生长性能.实验结果显示,AB组凡纳滨对虾的生长性能与对照组差异不显著(P>0.05).C组与对照组差异极显著(P<0.01).结果表明,饲料中添加适量的蝇蛆蛋白粉对凡纳滨对虾有一定的促生长作用,可用适量的蝇蛆蛋白粉替代对虾配合饲料中的部分鱼粉.     

一株凡纳滨对虾源维氏气单胞菌的分离鉴定及药敏特性

【目的】凡纳滨对虾(Litopenaeus vannamei)是世界范围内最主要的对虾养殖品种之一,2017年5-6月上海某凡纳滨对虾养殖场出现不明原因的死亡病例,发病急,死亡率高。从患病凡纳滨对虾体内分离到一株优势菌AVZ01,旨在确定病因并筛选出敏感药物,为今后凡纳滨对虾维氏气单胞菌(Aeromonas veronii)的防治提供参考。【方法】从患病凡纳滨对虾肝胰腺和肠道中分离致病菌,通过理化特性及16S r RNA基因序列分析进行鉴定,通过人工感染试验确定病原,使用Bliss法计算出半数致死剂量(LD50),并通过纸片扩散法进行药敏试验。【结果】从患病凡纳滨对虾体内分离到一株优势菌AVZ01,进行人工回归感染试验后,对虾发病症状与自然发病症状相似,凡纳滨对虾的LD50为8.7×105 CFU/m L。根据该菌株的形态特征、理化特性、16S r RNA基因序列分析,综合判断该病原菌为维氏气单胞菌。药敏试验结果显示,该菌株对米诺环素、诺氟沙星、庆大霉素等16种抗生素高度敏感,对青霉素、苯唑西林、头孢氨苄等9种抗生素耐药。【结论】分离菌株AVZ01对凡纳滨对虾有较强的致病性,养殖过程中可选用庆大霉素及新霉素等药物进行防控。     

碳酸盐碱度和pH值对凡纳滨对虾仔虾存活率的影响

采用静态急性毒理学方法,探讨了碳酸盐碱度和pH值对凡纳滨对虾(Litopenaeus vannamei)仔虾存活率的影响。结果表明:在pH值为7.5、8.0、8.5、9.0、9.5、10.0及10.5的试验组中,凡纳滨对虾仔虾存活率随着pH值的升高而下降,碳酸盐碱度在3mmol·L-1、pH值在9.0以上时,凡纳滨对虾仔虾的存活率受到影响显著;在碳酸盐碱度0～44.43mmol·L-1各试验组中,随着碳酸盐碱度升高,凡纳滨对虾仔虾的存活率下降,凡纳滨对虾仔虾对碳酸盐碱度的耐受性随着pH的升高明显下降;pH值为8.8时,碳酸盐碱度的48hLC50为36.81mmol·L-1,pH值为9.2时,碳酸盐碱度的48hLC50为33.05mmol·L-1,pH值为9.6时,碳酸盐碱度的48hLC50为5.55mmol·L-1;在本试验范围内,凡纳滨对虾对高碳酸盐碱度显示出较强的耐受性,是一种适宜移植到盐碱水域的养殖品种;碳酸盐碱度和pH对凡纳滨对虾的致毒作用是一个综合致毒效应,其中CO32-为主要致毒因子。     

凡纳滨对虾TCP-1-Beta基因的克隆及其与耐寒性状的相关性

为研究凡纳滨对虾耐寒性状的分子机理,研究克隆了凡纳滨对虾耐寒相关基因TCP-1-Beta并对其与耐寒性状的关系进行了研究.根据电子克隆所得序列设计引物,采用RT-PCR方法克隆得到长1691 bp的凡纳滨对虾TCP-1-Beta基因序列,其中包括1608 bp的完整开放阅读框,编码535个氨基酸残基.然后,运用荧光定量PCR对TCP-1-Beta基因进行时空表达谱的分析:组织表达谱的结果显示,该基因在凡纳滨对虾肝胰腺组织中表达量最高;不同低温处理下的表达结果显示,在28℃和15℃处理下基因表达量无显著变化,13℃开始呈上调表达,11℃时表达量升高;13℃低温处理发现该基因在24h内表达量无显著变化,但36h后表达量显著升高.采用PCR-RFLP方法对216尾凡纳滨对虾TCP-1-Beta基因进行了SNP多态性检测,并将其与耐寒性状进行了关联分析.在该基因编码区第420碱基上发现G/A突变,方差分析结果表明该位点的不同基因型与耐寒力指标CDH值相关(P＜0.05),其中GG基因型的耐寒能力比AA基因型强.     

通径分析在脊尾白虾育种形态性状选择中的应用

选择胶州湾134只野生脊尾白虾（Exopalaemon carinicauda）,对其体长、全长、头胸甲长及体重等24项性状进行测量,采用相关分析和通径分析的方法,分析了形态性状对体重的影响效果,并构建形态性状与体重的多元回归方程.结果表明,各形态性状与体重的相关系数均达到了极显著水平（P<0.01）;全长、头胸甲宽、头胸甲高、第一腹长、第二腹高、第三腹宽对体重的通径系数达到显著水平（P<0.05）;所选形态性状与体重的复相关指数R²=0.954;多元回归分析建立了全长、头胸甲宽、头胸甲高、第一腹长、第二腹高、第三腹宽对体重的回归方程Y=-2.783+0.014X₁+0.130X4+0.095X₁₃+0.126X5+0.045X6+0.149X11.试验结果为脊尾白虾良种选育研究提供了理想的测度指标.     

虾头提取物对凡纳滨对虾生长和免疫因子的影响

以添加不同量虾头提取物(0、1.0%、1.5%、2.0%、2.5%、3.0%)的饲料投喂初体质量为6.35±0.38 g的凡纳滨对虾49 d,研究其对对虾的生长及免疫因子的影响。各组凡纳滨对虾的生长及体成分组成没有显著差异。与对照组相比,1.5%~3.0%添加量组对虾血清中的ACP活力明显提高;2.0%~3.0%添加量组对虾血清中的AKP活力明显提高;各添加量组对虾血清中的PO活力都有明显提高。实验结果表明,添加适当剂量的虾头提取物可以增强凡纳滨对虾的免疫能力。     

云南红花种质资源主要农艺性状的遗传多样性分析

为加强红花种质资源的研究利用,对筛选出的66份云南红花优异种质资源16个形态性状进行聚类分析与主成分分析。结果表明:云南红花种质资源具有丰富的遗传多样性,多样性指数最高的是果球着粒数,其次是株高、最末分枝高度和千粒重;性状变异系数最大的是分枝总数,其次分别是单株有效果球数和第一分枝高度,最小的为顶果球直径;基于各种质间形态性状的遗传差异,把66份红花种质聚类并划分为6大类群。第Ⅰ类群可作为有增产潜力的亲本材料,第Ⅲ类群可作为高产量目标选育的亲本,第Ⅳ类群可作为大粒型选育亲本,第Ⅴ类群可作为高含油量选育目标亲本,第Ⅵ类群既是大粒型又是高含油量双重选育目标亲本。11个数量性状的主成分分析结果表明,前4个主成分累计贡献率达82.59%,第一主成分反映植株高度,第二主成分反映产量构成因子,第三、第四主成分分别反映千粒重和果球着粒数。研究结果表明云南红花地方种质资源的变异较大,遗传较丰富。     

影响水稻光合日变化的酶和相关因素的分析

水稻叶片的最大光合速率出现在上午１０：００时,Ｒｕｂｉｓｃｏ初始活力也在此时达到最大,然后逐渐降低,下午１４：００时略上升后又下降．Ｒｕｂｉｓｃｏ初始活力与光合速率之间极显著相关,相关系数为 ０．９４７４．运用相关性分析、回归分析、通径分析,对晴（有时有云）天气水稻叶片的光合速度、光合关键酶及有关因素的日变化进行综合评估,结果发现中午光合下降主要来自气孔限制,同时Ｒｕｂｉｓｃｏ活性也下降;Ｒｕｂｉｓｃｏ活性是影响光合日变化的又一重要生化因子．体内Ｒｕｂｉｓｃｏ活性受Ｒｕｂｉｓｃｏ活化酶的调节．     

甲醇对酵母过氧化氢酶活性的影响机理研究

将酵母过氧化氢酶加入一定比例的甲醇,测定其活性变化。结果表明:在含2%甲醇时酶活比对照提高4026%。将粗酶液用70%饱和度的硫酸铵盐析后离心所得的上清液再加入硫酸铵至80%饱和度,离心的沉淀溶解在缓冲液中,上SephadexG75柱,分离出的有酶活性的蛋白峰经电泳得一条蛋白带,说明过氧化氢酶已经被提纯到电泳纯。光谱分析发现,甲醇处理后过氧化氢酶纯酶的吸收光谱和荧光发射光谱与未经处理的比较基本不变,而差示光谱出现明显的正峰和负峰。由动力学分析可知,在甲醇中,过氧化氢酶的Vmax和Km值均有不同程度提高 。     

Discrimination of higher plant calluses based on embryogenic capacity and taxonomic classification by pyrolysis mass spectrometry

Pyrolysis mass spectrometry (PyMS) is a rapid, simple, high-resolution analytical method based on thermal degradation of complex material in a vacuum, and has been widely applied to the discrimination of closely related microbial strains. Minimally prepared samples of embryogenic and non-embryogenic calluses derived from various higher plants (sweet potato, morning glory, Korean ginseng, Siberian ginseng, and balloon flower) were subjected to PyMS for spectral fingerprinting. A dendrogram based on the unweighted pair group method, with arithmetic mean of pyrolysis mass spectra, divided the calluses into Siberian ginseng embryogenic callus and the others, which were subsequently divided into embryogenic and non-embryogenic callus groups, regardless of plant species from which the calluses were derived. In the non-embryogenic callus group, the dendrogram was in agreement with the known taxonomy of the plants. These results indicate that PyMS analysis could be applied for discriminating plant calluses based on embryogenic capacity and taxonomic classification.     

Normal Approximations of Exact Tests in Configural Frequency Analysis

The most common tests for types and antitypes in configural frequency analysis are normal approximations of exact tests. In the paper such statistics under the complete independence model and under the fixed margins model are discussed. It turns out that these test statistics are not acceptable when the number of simultaneously performed tests is large or when the expected frequencies are small. In these cases, the use of exact tests is advocated and some existing computer programs for such tests are indicated. A normal approximation based on the strong version of the De Moivre-Laplace limit theorem is also discussed. Empirical examples are given from longitudinal data describing psychological development of boys.     

Some remarks about the analysis of active control studies

In an active-controlled trial, the experimental treatment can be declared to be non-inferior to the control if the confidence interval for the difference excludes a fixed pre-specified margin. Recently, some articles have discussed an alternative method where the data from the current study and placebo-controlled studies for the active control are combined together into a single test statistic to test whether a fixed fraction of the effect of the active control is preserved. It has been shown that, conditional on nuisance parameters from the active-controlled study, a fixed margin can be defined that will be operationally equivalent to this latter method. In this article, we will discuss statistical properties associated with these approaches. Specifically, the interim monitoring boundaries and level of evidence will be considered.     

Phenotypic evaluation of genetic variability and selection of yield contributing traits in chickpea recombinant inbred line population under high temperature stress

Heat is a major abiotic stress that drastically reduces chickpea yield. This study aimed to identify heat-responsive traits to sustain crop productivity by screening a recombinant inbred line (RILs) population at two locations in India (Ludhiana and Faridkot). The RIL population was derived from an inter-specific cross between heat-tolerant genotype GPF 2 (C. arietinum L.) and heat sensitive accession ILWC 292 (C. reticulatum). The pooled analysis of variance showed highly significant differences for all the traits in RILs and most of the traits were significantly affected by heat stress at both locations. High values of genotypic coefficient of variation (19.52–38.53%), phenotypic coefficient of variation (20.29–39.85%), heritability (92.50–93.90%), and genetic advance as a percentage of mean (38.68–76.74%) have been observed for plant height, number of pods per plant, biomass, yield, and hundred seed weight across the heat stress environments. Association studies and principal component analysis showed a significant positive correlation of plant height, number of pods per plant, biomass, hundred seed weight, harvest index, relative leaf water content, and pollen viability with yield under both timely-sown and late-sown conditions. Path analysis revealed that biomass followed by harvest index was the major contributor to yield among the environments. Both step-wise and multiple regression analyses concluded that number of pods per plant, biomass and harvest index consistently showed high level of contribution to the total variation in yield under both timely-sown and late-sown conditions. Thus, the holistic approach of these analyses illustrated that the promising traits provide a framework for developing heat-tolerant cultivars in chickpea.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12298-021-00977-5.     

Comparison of the Halving of Tablets Prepared with Eccentric and Rotary Tablet Presses

The aim of this study was to compare the densification of powder mixtures on eccentric and rotary tablet presses and to establish relationships with the halving properties of the resulting scored tablets. This is an important problem because the recent guidelines of EU require verification of the equal masses of tablet halves. The models of Walker, Heckel, and Kawakita were used to describe the powder densification on the two machines. The calculated parameters revealed that the shorter compression cycle of rotary machines results in poorer densification and lower tablet hardness at a given compression force. This is manifested in poorer halving properties, which are influenced mainly by the hardness. Better densification improves the halving even at lower tablet hardness. This demonstrates that these parameters can be good predictors of tablet halving properties.     

土壤中微生物含量影响因素的统计方法分析

【目的】采用多元方差分析、多元线性回归分析、通径分析等统计方法,并利用多元统计方法对土壤中微生物含量进行分析。【方法】通过研究这3种常用统计方法的原理、应用条件、适用于解决的问题等,用不同的方法分析影响土壤中微生物含量的各种因素,利用SPSS软件求解。【结果】得出不同降雨量下土壤中的微生物含量存在差异性;铵态氮含量和海拔高度与变形菌门含量呈显著的线性关系,土壤中变形菌门含量随着铵态氮含量增多而增多,且铵态氮含量对变形菌门含量所起的直接作用最大;土壤中铵态氮含量、总氮量和海拔高度与放线菌门含量呈显著的线性关系,且均为负相关;其中总氮量对土壤中放线菌门含量的变化所起的负面作用最大,但铵态氮含量对放线菌门含量所起的直接作用最大。对比描述性统计方法与多元方差分析方法可知,应用描述性统计方法只能得出降雨量是影响土壤中不同细菌群落相对含量的因素之一,而不知降雨量对微生物含量变化的影响程度,6个梯度降雨量引起地显著差异究竟是由哪种微生物引起的,方差分析方法可以解决以上的问题。对比多元线性回归分析方法与通径分析方法可知,多元线性回归分析得出的相关系数只能表示铵态氮含量、总氮量和海拔与变形菌门含量(放线菌门含量)之间关系的密切程度,但无法解释和分析这种关系的构成和来源,通径分析方法可以解决这个问题。【结论】通径分析方法在分析相关问题时要优于多元线性回归分析方法,通径分析比多元线性回归分析方法更能体现因素对变形菌门含量(放线菌门含量)的直接影响和间接影响,分析结论更直观、更能说明问题。     

Fish ecoregions of Kansas: stream fish assemblage patterns and associated environmental correlates

Synopsis Principal components analysis was performed on fish presence/absence data for 39 common fish species from 410 stream sites in Kansas. The analysis confirmed ten ecologically meaningful fish assemblages, based on species associations. Factor scores based on these assemblages were then clustered into six geographic areas or fish ecoregions. Canonical discriminant analysis identified environmental variables that distinguished the derived fish ecoregions. Mean annual runoff, mean annual growing season, and discharge appear most important. Mean width, mean depth, chloride concentration, water temperature, substrate type, gradient, and percent of pool habitat were less important. Correspondence exists between these fish ecoregions and the patterns of physiographic regions, river basins, geology, soil, and potential natural vegetation in Kansas. The multivariate statistical approach used to classify fish ecoregions should have considerable potential value for fish assessment and management purposes in areas other than the state of Kansas.