桃(Prunus persica)种质资源物候期性状遗传多样性的评价指标探讨

本试验对桃（Prunus persica）的301～480份种质资源的需冷量、始花期、大量落叶开始期、大量落叶终止期、果实生育期、营养生长期6个性状的遗传多样性进行了统计分析,根据性状在不同区问的频率分布,提出我国桃种质资源物候期性状评价系统的数值分级指标和参照品种,为我国桃种质资源描述系统的数量化、规范化奠定基础。     

枇杷属植物4个种的花序性状多样性研究

在相同的种植和管理条件下,对普通枇杷、栎叶枇杷、大瑶山枇杷和南亚枇杷等4个种210份种质资源的8个花序性状多样性进行鉴定,旨在为进一步的分类鉴定、利用研究提供参考依据。结果表明:(1)枇杷属种质资源的花序支轴姿态、花序支轴密度、花序支轴数、花序形状、花序长度、花序宽度、花瓣颜色、花冠直径Shannon-Weaver多样性指数1.352～2.951,存在丰富的多样性。(2)不同来源地的种质资源花序性状多样性水平差异较大,多样性指数最高的为云南(2.108),其次是贵州(1.962)、四川(1.953)、福建(1.900),美国的最低(1.137)。(3)云南、贵州的枇杷种质资源花序长度、宽度显著或极显著地大于其他地区;野生资源的花序长度、花序宽度和花冠直径均极显著地大于地方品种、选育品种。     

桃种质资源亲缘关系的研究进展

种质资源是现代育种和生物技术研究的物质基础。桃种质资源亲缘关系的研究将为探讨桃的起源、进化、分类、育种和资源利用提供科学依据。本文从形态学、细胞学、孢粉学、生物化学及DNA分子标记等几个方面综述了桃种质资源亲缘关系的研究进展,探讨了桃种质资源亲缘关系的研究现状、前景及尚需解决的问题,并就进一步开展桃种质资源亲缘关系的研究进行了分析,提出桃种质野生种、近缘野生种厦不同栽培品种群间的分子系统学关系是今后研究的重点。     

贵州桃种质资源遗传多样性的SCoT分析

应用SCoT分子标记技术对71份贵州桃种质进行遗传多样性分析,以期从分子水平上揭示其遗传多样性及资源间的遗传关系,为科学保存与利用贵州桃种质资源提供依据。结果表明:(1)16条引物共检测出192个位点,其中多态性位点数156个,多态性比例为81.25%,平均每条引物扩增位点为12个;供试材料Nei’s遗传多样性指数(H)为0.265 0±0.186 1,Shannon’s信息指数(I)为0.400 3±0.254 3,遗传相似系数变幅为0.400 0~0.852 5。(2)UPGMA聚类分析显示,在相似系数0.65处可将71份桃资源分成6类,其中2份白花桃资源、2份血桃资源、2份青桃资源分别为同名异物。研究认为贵州桃种质具有较丰富的遗传多样性,采用该分子标记技术区分了同名异物的桃资源。     

陆地棉种质资源花铃期抗旱性鉴定及抗旱指标筛选

大田试验设置正常灌水和干旱胁迫处理,于花铃期开始干旱处理,以株高、果枝数等12个农艺性状的平均数为基础,采用综合抗旱系数、模糊隶属函数、主成分分析、关联分析和聚类分析等统计分析方法相结合进行品种抗旱性鉴定和抗旱指标的筛选,为棉花抗旱品种鉴定和棉花生产提供理论依据。12个农艺性状对水分胁迫的敏感程度各异,基于D值、CDC值和WDC值的棉花种质抗旱性分析;通过D值的聚类分析结果,将153份种质资源分为5级,Ⅰ级(强抗旱型)5份、Ⅱ级(抗旱型)35份、Ⅲ级(中抗旱型)56份、Ⅳ级(较敏感型)56份和Ⅴ级(敏感型)1份。供试棉花种质的籽棉产量与D值、CDC值和WDC值均呈极显著正相关。筛选出花铃期抗旱性强的棉花种质有以色列1101,抗旱性弱的品种盐早2号。株高、籽棉产量、单铃重、有效铃数和果枝始节高度可作为棉花种质资源花铃期抗旱性评价的指标。     

利用DNA ISSR分子标记技术对芍药属植物栽培品种的分类鉴定方法

以利用DNA ISSR分子标记逐级区分品种为主要研究目标,通过ISSR引物的设计与实验筛选,取得了进展。该方法类似于经典的植物形态检索表式的分类策略,不同之处在于利用基因组DNA分子性状作为品种分类的依据,即"ISSR引物结合位点"与"DNA ISSR片段长度差异"的组合信息。该方法不仅可以有效鉴定品种,而且可以很容易地生成富含遗传变异信息的0、1矩阵,通过运算揭示品种间的遗传关系与演化规律。该方法成本低廉、操作便捷,对于建立客观、科学的牡丹及芍药品种分类体系,对于芍药属品种种质资源的保存、评价与合理利用具有重要价值。应该加大支持力度推进其实际应用。     

270份陆地棉种质资源农艺性状与品质性状的遗传多样性分析

对270份陆地棉种质资源的7个农艺性状和5个纤维品质性状进行遗传多样性、相关性、主成分和聚类分析,进而筛选适宜优良性状的棉花种质资源材料,为棉花育种工作中亲本选配与品种选育提供一定的理论参考依据。结果表明该批棉花种质资源具有丰富的遗传多样性,12个农艺性状的变异系数从大到小依次为结铃数(24.2%)、第一果枝长度(17.500%)、第一果枝节位(14.100%)、单铃重(13.329%)、马克隆值(11.091%)、株高(11.010%)、衣分(10.984%)、果枝数(9.625%)、断裂比强度(8.574%)、上半部平均长度(6.257%)、伸长率(2.005%)和整齐度指数(1.562%);相关分析表明上半部平均长度与株高呈显著正相关,与马克隆值呈显著负相关,衣分与株高和断裂比强度呈显著正相关,与果枝数呈显著负相关,马克隆值与伸长率呈极显著正相关,结铃数与第一果枝节位呈显著正相关;主成分分析表明前4个主成分累计贡献率达到67.358%,第1主成分主要和纤维品质有关,第2主成分主要与结铃数、第一果枝长度有关,第3主成分主要与果枝数有关,第4主成分主要与第一果枝节位有关;聚类分析将270份陆地棉种质资源在遗传距离为7.5时划分为6类,第1类群的棉花材料可作为改良棉花断裂比强度的材料加以利用,泗棉2号、南丹巴地大花、鄂抗棉8号和Qik可作为改良棉花产量构成的材料加以利用,聊113、军棉1号、辽阳绿绒棉和保2367可作为改良棉花马克隆值的材料加以利用,陕三原78-782可作为株型改良的材料加以利用,育种工作中可以结合性状之间的关系,培育新品种与新品系,为棉花品种选育提供理论依据。     

桃花器和开花特性研究

对国家果树种质资源南京桃圃保存的507份桃种质资源进行了花期、花型、花径、雌蕊高度(与雄蕊比)、花粉育性的调查,结果表明,需冷量少的品种花期早于其他大部分种质资源,始花期以及花期持续的时间与当年的气候和花期天气尤其是温度有关.84.4%的种质资源具蔷薇形花,78.5%的铃形花种质资源为黄桃;66.1%的种质资源花径在3.7～4.7cm,花径最大的是观赏鲜食兼用的重瓣花种质资源花玉露;90. 5%的种质资源雌蕊高于或近等于雄蕊,蟠桃88.2%的种质资源雌蕊低于雄蕊;花粉可育种质资源443份,占种质资源总数的87.4%.     

东北大豆种质群体在大庆的表现及其育种意义

表型评价是鉴别高产、优质和抗逆性优良大豆资源的必要步骤。为更好利用东北大豆种质资源,2012-2014年在大庆农科院将搜集到的东北地区各育种单位现存的361份大豆地方品种和育成品种(系)进行田间试验,采用重复内分组试验设计,对4类13个农艺、品质性状进行统计分析。结果表明:(1)东北大豆种质群体在大庆表现为:全生育期121 d(94~134 d)、蛋白质含量40.68%(36.66%~45.33%)、脂肪含量20.68%(15.77%~22.90%)、蛋脂总量61.36%(57.08%~65.45%)、百粒重17.48 g(9.69~28.42 g)、株高66 cm(33.1~96.2 cm)、主茎17节(9.76~24.00)、分枝1.25个(0.0~7.4)、倒伏1.4级(1.0~4.0)。(2)大庆地区适合熟期组(MG)为MG0和MGⅠ,更趋向于MGⅠ,两熟期组内品种的各性状平均值与东北大豆种质群体的总平均值相近。MG000~MG00组生育期较短,未能充分利用当地生态气候资源,品质性状与MG0~MGⅠ相差不大;而株高、产量性状表现较MG0~MGⅠ偏低(如株高低约20 cm,地上部生物量低约1.2 t/hm2)。MGⅡ~MGⅢ品种则大多未能充分成熟,导致其他性状表达不正常。大庆地区未来大豆改良的主要方向是适合的熟期组(MG0~MGⅠ)、高产、高蛋白兼顾高脂肪含量,应重视耐逆性。从资源群体中优选出一批用以改良大庆大豆性状的不同熟期组亲本,为育种工作者提供参考。     

新收集大豆种质资源主要品质鉴定与评价

对"十五"期间新收集、保存入国家种质资源库的841份大豆种质资源的蛋白质、脂肪两个主要品质性状进行了鉴定评价.结果表明,蛋白质、脂肪含量均近似正态分布,最大频度分别出现在41.01%～ 42.00%含量范围和20.01%～21.00%含量范围.与以前收集、保存的种质资源相比,新收集种质资源的蛋白质含量呈下降趋势,而脂肪含量和蛋脂总量呈上升趋势.不同类型种质资源的品质性状比较结果表明,地方品种的蛋白质总体水平明显高于育种材料、引进种质和选育品种3种类型,引进种质的脂肪、蛋脂总量的总体水平明显高于其他3种类型.国内种质资源高蛋白质大豆占有率高于引进种质资源;引进种质资源高脂肪、高蛋白兼高油的大豆占有率高于国内种质资源.     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Entwicklungsgeschichte und Ultrastruktur von Pollenkitt und Exine bei nahe verwandten entomophilen und anemophilen Angiospermensippen derAlismataceae,Liliaceae, Juncaceae,Cyperaceae, Poaceae undAraceae

Some closely related members of the monocotyledonous familiesAlismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae andAraceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate (ambophilous or amphiphilous) monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly dry and powdery pollen of anemophilous plants always contains a variable amount of inactive pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout.

     

Identification and Characterization of the First Equine Parainfluenza Virus 5

正Dear Editor,Parainfluenza virus 5 (PIV5), known as canine parainfluenza virus in the veterinary field, is a negative-sense,nonsegmented, single-stranded RNA virus belonging to the Paramyxoviridae family (Chen 2018). The virus was first reported in primary monkey kidney cells in 1954 (Hsiung1972), then it has been frequently discovered in various     

Pathogenic Characterization and Full Length Genome Sequence of a Reassortant Infectious Bursal Disease Virus Newly Isolated in Pakistan

<正>Dear Editor,Infectious bursal disease (IBD) is one of the most important diseases of the poultry. The IBD virus (IBDV), a nonenveloped virus belonging to the Birnaviridae family with a genome consisting of two segments of double-stranded RNA (segments A and B), targets B lymphocytes of bursa of Fabricious leading to immunosuppression. In Pakistan,poultry farming is the second biggest industry and IBD is the second biggest disease threating the poultry sector.However, there is limited genome information of IBDV