甘蔗蓟马在不同甘蔗品种上空间分布型及理论抽样数

为了解甘蔗蓟马在不同甘蔗品种上的种群空间分布型,获得准确的田间调查资料,提高甘蔗蓟马预测及防治效果,2015年7月在云南省农业科学院甘蔗研究所第一科研试验基地,通过调查10个甘蔗品种上甘蔗蓟马成虫和若虫数量,利用5种聚集度指标、Iwao回归分析法和Taylor幂法则测定了甘蔗蓟马的种群空间格局。结果表明,甘蔗蓟马成虫和若虫在不同甘蔗品种上均以个体群形式存在,个体间相互吸引;其空间分布型均为聚集分布,聚集强度随种群密度的升高而增加,聚集是由于自身的生物学习性和环境因素共同作用引起的。利用Iwao回归分析法中的α、β参数计算出在允许误差范围内的理论抽样数。因此,甘蔗蓟马在不同甘蔗品种上均呈聚集分布,调查时应根据当地栽培品种平均虫口密度选择适宜的抽样数量。     

西花蓟马在黄瓜和架豆上的空间分布型及理论抽样数

西花蓟马Frankliniella occidentalis（Pergande）已在北京部分蔬菜园区成功定居,对蔬菜生产造成危害。为了解该虫在蔬菜田的种群空间分布型,指导田间取样,本文应用几种聚集度指标的计算公式以及Taylor、Iwao的回归方程式,分析和测定了西花蓟马的种群空间分布格局。结果表明：在黄瓜和架豆上西花蓟马的空间分布型一致,均为聚集分布型;该虫的空间分布型不受种群密度的影响,并且也不随取样时间的变化而变化。种群数量动态研究显示西花蓟马成虫和若虫在黄瓜植株的中部叶片分布较多（从顶部向下数第4叶至第17叶片上成、若虫的分布数量多于其他叶片上的数量）,未展开的叶片、嫩叶和下部老叶危害较轻。用Iwao回归法中α、β参数计算出在允许误差范围内的理论抽样数。     

广东省榕树虫瘿蓟马种类及营瘿蓟马寄主专一性调查

2013年对广东地区榕树虫瘿中的蓟马种类进行了调查,共发现榕母管蓟马Gynaikothrips ficorum(Marchal)、榕管蓟马Gynaikothrips uzeli(Zimmerman)、榕端宽管蓟马Mesothrips jordani Zimmermann、拉马棘腿管蓟马Androthrips ramachandrai Karny和黄胫棘腿管蓟马Androthrips monsterae(Moulton)5种管蓟马科种类,其中黄胫棘腿管蓟马为中国新纪录种。榕母管蓟马和榕管蓟马为营瘿蓟马,诱导初始虫瘿具有寄主专一性,榕母管蓟马是细叶榕Ficus microcarpa初始虫瘿的诱导者,而榕管蓟马仅在垂叶榕Ficus benjamina Linn.上诱导形成虫瘿;但当两种榕树种植在一起时,榕母管蓟马和榕管蓟马偶尔会入侵到对方成熟虫瘿中并与之生活在一起。榕端宽管蓟马属于盗寄生种类,而拉马棘腿管蓟马和黄胫棘腿管蓟马主要捕食营瘿蓟马的幼体(包括卵、若虫和"蛹"),三者均为寄居性蓟马,无寄主专一性。     

苜蓿籽蜂幼虫空间分布型及抽样技术的研究

应用多个聚集度指标和Iwao、Taylor回归分析方法,对苜蓿籽蜂Bruchophagus roddi幼虫的空间分布型进行研究。结果表明其空间分布型为负二项分布,个体间相互排斥,其基本成分的空间分布格局为聚集分布,其聚集是由昆虫行为或环境条件引起的,聚集强度随着种群密度的升高而增加。应用 Iwao抽样模型建立了籽蜂幼虫的田间理论抽样数公式：N=(0.5833/m+2.3370)/D∧2。      

水稻粘虫混合种群幼虫空间分布型和抽样技术的研究

水稻粘虫混合种群幼虫空间分布型测定结果表明：(1)频次分布检验为负二项分布;（2)聚集度指标测定为聚集分布;(3)m^*-m的钱性回归方程为m^*=0．8870 1．1058m,属于最普通的聚集分布。在分布型研究基础上,探讨了资料代换模式、Iwao序贯抽样模型和最适抽样数模型。     

柳厚壁叶蜂幼虫空间格局及抽样技术

应用Taylor的幂法则、Iwao m^*-m回归分析法及6个聚集指标,对柳厚壁叶蜂幼虫空间分布型进行了研究,并进行了影响因素分析.结果表明,该幼虫在柳树的枝条和叶片两个空间阶元都属于聚集分布,分布的基本成分是个体群,其聚集性随密度的增大而增加.在枝条上,聚集的原因是由柳厚壁叶蜂成虫集中产卵的习性与枝条上叶片空间位点共同影响所致;在叶片上,当m＜2.37时,其聚集原因与春季柳树新叶空间位置有关,当m＞2.37时,虫瘿聚集除与春季新叶空间位置有关外,还与柳厚壁叶蜂成虫羽化和在叶片上集中产卵的习性有关.运用Iwao m^*-m回归中的两个参数α和β值,确定了在不同精度下的理论抽样数及序贯抽样数.     

红腹缢管蚜空间分布型及抽样技术研究

对红腹缢管蚜的空间分布型及抽样技术进行了研究。 11组样本各项指标均符合聚集分布的检定标准。应用 Taylor幂法则、Iwao回归分析法 ,测定出红腹缢管蚜的空间格局是基本成份为个体群的聚集分布 ,聚集强度随种群密度的升高而增加。聚集原因是昆虫本身行为和环境因素综合影响的结果。应用 Iwao提出的 N=t2D2 (α+1x +β- 1) )公式 ,确定了在一定精确水平下的理论抽样数。当 t=1,m0 =2时 ,序贯抽样的上、下限为 :T(n) =2 n± 6 .8577n。     

盆栽榕树蓟马种类及优势种榕管蓟马对寄主植物的致害性

为明确盆栽榕树蓟马的种类, 了解蓟马优势种对在同一温室内混合种植的榕属及非榕属盆栽植物的致害性差异, 以福建漳州、 福州和泉州等地的盆栽榕树种植基地为观测点, 采集榕树叶片, 调查蓟马种类, 确定优势种蓟马; 以天南星科喜林芋属、 紫葳科菜豆树属、 木棉科瓜栗属和桑科榕属等不同科属盆栽植物为试验材料, 测试榕管蓟马Gynaikothrips uzeli Zimmerman对寄主植物的致害性。结果表明： 盆栽榕树蓟马种类有2亚目, 2科, 8属, 9种, 优势种为榕管蓟马, 常见种为棘腿管蓟马Androthrips ramachandrai Karny和榕腿管蓟马Mesothrips jordani Zimmermann, 其他6种蓟马均为偶见种。榕管蓟马对不同寄主植物的致害性差异显著, 以对桑科榕属植物致害性为最强, 而对天南星科喜林芋属、 紫葳科菜豆树属和木棉科瓜栗属等其他植物的致害性较弱。在6种榕属植物中, 榕管蓟马对垂叶榕Ficus benjamina Linn.、 榕树F. microcarpa Linn. f.、 花叶垂叶榕F. benjamina cv. Golden Princess等3种榕属植物的为害等级均达3级以上, 以垂叶榕最重, 榕树次之, 花叶垂叶榕略轻; 对金叶榕F. microcarpa cv. Golden Leaves、 黑叶橡胶榕F. elastica cv. Deocora Burgundy、 斑叶橡胶榕F. elastica var. variegata等3种榕属植物的为害很轻, 为害等级均仅为1级; 同时, 榕管蓟马在金叶榕、 黑叶橡胶榕和斑叶橡胶榕上繁殖力弱、 无法完成世代, 而在榕树、 垂叶榕和花叶垂叶榕上繁殖力强、 能完成世代, 但以在垂叶榕上的发育情况最好。研究可为选择利用寄主植物抗虫性来有效防控盆栽榕树蓟马提供技术支撑。     

中华微刺盲蝽在黄瓜植株上的空间格局

中华微刺盲蝽是-种重要的捕食性天敌,在华南地区分布极为普遍.本文通过计算1wao聚片回归、Taylor幂法则等聚集强度指数,结果表明中华微刺盲蝽在黄瓜植株上的分布属于聚集分布,基本成分是个体群.分布的聚集强度与密度有关,随种群密度的升高而增大.聚集原因分析表明:当种群密度不太大(m＜1头.叶-1)时,聚集原因由环境因素引起,即由它的食物节瓜蓟马的聚集特性引起:当种群密度较大(m≥1头.叶-1)时,聚集原因由节瓜蓟马的聚集特性和它本身的聚集特性引起.     

番茄潜叶蛾幼虫和卵在新疆大棚番茄的空间分布型及理论抽样数

【目的】明确新疆新发外来入侵生物番茄潜叶蛾幼虫和卵在不同种群密度下的垂直分布、空间分布型和理论抽样数,探索田间易观察的危害症状和幼虫密度的关系,为田间取样和调查提供理论指导。【方法】在察布查尔县连续调查3个大棚同一品种京番502杂交一代上的番茄潜叶蛾的不同种群密度,利用聚集度指标及Iwao回归分析,计算并分析了番茄潜叶蛾卵和幼虫在不同种群密度下的空间分布型、垂直分布和理论抽样数,分析危害叶片数、虫道长度和虫道数与幼虫密度的动态关系。【结果】计算并统计番茄潜叶蛾幼虫和卵的空间分布聚集度指标的均值m、扩散系数C、扩散型指数I、负二项分布值K、平均拥挤度m~*、聚块指数m~*/m、扩散指数CA和种群聚集均数λ。番茄潜叶蛾卵主要集中在上部,占比43.9%～100%。幼虫主要集中在下部,占比53.3%～100%。番茄潜叶蛾幼虫数与虫道数、虫道长度或为害叶片数的比值随为害加剧呈动态变化。番茄潜叶蛾幼虫和卵Iwao直线回归方程拟合公式为m~*=1.9114+1.2055m (R~2=0.9703)和m~*=0.0536+1.4147m (R~2=0.9014)。根据空间分布型参数,在D=0.1、0. 2和0. 3时,幼虫的理论抽样数模型分别为n=1118. 4/x+78. 9、n=279. 6/x+19.7、n=124.3/x+8.8,卵的理论抽样数模型分别为n=404.8/x+159.3、n=101.2/x+39.8、n=45.0/x+17.7,该模型适用于不同虫口密度下的田间抽样。【结论】在京番502杂交一代上,番茄潜叶蛾幼虫为m=0.6头·株~(-1)以上,卵在达到密度最大值前,均呈聚集性分布。番茄潜叶蛾成虫偏好在幼嫩的叶片产卵,随植株被害加剧该偏好略有减弱。当番茄潜叶蛾幼虫的虫口密度为10和30头·株~(-1)时,建议分别取样50和30株;当卵量为10和30粒·株~(-1)时,分别取样50和45株。     

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