珠海市淇澳岛肉实树群落及其物种多样性特征

对珠海淇澳岛地区肉实树占优势的植物群落进行研究,结果表明：（1）肉实树群落中共有维管植物38科51属61种,种类组成具有极强的南亚热带性质;（2）年龄结构显示群落的主要优势种属于稳定型种群,群落总体处于稳定状态;群落的频度指数规律为A〉B〉C〉D〈E,与RaunKiaer频度规律相一致;（3）物种多样性指数为D=13．70,H=4．12,均匀度指数为E=0．39,E’=0．82,群落物种多样性指数和均匀度指数均较高,接近典型南亚热带常绿阔叶林顶极群落类型。     

三峡库区残存的常绿阔叶林及其意义

三峡库区世坪森林公园的常绿阔叶林处在中亚热带北部,群落中４８．６５％的物种具热带性质,３５．１４％的物种具温带性质;３３．７８％的物种集中在忍冬科（Ｃａｐｒｉｆｏｌｉａｃｅａｅ）、壳斗科（Ｆａｇａｃｅａｅ）等７个科,全部３８个科中８１．５８％的科仅有１～２种植物在群落中出现;群落含有具先锋意义的伴生种。这些都反映出该地带的次生常绿阔叶林的一般特点。栲树（Ｃａｓｔａｎｏｐｓｉｓｆａｒｇｅｓｉ）的重要值在乔木层和灌木层均居第一,特别是在乔木层该值显著高于其它种,说明此处的常绿阔叶林是以栲树为建群种的单优群落,而且栲树种群径级结构符合其正常发育规律,因而群落相对稳定。该群落对于中亚热带地带性植被的生态学和生物多样性的基础研究具有重要意义,对于退化生态系统的恢复和三峡水库的水源涵养具有典范作用。     

极危植物焕镛木的群落学特征及其保护

对广西罗城大黄泥常绿阔叶林进行样方调查,分析了极危植物焕镛木(Woonyoungia septentrionalis (Dandy)taw)群落的组成结构特征.1200 m2样地内有维管植物129种,隶属57科103属,以热带属占绝对优势;优势科为樟科、壳斗科、茜草科等.群落中焕镛木为优势种,重要值最大,为35.06,其次为粗丝木、红锥,重要值分别为22.09和19.66,因此,本群落可命名为焕镛木-粗丝木-红锥群落(Woonyoungia septentrionalis+Gomphandra tetrandra+Castanopsis hickelii Community).群落成层现象明显,可分为乔木层(3亚层)、灌木层和草本层3个层次,层间植物丰富.生活型以中、小高位芽为主,占67.18%.叶型以中、小型革质单叶为主.种群频度分布规律为A>B>CE,属于A级的种类占优势,为总种数的41.09%.乔木径级以小径级为主.焕镛木是我国南亚热带常绿阔叶林中非常珍稀濒危的物种,希望有关部门尽快在此设立保护区,以保护焕镛木的种质基因资源.     

濒危植物厚叶木莲的群落学特征及其保护

根据从化三角山次生常绿阔叶林的样方调查结果,分析了中国特有植物厚叶木莲（ManglietiapachyphyllaChang）的天然分布特点,分布区的自然环境概况,群落的区系特点,群落学特征及其保护策略．厚叶木莲仅零散分布于广东从化三角山、龙门南昆山和新丰小沙罗等地海拔650－1000m的常绿阔叶林中,分布区非常狭窄．在1200m~2的样地里有维管植物132种,隶属于57科89属。Shannon－Wiener物种多样性指数为5．45,均匀度为84．39％,类似于其他类群的南亚热带常绿阔叶林,但较低于海南的热带雨林类群．本群落植物区系的分布类型是以泛热带分布和热带亚洲分布两大类为主,热带－亚热带区系植物成分在本群落中占有明显的优势,其区系特点具有从热带向亚热带过渡的性质．该群落命名为赤楠、假轮叶虎皮楠、厚叶木莲群落,可分为乔木层（2亚层）、灌木层及草本层等层次．本群落以中、小高位芽植物占优势,缺乏大高位芽、地面芽和一年生植物,叶型以中型叶为主．种群分布格局分析表明,大部分优势种呈集群分布,其中厚叶木莲呈集群分布。种群的立木结构分析表明,厚叶木莲种群已处于衰退模式,有即将在群落中消失的可能,属于濒危物种,应加以保护,对厚叶木莲及其群落的保护应立足于就地保护．     

三峡库区常绿阔叶林优势种群的结构和格局动态

重庆丰都世坪森林公园的常绿阔叶林是长江三峡库区低海拔区残存的较典型的常绿阔叶林.在此地选择具有代表性群落设立1hm2固定样地,应用相邻格子法进行每木调查,通过乔木层优势种群结构和格局研究,探讨群落的特点和动态.结果表明(1)此群落的优势树种是小红栲(Castanopsis carlesii)、丝栗栲(Castanopsis fargesii)和枫香(Liquidambar formosana).(2)小红栲和丝栗栲种群立木级结构呈不规则金字塔型,幼苗储备丰富,为增长种群,种群从Ⅰ、Ⅱ级幼苗发育到幼树过程中的死亡率较高,中等径级的株数偏少.枫香种群幼苗缺乏,为衰退种群.(3)应用偏离指数、Lloyd的平均拥挤度和聚块性指数及Morisita指数,在10×10m2尺度下对优势种群进行格局分析,发现3种优势种群成树总体上均为集群分布;小红栲和丝栗栲种群在发育过程中分布格局是由集群分布过渡到随机分布,而枫香是由随机分布过渡到集群分布.     

深圳马峦山华南紫萁群落及其物种多样性特征研究

对深圳马峦山地区华南紫萁占优势的植物群落进行研究,结果表明：华南紫萁群落中共有维管植物48科69属82种,种类组成具有明显的南亚热带性质;年龄结构显示群落的主要优势种属于稳定型种群,群落总体处于稳定状态;群落的频度指数规律为A＞B＜C＞D＞E,与RaunKiaer频度定律、海南岛山地雨林优势种群的频度规律等不相符合;华南紫萁种群树高和个体数百分比显示,种群高度0.3~0.7 m植株占比例较大,种群处于旺盛发展期;物种多样性指数为SP＝16.42,SW＝4.56,均匀度指数为E＝0.33,E′＝0.83,群落物种多样性指数和均匀度指数均较高,接近典型南亚热带常绿阔叶林顶极群落类型。本研究揭示了华南紫萁野外生存状态,为该种的保护和利用提供了基础资料。     

湖北省栲类林群落学特征研究

通过设置样方,在全面调查湖北省内各栲类林的基础上,对湖北省栲类林的物种组成、区系成分、群落结构及类型,以及影响群落结构的环境因子进行研究。结果显示：（1）在所调查的湖北省栲类林中共记录维管植物88科210属376种,其中乔木层中常绿树种有73种、落叶树种有48种,构成了以常绿树种为主的典型常绿阔叶林;（2）从科的区系组成来看,热带成分多于温带成分;从属的区系组成来看,热带成分与温带成分大体相当;（3）湖北栲类林生物多样性有显著的经度和海拔格局,但受纬度影响不大。土壤因子中仅氮含量对物种多样性格局影响显著;（4）湖北省栲类林可分为5个群系,即：苦槠（Castanopsis sclerophylla（Lindl.）Schott）林、钩栲（Castanopsis tibetana Hance）林、栲（Castanopsis fargesii Franch）林、甜槠（Castanopsis eyrei（Champ.）Tutch.）林和罗浮栲（Castanopsis faberi Hance）林。在各环境因子中,海拔、经度、坡度和土壤磷含量对群落组成的影响最大,地理因子和土壤因子对栲类林群落组成影响的总解释率为68.94%;（5）在5个群系中大部分乔木及栲属植物的径级分布呈单峰形,种-多度分布表现为典型的具有少数常见种、多个偶见种的倒“J”形曲线。研究表明湖北省栲类林物种多样性高,生物多样性丰富,植物区系热带成分明显,主要包含5个群系,地理因子和土壤因子可以解释大部分的群落物种组成变异。该研究可为湖北省常绿阔叶林保护和管理提供理论依据和数据支持。     

粤北南方红豆杉植物群落的物种多样性和种群格局

在用样方法取样的基础上 ,分析粤北南方红豆杉生长地植物群落的物种多样性和种群分布格局 ,结果表明 :在调查地南方红豆杉出现于 5种类型的群落中 ;从物种多样性指数的平均值来看 ,灌木层的物种多样性大于乔木层 ,但乔木层和灌木层之间的 Shannon指数和群落均匀度无明显的差异 ;从乔木层和灌木层的变异系数看 ,丰富度、Shannon指数和群落均匀度均表现为乔木层 >灌木层。所调查的南方红豆杉生长地的植物群落的多样性指数和均匀度高于其他类群的南亚热带常绿阔叶林 ,但低于海南岛的热带雨林类群。南方红豆杉生长地植物群落中各优势种群均呈集群分布 ,且集群强度也都较高。南方红豆杉种群在大多数样地中亦呈集群分布     

海南岛尖峰岭热带山地雨林的群落结构特征

本文讨论了海南岛尖峰岭热带山地雨林乔木层的群落结构的一些基本特征,结果表明：热带山地雨林种类成份复杂,生物多样性指标高,原始林的Shannon－Wiener多样性指数（乔木层）为5．8—6．3,而更新林则在4．5—4．8之间,均匀度指标均在81％以上,反映了优势种群不明显的特点。群落组成种类以热带成份占优势,达80％以上。乔木层的胸径和树高分布均合理;群落组成种群的频度分布不同于RaunKiaer提出的频度定律,而是以A＞＞B＞C＞DE→0（原始林）和A＞＞B＞C＞D→0＜E（天然更新林）的形式存在,并且以A级频度占绝对优势,反映了热带林在世界植被中的特殊性。     

格氏栲自然保护区常绿阔叶林群落特征

在11000m^2样地调查材料的基础上,分析了福建三明格氏栲自然保护区常绿阔叶林群落的种类组成、乔木种群的重要值、群落外貌、物种多样性、水平结构和垂直结构特征。该群落计有维管植物223种,隶属于80个科159属,其中单种属古总属数的80．5％,包括藤本在内的高位芽植物占总种数的85．2％。重要值高的乔木种群足格氏栲、木荷、米槠、马尾松、甜槠和山黄皮。主要乔木种群均服从聚集分布。群落垂直结构复杂,可分为乔木层、灌木层和草本层。生活型谱和物种多样性指数介于南旺热带季风常绿例叶林和中亚热带常绿阔叶林之间。     

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     

Mink Circovirus Can Infect Minks,Foxes and Raccoon Dogs

正Dear Editor,Mink circovirus (MiCV), which is clustered in the genus Circovirus of the family Circoviridae, was first described in minks from farms in Dalian, China in 2013 (Lian et al.2014). The complete single-stranded circular genome of the virus is 1,753 nucleotides long and contains two major open reading frames (ORFs), designated ORF1 (Rep gene)and ORF2 (Cap gene)(Lian et al. 2014; Ge et al. 2018).Sequence analysis has shown that MiCV is most closely     

CypA Regulates AIP4-Mediated M1 Ubiquitination of Influenza A Virus

Cyclophilin A (CypA) is a peptidyl-prolyl cis/trans isomerase that interacts with the matrix protein (M1) of influenza A virus (IAV) and restricts virus replication by regulating the ubiquitin–proteasome-mediated degradation of M1. However,the mechanism by which CypA regulates M1 ubiquitination remains unknown. In this study, we reported that E3 ubiquitin ligase AIP4 promoted K48-linked ubiquitination of M1 at K102 and K104, and accelerated ubiquitin–proteasome-mediated degradation of M1. The recombinant IAV with mutant M1 (K102 R/K104 R) could not be rescued, suggesting that the ubiquitination of M1 at K102/K104 was essential for IAV replication. Furthermore, CypA inhibited AIP4-mediated M1 ubiquitination by impairing the interaction between AIP4 and M1. More importantly, both the mutations of M1 (K102 R/K104 R) and CypA inhibited the nuclear export of M1, indicating that CypA regulates the cellular localization of M1 via inhibition of AIP4-mediated M1 ubiquitination at K102 and K104, which results in the reduced replication of IAV.Collectively, our findings reveal a novel ubiquitination-based mechanism by which CypA regulates the replication of IAV.