七筋姑属叶表皮形态特征及其系统学意义

利用扫描是镜和光地七筋姑属北美全部４种和东亚１种１１个居群的叶表皮形态进行了观察。其总体特征如下;上表皮细胞５－７边形、近等径或狭长,下表皮细胞长条形;垂周壁向外隆起,平直,有明显加厚或加厚不明显,平周壁内陷,平滑具浅坑,有时具细条纹状纹饰或细小突起。气孔器散生于下表皮,均为无规则型,长度约为表皮细胞的１／４－１／３,隆起于表皮细胞或有时稍下陷。北美４种中,Ｃ．ｕｎｉｆｌｏｒａ下表皮生有长的扁平状     

东亚七筋姑的传粉生物学研究

以陕西镇坪化龙山地区的东亚七筋姑自然居群为对象,通过重力玻片法、套袋法和人工授粉对其进行连续的传粉生物学观察和研究,以明确其散粉规律和繁育系统.结果表明,东亚七筋姑的花期在五月中下旬,单花花期2～3 d,整个花序的花期随花序大小的不同而异,一般为3～7 d;东亚七筋姑为虫媒传粉,其访花昆虫大多为小型昆虫,主要种类有小型甲虫、蚁类和蝇类等;东亚七筋姑自花传粉是可育的,存在异花传粉,不存在无融合生殖,自然条件下结籽率为58%,人工异株异花授粉结籽率为82%.可见,东亚七筋姑的繁育系统为兼性异交类型,需要传粉者.     

七筋姑的细胞地理学研究

根据本文对中国境内(从西藏聂拉木—吉林长白山)七筋姑10个居群的核型及细胞地理学和形态学分化的研究结果及前人的资料指出,东亚的七筋姑具有两种倍性,2n＝14的二倍体和2n=28的四倍体。二倍体分布于云南～俄罗斯远东滨海边区,核型相当一致：K(2n)=2V+6J+2V+4j(2NOR+2j), 2A(→2B)。四倍体除出现在东亚(或二倍体分布区)的两端——云南及其以西的喜马拉雅地区和日本外,目前仅在陕西南部化龙山北坡中山一带较狭的范围内发现。在东亚两端四倍体的核型为K(2n)=4V+12J+4v+8j(2NOR十6j),2A(→2B),且相当一致;在中部为K(2n)＝4V+12J(2NOR+10J)+4v+8j[K(2n)＝10m+16sm(2SAT)+2st],2A,二者核型具有相似性但有一定的差异。北美4种全部为2n＝28,且核型一致。因此,七筋姑属的染色体基数x＝7而非14。该属核型的原始类型在东亚,北美是该属的次生分化中心和现代分布中心。在东亚类群中,除种子随多倍化而增大,种子的颜色与地理分布有关外,很难从其它形态特征上作进一步区分。因此,主要以叶子大小、花序类型和花的数目,果实、种子的大小和颜色等特征作为(Clintonia alpina或C．udensis var．alpina的分类依据是不充分的。     

东亚七筋姑多倍体ITS区的序列测定与分析

通过对13个东亚七筋姑二倍体居群和5个四倍体居群的ITS区(包括ITS1、5.8SrDNA和ITS2)进行克隆测序。ITS序列长度显示出比较高的多态性,ITS1长度为171~270bp,ITS2长度为205~238bp,5.8S序列的长度在162~164bp之间,序列中G C含量为45.83%~54.13%,当空位(gap)作缺失处理时,东亚七筋姑ITS区全序列排序后的长度为682bp,其中简约性位点289个;最大简约法分析获得一致性指数(CI)为0.630,保留系数(RI)为0.684,四倍体居群没有单独聚为一支,而是和相邻地理单元的二倍体居群聚为一支,本研究结果支持东亚七筋姑异地多起源的推断。     

七筋姑花粉形态种内变异及其系统学意义

对东亚七筋姑分布区内１０个产地１１号材料花粉扫描电镜观察结果表明,花粉外壁纹饰具有三种类型：１．芽孢形,即外壁密布芽孢状突起;２．拟网状芽孢形。外壁呈不规则网状,网脊由大小不等的小芽孢相互融合或连接而成;３．具穿孔芽孢形。芽孢部分连接或融合,并有穿孔形成。这三种类型在陕西南部－喜马拉雅地区均有分布,而第１种类型则主要分布在秦岭－东亚东北部。花粉外壁纹饰的多样性显示该种目前正处于强烈的分化阶段,但反     

叶表皮及种皮特征在黄精族系统学研究中的应用

通过光学显微镜和扫描电子显微镜对黄精族trib．Polygonateae 7属79种以及相关类群12属15种 的叶下表皮形态及种皮微形态进行了观察。结果表明广义黄精族植物的叶表皮形态和种皮形态可分别 分为4种类型和6种类型。在黄精族中,鹿药属Smilacina和黄精属Polygonatum的叶表皮和种皮特征在 属内表现出一定的多样性,据此可将黄精属植物分为两类：第一类多表现为叶表皮细胞形状不规则,其垂周壁为波曲形或无皱褶但弯曲,种皮表面浅穴状;另一类叶表皮细胞形状为长方形或菱形,其垂周壁 直或无皱褶但弯曲,种皮表面具脊状突起或网状结构。其中,叶表皮细胞垂周壁无皱褶但弯曲为过渡 类型,在两类植物中均有表现。本研究结果还显示出竹根七属Disporopsis和黄精属的互叶类以及鹿药属 同具有波状垂周壁的叶表皮细胞和穴型种皮。舞鹤草属Maianthemum和鹿药属的S．stellata,S．trifolia 等的种皮特征相似。万寿竹属Disporum的叶表皮特征在属内表现得相当一致,但种皮特征在东亚分布 的种和北美分布的种之间区别明显。扭柄花属Streptopus叶表皮和种皮特征在属内没有分化。卵叶扭 柄花S．ovalis的叶表皮和种皮特征与属内其它种之间没有区别,确证了它在本属中的位置。扭柄花属、 万寿竹属、七筋菇属Clintonia与黄精族其它类群差别较大,但前两者与Uvulariaceae科的油点草属Tricyr- tis和细钟花属Uvudaria较为接近,从而支持了Dahlgren将其移至Uvulariaceae的观点。而在与外类群的关系中,铃兰族的铃兰属Convallaria与黄精族具相近的叶表皮和种皮特征。     

中国蜜环菌生物种与北美种的交配关系

将中国三个未知蜜环菌生物种Ａ、Ｃ、Ｄ的３８个代表菌株与北美蜜环菌Ａ．ｓｉｎａｐｉｎａ、Ａ．ｃａｌｖｅｅｓｃｅｎｓ、Ａ．ｎａｂｓｎｏｎａ、Ａ．ｇｅｍｉｎａ、Ａ．ｏｓｔｏｙａｅ、ＮＡＢＳＸ等六个种的２２个代表菌株进行了配对试验,结果表明中国生物种Ａ与北美种Ａ．ｓｉｎａｐｉｎａ互交可育,属于同一种。中国生物种Ｃ与任一北美种都互交不育不存在部分可育现象,为亚洲特有种,中国生物种Ｄ与欧美的Ａ．ｏｓｔｏｙａｅ     

东北槭属的种子表皮雕纹及其在分类上的意义

借助于扫描电子显微镜,对我国东北地区槭属（Ａｃｅ）的１１种变种的种皮雕纹进行了扫描观察,并拍制了电镜照片。从种皮的雕纹类型看,槭树属的种皮可以概括为四种类型：（１）嵌合型;（２）穴状条纹型;（３）条纹型;（４）网格型;雕纹的形态也支持了色木槭和元宝械作为两个独立种的处理意见;以及小果紫花槭作为紫花槭（Ａｃｅｒｐｓｅｕｄｏ－ｓｉｅｂｏｌｉｄｉａｎｕｍ（Ｐａｘ．）Ｋｏｍ）的种下等级变种（ｖａｒ．ｋｏｒ     

华南胡椒化学成分的研究

从胡椒科植物华南胡椒（Ｐｉｐｅｒ ａｕｓｔｒｏｓｉｎｅｎｓｅ Ｃ．ＤＣ．）中分离出七个成分,经光谱分析和理化常数测定,分别鉴定为Ｎ－ｉｓｏｂｕｔｙｌ－３（３＇,４＇－ｍｅｔｈｙｌｅｎｅｄｉｏｘｙ－５＇－ｍｅｔｈｏｘｙｐｈｅｎｙｌ）－２Ｅ－ｔｒｉｍｏｎｏｉｅｎａｍｉｄｅ（Ｉ）、Ｎ－ｉｓｏｂｕｔｙｌ－７（３＇,４＇－ｍｅｔｙｌｅｎｅｄｉｏｘｙｐｈｅｎｙｌ）－２Ｅ,４Ｅ－ｈｅｐｔａｄｉｅｎａｍｉｄｅ（Ⅱ     

感染蛴螬的一种新虫草

描述了感染鞘翅目幼虫的茂兰虫草新种（ＣｏｒｄｙｃｅｐｓｍａｏｌａｎｅｎｓｉｓＺ．Ｙ．ＬｉｕｅｔＬｉａｎｇｓｐ．ｎｏｖ）其主要特征为子座单生,可孕部分白色,近球形或卵圆形,其皮层栅状,１００～１２５μｍ柄中部地上和地下相交处有瘤节,子囊壳黄色,埋生,６００～７００ｘ３００～３５０μｍ子囊柱状,３００～４５０×３～４．５μｍ,每个子囊具有４个丝状多隔的子囊Ｃ．ｇｒａｃｉｌｉｏｉｄｅｓ．Ｃ．ｉｎｓｉｇｎ     

A Cytogeographical Study on Clintonia udensis (Liliaceae)

The genus Clintonia has four species in North America and one in eastern Asia (Fig．1)．In this paper,the karyotypes and the intraspecific morphological and cytogeographic differentiations of ten populations of C．udensis from China are analysed,and the probable origin area of the genus is also discussed．The conclusions are as follows： (1)Based On the chromosome numbers 2n=28 from the North American species,the Japanese and Himalayan groups,the earlier investigators established x=14 as the basic chromosome number of Clintonia,and they thought that there was polyploid in this genus except for aneuploid only in C．borealis (Utech,1975;Utech and Suda,1975),but a few authors(Sen,1975;Wang et al,1993)pointed out the x=7 basic number of this genus based on 2n=14 in C．udensis from Primorskiy Kray of Russia(Skolovskaya,1966)and Yunlong,Yunnan Province of China(Wang et al,1993)respectively．Our result along with there reports by previous authors(see table 1)shows that at least two ploid levels exist in C．udensis,i.e．2n＝14 and 2n＝28．The diploids are widely distributed from northwest Yunnan of China to Primorskiy Kray of Russia,while the tetraploids are located in northwest Yunnan,Himalayas,Japan,and a narrow area in Mt．Hualongshan of southern Shaanxi(07 population)(Fig．2)．Therefore,the basic chromosome number of Clintonia certainly is x=7 ratherthan x=14,while 2n=28 in North America,Japan and Himalayan area are tetraploid, not diploid, According to the previous data,so far no diploid taxa of Clintonia has been found in North America and Himalayas．So we consider that the primitive type of Clintonia is in eastern Asia,and the secondary diversity center and the present distribution center of this genus are in North America． (2)C．udensis is widely distributed in eastern Asia(Fig．2);it has two cytotypes．The karyotypes for all the diploid populations are remarkablely similar. Taken together, they can be roughly repersented by the formula:K(2n)=14=2V+6J+2v+4j(2NOR+2j). The chromosomes range in length 25.55～12.78 μm, with the ratio of the longest to the shortest 2.0. The karyotype belongs to Stebbins (1971)2A(→2B). For the tetraploid taxa, except for 07 population, karyotypes are also identical and may be roughly symbolized as: K (2n)=28=4V + 12J + 4v+8j ( 2NOR + 6j ). The length of chomosomes is from 27.87 to 13.93 μm, with the ratio of the longest to the shortest 2.0, and thus the karyotype belongs to 2A(→2B). The karyotype of 07 population is similar to those of above tetraploid taxa but also has some differences, especially in the position of satellites and the morphology of 10th and 14th pairs of chromosomes. Its formula is K(2n)=28=4V+12J(2NOR+10J)+4v+ 8j(2n=28=10m+16sm(2SAT)+2st). The ratio of the longest (23.72μm)to the shortest(12.97μm) chromosomes is 1.83. The Karyotype belongs to 2A. And the distribution range of this population is very narrow. We think that it is probably a recent evolutionary event in C. udensis. (3)Wether Clintonia in eastern Asia has 1 sp. or 2 spp. or 1 spp. and 1 var. has been debated for a long period. According to our observation, within C. udensis, only the size of seeds is related to its ploidy level, i.e. diploid individuals have smaller seeds and tetraploid ones have larger ones; the colour of seeds is related to its geographic distribution, i.e. the materials from the Himalayas through Yunnan, Sichuan to eastern Qinling Range have pale brown seeds, while those from Mt. Lüliang, Shanxi Province via Hebei, Liaoning, Jilin to Siberia and Japan have dark brown seeds. Some other morphological characters, such as the size of leaves and fruits, inflorescence type and flower numbers between individuals in one locality, even within one populaion have evident variation. Therefore, we consider that evidence(see Table 4 )for separating C. alpina or C. udensis var. alpina from C. udensis is notsufficient.     

七筋菇自然居群的遗传结构分析

采用ISSR分子标记,对七筋菇(Clintonia udensis)17个居群的遗传多样性与遗传结构进行了研究。结果表明:七筋菇不同居群的多态位点百分率PPB为11.90%~59.52%,总的多态位点百分率PPB为98.8%,具有高的遗传多样性。Shannon多样性指数(0.6903)和基因分化系数(GST=0.6944)均揭示出七筋菇居群间存在明显的遗传差异,AMOVA分析结果也显示遗传变异主要发生在居群之间(81.47%),而居群内部的遗传变异仅为18.53%。七筋菇居群间的遗传距离从0.1871~0.6632,平均为0.3838,大于同一物种居群间的平均遗传距离值(0.05),同样表明七筋菇居群间的遗传多样性存在较大差异。七筋菇居群间的基因流Nm=0.2200,远远低于一般广布种植物的基因流(Nm=1.881)。Mantel检测显示居群间的遗传距离与地理距离之间没有显著相关性(r=0.029,P=0.3196)。七筋菇分布范围广以及其进化历史是其具有高遗传多样性的原因;居群间存在较高遗传变异可能是由于七筋菇本身的生物学特性、有限的基因流以及遗传漂变等原因造成的。     

Rapid divergence and postglacial colonization in western North American Steller's jays (Cyanocitta stelleri)

Post-Pleistocene avian colonization of deglaciated North America occurred from multiple refugia, including a coastal refugium in the northwest. The location of a Pacific Coastal refugium is controversial; however, multiple lines of evidence suggest that it was located near the Queen Charlotte Islands (also known as Haida Gwaii). The Queen Charlotte Islands contain a disproportionately large number of endemic plants and animals including the Steller's jay Cyanocitta stelleri carlottae. Using five highly variable microsatellite markers, we studied population structure among eight populations of Steller's jay (N = 150) from geographical areas representing three subspecies in western North America: C. s. carlottae, C. s. stelleri and C. s. annectens. Microsatellite analyses revealed genetic differentiation between each of the three subspecies, although more extensive sampling of additional C. s. annectens populations is needed to clarify the level of subspecies differentiation. High levels of population structure were found among C. s. stelleri populations with significant differences in all but two pairwise comparisons. A significant isolation by distance pattern was observed amongst populations in the Pacific Northwest and Alaska. In the C. s. carlottae population, there was evidence of reduced genetic variation, higher number of private alleles than northern C. s. stelleri populations and higher levels of divergence between Queen Charlotte Island and other populations. We were unable to reject the hypothesis that the Queen Charlotte Islands served as a refugium during the Pleistocene. Steller's jay may have colonized the Queen Charlotte Islands near the end of the last glaciation or persisted throughout the Pleistocene, and this subspecies may thus represent a glacial relic. The larger number of private alleles, despite reduced genetic variation, morphological distinctiveness and high divergence from other populations suggests that the Queen Charlotte Island colonization pre-dates that of the mainland. Furthermore, our results show rapid divergence in Steller's jay populations on the mainland following the retreat of the ice sheets.     

Genetic differentiation in natural populations of a Keystone Bunchgrass (<Emphasis Type="Italic">Aristida stricta</Emphasis>) across its native range

Aristida stricta Michx. (Poaceae) is a perennial bunchgrass native to the Southeastern Coastal Plain of North America where it is a keystone species in the longleaf pine savannas and slash pine flatwoods from southeastern North Carolina to Florida, and westward to the coast of Mississippi. We examined genetic relationships within and among ten populations of A. stricta by using eight inter-simple sequence repeat (ISSR) markers to generate band frequency data for 32 individuals from each sampled population. An analysis of molecular variance showed that 38% of the variation resided among populations while 62% was attributable to variation within populations. Grouping the populations by habitat or by geographic location did not show significant differentiation between the groups. Overall, pair-wise geographic and genetic distances were not correlated. Data indicate that while individuals within each population are genetically diverse, there seemingly are barriers to gene flow across populations leading to their divergence. Each population contains several exclusive loci suggesting that limited gene flow and/or genetic drift are likely leading to this pattern of localization. Our results, coupled with those of the previous studies that presented evidence for local adaptation and phenotypic differences among populations, suggest that there is sufficient differentiation among populations of this species to warrant: (1) maintenance of the existing genetic diversity at individual sites, and (2) use of local seed and plant sources for conservation projects.     

Inferring long-distance dispersal and topographic barriers during post-glacial colonization from the genetic structure of red maple (Acer rubrum L.) in New England

Aim  This study aims to assess the role of long-distance seed dispersal and topographic barriers in the post-glacial colonization of red maple ( Acer rubrum L.) using chloroplast DNA (cpDNA) variation, and to understand whether this explains the relatively higher northern diversity found in eastern North American tree species compared with that in Europe.
Location  North-eastern United States.
Methods  The distribution of intraspecific cpDNA variation in temperate tree populations has been used to identify aspects of post-glacial population spread, including topographic barriers to population expansion and spread by long-distance seed dispersal. We sequenced c.  370 cpDNA base pairs from 221 individuals in 100 populations throughout the north-eastern United States, and analysed spatial patterns of diversity and differentiation.
Results  Red maple has high genetic diversity near its northern range limit, but this diversity is not partitioned by topographic barriers, suggesting that the northern Appalachian Mountains were not a barrier to the colonization of red maple. We also found no evidence of the patchy genetic structure that has been associated with spread by rare long-distance seed dispersal in previous studies.
Main conclusions  Constraints on post-glacial colonization in eastern North America seem to have been less stringent than those in northern Europe, where bottlenecks arising from long-distance colonization and topographic barriers appear to have strongly reduced genetic diversity. In eastern North America, high northern genetic diversity may have been maintained by a combination of frequent long-distance dispersal, minor topographic obstacles and diffuse northern refugia near the ice sheet.     

Clonal diversity of Clintonia udensis Trautv. et Mey. populations and its correlation with ecological factors

The clonal diversity of Clintonia udensis Trautv.et Mey.was detected by ISSR markers among 16 populations,and its correlation with ecological factors was analyzed as well in this work.Results showed that individuals(clonal ramets)per genotype were 1.12 and 1.149 at population and species levels,respectively,and that the 16 populations were all multiclonal.The detected genotypes were localized,without exception,within populations but demonstrated relatively high clonal differentiation among populations.The clonal diversity of the studied populations was high,with the average Simpson's index of 0.975,while the genets showed a clonal architecture of"guerilla".The population genetic diversities revealed by genet were consistent with those by ramet,further confirming their genetic differentiation among populations.And its genotype diversity within populations probably resulted largely from the frequent seedling regeneration and self-compatibility.In addition,the correlation analysis further revealed that,among the ecological factors,Simpson's index of C.udensis had a significant positive correlation(P<0.05)with pH values in the soil but not others.     

Glinal variation in morphology among eastern populations of the waterstrider, Aquarius remigis Say (Hemiptera: Gerridae)

We examined morphological variation among populations of the stream-dwelling waterstrider, Aquarius remigis. A previous analysis of allozyme variation along a transect from southern Quebec to southern North Carolina revealed two distinct 'types' of A. remigis, north and south of a transition zone in southern New York and northern Pennsylvania. To assess the concordance of morphological and allozyme differentiation, adults were sampled from 15 populations along the original transect, as well as 11 additional populations in New York, Connecticut and New Jersey. Eight measurements of leg and body size were taken of preserved individuals. Univariate and multivariate analyses (multiple regression, PCA, discriminant analysis) reveal significant differentiation between northern and southern populations with a transition zone between latitudes 39^oand 42^onorth. Strong clines within each region and a clear transition between regions support previous suggestions that there are two distinct 'types' of this species in eastern North America. The transition zone, in morphology coincides with that revealed by the allozyme variation, but extends further south. The covariance of allozyme frequency and morphometric traits suggests that differentiation has occurred through vicariance and secondary contact, and that in this system, cladistic and adaptive differentiation are coupled.     

Latitudinal population differentiation in two species of Solidago (Asteraceae) introduced into Europe

Solidago altissima and S. gigantea were introduced from North America to Europe ~250 yr ago and are now considered aggressive weeds in abandoned fields and conservation areas. We studied patterns of genetic differentiation in these two species along their present latitudinal range in Europe (44-61 degrees N). Two generations of clonally propagated ramets from randomly selected genets of 24 populations of each species were grown in a common-garden experiment at latitude 47 degrees N from 1991 to 1992. Both species showed significant variation among populations in morphological and life-history characters: at this southern location, plants from northern populations were smaller and flowered earlier than plants from southern populations. The gradient of clinal variation was more pronounced in the second year of cultivation than in the first and was steeper in S. altissima than in S. gigantea. Within-population variation among genotypes was significant tot most characters in the case of S. altissima. Phenological rate (reciprocal of days to flowering) and size at maturity showed a significant negative correlation among populations bot not among genotypes within populations, indicating that genetic trade-offs may occur at one but not another infraspecific level. We suggest that the pattern of among-population variation reflects rapid adaptive population differentiation after introduction of the species to Europe.     

Genetic diversity and population structure identify the potential source of the invasive red clover casebearer moth, <Emphasis Type="Italic">Coleophora deauratella</Emphasis>, in North America

The red clover casebearer, Coleophora deauratella, is an invasive pest of red clover grown for seed in North America. In 2006, an outbreak in Alberta, Canada was discovered that resulted in significant seed losses, while further invasion threatens the world’s largest red clover forage seed production region in Oregon, USA. Prior to the recent outbreak, C. deauratella was thought to be restricted to eastern North America in its invasive range. We sequenced a 615-bp fragment of the mitochondrial cytochrome c oxidase subunit 1 gene, and developed three microsatellite markers to assess the genetic diversity and population structure of C. deauratella in North America and its native range in Europe. We observed signatures of a founder effect in North American populations and a further loss of genetic diversity within Alberta populations. Most genetic differentiation was found between continents, with no evidence of isolation-by-distance within each continent. From the limited number of European populations sampled, a single introduction from Switzerland is the most probable source of North American populations based on similar mitochondrial diversity and lack of population differentiation. Within North America, based on increased genetic diversity compared to the rest of the continent, the first North American record from Ithaca, NY, and the first documented outbreak in southern Ontario in 1989, the initial C. deauratella invasion most likely occurred in southern Ontario, Canada or adjacent states in the USA, followed by transport throughout the continent. This study provides insight into the phylogeographic history of C. deauratella in North America and Europe and may help to identify a regional source of future classical biological control agents.