黄龙山林区不同培育措施对辽东栎种群结构与动态的影响

采用样地法对黄龙山林区实施抚育和封育措施的辽东栎林进行了调查,分析了2种培育措施对辽东栎种群径级结构、静态生命表和存活曲线的影响,并运用时间序列模型对不同培育措施的辽东栎种群数量动态进行了预测,结果表明:黄龙山林区辽东栎种群的径级结构从整体上为金字塔形,小径级个体数量较多,中、大径级个体数量较少,属于稳定型,经过抚育,辽东栎种群的径级结构更加合理;不同培育措施的辽东栎种群存活曲线都基本接近DeeveyⅢ型,种群个体早期死亡率较高,进入生理衰退年龄之后,死亡率趋于稳定;时间序列分析表明不同培育措施的辽东栎各径级株数均有不同程度的增加,径级越小增加幅度越大。根据黄龙山林区辽东栎种群的生长特点,建议在辽东栎林发育到一定时期进行抚育以创造有利的生长和发育条件,另外在种子丰产年,适时采收种子,建立苗圃,扩大人工种群。     

Genetic Differentiation of Quercus mongolica and Q. liaotungensis Based on Morphological Observation,Isozyme and DNA Analysis

The Liaodong oak ( Quercus liaotungensis Koidz. ) is a close relative of the Mongolia oak ( Q. mongolica Fisch. ) which were separated by some morphological characters, such as the number of leaf lobes and the squamate form of cupula. Recently some authors observed that morphological diversity made the Liaodong oak unable to separate clearly from the Mongolia one, therefore, plant materials have been collected from Maoer Mountain of Heilongjiang province as a typical Q. mongolica population, and from Guandi Mountain of Shanxi Province which represented the typical Liaodong oak population to compare isozyme and DNA diversity between both species. The winter bud samples were also analysed from Dongling Mountain near Beijing City since Dongling population is an intermediate form between the Maoer population and the Guandi population morphologically. Statistics of 13 putative loci belonging to 5 enzymes showed a high level of diversity within all populations. The value of genetic distance among populations was low, and showed that the Dongling population genetically located at the middle of both typical species. DNA data also showed that both typical oak populations shared similar variation with the Dongling population. Among 172 polymorphic RAPD and DAF loci, no population-specific band has been found. A significant difference in frequency of amplified products existed in 26 loci. Except for 3 irregular ones, frequency distribution of 23 loci seems clinal. The Dongling population also genetically located at the middle of both flanking populations. It was worth to note that the OPD-08434 was probably unique to the Dongling oak since its frequency in the Guandi population has been estimated up to 100% and decreased to 0 in the Maeer population. The Dongling population received this unique DNA from the Guandi population probably by introgression. The strong gene flow in both directions implied a long history of distributive continuity for both oak species. High levels of morphological, isozymatic and DNA diversity supplied enough genetic basis for reconstruction of degraded oak ecosystems.     

灰背栎遗传多样性和遗传结构的AFLP指纹分析

用AFLP方法对灰背栎 (Quercussenescens) 8个居群进行了遗传多样性、居群遗传结构研究。TFPGA软件分析两组引物组合共产生 12 5个位点 ,其中 94个为多态位点 ,多态位点百分率为 75 2 % ,发现灰背栎居群的遗传变异水平有随着海拔升高而遗传多样性下降的趋势。Arliquin 2 0 0 0中的AMOVA分析表明灰背栎居群间分化大 ,分化指数达 φst=0 2 95 6。用PAUP软件对所有个体间的遗传关系进行了聚类分析     

果蝇自然群体同工酶遗传多态的研究

用凝胶电泳技术我们检测了果蝇(D.virilis)4个地方群体6个编码酶的基因位点的遗传变异。发现50％的检测位点是多态的。每个个体杂合位点所占的比例为27.13％。遗传变异量在不同位点上相差是很大的,Est-α,Est-β,Amy位点是高度多态的,Mdh,αGpdh,Acph则几乎是单态的。Mdh在53℃的热稳定性没有差异。对一个给定的位点来说等位基因频率在各地方群体之间是很相似的。测定4个地方群体间的遗传分化,发现地理距离与遗传距离间没有线性相关性。结果表明自然选择和随机过程都可以造成遗传变异,而我们所研究的6个基因位点的变异究竟是自然选择造成的,还是随机过程决定的则有待于进一步的研究。     

辽东栎幼苗对干旱和去叶的生态反应的初步研究

幼苗阶段是植物种群生活史中亏损最严重的时期之一。通过干旱处理和去叶试验研究了辽东栎幼苗的生态反应。结果表明：⑴干旱处理显著降低了单叶面积、叶面积比和叶比重,从而也降低了单株生物量,但根比重却较对照组有显著上升;⑵去叶显著提高了单株叶数、叶面积比和叶比重,尽管单株生物量只稍高于对照组,这说明辽东栎在去叶后有一定的补偿能力。     

中国大鲵四种群的遗传结构和地理分化

为了确定栖息地的破碎化和片断化引起中国大鲵的地理分化和遗传结构变异,本文测定了来自广西、河南、陕西和湖南4个地理种群的28条大鲵的mtDNAD loop基因全序列。根据这4个地理种群的地理分布,分成珠江单元(广西种群)、黄河单元(河南种群)和长江单元(湖南和陕西种群)。通过ClustalX、MEGA2.0、DnaSP4.0、Arlequin1.1分析发现,全序列长度为771bp,其中64个多态性核苷酸变异位点,占全部碱基数的8.26%。转换和颠换分别为6和2个,插入/缺失11个。27个单倍型间的序列差异平均为1.32%。3个单元的单倍型多样性指数和核苷酸多样性指数值都偏低,而且珠江单元的这两个指数值都低于长江和黄河两个单元。珠江单元和黄河、长江单元之间分化程度显著(P<0.001),而长江和黄河单元之间差异不显著(P>0.05)。地理单元内分化程度占99.31%,而单元间只有0.69%,表明遗传差异主要发生在单元内,而且各地理单元之间的基因流较频繁。构建的NJ树和MP树显示,27个单倍型呈现一种混杂的分布格局,并未分成代表3个地理单元的聚合群。     

兰花蕉的遗传多样性研究

采用简单重复序列区间(ISSR,Inter-Simple Sequence Repeat)分子标记技术,对采自广东省的濒危植物兰花蕉(Orchidantha chinensisT.L.Wu)的7个居群137个个体进行遗传变异分析。用10个ISSR引物共扩增出清晰谱带101条,其中58条具有多态性,总多态位点百分率为57.43%。居群水平相对较低,多态位点百分率在6.93%-35.64%之间,平均为18.24%。经POPGENE1.31数据处理,结果表明:在物种水平上Nei基因多样性为0.1254±0.1686;Shannon信息指数为0.2000±0.2429;Nei基因分化系数为0.5481,表明54.81%的遗传变异分布在居群间,45.19%的遗传变异分布在居群内。物种居群间的遗传一致度在0.8855-0.9511之间。我们认为红花潭是其最适合生境,建议在此建立自然保护区;鉴于兰花蕉居群间出现了一定程度的分化,为最大限度地保护兰花蕉的遗传多样性,建议在自然居群间进行相互移栽,以提高群体间的基因交流。     

A Study of Genetic Structure of Stephania yunnanensis (Menispermaceae) by DALP

Genetic diversity and genetic structure within and among ten populations of Stephania yunnanensis H. S. Lo and three populations of S. epigaea H. S. Lo from Yunnan province were evaluated by direct amplification of length polymorphism (DALP) markers. Five primer groups were screened, and a total of 287 DNA fragments were amplified, among which 266 were polymorphic, averaging 53.2 polymorphic bands per primer group in S. yunnanensis. The percentage of polymorphic bands of S. yunnanensis was 92.68% at the species level and 61.92% within the ten populations sampled. At the species level, the observed number of alleles (N _a) was 1.9268 and the effective number of alleles (N _e) was 1.5933; Nei’s gene diversity (H) was 0.3414; Shannon’s information index (I) was 0.5057. At the population level, N _a = 1.6192, N _e = 1.4001, H = 0.2298, and I = 0.3401. Total gene diversity of S. yunnanensis was 0.3419. Gene diversity within population was 0.2298, coefficient of gene differentiation was 0.3278, and estimated gene flow was 1.0254. The results indicated that the genetic differentiation was relatively higher among populations of S. yunnanensis. DALP markers were an informative and useful method for assaying genetic diversity and authenticating species of Stephania. These data could provide basic molecular evidence for establishing a reasonable strategy for protecting and exploiting the resource of S. yunnanensis.     

空心莲子草茎的解剖结构对不同水湿生境的适应研究

研究了空心莲子草茎的解剖结构对水分变化的适应,这些空心莲子草生活在因水分差异而形成的3种生境类型中。对茎表蜡质层厚度、髓腔面积/髓部面积、厚角细胞层数、厚角细胞壁厚、韧皮纤维束数、韧皮纤维壁厚、导管束数、导管腔大小8个结构参数的分析结果表明:茎的全部结构参数随水分条件的变化都有显著或极显著的差异,其趋异程度的大小顺序是,导管腔大小>厚角细胞壁厚>蜡质层厚度>髓腔面积/髓面积>韧皮纤维细胞壁厚>韧皮纤维束数>厚角细胞层数>导管束数;水分变化对机械组织细胞壁结构影响较大,而对细胞数量的影响较小;茎的结构在旱生生境中变异较大,保证了它对不均一环境的适应;空心莲子草茎的结构既具有旱生性特点又具有水生性特点,其结构究竟朝哪个方向发展,取决于环境水分条件。从茎的结构上看,治理该种应以限制其导管腔和髓腔分化为主要手段。     

猕猴桃野生居群的SSR分析初报

采用SSR分子标记技术对我国猕猴桃的2个商业栽培物种——中华猕猴桃和美味猕猴桃的9个天然居群(共221个样)的遗传多样性进行了初步分析。通过对14对猕猴桃引物的筛选,8对重现性好的引物扩增结果表现出良好的多态性。在8个多态性位点上共获得222个等位基因。居群等位基因平均数A=17．3,多态位点百分率P-100,多态信息指数PIC为0．87～0．96,显示出我国的猕猴桃野生居群具有极高的遗传多样性。中华猕猴桃和美味猕猴桃野生居群拥有高比例的共同等位基因,反映出二者的亲缘关系极近。     

Genetic diversity and population structure in Tunisian Lavandula stoechas L. and Lavandula multifida L. (Lamiaceae)

The genetic diversity and population structure of 20 Tunisian Lavandula stoechas L. and Lavandula multifida L. populations, from different bioclimates, were analysed by starch gel electrophoresis using seven isozymes. The genetic diversity within populations varied according to species. Variation in L. multifida was higher than that observed for L. stoechas, and exclusive alleles were detected for taxa.

A high differentiation among populations, for each species, estimated by Wright's F-statistics was revealed. The genetic structure of populations from the same bioclimate was substantial. Nei's, R. [1978. Estimation of average heterozygosity and genetic distance from a small number of individuals. Genetics 89, 583–590] genetic distance among pairs of populations was low. The UPGMA cluster analysis of genetic distance values revealed that populations for each species were not strictly clustered together according to bioclimate or geographic proximity.

For each species, the low genetic divergence among populations and their substantial structure indicate their recent fragmentation due to anthropic pressures. The dendrogram generated from pairwise genetic distance among all populations showed two distinct clusters each corresponding to one species. The high genetic divergence between the two species, based on isozymes, corroborates their taxonomic status, as previously reported using morphological traits. The strategy for the management and conservation of populations should be made for each taxa according to its level of diversity and bioclimate.     

Allozyme Diversity and Population Structure in Korean Populations of Cymbidium goeringii (Orchidaceae)

Cymbidium goeringii (Orchidaceae). Mean observed population heterozygosity (H _op=0.181), expected heterozygosity (H _eP=0.240), and total genetic diversity (H _T =0.351) were all higher than average values for species with similar life-history characteristics. A considerable deficit of heterozygotes relative to Hardy–Weinberg expectations was detected (77% of fixation indices were positive) with a mean F _IS of 0.278. On average, 90% of the total genetic diversity was found within populations (mean G _ST = 0.098). An indirect estimate of the number of migrants per generation (Nm=2.30, calculated from G _ST , Nm=8.48, calculated from the frequencies of unique alleles) indicated that gene flow has been extensive in C. goeringii. Results of a spatial autocorrelation analysis based on allele frequencies of 16 populations revealed a trend with respect to the distance classes (0<63 km, six significant positive values; beyond that distance, 12 significant negative values). It is highly probable that C. goeringii has a history of relative large, continuous populations that had greater chance for gene movement among adjacent populations via large numbers of small seeds, following the last Ice Age. Factors contributing to the high levels of genetic diversity found within populations of C. goeringii include its large and continuous populations, its long-lived perennial habit, its widespread geographical distribution, and its ability for relatively long distance seed movement by wind. Received 18 June 1998/ Accepted in revised form 18 November 1998     

羚牛的遗传多样性及其种群遗传结构分析

羚牛是亚洲大陆一种特有的大型珍稀动物,目前正面临着栖息地丧失、片段化和人类活动的严重威胁。为了有效地保护这种濒危动物,全面了解羚牛的种群结构、进化历史和整个分布区内遗传多样性的分布是至关重要的。本研究以mtDNA D-loop330bp基因片段为分子标记,比较分析了来自陕西秦岭、甘肃南部、四川岷山、邛崃山和云南贡山的40个样品的序列差异,根据分布特点将所采集到的羚牛分为3个地理单元,即秦岭、四川和云南。结果表明,在3个地理单元中存在4种单倍型,且地理单元间不存在共享单倍型,相互单倍型之间的平均序列差异为1.66％。进一步分析表明,3个地理单元间的基因流较低,存在着显的遗传分化 ,说明羚牛具有明显的系统地理分布格局。同时提出应将分布于秦岭山区、唐家河青川地区、天全以及云南贡山地区作为独立的管理单元分别加以保护。     

Genetic diversity of the endangered endemic Microcycas calocoma (Miq.) A. DC (Zamiaceae, Cycadales): Implications for conservation

The diversity and genetic structure of seven populations of Microcycas calocoma (Miq.) A. DC, were analyzed by gel electrophoresis using 19 allozymes. The mean number of alleles per locus (A) was 1.49 and the percentage of polymorphic loci was relatively high (P = 48.09). The mean observed (H_o) and expected heterozygosity (H_e) were 0.20 and 0.17, respectively. The F-statistics revealed a high population structure (F_st = 0.34). Mean gene flow between population pairs was Nm = 0.96. Results were compared with those of other cycad species, and indicate that M. calocoma populations have become fragmented due to increasing pressures of habitat conversion and disturbance. Also, geographical isolation among populations has generated allele loss in relation to altitude. The establishment and maintenance of protected areas for in situ conservation is critical to preserve the high genetic diversity of M. calocoma. Conservation strategy guidelines have been specified.     

Genetic Diversity and Population Structure of Alnus hirsuta (Betulaceae) in Korea

Alnus hirsuta in Korea was measured to estimate the amount and pattern of genetic diversity and population structure. The mean genetic diversity within populations was 0.166. Korean alder populations have slightly high levels of genetic diversity compared to those of two Canadian alder species. The genetic differentiation among populations accounted for 9% of the total variation. The rate of gene flow was estimated high (Nm=2.63). Analysis of inbreeding coefficient, calculated for all polymorphic loci in each population, showed a substantial heterozygote deficiency relative to Hardy-Weinberg expectations. The mean G _ST value of A. hirsuta in Korea was 0.087. The low value of G _ST in this species, reflecting little spatial genetic differentiation, may indicate extensive gene flow. A relationship between the mean heterozygosity and annual rainfall showed a positive relationship (r ²=0.54, F=4.67). Received 8 August 1998/ Accepted in revised form 7 July 1999     

大王马先蒿云南五个居群遗传变异研究

采用随机扩增多态DNA(RAPD)分子标记方法,对大王马先蒿(PedicularisrexL.)分布在云南中甸、丽江、大理、武定和昆明的5个居群(其中中甸居群有3个亚居群)的遗传多样性和遗传结构进行了研究。结果表明,大王马先蒿居群具有较高的遗传多样性,多态位点百分率P、Shannon表型多样性指数I和Nei的基因多样性指数h分别为82.0%、0.361和0.240,遗传多样性水平与居群的地理分布范围相关;大王马先蒿居群间的遗传变异较高,遗传变异主要发生在居群之间,而不是居群内部;居群间遗传分化系数Gst为0.747,遗传分化明显,居群间基因交流较少。居群间的遗传距离与居群间的相对地理距离具有一定的相关性。对云南西北部中甸居群的3个亚居群的遗传多样性分析表明,居群的遗传多样性水平与海拔高度有一定的相关性。居群间遗传变异较高可能是由于大王马先蒿为短命多年生植物,繁育系统为混交型,且自交占较大比例等原因造成的。     

Genetic Structure of Natural Populations of Wild Soybean (Glycine soja) in Beijing Region

In order to exploit the genetic resources of wild soybean (Glycine soja) which is the progenitor of cultivated soybean (Glycine max), the genic frequencies of Ti (coding trypsin inhibitors) and Sp1 (coding β-amylase isozymes) for 13 populations of wild soybean in Beijing region were determined. There are 2 alleles (Tia and Tib) in Ti locus of Beijing populations. Calculation of heterozygosity indicates Sp1 is polymorphic, while this monomorphic within a population. Based on the vatiation (from 0 to 50%) for heterozygosity of Sp1 among populations, with special reference to the values of genetic distances among populatious, and no heterozygote has been found in 1300 plants which would be heterozygotes if they were outbreeder, we suggested that wild soybean in natural populations is absolute inbreeder. The frequencies of Ti and Sp1 alleles vary from place to place extremely, however, no correlation exists between allozyme frequencies and ecological factors. Field investigation has shown that there is a threat from the reduction in available habitats, caused by building irrigation works .and urbanization. Finally, sampling strategy for conservation of genetic resources of wild soybean was discussed and some suggestions were made.     

草鱼EST-SSR标记及5个不同地域群体的遗传结构分析

以草鱼(Ctenopharyngodon idella)脑、肌肉、肝等组织构建cDNA文库,经测序获得unigenes序列45 318个,从中筛选微卫星序列共5 556个,据此设计EST-SSR引物118对,其中19对引物能够扩增出带型清晰且多态性较高的谱带。用这19个EST-SSR标记研究3个长江水系群体(石首、监利和长沙)和2个珠江水系群体(清远和肇庆)草鱼的遗传结构。结果表明,5个群体的平均多态信息含量(PIC)为0.415 4～0.460 4,显示草鱼群体的遗传多样性偏低;平均观测杂合度(Ho)为0.415 8～0.501 3,平均期望杂合度为(He)0.450 6～0.502 8,其中,长沙群体平均期望杂合度最高,为0.502 8,监利群体的平均观察杂合度和平均期望杂合度均最低,分别为0.415 8和0.450 6,即长沙群体的遗传多样性最高,监利群体的遗传多样性最低;对数据进行F-检验,结果表明,群体间的遗传分化程度低。Hardy-Weinberg平衡的卡方检验结果表明,5个群体均一定程度上偏离了平衡;聚类分析显示长沙群体、石首群体与监利群体聚成一支;肇庆群体与清远群体聚成一支,这与草鱼群体的流域分布一致。     

利用COI基因序列分析长江与澜沧江水系日本沼虾群体的遗传结构

测定了我国长江水系和澜沧江水系的日本沼虾9个群体,共79个个体的线粒体COI基因序列片段(约450bp),结果发现有89个变异位点,共计有46个单倍型。其中云南昆明(KM)群体具有较丰富的遗传多样性(h=1.000,π=0.028),而重庆(CQ)群体的遗传多样性最小(h=0.700,π=0.008)。AMOVA分析表明,群体间的遗传变异占总遗传变异的9.66%,而90.34%的遗传变异源于群体内。采用邻接法(NJ)构建的分子系统树显示,46个单倍型明显地聚为长江中下游和长江上游与澜沧江两个族群。其结果可以为合理开发和利用日本沼虾自然野生资源,以及建立和保护日本沼虾种质资源库及基因库提供必要的参考。