海三棱藨草及其近缘种果实形状和果皮微形态特征研究

利用光学显微镜和扫描电镜对海三棱藨草(× Bolboschoenoplectus mariqueter (Tang & F. T. Wang))及其5个近缘种的果实形状、果皮微形态特征进行观察和分析。结果显示,海三棱藨草果实形状为双凸状,表面为波形网状纹饰,外果皮为中果皮厚度的2倍,与扁秆荆三棱( Bolboschoenus planiculmis (F. Schmidt) T. V. Egorova)明显不同,而与海滨三棱草( Bolboschoenus maritimus (L.) Palla)相似。研究结果支持将海三棱藨草归入三棱草属,不支持将海三棱藨草作为扁秆荆三棱的异名,推测其可能为海滨三棱草水滨亚种( Bolboschoenus maritimus subsp. paludosus (A. Nelson) T. Koyama)的异名。     

海三棱藨草及其近缘种果实形状和果皮微形态特征研究

利用光学显微镜和扫描电镜对海三棱藨草（×Bolboschoenoplectus mariqueter（Tang&F.T.Wang））及其5个近缘种的果实形状、果皮微形态特征进行观察和分析。结果显示,海三棱藨草果实形状为双凸状,表面为波形网状纹饰,外果皮为中果皮厚度的2倍,与扁秆荆三棱（Bolboschoenus planiculmis（F.Schmidt） T.V.Egorova）明显不同,而与海滨三棱草（Bolboschoenus maritimus（L.） Palla）相似。研究结果支持将海三棱藨草归入三棱草属,不支持将海三棱藨草作为扁秆荆三棱的异名,推测其可能为海滨三棱草水滨亚种（Bolboschoenus maritimus subsp.paludosus（A.Nelson） T.Koyama）的异名。     

海三棱藨草及其近缘种的DNA条形码研究

海三棱藨草[×Bolboschoenoplectus mariqueter(Tang&F. T. Wang) Tatanov]的分类学地位至今尚无定论。为明确海三棱藨草的分类学地位并探讨其与近缘种的关系,该研究分别利用1个核基因(ITS)和5个叶绿体基因(matK、ndhF、rbcL、trnL和trnL-trnF)的DNA条形码序列对海三棱藨草及其近缘种的4种21批样品进行扩增和测序,通过采用相似性搜索算法对单一序列和序列组合的物种鉴定效率进行评价,并基于贝叶斯推断方法构建系统发育树进行鉴定分析。结果表明：(1)ITS+matK序列组合的物种鉴定效率最高,为71.4%,可实现海三棱藨草及其近缘种的种间区分、鉴定。(2)基于ITS+matK序列组合构建海三棱藨草及其近缘种的系统发育树,发现同一物种的样品聚集度较好,海三棱藨草与三棱草属[Bolboschoenus(Asch.) Palla]的物种聚为一支,明显与水葱属[Schoenoplectus(Rchb.) Palla]物种分开,并且海三棱藨草与海滨三棱草[Bolboschoenus maritimus(Linnaeus) P...     

扁果草叶绿体基因组特征分析

为探讨扁果草(Isopyrum anemonoides)叶绿体基因组特征及该属物种的系统发育关系,采用Illumina Hiseq高通量测序技术,对扁果草进行全基因组测序,组装、注释和完成扁果草叶绿体全基因组图谱绘制。结果显示,扁果草叶绿体全基因组总长161 034 bp,为典型的四分体结构,包含85个蛋白编码基因、37个转运RNA和8个核糖体RNA。共检测到44个散在重复序列和47个简单重复序列。此外,扁果草叶绿体基因组中共包含53 678个密码子,其中编码亮氨酸的密码子最多(5 251个),编码色氨酸的密码子最少(712个)。共线性分析结果显示,扁果草与近缘种叶绿体基因组中不存在倒位或重排现象。系统发育分析表明,扁果草并未与该属的东北扁果草(I.manshuricum)聚在一个分支上,而是与假耧斗菜(Paraquilegia microphylla)有很近的亲缘关系。本研究为开展后续的扁果草属物种鉴定、系统发育研究提供基础资料。     

海三棱蔍草种群的物候与分布格局研究

海三棱藨草群落是生长在海岸带滩涂原生裸地上的原生植被,在上海地区分布面积达20多万亩。本项工作研究了上海市南汇县东海农场海堤外侧滩涂上海三棱藨草种群的物候和分布格局。根据滩涂高程以及海三棱藨草种群生长状况,可以划分成三个地带,即地带A,海三棱藨草与芦苇群落交错区;地带B,海三棱藨草种群生长最适的中潮位地带;地带C,海三棱藨草种群定居地带。由于三个地带内,生境条件不同,海三棱藨草种群的物候有明显差异。从地带A至C,海三棱藨草种群的分布格局依次为随机分布、均匀分布和随机分布或群聚分布。其空间分布格局在随时间变化的同时也在空间上改变其位置。     

海三棱藨草种群的物候与分布格局研究

海三棱藨草群落是生长在海岸带滩涂原生裸地上的原生植被,在上海地区分布面积达20多万亩。本项工作研究了上海市南汇县东海农场海堤外侧滩涂上海三棱藨草种群的物候和分布格局。根据滩涂高程以及海三棱藨草种群生长状况,可以划分成三个地带,即地带A,海三棱藨草与芦苇群落交错区;地带B,海三棱藨草种群生长最适的中潮位地带;地带C,梅三棱藨草种群定居地带。由于三个地带内,生境条件不同,海三棱藨草种群的物候有明显差异。从地带A至C,海三棱藨草种群的分布格局依次为随机分布、均匀分布和随机分布或群聚分布。其空间分布格局在随时间变化的同时也在空间上改变其位置。     

莫莫格扁秆藨草恢复湿地土壤种子库对长芒稗入侵的响应

湿地恢复过程中,时常有外来种或本地杂草入侵。土壤种子库作为未来植被的潜在种源,对湿地恢复效果具有重要的指示意义。在莫莫格国家级自然保护区,以恢复白鹤栖息地(扁秆藨草(Scirpus planiculmis)沼泽)为目的,进行了退化湿地的水文恢复;但退化湿地恢复2a后,一年生杂草长芒稗(Echinochloa caudata)在大部分区域成为建群种。以长芒稗入侵湿地和扁秆藨草自然湿地为研究对象,对比分析了长芒稗和扁秆藨草的土壤种子库及生长结实特征。结果表明,在自然湿地扁秆藨草种子库规模是长芒稗的18.42倍,而在恢复湿地长芒稗种子库大小是扁秆藨草的5.04倍。与自然湿地相比,扁秆藨草种子库密度在入侵湿地明显减少,但仍保留了一定量具有活力的种子(664.32±105.98)粒/m~2,这与研究区扁秆藨草较高的种子生产力(9210.4±1513.4)粒/m~2及种子较强的浮力(FP50=39.7d)有关,说明扁秆藨草具备通过种子库或水传播恢复的潜力。长芒稗土壤种子库密度在入侵湿地高达(3345.9±520.3)粒/m~2,明显高于自然湿地种子库规模(P0.01),说明恢复湿地受长芒稗入侵影响严重,这与长芒稗较高的种子生产力(7621.4±376.25)粒/m~2及较弱的种子浮力(FP0=5d)有关,同时也表明长芒稗通过水传播扩散的能力较弱。另外,研究区长芒稗平均高度超过1m,且盖度较大,不仅阻碍扁秆藨草种子的水播,也降低了到达地表的光照水平,从而抑制扁秆藨草更新。因此,在莫莫格受长芒稗入侵湿地,于开花结实前收获长芒稗地上植物体及凋落物应是限制长芒稗扩展、同时促进扁秆藨草恢复的有效措施。     

密度对三种莎草科植物克隆生长的影响

以三种莎草科克隆植物藨草(Scirpus triqueter), 海三棱藨草(Scirpus mariqueter)和糙叶苔草(Carex scabrifolia)为研究对象, 通过盆栽受控实验, 探讨三种初始种植密度处理(1 株/盆、4 株/盆和16 株/盆)对个体表现与种群增长的影响。结果表明, 三种植物种群经过一个月左右的适应后均开始加速增长, 生长季后期增长率逐渐降低, 而海三棱藨草种群甚至出现了一定程度的衰退。生长季中前期藨草在中低密度处理下密度增长率高于高密度和整簇种植处理, 而海三棱藨草、糙叶苔草种群的整体密度增长与初始种植密度成反比。最终收获时, 藨草和海三棱藨草不同处理下的密度、冠层高度、最高高度、地上生物量和地下生物量均没有显著差异, 糙叶苔草在低种植密度下的密度最低, 中等种植密度下冠层高度最高。藨草、海三棱藨草的单株平均生物量与密度呈显著负相关, 而藨草、糙叶苔草的总生物量与密度呈显著正相关, 三种莎草科植物的根冠比都没有随密度发生显著变化。三种莎草科植物在高密度下的种内竞争效应均强于中密度。     

中国禾本科植物新资料(Ⅱ)

报道了我国境内新发现的2种外来禾草：宽叶臂形草[Brachiaria platyphylla (Munro ex C. Wright) Nash]和车前臂形草[B. plantaginea (Link) Hitchc.],这2物种有时被处理为尾稃草属(Urochloa)的成员。依据小穗第一颖背部具向轴性,第二外稃先端不具小尖头的形态特征,认为他们更接近于国产臂形草属(Brachiaria)的物种,编制了他们与国产近缘物种、属的分类检索表,并讨论了2外来种的潜在入侵风险。     

扁秆藨草种群内禀增长率的研究

采用“定期起苗”法,从６ 月１０ 日—８ 月３０ 日止,分别统计从越冬块茎上萌发出的再生苗及其后代蔓生枝系再生苗的数量,从而得出扁秆藨草再生苗各旬株数增长的指数方程;又用“定株观察”法,对１２ 株越冬块茎上的再生苗及其全部后代植株开花、结实数量进行统计,探讨扁秆藨草有性繁殖的能力,然后进行综合计算,求得扁秆藨草种群的内禀增长率ｒ＝７．２４,阐明了扁秆藨草很高的内禀增长率是其种群过度生长的根本原因;通过对其过度生长关键时刻的判断,选择灭草的关键期,有效地灭杀此种恶性杂草     

AFLP markers in the detection of Scirpus × mariqueter (CYPERACEAE) hybrid in China

Scirpus × mariqueter Tang & F.T. Wang (CYPERACEAE) is a pioneer plant of the tidal zone of estuaries of East Asia. Amplified fragment length polymorphisms (AFLP) were used to infer the relationship between S. × mariqueter and its putative progenitors, Scirpus planiculmis F. Schmidt and Scirpus triqueter L. The genetic distance between S. × mariqueter and S. triqueter was much higher than that between S. × mariqueter and S. planiculmis, and samples of S. × mariqueter and those of S. planiculmis did not form a monophyletic group, while the S. triqueter group formed a distinct monophyletic group. However, we also detected an apparent clustering of individuals of S. × mariqueter and S. planiculmis separately. Our results disprove the hybrid origin of S. × mariqueter and rather suggest that it is more closely related to S. planiculmis.     

AFLP markers in the detection of Scirpus × mariqueter (CYPERACEAE) hybrid in China

Scirpus × mariqueter Tang & F.T. Wang (CYPERACEAE) is a pioneer plant of the tidal zone of estuaries of East Asia. Amplified fragment length polymorphisms (AFLP) were used to infer the relationship between S. × mariqueter and its putative progenitors, Scirpus planiculmis F. Schmidt and Scirpus triqueter L. The genetic distance between S. × mariqueter and S. triqueter was much higher than that between S. × mariqueter and S. planiculmis, and samples of S. × mariqueter and those of S. planiculmis did not form a monophyletic group, while the S. triqueter group formed a distinct monophyletic group. However, we also detected an apparent clustering of individuals of S. × mariqueter and S. planiculmis separately. Our results disprove the hybrid origin of S. × mariqueter and rather suggest that it is more closely related to S. planiculmis.     

The Tnt1 family member Retrosol copy number and structure disclose retrotransposon diversification in different <Emphasis Type="Italic">Solanum</Emphasis> species

Eukaryotic genome expansion/retraction caused by LTR-retrotransposon activity is dependent on the expression of full length copies to trigger efficient transposition and recombination-driven events. The Tnt1 family of retrotransposons has served as a model to evaluate the diversity among closely related elements within Solanaceae species and found that members of the family vary mainly in their U3 region of the long terminal repeats (LTRs). Recovery of a full length genomic copy of Retrosol was performed through a PCR-based approach from wild potato, Solanum oplocense. Further characterization focusing on both LTR sequences of the amplified copy allowed estimating an approximate insertion time at 2 million years ago thus supporting the occurrence of transposition cycles after genus divergence. Copy number of Tnt1-like elements in Solanum species were determined through genomic quantitative PCR whereby results sustain that Retrosol in Solanum species is a low copy number retrotransposon (1–4 copies) while Retrolyc1 has an intermediate copy number (38 copies) in S. peruvianum. Comparative analysis of retrotransposon content revealed no correlation between genome size or ploidy level and Retrosol copy number. The tetraploid cultivated potato with a cellular genome size of 1,715 Mbp harbours similar copy number per monoploid genome than other diploid Solanum species (613–884 Mbp). Conversely, S. peruvianum genome (1,125 Mbp) has a higher copy number. These results point towards a lineage specific dynamic flux regarding the history of amplification/activity of Tnt1-like elements in the genome of Solanum species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

长三角及邻近地区138种草本植物DNA C-值测定及其生物学意义

为了评估DNA C-值和基因组大小(genome size)在植物入侵性评估中的价值,应用流式细胞仪测定了长三角及邻近地区138种草本植物的核DNA含量,其中111种为首次报道。在此基础上比较了不同植物类群这两个值的差异,特别是入侵性与非入侵性植物这两个值的差异。结果表明:(1)138种草本植物平均DNA C-值为1.55 pg,最大者是最小者的37.17倍。127个类群平均基因组大小为1.08 pg,最大者是最小者的34.11倍;(2)统计了菊科(Asteraceae)、禾本科(Poaceae)、石竹科(Caryophyllaceae)、十字花科(Brassicaceae)、玄参科(Scrophulariaceae)、蓼科(Polygonaceae)、唇形科(Labiatae)和伞形科(Umbelliferae)的DNA C-值和基因组大小,发现禾本科植物的这两个值显著地大于其他7个科(P0.01)。单子叶的DNA C-值和基因组极显著地大于双子叶植物(P0.01);(3)杂草比非杂草具有更低的DNA C-值(P0.01)和基因组大小(P0.001);与DNA C-值相比,基因组大小在这两个类群之间的差异更为明显(P0.001),这种现象也体现在菊科植物中。随着基因组(X1)和DNA C-值(X2)由大变小,植物的杂草性(入侵性,Y)由弱变强,两者关系分别符合:Y=2.2334-1.2847 ln(X1)(r=0.4612,P0.01)和Y=2.4421-0.7234 ln(X2)(r=0.2522,P0.01),DNA C-值和基因组大小可以作为植物入侵性评估的一个指标;(4)多倍体杂草的基因组极明显地小于二倍体杂草(P0.01),前者为后者的0.63倍。在非杂草中,多倍体基因组比二倍体的略小,前者仅为后者的0.84倍,差异不显著(P0.5)。菊科植物中多倍体杂草的基因组也显著地小于二倍体杂草(P0.1)。基因组变小和多倍体化相结合,进一步增强了植物的入侵性。在多倍体植物入侵性评估中,基因组大小比DNA C-值更有价值。     

Smallest angiosperm genomes found in lentibulariaceae, with chromosomes of bacterial size

Nuclear holoploid genome sizes (C-values) have been estimated to vary about 800-fold in angiosperms, with the smallest established 1C-value of 157 Mbp recorded in Arabidopsis thaliana. In the highly specialized carnivorous family Lentibulariaceae now three taxa have been found that exhibit significantly lower values: Genlisea margaretae with 63 Mbp, G. aurea with 64 Mbp, and Utricularia gibba with 88 Mbp. The smallest mitotic anaphase chromatids in G. aurea have 2.1 Mbp and are thus of bacterial size (NB: E. coli has ca. 4 Mbp). Several Utricularia species range somewhat lower than A. thaliana or are similar in genome size. The highest 1C-value known from species of Lentibulariaceae was found in Genlisea hispidula with 1510 Mbp, and results in about 24-fold variation for Genlisea and the Lentibulariaceae. Taking into account these new measurements, genome size variation in angiosperms is now almost 2000-fold. Genlisea and Utricularia are plants with terminal positions in the phylogeny of the eudicots, so that the findings are relevant for the understanding of genome miniaturization. Moreover, the Genlisea-Utricularia clade exhibits one of the highest mutational rates in several genomic regions in angiosperms, what may be linked to specialized patterns of genome evolution. Ultrasmall genomes have not been found in Pinguicula, which is the sister group of the Genlisea-Utricularia clade, and which does not show accelerated mutational rates. C-values in Pinguicula varied only 1.7-fold from 487 to 829 Mbp.     

轮叶蒲桃叶绿体基因组特征及系统发育分析

轮叶蒲桃(Syzygium grijsii)系桃金娘科(Myrtaceae)蒲桃属(Syzygium)常绿灌木，其开发前景较好，但其叶绿体基因组特征及系统发育关系尚未有相关报道。为弥补轮叶蒲桃基因组学方面的空缺，该文对轮叶蒲桃的叶绿体基因组进行了系统的研究。运用Illumina高通量测序，并在GetOrganelle平台进行完整组装，同时利用组装好的数据分析轮叶蒲桃叶绿体基因组的结构特征和系统发育关系，其中包括轮叶蒲桃叶绿体基因组结构、功能及特征、密码子偏好性分析、叶绿体基因组的比较分析和系统发育的分析。结果表明：(1)轮叶蒲桃叶绿体基因组大小为158 591 bp,包含129个基因。其中，rRNA基因8个，tRNA基因37个，蛋白编码基因84个。分析检测到39个重复序列和84个SSR位点。(2)密码子偏好性分析发现轮叶蒲桃叶绿体基因组中末端存在对A/U的偏性，使用最多的是编码亮氨酸的密码子。(3)与近缘种比较，轮叶蒲桃的边界长度保守，边界处的基因种类与多个蒲桃属物种相似；轮叶蒲桃叶绿体基因组在LSC和SSC区变异度较大，有45处0.010i<0....     

禾本科植物基因组大小与种子特性的相关性分析

在检索植物C值数据库和种子数据信息库的基础上,对禾本科282种植物的基因组参数（倍性、染色体数、C值、GS值和平均每条染色体DNA含量）和种子特性（千粒重、含油量和蛋白含量）进行了统计分析。分析结果表明,禾本科植物C值在0.35～19.7 pg,大多位于1.6～3.2 pg之间,呈偏正态分布,种子千粒重在0.05～252 g,绝大多数位于0.05～20.0 g,呈偏态分布,二者平均值分别为4.14 pg和7.1 g。随着染色体倍性增加,C值在二倍体到八倍体之间显著增加,而GS值和平均每染色体DNA含量在二倍体到六倍体之间显著下降（p<0.05)。雀麦属和羊茅属随着倍性增加,C值显著增加,表现与禾本科相似的变化规律,GS值下降却不明显。相关性分析表明,禾本科植物C值与倍性、染色体数、GS值及平均每条染色体DNA含量均呈极显著正相关（p<0.01),与种子千粒重无相关性。GS值与染色体数、倍性呈极显著负相关,而与千粒重呈极显著正相关。C值与种子含油量呈显著负相关,但与种子蛋白含量之间无相关性。以上结果表明,禾本科植物在系统演化和进化过程中,主要通过倍性和染色体的增加来增大C值,可能通过某种删除或丢失机制来降低GS值,从而保持较高的适应环境能力和进化速率。     

A repeated sequence probe for the C genome in Avena (Oats)

Summary The genus Avena consists of at least 23 species composed of three ploidy levels. Cytogenetic analysis has characterised four distinct karyotypes. These are the A, B, C and D genomes. We have isolated a repeated sequence clone that can be used for the detection of the C genome in Avena by filter hybridization techniques. This clone, termed RS-1, is a genomic DNA clone containing at least one highly repeated sequence that is abundant in Avena species containing the C genome. This sequence or a related sequence is also present, but at much reduced levels, in species that do not contain the C genome. Because of its abundance and the characteristic Southern blot pattern, we have termed this clone a C genome specific clone. We have also done similar analysis of the Avena genus using a rDNA clone from wheat. The results of these experiments demonstrate that clearly definable C genome-specific markers can be identified with both probes. These molecular probes can be useful in studying the genomic relationships of Avena and can provide some clues as to the origin of the cultivated Avena species. These results can, therefore, provide breeders with directions for the efficient transfer of desirable traits of wild Avena species into commencal varieties.     

弯曲菌基因组学的研究进展

弯曲菌是世界范围内引起细菌性胃肠炎疾病的重要人兽共患病原菌,对公众健康造成严重威胁,其流行、传播、扩散的复杂性与基因组的高变异有关。全基因组测序(WGS)是一种基于基因水平的快速简便工具,可快速准确地进行物种鉴定、分析不同个体基因组间的差异、预测细菌耐药和毒力基因以及预测种群演化模型等。本文旨在对近年来全基因组测序在弯曲菌基因组学中的应用展开综述,以期为弯曲菌的流行和防控提供依据。     

Genome size variation in some representatives of the genus <Emphasis Type="Italic">Tripleurospermum</Emphasis>

Genome size has been estimated by flow cytometry in 14 populations belonging to eight taxa (seven species, one of them with two varieties) of the genus Tripleurospermum. 2C nuclear DNA amounts range from 4.87 to 9.22 pg, and nuclear DNA amounts per basic chromosome set from 1.99 to 2.75 pg. Statistically significant differences depending on ploidy level, life cycle or environmental factors such as altitude have been found. Also, genome size is positively correlated with total karyotype length. The presence of rhizome is related to nuclear DNA content in these species.This work was supported by project BOS2001-3041-C02-01 of the Spanish government, and one of the authors (S.G.) received a predoctoral grant from the Spanish government.