首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
Abstract This paper describes an assessment of the effect of exposure to fire‐related cues (heat shock, smoke and nitrate) and the interactions between the cues on seed dormancy release of tropical savanna legumes in north‐eastern Australia. Ten legume species were tested, comprising both native and exotic species. The ten species responded variously to the treatments. Brief exposure to temperatures between 80 and 100°C was found to break the seed dormancy of the native ephemeral herbs Chamaecrista mimosoides, Crotalaria calycina, Crotalaria montana, Indigofera hirsuta and Tephrosia juncea, as well as the exotic ephemeral herb Crotalaria lanceolata. Exposure to 80°C combined with treatment with a nitrate solution produced an additive effect on the germination of Chamaecrista mimosoides and Crotalaria lanceolata. However, the four species with the heaviest seeds, two exotic ephemeral herbs (Chamaecrista absus and Crotalaria pallida) and two native perennials (Galactia tenuiflora and Glycine tomentella) displayed no significant increase in germination with exposure to fire‐related cues. Exposure to 120°C for 5 min produced seed mortality in all species tested. Two of the largest seeded species, Crotalaria pallida and Galactia tenuiflora, displayed the lowest tolerance to heat shock, with seed mortality after exposure to 100°C for 5 min. These data indicate that fire can promote the germination of some tropical savanna legumes. As a proportion of seeds of each species displayed no innate dormancy, some germination may occur in the absence of fire, especially of exotic species.  相似文献   

2.
The genetic diversity of the genus Crotalaria is unknown even though many species in this genus are economically valuable. We report the first study in which polymorphic expressed sequence tag-simple sequence repeat (EST-SSR) markers derived from Medicago and soybean were used to assess the genetic diversity of the Crotalaria germplasm collection. This collection consisted of 26 accessions representing 4 morphologically characterized species. Phylogenetic analysis partitioned accessions into 4 main groups generally along species lines and revealed that 2 accessions were incorrectly identified as Crotalaria juncea and Crotalaria spectabilis instead of Crotalaria retusa. Morphological re-examination confirmed that these 2 accessions were misclassified during curation or conservation and were indeed C. retusa. Some amplicons from Crotalaria were sequenced and their sequences showed a high similarity (89% sequence identity) to Medicago truncatula from which the EST-SSR primers were designed; however, the SSRs were completely deleted in Crotalaria. Highly distinguishing markers or more sequences are required to further classify accessions within C. juncea.  相似文献   

3.
The new species Crotalaria jijigensis Thulin, C. polhillii Thulin and C. awasensis Thulin are described from Ethiopia.  相似文献   

4.
We studied a collection of 126 rhizobial isolates from eight species of Crotalaria (C. comosa, C. glaucoides, C. goreensis, C. hyssopifolia, C. lathyroides, C. perrottetii, C. podocarpa, and C. retusa) growing in Senegal. Nodulation and nitrogen-fixation tests on nine Crotalaria species revealed two specificity groups within the genus Crotalaria. Group I consists of plants solely nodulated by very specific fast-growing strains. Group II plants are nodulated by slow-growing strains similar to promiscuous Bradyrhizobium spp. strains already reported to nodulate many tropical legumes. SDS-PAGE studies showed that slow-growing strains grouped with Bradyrhizobium while fast-growing strains constituted a homogeneous group distinct from all known rhizobia. Amplified ribosomal DNA restriction analysis (ARDRA) of 10 representative strains of this group using four restriction enzymes showed a single pattern for each enzyme confirming the high homogeneity of group I. The 16S rDNA sequence analysis revealed that this specific group belonged to the genus Methylobacterium, thus constituting a new branch of nodulating bacteria.  相似文献   

5.
选取铁线莲属 (Clematis) 尾叶铁线莲组(sect. Campanella)中37个种以及西南铁线莲组 (sect. Bebaeanthera) 中的2个种为内类群, 以Clematis alternata作为外类群, 通过对全世界10个标本馆的近2 000份腊叶标本的形态学特征统计, 选取了35个性状进行编码, 利用PAUP 4.0 beta 10 软件进行系统发育重建。通过最简约法(maximum parsimony)分析共得到182棵最简约分支树, 树长为182步, 一致性指数(CI)=0.385, 保持性指数(RI)=0.685。结果表明: (1)尾叶铁线莲组并非是一个单系类群; (2)以花序发生位置这一性状建立的sect. Bebaeanthera不能成立, 应并入尾叶铁线莲组; (3)本研究结果不支持 在尾叶铁线莲组中建立subsect. Henryianae或ser. Henryianae; (4) C. ranunculoides等萼片外面具纵翅的一群植物与本组中萼片红色的种类C. lasiandra和C. dasyandra有较近的亲缘关系; (5)C. otophora、C. pogonandra、C. repens和C.barbellata等几个种聚为一支, 且支持率很高, 它们具有一系列的共衍征, 即萼片质地较厚, 花丝扁平, 宽条形, 被短柔毛, 花药被黄色短毛, 药隔先端凸起, 因此不支持建立Ser. Pogonandrae; (6)本组中非洲分布的2个种无论从形态上还是从地理分布和生境上都十分特殊, 是本组植物的特化类群。  相似文献   

6.
The following new species are described: Chamaecrista dunensis (Somalia), Acacia densispina (Somalia), A. flagellaris (Somalia), Tephrosia karkarensis (Somalia), T. scopulata (Somalia), Indigofera ancistrocarpa (Kenya), I. curvirostrata (Ethiopia), I. hiranensis (Somalia), I. karinensis (Somalia), I. kucharii (Somalia), I. nugalensis (Somalia), I. pellucida (Kenya, Somalia), I. sabulosa (Ethiopia, Somalia), I. sessilis (Somalia), I. ienuirostris (Somalia), Rhynchosia megalocalyx (Somalia), Crotalaria allophylla (Somalia), C. intricata (Somalia), C. warfae (Somalia), and Coronilla somalensis (Somalia). 2n = 22 is reported in Tephrosia karkarensis. Cassia somalensis, Acacia puccioniana, Sophora somalensis , and Crotalaria sennii are reduced to synonyms of respectively Senna hookeriana, Dichrostachys kirkii, Millettia usaramensis and Crotalaria boranica subsp. trichocarpa . Thirty-seven taxa are reported from Somalia for the first time, including Ptycholobium biflorum , known previously only from Southern Africa. Crotalaria pieropoda , known previously only from Socotra, is reported from Somalia and Oman. Neptunia oleracea and Vatovaea pseudolablab are new generic records for respectively Ethiopia and Oman. The fruits of Indigofera boranica are described. Vigna somaliensis and an allied species are discussed. Rhynchosia gansole is lectotypified and its flowers and fruits are described.  相似文献   

7.
嵩草属植物硅酸体系统的研究   总被引:1,自引:0,他引:1  
邓德山 《广西植物》2002,22(5):394-T003
对国产狭义嵩草属 (K obresia,Cyperaceae) 3个组 2 7种植物进行了硅酸体系统分析研究 ,同时结合近缘的苔草属 (Carex) 2个组的植物硅酸体特征 ,深入探讨了植物硅酸体系统分析研究在莎草科苔草族 (Cariceae)中的系统分类学意义。认为 :(1 )嵩草属及其临近类群在属间、种间及种下水平的系统分类学比较研究都可以借助植物硅酸体系统研究的证据。 (2 )穗状嵩草组 (sect. Elyna)的硅酸体系统特征具有较高的一致性 ,除矮嵩草 (K.humilis)及其近缘种同其他穗状嵩草组的种类有所不同 ,它很可能有一个不同于穗状嵩草组其他类群的嵩草组(sect. K obresia)的亲缘。 (3 )从植物硅酸体系统特征的研究来看 ,拟苔草组 (sect. H emicarex)的一些种接近于穗状嵩草组 ,如高山嵩草 (K . pygmeae) ;而另一些种接近于嵩草组 ,如禾叶嵩草 (K . graminifolia) ;也有一些种类的硅酸体系统特征更接近苔草属 ,说明这个组很可能是多源的 ,即本组的单一花穗和果囊形态特征由不同类群的复合花序种类趋同演化而出。(4 )嵩草组的硅酸体系统特征具有较高的一致性 ,说明嵩草属原始类群在硅酸体系统特征方面与外部形态特征演化的某些相关性。  相似文献   

8.
9.
Most Crotalaria species display a symmetric karyotype with 2n = 16, but 2n = 14 is found in Chrysocalycinae subsection Incanae and 2n = 32 in American species of the section Calycinae. Seven species of the sections Chrysocalycinae, Calycinae, and Crotalaria were analyzed for the identification of heterochromatin types with GC- and AT-specific fluorochromes and chromosomal location of ribosomal DNA loci using fluorescent in situ hybridization (FISH). A major 45S rDNA locus was observed on chromosome 1 in all the species, and a variable number of minor ones were revealed. Only one 5S rDNA locus was observed in the species investigated. Chromomycin A(3) (CMA) revealed CMA(+) bands colocalized with most rDNA loci, small bands unrelated to ribosomal DNA on two chromosome pairs in Crotalaria incana, and CMA(+) centromeric bands that were quenched by distamycin A were detected in species of Calycinae and Crotalaria sections. DAPI(+) bands were detected in C. incana. The results support the species relationships based on flower specialization and were useful for providing insight into mechanisms of karyotype evolution. The heterochromatin types revealed by fluorochromes suggest the occurrence of rearrangements in repetitive DNA families in these heterochromatic blocks during species diversification. This DNA sequence turnover and the variability in number/position of rDNA sites could be interpreted as resulting from unequal crossing over and (or) transposition events. The occurrence of only one 5S rDNA locus and the smaller chromosome size in the polyploids suggest that DNA sequence losses took place following polyploidization events.  相似文献   

10.
Intercropping green manure crops—effects on rooting patterns   总被引:1,自引:0,他引:1  
Greater productivity under intercropping has been attributed to the complementary use of environmental resources. However, the rooting pattern of component species under intercropping, which is an important morphological feature considering the complementary uptake of nutrients, has been studied only rarely under field conditions because of inherent technical difficulties. We examined rooting patterns of three green manure species, both sole cropped and intercropped, using a newly developed multi-color staining technique. Species were chosen from different functional groups: sorghum (Sorghum bicolor (L.) Moench.), a C4 grass; crotalaria (Crotalaria juncea L.), a legume; and sunflower (Helianthus annuus L.), a C3 dicot. We also investigated these species’ aboveground biomass and N uptake. Sorghum distributed roots deeper under intercropping than under sole cropping; it was the most important contributor to increased biomass under intercropping. Crotalaria had a deep rooting system under both sole cropping and intercropping. Sunflower, with a shallow rooting system, was suppressed extremely under intercropping, possibly because of water deficiency in late in the season. The rooting patterns of green manure species examined using multi-color staining were related closely to the aboveground performance of these species under intercropping.  相似文献   

11.
为探讨山茶属茶亚属(Camellia subgen.Thea)中长柄山茶组(sect.Longipedicellata)、金花茶组(sect.Chrysantha)和超长柄茶组(sect.Longissima)的系统位置和亲缘关系,本研究选取了该属4个亚属11组28个种及2个外类群的材料,对这些材料的叶绿体4个DNA片段(rp/16、psbA-trnH、trnL-F和rp/32-trnL)进行了测序,运用邻接法(neighbor-joining)、最大简约法(maximum-parsimony)和贝叶斯推断(Bayesian inference)对获得的序列进行了联合矩阵分析.并构建基因树.基因树的拓扑结构显示:1)金花茶组包括3个平行的支系,并且长柄山茶组的模式种长柄山茶(Camellia longipedicellata)嵌于其中一个支系,因而金花茶组可能是一个并系或多系类群;2)长柄山茶与越南分布的金花茶组种类在分子系统树上构成一个单系支,暗示了长柄山茶组和金花茶组之间可能具有紧密的亲缘关系;3)超长柄茶组不是一个单系类群,该组的河口超长柄茶(C.hekouensis)位于系统树的基部,与山茶属其余种构成姐妹群.由于缺乏更广泛取样的分析,超长柄茶在山茶属中的系统位置仍然不明确,超长柄茶组与长柄山茶组的亲缘关系问题也没有得到解决.  相似文献   

12.
为探讨山茶属茶亚属 (Camellia subgenThea) 中长柄山茶组 (sectLongipedicellata)、金花茶组 (sectChrysantha)和超长柄茶组 (sectLongissima) 的系统位置和亲缘关系,本研究选取了该属4个亚属11组28个种及2个外类群的材料,对这些材料的叶绿体4个DNA片段 (rpl16、psbA trnH、trnL F和rpl32 trnL) 进行了测序,运用邻接法 (neighbor joining)、最大简约法 (maximum parsimony) 和贝叶斯推断 (Bayesian inference) 对获得的序列进行了联合矩阵分析,并构建基因树。基因树的拓扑结构显示:1) 金花茶组包括3个平行的支系,并且长柄山茶组的模式种长柄山茶 (Camellia longipedicellata) 嵌于其中一个支系,因而金花茶组可能是一个并系或多系类群;2) 长柄山茶与越南分布的金花茶组种类在分子系统树上构成一个单系支,暗示了长柄山茶组和金花茶组之间可能具有紧密的亲缘关系;3) 超长柄茶组不是一个单系类群,该组的河口超长柄茶 (C. hekouensis) 位于系统树的基部,与山茶属其余种构成姐妹群。由于缺乏更广泛取样的分析,超长柄茶在山茶属中的系统位置仍然不明确,超长柄茶组与长柄山茶组的亲缘关系问题也没有得到解决。  相似文献   

13.
We focused on the systematic positions and relationships of three sections of Camellia subgenThea of Theaceae, i.e., sect.Longipedicellata, sect.Chrysantha (golden camellias) and sect.Longissima by using four chloroplast DNA regions (rpl16, psbA trnH, trnL F & rpl32 trnL). We sampled 28 species representing four subgenus, 11 sections in Camellia and two outgroups. Combined analyses of chloroplast DNA sequence data sets are performed with the neighbor joining, maximum parsimony and Bayesian inference methods, and the gene trees are constructed. The topologies of gene trees revealed that: 1) sect. Chrysantha is paraphyletic or polyphyletic, containing three parallel lineages and Camellia longipedicellata (type of sectLongipedicellata) nested inside; 2) all four species from Vietnam, together with C. longipedicellata, forming a well supported monophyletic clade, which implies the close relationship between sect. Longipedicellata and sect.Chrysantha; and 3) sectLongissima is not monophyletic because C.hekouensis is the sister to the rest of Camellia species. The systematic position of C.longissima and the relationship between sect.Longissima and sect.Longipedicellata are unsolved.  相似文献   

14.
Five new species are described, three of which, C. crassiflora, C. paucipetala, and C. trochilus, belong to sect. Heterodon, a group of predominantly annual, western Mexican species. The perennial C. rasilis is a new member of sect. Melvilla and the perennial C. spectabilis is new to sect. Diploptychia. Chromosome numbers for the annual species and two additional ones, C. procumbens and C. koehneana, closely related to the novelties, are reported for the first time.  相似文献   

15.
对毛茛科铁线莲属Clematis的黄花铁线莲组sect. Meclatis进行了全面修订, 确定此属含13种和13变种(包括1新变种和2新变种等级); 写出了此组的分类学简史和地理分布, 并对其在铁线莲属中的系统位置和组内诸种的亲缘关系进行了讨论; 还写出了此组的分种、分变种检索表, 以及各种植物的形态描述、地理分布、生长环境等, 并附有各种的插图。此组的花构造与对枝铁线莲组sect. Brachiatae的近似, 与后者在亲缘关系上相近, 区别在于此组的萼片通常斜上方开展, 呈黄色, 被毛的花丝下部变宽, 呈狭披针形, 而在对枝铁线莲组, 萼片水平开展, 呈白色, 被毛的雄蕊花丝呈狭条形, 下部不变宽; 二组可能均起源于欧洲铁线莲组的sect. Clematis subsect. Clematis, 因此, 均应是隶属欧洲铁线莲亚属subgen. Clematis的成员。根据对此组植物形态特征的分析, 观察到以下演化趋势: (1)叶的颜色由于适应干旱气候, 由绿色变为灰绿色; (2)卵形或宽卵形、掌状分裂、边缘具齿的小叶可能是原始的特征, 而披针形或条形、不分裂、全缘的小叶是衍生的特征; (3)单独、顶生、只是花梗的花是由具花序梗和二苞片的聚伞花序发生减化(reduction)而衍生的; (4)萼片形状的演化趋势与小叶形状的演化趋势近似, 也由卵形演变到披针形或条形; (5)萼片内面无毛是原始现象, 而被毛则是衍生现象; (6)萼片顶端无突起是原始现象, 出现突起则为衍生现象; (7)花药形状由长圆形演变到狭长圆形和条形。根据上述演化趋势, 推测具较多原始特征的甘川铁线莲C. akebioides和甘青铁线莲C. tangutica为此组的原始种, 而具较多衍生特征的尾尖铁线莲C. caudigera和角萼铁线莲C. corniculata为此组的进化种。组成世界屋脊的青藏高原西缘、帕米尔高原和邻近山地集中分布有此组10种(包括7特有种), 当是此组的分布中心; 而甘川铁线莲和甘青铁线莲二种分布区的主要重叠部分所在的青藏高原东缘则可能是此组的起源中心。过去,一些铁线莲属专家将属于欧洲铁线莲组的C. ispahanica Boiss.和属于对枝铁线莲组的C. graveolens Lindl.误置于黄花铁线莲组中, 对此, 本文予以纠正。  相似文献   

16.
铁线莲属威灵仙组修订   总被引:21,自引:11,他引:10  
对铁线莲属铁线莲亚属 Clematis subgen. Clematis 中的欧洲铁线莲 C. vitalba L.演化干的原始群威灵仙组sect. Clematis 进行了全面修订,确定此组共含有73种和45变种。写出了威灵仙组的分类学简史及地理分布;对威灵仙组中各亚组的亲缘和主要区别特征以及铁线莲亚属欧洲铁线莲演化干中各群的亲缘关系进行了讨论。将威灵仙组分为5个亚组,写出了分亚组检索表和各亚组的分种检索表,以及各种植物的形态描述、地理分布、生长环境等,并附有多幅插图。在5亚组中,欧洲铁线莲亚组(钝萼铁线莲亚组) subsect. Clematis 为此组的原始群,其主要特征:藤本;小叶通常草质或纸质,通常边缘具齿,有时全缘;萼片4,外面的毛长1 mm以下;花药长圆形、椭圆形或狭长圆形,稀条形,药隔顶端不突起,稀稍突起。此亚组的瘦果两侧扁压,但多数不扁平,不具边缘,只在短毛铁线莲 C. puberula Hook. f. &; Thoms.强烈扁压,扁平,周围具宽边缘。在铁线莲属中,除短毛铁线莲外,特产朝鲜的 C. brachyura Maxim. (sect. Pterocarpa Tamura)也具有近似这种进化类型的瘦果。铁线莲组的其他4个亚组各含有较进化的特征,可能均自欧洲铁线莲亚组演化而出:单种的厚叶铁线莲亚组subsect. Crassifoliae (Tamura) Tamura为藤本;小叶革质,全缘,很像威灵仙亚组的小叶;雄蕊花丝皱缩,花药宽长圆形或长圆形。单种的长毛铁线莲亚组subsect. Baominianae (W. T. Wang) W. T. Wang为藤本;小叶纸质,具齿;花大,具6枚萼片;萼片外面的毛长1.6-3 mm; 花药长圆形。棉团铁线莲亚组subsect. Angustifoliae 的主要特征:茎直立;花常具5-6枚萼片。威灵仙亚组subsect. Rectae Prantl的主要特征:藤本,稀茎直立;小叶常革质,全缘,稀具齿;萼片通常4枚,稀较多,外面的毛长在1 mm以下;花药条形,有时狭长圆形,药隔顶端常突起。此亚组的威灵仙系ser. Rectae Prantl具有进化类型的瘦果,其瘦果强烈扁压,扁平,有膨胀的框状边缘。主要分类学处理为:(1)披针叶铁线莲 C. lancifolia Bur. &; Franch.、准噶尔铁线莲 C. songarica Bunge、 C. ispahanica Boiss.、银叶铁线莲 C. delavayi Franch.和 C. phlebantha Williams 5种过去被Tamura和其他学者与灌木铁线莲 C. fruticosa Turcz.等同置于灌木铁线莲组sect. Fruticella Tamura中,但这5种的花构造(萼片水平方向开展,白色,边缘不展宽;花丝条形或狭条形)与灌木铁线莲(萼片斜上方开展,黄色,在花开放后边缘展宽成狭翅;花丝较宽,条状披针形)不同,而与棉团铁线莲 C. hexapetala Pall.的花构造相似。据此,本修订将此5种从灌木铁线莲组移到威灵仙组的棉团铁线莲亚组subsect. Angustifoliae Tamura中。(2)在欧洲铁线莲群 C. vitalba group与威灵仙群C. flammula group之间有不少过渡类型,因此,这两个群不易区分。根据这种情况,本修订将这两个群作为亚组处理,同置于威灵仙组sect. Clematis 中,而未采用Tamura和Grey_Wilson将这两个群分别置于两个亚属中,以及Johnson将这两个群分别置于两个组中的分类学处理。描述了2新系、6新种和1新变种;建立了5个新等级。  相似文献   

17.
Cousinia kermanensis sp. nov. (sect. Congestae Bunge) and C. pulcherantha sp. nov. (sect. Leiocaules Bunge) are described from Kerman in southeastern Iran. These species are compared to their closest related species, C. decurrens Regel and C. oophora Rech. f., respectively. The habitat of C. kermanensis is lowland mountains or hills with poor soils inside the steppe of Artemisia sieberi Besser. Cousinia pulcherantha grows on highland slopes of mountains with deep soils inside the steppe of Artemisia aucheri Boiss. Illustrations of the new species are presented.  相似文献   

18.
Clematis sect. Clematis is revised in this paper. Seventy-three species and 45 varieties are recognized. They are keyed, described, and illustrated in some cases, and are classified into five subsections. Brief taxonomic history and geographical distribution of the section are given, and the relationships of its subsections and with its close allies of the C. vitalba evolutionary stock of the subgenus Clematis are discussed. Main taxonomic changes are made as follows: (1) C. lancifolia Bur. & Franch., C. songarica Bunge, C. ispahanica Boiss., C. delavayi Franch. and C. phlebantha Williams, which have been previously regarded to be close to C. fruticosa Turcz. and its allies, and placed in sect. Fruticella Tamura by Tamura and some other authors, are here transferred to subsect. Angustifoliae Tamura according to the floral structure. (2) The existence of intermediate forms between the C. vitalba group and the C. flammula group indicates that these two groups are closely related to each other and should not be treated as two sections or even two subgenera. They are treated as two subsections within sect. Clematis . Two series, six species, and one variety are described as new, and five new ranks are made.   相似文献   

19.
In this paper, a new Centaurea L. (Asteraceae) species from Turkey is described and illustrated. Centaurea sakariyaensis Uysal & Dural grows on rocky crevices in Sakarya province in north-western Anatolia. It belongs to C. sect. Centaurea L. and taxonomically its closest relative is C. wiedemanniana. Diagnostic morphological characters from a very similar taxon are provided, and a key from flora of Turkey is modified that includes related species of sect. Centaurea. The geographical distribution of the new species and species of other related taxa of the same section are mapped. The chromosome number of C. sakariyaensis, 2n = 18, counted in root tips, is also reported and illustrated.  相似文献   

20.
Clematis sect. Brachiatae is revised in this paper. Twenty-four species and four varieties are recognized. They are keyed, described, and illustrated in most cases, and classified into two series. Brief taxonomic history and geographical distribution of the section are given, and its systematic position and origin are discussed. A western Himalayan species, C. graveolens Lindl., which has long been misplaced in the C. orientalis group (sect. Meclatis), is transferred to sect. Brachiatae on the basis of its floral structure being identical with that of C. brachiata Thunb. and its allies. Two new combinations, sect. Brachiatae Snoeijer ser. Wightianae (W. T. Wang) W. T. Wang and ser. Dissectae (W. T. Wang) W. T. Wang, are made, and two species, C. zaireensis W. T. Wang and C. bowkeri Burtt Davy, are described as new.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号