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1.
Cotyledon venation patterns are described for 93 species representing all tribes of the Caesalpinioideae. Patterns are grouped into a series of levels of complexity according to the number of primary veins, nine, seven, six, five, three or one, but five- and three-vein patterns predominate. The number of petiolar vascular strands varies from one to eight but most species have two or four strands. It is proposed that all the patterns have been derived from one in which four strands and a protoxylem trace in the petiole branch and anastomose to form seven primary veins in the lamina. Venation patterns show correlations with cotyledon anatomy, size and shape and with taxonomic grouping at tribal, infratribal and generic levels. Each tribe is characterized by a particular set of related patterns, pattern frequencies and evolutionary trends.  相似文献   

2.
Summary The nodule shape of more than four hundred species of wild legumes indigenous to Rhodesia is found to be related to the tribal classification of the host. Characteristic nodule-shapes of the papilionaceous tribes Galegeae, Genisteae, Hedysareae, and Phaseoleae, and of the subfamilies Mimosoideae and Caesalpinioideae are described and figured. Non-nodulating species were found to have coloured roots much more frequently than nodulating species.  相似文献   

3.
Siphocampylus is a neotropical genus that comprises 221 species distributed from Costa Rica to Argentina and in the Greater Antilles. Twenty-eight species have been reported from Brazil, mainly occupying mountainous terrain. The floral venation patterns and the origin of the hypanthium in eight Brazilian species, including three varieties, are described. Eleven ovarian vascular bundles depart from the siphonostele or receptacular stele: five of these bundles result from sepalar and staminal adnation and are alternate to five petalar bundles; the remaining bundle is central carpellary. The staminal bundles diverge from the sepalar bundles at the sinus, while the carpellary bundles form a cross, resulting in four ventral bundles; two of these feed the ovules; the other two feed the style. Apparently, the dorsal carpellary bundles diverge at the same site and then ramify profusely. The venation pattern observed is unprecedented in Siphocampylus and is quite different from other reports on genera of Campanulaceae. Further, these findings suggest that the origin of the hypanthium is appendicular, increasing knowledge of venation in this group, thus providing data for phylogenetic considerations.  相似文献   

4.
采用解剖学方法,研究了水龙骨科鹿角蕨亚科石韦属(Pyrrosia)17种植物的脉序特征,并与该科其它3亚科8属8个代表种的脉序进行了对比。结果显示,石韦属植物的脉序属于结合脉序,并可进一步细分为弯脉蕨型和拟槲蕨型。根据脉序特征的聚类分析表明,石韦属植物的结合脉序与水龙骨科其它属植物的结合脉序具有显著差异,且此脉序特征是石韦属内较稳定的分类性状,具有一定的分类学价值。本研究还基于脉序特征,讨论了石蕨(P.angustissimum(Giesenh.ex Diels)TagawaK.lwats.)、抱树石韦(P.piloselloides M.G.Price Kalikasan)与其它石韦属植物的亲缘与进化关系。  相似文献   

5.
A general procedure is described for measuring and testing population differences in gametic frequencies. The total dispersion among populations is subdivided in hierarchical fashion. The multiple-locus treatment is simply the sum of the single-locus analyses, provided gametic equilibrium obtains among the loci. In the event that gametic equilibrium does not obtain, correlations among loci need to be dealt with.—The analysis is then used to examine the genetic infrastructure of two Indian tribes from South America, the Ye'cuana (Makiritare) and the Yanomama. From historical evidence, we may identify several "clusters" of villages within each tribe. The demographic and cultural practices affecting village formation and the maintenance of peer integrity are rather different in these tribes, however, and lead us to postulate rather different patterns of genetic variation among villages. Analyses of five codominant two-allele loci, four dominant two-allele loci and two complex loci (with four codominant haplotypes each) demonstrate that Yanomama clusters are more disparate than Ye'cuana clusters, as would have been predicted on sociocultural grounds.  相似文献   

6.
对油果樟属(Syndiclis Hook.f.)及其近缘属琼楠属(Beilschmiedia Nees)、孔药楠属(Sinopora J.Li et al.)、国产土楠属(Endiandra R.Br.)和Potameia的网脉结构进行了观察。结果表明,它们的网脉结构可分为3种类型:A型网格小且小脉无游离末端;B型网格小但有不分枝或简单分枝的游离末端;C型网格粗且网脉末端多分枝。琼楠属网脉结构多样,具有全部3种类型,其余4属均仅有1种类型,油果樟属、孔药楠属以及土楠属均为A型,明显不同于Potameia的C型网脉结构。  相似文献   

7.
A survey of corolla venation patterns in the Phacelia Humiles group (Hydrophyllaceae) revealed considerable diversity, ranging from open venation and no interpetal vascular connections in some taxa to closed venation and interpetal vascular connections in others. In general, the distribution of the different venation patterns agrees with recent taxonomic treatments and provides evidence for the artificiality of sections based on ovule number. In several cases where the affinity of a species was ambiguous, the venation pattern of its corollas provides evidence for its placement.  相似文献   

8.
9.
Leaves of representative taxa within the vanilloid clade of Orchidaceae were cleared and their venation patterns studied. Within subtribe Pogoniinae, Isotria and Pogonia exhibit a prominent reticulate venation pattern, although only Pogonia ophioglossoides is characterized by free vein endings. Within subtribe Vanillinae, all species of Epistephium , as well as the New Caledonian endemics, Eriaxis rigida and Clematepistephium smilacifolium , have reticulate-veined leaves that are characterized by numerous free vein endings. Leaves of most species of Vanilla exhibit a parallel-veined pattern stereotypical of monocots, although branched secondaries with free endings were observed in V. africana. Most members of subtribe Galeolinae are 'saprophytes' with reduced bract-like leaves. Vascular bundles enter these leaf-homologues in a parallel manner, but quickly ram+ throughout the tissue in an irregular manner. Leaf venation is used to hypothesize patterns of generic relationships within the vanilloid clade. Molecular evidence for phylogenetic relationships among angiosperms indicates that reticulate leaf venation has arisen independently in several unrelated monocot families, including the vanilloid Orchidaceae, perhaps by a similar evolutionary scenario.  相似文献   

10.
The leaf protein content for 17 species of legumes ranges from 2.8 to 9.4 g% fr. wt, with an average of 5.3 g % fr. wt. Taxonomic pattern is detectable in leaf amino acid patterns, those of the Mimosoideae being distinguishable from those of the Papilionoideae and Caesalpinioideae.  相似文献   

11.
Evolution and Function of Leaf Venation Architecture: A Review   总被引:24,自引:4,他引:20  
The leaves of extant terrestrial plants show highly diverseand elaborate patterns of leaf venation. One fundamental featureof many leaf venation patterns, especially in the case of angiospermleaves, is the presence of anastomoses. Anastomosing veins distinguisha network topologically from a simple dendritic (tree-like)pattern which represents the primitive venation architecture.The high degree of interspecific variation of entire venationpatterns as well as phenotypic plasticity of some venation properties,such as venation density, indicate the high selective pressureacting on this branching system. Few investigations deal withfunctional properties of the leaf venation system. The interrelationshipsbetween topological or geometric properties of the various leafvenation patterns and functional aspects are far from beingwell understood. In this review we summarize current knowledgeof interrelationships between the form and function of leafvenation and the evolution of leaf venation patterns. Sincethe functional aspects of architectural features of differentleaf venation patterns are considered, the review also refersto the topic of individual and intraspecific variation. Onebasic function of leaf venation is represented by its contributionto the mechanical behaviour of a leaf. Venation geometry anddensity influences mechanical stability and may affect, forexample, susceptibility to herbivory. Transport of water andcarbohydrates is the other basic function of this system andthe transport properties are also influenced by the venationarchitecture. These various functional aspects can be interpretedin an ecophysiological context. Copyright 2001 Annals of BotanyCompany Review, leaves, leaf venation, evolution, network, transport, flow, mechanical stabilization  相似文献   

12.
13.
The venation patterns characteristics of different insect orders and of families belonging to the same order possess enormous variation in vein number, position and differentiation. Although the developmental basis of changes in vein patterns during evolution is entirely unknown, the identification of the genes and developmental processes involved in Drosophila vein pattern formation facilitates the elaboration of construction rules. It is thus possible to identify the likely changes which may constitute a source of pattern variation during evolution. In this review, we discuss how actual patterns of venation could be accounted for by modifications in different Pterygota of a common set of developmental operations. We argue that the individual specification of each vein and the modular structure of the regulatory regions of the key genes identified in Drosophila offer candidate entry points for pattern modifications affecting individual veins or interveins independently. Assuming a general conservation of the processes involved in different species, the transitions between different patterns may require few changes in the regulatory gene networks involved.  相似文献   

14.
国产五味子科五种植物叶片脉序研究   总被引:4,自引:0,他引:4  
首次报道了国产五味子科5种植物的叶脉特征,对科、属、种的特征作了描述,编排有分种检索表.通过与八角科叶脉的比较,支持建立五味子科与八角科的观点,认为五味子属的系统位置在南五味子属之后,并讨论了八角目的演化趋势  相似文献   

15.
Dede , Roland A. (California Concordia Coll., Oakland.) Foliar venation patterns in the Rutaceae . Amer. Jour. Bot. 49(5): 490–497. Illus. 1962.—A study of herbarium specimens selected from 80 genera of the Rutaceae revealed a series of 7 venation types. The series is based on the spatial relationship of the venation system to the secretory cavities. The hypothesis is advanced that the uncorrelated venation pattern is primitive and that the more complex types represent end products involving a branching pattern of phylogenetic sequences. A key to the illustrated representatives of the 7 types is included.  相似文献   

16.
The taxonomy of the genus Bursera has been traditionally supported by morphological characters such as fruit form, bark and leaves. Nonetheless, leaf architecture, another important source of phylogenetic information, has not been well studied in this group. For this purpose, venation patterns of 30 species of the genus Bursera in Mexico were studied. Clarified leaves allowed finding four types of venation patterns: brochidodromous and eucamptodromous in complex B. simaruba (section Bursera); a cladodromous pattern in fragilis, microphylla and fagaroides groups (herein informally called group Quaxiotea (section Bursera), and semicraspedodromous in section Bullockia species. Only bipinnated species of section Bullockia showed a brochidodromous venation pattern. Furthermore, section Bullockia and complex Simaruba presented reticulate tertiary veins, whereas the group of Quaxiotea species presented a ramified pattern in the tertiary veins and tracheoblasts.  相似文献   

17.
本文对代表豆科云实亚科紫荆族全部五个属.即紫荆属、腺叶紫荆属、格里芬豆属、拟羊蹄甲属和羊蹄甲属的几乎全部系或亚组的134个种或种下分类单元的叶脉序进行了研究,并描述了本族20个基本脉序类型.在紫荆族中,腺叶紫荆属和拟羊蹄甲属的脉序式样非常相似;紫荆属的种类的脉式样以全绿叶,一级脉不及绿等特征组合有别于本族其它属;格里芬豆属的脉序高度特化,有别于紫荆亚族的所有类群;羊蹄甲属是叶脉序式样最多样化的类群.在羊蹄甲属中,羊蹄甲亚属和显托亚属的脉序式样非常多样化.Elayuna亚属的两个组和Barklya亚属的脉序式样非常相似.Barklya亚属的仅有种了香叶羊蹄甲的脉序仅以其叶全缘区别于Elayuna亚属.脉序性状支持把Cansenia系、白花羊蹄甲系、羊蹄甲系、绿花羊蹄甲亚组、总状花羊蹄甲亚组、Elayuna亚属、伞房系、Chloroxanthae系、棒花系、掌叶组和萼管组等作为自然类群的观点.在本族植物的脉序类型中,一级脉及缘、全缘叶、发育完好的脉岛等性状常相关出现;另一方面,一级脉不及缘,具二小叶或叶深裂,脉岛发育不完善及盲脉多分枝等性状常相关出现.如同形态和花粉性状,脉序性状能为紫荆族的分类提供另一方面的佐  相似文献   

18.
The relationships among the genera and tribal groupings of Riodininae with five forewing radial veins, and between these and tribes with four forewing radial veins, were examined using a phylogenetic analysis. Using the type species from all sixteen genera in the tribal groupings Eurybiini, Mesosemiini and incertae sedis (a presumed paraphyletic group of loosely related genera), and representatives from the four forewing radial‐veined riodinine tribes, thirty‐five new and traditional characters were coded from adult ecology, wing venation and pattern, the adult head and body, male and female genitalia, and early stage ecology and morphology. The majority of characters are illustrated. Phylogenetic analysis of these data produced five equally most parsimonious cladograms using equal weights and after successive weighting. The strict consensus of these confirms the monophyly of Eurybiini and Mesosemiini as currently conceived, but also indicates several higher‐level relationships not previously hypothesized. Mesosemiini is here more broadly defined to also include the entire incertae sedis section, and the tribe is divided into Mesosemiina, for the previously delimited Mesosemiini plus Eunogyra and Teratophthalma, and Napaeina, subtr.n. for the incertae sedis section minus these two genera. The following hypothesis of relationships is tentatively proposed for the basal clades of Riodininae: Mesosemiini + (Eurybiini + remainder of Riodininae). These new hypotheses, and the characters supporting them, are discussed and compared with those previously proposed.  相似文献   

19.
20.
Venation networks and the origin of the leaf economics spectrum   总被引:1,自引:0,他引:1  
The leaf economics spectrum describes biome-invariant scaling functions for leaf functional traits that relate to global primary productivity and nutrient cycling. Here, we develop a comprehensive framework for the origin of this leaf economics spectrum based on venation-mediated economic strategies. We define a standardized set of traits - density, distance and loopiness - that provides a common language for the study of venation. We develop a novel quantitative model that uses these venation traits to model leaf-level physiology, and show that selection to optimize the venation network predicts the mean global trait-trait scaling relationships across 2548 species. Furthermore, using empirical venation data for 25 plant species, we test our model by predicting four key leaf functional traits related to leaf economics: net carbon assimilation rate, life span, leaf mass per area ratio and nitrogen content. Together, these results indicate that selection on venation geometry is a fundamental basis for understanding the diversity of leaf form and function, and the carbon balance of leaves. The model and associated predictions have broad implications for integrating venation network geometry with pattern and process in ecophysiology, ecology and palaeobotany.  相似文献   

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