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1.
Petrorhagia grandiflora Iatroú sp. nov. is described from limestone rocks on the eastern side of Mt. Parnon, in the province of Arkadhia, Peloponesos, Greece. This species, belonging to sect. Petrorhagia subsect. Thessalae Ball & Heywood, is related to the P. thessala (Boiss.) Ball & Heywood and P. dianthoides (Smith) Ball & Heywood with which it is compared. Chromosome numbers (2n = 30) and karyotypes are presented; seeds are examined by a Scanning Electron Microscope (SEM); and their distribution in Greece are presented.  相似文献   

2.
Background and Aims Evolutionary transitions from outcrossing to self-fertilization are thought to occur because selfing provides reproductive assurance when pollinators or mates are scarce, but they could also occur via selection to reduce floral vulnerability to herbivores. This study investigated geographic covariation between floral morphology, fruit set, pollen limitation and florivory across the geographic range of Camissoniopsis cheiranthifolia, a Pacific coastal dune endemic that varies strikingly in flower size and mating system.Methods Fruit set was quantified in 75 populations, and in 41 of these floral herbivory by larvae of a specialized moth (Mompha sp.) that consumes anthers in developing buds was also quantified. Experimental pollen supplementation was performed to quantify pollen limitation in three large-flowered, outcrossing and two small-flowered, selfing populations. These parameters were also compared between large- and small-flowered phenotypes within three mixed populations.Key Results Fruit set was much lower in large-flowered populations, and also much lower among large- than small-flowered plants within populations. Pollen supplementation increased per flower seed production in large-flowered but not small-flowered populations, but fruit set was not pollen limited. Hence inadequate pollination cannot account for the low fruit set of large-flowered plants. Floral herbivory was much more frequent in large-flowered populations and correlated negatively with fruit set. However, florivores did not preferentially attack large-flowered plants in three large-flowered populations or in two of three mixed populations.Conclusions Selfing alleviated pollen limitation of seeds per fruit, but florivory better explains the marked variation in fruit set. Although florivory was more frequent in large-flowered populations, large-flowered individuals were not generally more vulnerable within populations. Rather than a causative selective factor, reduced florivory in small-flowered, selfing populations is probably an ecological consequence of mating system differentiation, with potentially significant effects on population demography and biotic interactions.  相似文献   

3.
Scaphloclamys obcordata is described from the Naratiwat province in South Thailand. Its relationship with 5. klossii is discussed.  相似文献   

4.
顽拗型种子的生物学特性及种子顽拗性的进化   总被引:16,自引:0,他引:16  
综述了顽拗型种子的形态、大小、含水量、植物分类、植物生态方面的一般特性,分析了顽拗型种子对环境的生态适应性,并讨论了种子顽拗性的可能进化模式,进而指出顽拗型种子生理生态学研究的意义和应用前景.顽拗型种子一般千粒重和体积较大,含水量较高,萌发迅速且多无休眠特性;产生顽拗性种子的植物分布很广,与其系统分类地位无关,但多起源于湿润的生境;目前尚无足够的证据表明种子顽拗性是原始性状或是衍生性状,要解决这一问题还需更深入的研究,尤其是种子生理学和生态学家的合作研究.  相似文献   

5.
A central question in plant evolutionary ecology is how mixed mating systems are maintained in the face of selection against self-pollination. Recently, attention has focused on the potential reproductive assurance (RA) benefit of selfing: the ability to produce seeds via autonomous selfing when the potential for outcrossing is reduced or absent. To date, there is little experimental support for this benefit under natural pollination conditions. In addition, the RA hypothesis has not been tested experimentally in a species displaying morphological variation for traits expected to influence the mating system, such as flower size, which affects both attractiveness to pollinators and ability to self autonomously. Here, we document significant among-population variation in flower size in Collinsia parviflora and show that pollinators preferred large flowers over small flowers in experimental arrays. The pollinator community varied among three study sites, and two small-flowered populations had lower pollinator visitation rates than one large-flowered population. We compared seed production between intact flowers (can self) and experimentally emasculated flowers (require a pollinator) on large- and small-flowered plants. As predicted by the RA hypothesis, small-flowered plants show a greater RA benefit of selfing than large-flowered plants; emasculated, small flowers produced very few seeds, relative to intact, small flowers or either emasculated or intact, large flowers. We also show that the RA benefit is pollination-context dependent, differing between small- and large-flowered test sites, likely due to a combination of pollinator discrimination against small flowers and differences between test sites in the pollinator community. This paper is the first experimental evidence showing a trait-dependent RA benefit of selfing under natural pollination conditions.  相似文献   

6.
The productivity and morphology of fruit and seeds were studied in 30 species (and subspecies) of the tribe Genisteae (Fabaceae) in south-west Spain. The morphological characters of greatest taxonomic value both for the segregation of the two subtribes (Genistinae and Lupininae) recognized in Genisteae and for the delimitation of the lower taxonomic levels (genus and species) are the size of the pod and characters of the pericarp, the colour and weight of the seeds, whether or not an ad exists, and the shape, size, and position of the hilum. In contrast, characters of little taxonomic interest are pod colour, shape and number of seeds, and characters of the lens. There were also found to be major relationships between fruit and seed, and between these and other floral (e.g. corolla size) or reproductive (e.g. polledovule [P/O] and seed/ovule [S/O] ratios) attributes. Thus in this tribe, pod size was positively correlated with corolla size, seed size, the number of viable seeddfruit, and the S/O and P/O ratios. Corolla size was positively correlated with the number of viable seeds/ fruit and with the seed weight. Similarly, the number of seeddfruit was positively correlated with the fruit's weight and with the number of ovules/ovary. Also, the weight of the seeds was positively correlated with the pollen/ovule ratio. There was also positive correlation between the S/O and P/O ratios.  相似文献   

7.
This study investigated the extent to which the reproductive success of plants of Erythronium dens-canis (Liliaceae), a spring herb of mountain habitats, is dependent on floral morphology. To this end, a series of studies was performed in an area in northwest Spain. The results show that E. dens-canis plants in this area a) are self-compatible, b) need pollinator visits (largely Bombus terrestris and Andrena spp.) to produce seed, and c) show high fruit set under natural conditions. Only 20% of among-plant variance in floral morphology variables was explained by variation in plant size. Floral morphology variables (outer tepal length, stamen length, style length and ovule number) tend to vary in parallel, indicating the existence of an "integrated floral phenotype". Two floral morphology variables (initial number of ovules and outer tepal length) had statistically significant or near-significant effects on seed production. A more detailed experimental analysis indicated that small-flowered plants produce fewer seeds than large-flowered plants, and that this is attributable to less efficient pollination of small flowers. The results of this study thus suggest that among-plant variation in floral morphology in E. dens-canis has implications for reproductive success.  相似文献   

8.
The genus Stirtonia is described to accommodate three anomalous species, hitherto placed in Podalyria . The new genus differs from Podalyria mainly in the decussate (geminate) inflorescence structure (racemose in Podalyria ), the yellow flower colour (purple, pink or white in Podalyria ), the non-fleshy rim-aril of the seeds (seed aril invariably fleshy and collar-like in Podalyria ) and in the diagnostically different combination of quinolizidine alkaloids. The major alkaloidal metabolites are carboxylic acid esters of lupanine and virgiline, but these compounds are totally absent in Podalyria . The morphology of inflorescences, leaves, flowers and seeds are described and illustrated. Chromosome numbers (2n = 18) are reported for the first time. A formal taxonomic treatment of the three species, S. tayloriana, S. chrysantha and S. insignis , is presented.  相似文献   

9.
To increase our knowledge about mating-system evolution, we need to understand the relationship between specific floral traits and mating system. Species of Collinsia (Plantaginaceae) vary extensively in mating system; this variation is associated with variation in floral morphology and development and with the timing of self-pollination. Counterintuitively, large-flowered, more outcrossing species tend to have delayed stigma receptivity, reducing the amount of time that the stigma is receptive to cross-pollination before autonomous self-pollination. To understand how the timing of stigma receptivity is related to mating-system evolution, we studied in detail the timing of both stigma receptivity and self-pollination (anther-stigma contact) in two greenhouse-grown populations of large-flowered Collinsia heterophylla. Crosses on emasculated flowers at different stages of floral development always produced seeds, suggesting that cross-fertilization can be effected by pollen arriving prior to physiological receptivity. Phenotypic and genetic variation within populations in the timing of stigma receptivity and anther-stigma contact was substantial, although slightly less for the contact. Despite strong interspecific and interpopulation correlations, we did not find an among-genet phenotypic correlation between the traits. This indicates that each trait may respond independently to selection, and the trait association may be the result of correlational selection.  相似文献   

10.
The electrophoretic patterns of seven isozyme systems (ADH, AMY, AAT, GDH, LAP, MDH, and SOD) obtained from dormant seeds from 44 accessions belonging to 12 Petrocoptis taxa were compared in order to clarify taxonomic relationships within the genus. Overall, electrophoretic zymograms showed the presence of up 28 electromorphs, of which 26 were polymorphic among accessions. Mantel tests revealed a moderate level of correlation between the geographic distance matrix and several dissimilarity matrices based on the isozyme data (r=0.3052-0.3376). The electrophoretic profiles of seed isozymes did not match closely the analytical taxonomic framework drawn from morphology. Many electromorphs are widely distributed among Petrocoptis species, and since isozyme polymorphism is present within taxa, few species-specific markers have been found. However, a relationship between the geographic origin of the accessions and several electromorphs has been noticed. Isozyme data gave moderate support to the splitting of the genus into two groups previously defined on the basis of morphology and geographic distribution (western and eastern taxa). However, some samples belonging to P. hispanica and P. pseudoviscosa were somewhat intermediate between both groups as revealed by multivariate ordination techniques. Seed isozymes did not reveal any clear taxonomic grouping among western Petrocoptis species. In fact, no single segregate of this group is supported by the electrophoretic data.  相似文献   

11.
MAYO, S. J., 1989. Observations of gynoecial structure in Philodendron (Araceae). The gynoecial morphology and anatomy of 15 species of the genus Philodendron , representing all the subgenera and a majority of the sections, are described and illustrated. The study emphasizes the morphology of the style, compitum and stylar canals; gynoecial vasculature is only superficially treated. Variation of gynoecial morphology in P . subgenus Meconostigma is described and illustrated and a pilot study of gynoecial ontogeny in this subgenus is presented. Ideas on phylogenetic trends in style and stylar canal morphology, ovary locule number, placentation and ovule number are discussed. Gynoecial characters are shown to be taxonomically useful at the subgeneric and sectional level in Philodendron. The following taxonomic and nomenclatural changes are made: P. section Pteromischum is raised to subgeneric rank. In P. subgenus Philodendron sections Polyspermium and Oligospermium are reduced to the synonymy of sections Philodendron and Calostigma respectively, and the following new names and combinations are made at subsectional rank: subsections Canniphyllum, Oligocarpidium, Bulaoanum and Eucardium.  相似文献   

12.
Karyotype morphology of Psophocarpus tetragonolobus and P. scandens is described and the behaviour of chromosomes at meiosis discussed. Both species have a chromosome number of 2n = 18 and similar karyotypes of a sort unusual within the Phaseolinae. Differences between the species in detailed morphology of the chromosomes agree with data from external morphology, palynology and crossability in indicating that P. scandens cannot be the immediate wild ancestor of domesticated P. tetragonolobus . Study of meiotic chromosomes and analysis of qualitative and quantitative variation in Papua New Guinean P. tetragonolobus suggest that there are few restrictions to recombination other than those imposed by predominant self-pollination, The bearing of these data on the taxonomic relationships of Psophocarpus and on chromosomal evolution within the Phaseolinae is discussed.  相似文献   

13.
The seed morphology of nine taxa of Juncus from Egypt has been investigated using light and scanning electron microscopy, to determine the importance of seed coat features as taxonomic characters. Macro- and micromorphological characters, including seed shape, color, size, seed appendages, epidermal cell shape, anticlinal boundaries, and outer periclinal cell wall and secondary cell wall sculpture are presented. Four types of seed appendages are recognized: (i) seeds with two appendages; (ii) seeds without appendages; (iii) seeds with minutely a piculate at one end; and (iv) seeds with minutely a piculate at both ends. Two types of anticlinal cell wall boundaries,(i) raised-channeled, straight and (ii) raised, straight or sinuous, and three different shapes of outer periclinal cell wall are described: (i) flat; (ii) concave; and (iii) flat to slightly concave. The secondary sculpture of the cell wall varies from striate to microreticulate or reticulate, and smooth to finely folded. Seed characters provide useful data for formulating the taxonomy of Juncus both on the subgeneric and sectional level. A key for the identification of the investigated taxa based on seed characters is provided.  相似文献   

14.
The seed morphology of nine taxa of Juncus from Egypt has been investigated using light and scanning electron microscopy,to determine the importance of seed coat features as taxonomic characters.Macro-and micromorphological characters,including seed shape,color,size,seed appendages,epidermal cell shape,anticlinal boundaries,and outer periclinal cell wall and secondary cell wall sculpture are presented.Four types of seed appendages are recognized:(i)seeds with two appendages;(ii)seeds without appendages;(iii)seeds with minutely a piculate at one end;and(iv)seeds with minutely a piculate at both ends.Two types of anticlinal cell wall boundaries,(i)raised-channeled,straight and(ii)raised,straight or sinuous,and three different shapes of outer periclinal cell wall are described:(i)flat;(ii)concave;and(iii)flat to slightly concave.The secondary sculpture of the cell wall varies from striate to microreticulate or reticulate,and smooth to finely folded.Seed characters provide useful data for formulating the taxonomy of Juncus both on the subgeneric and sectional level.A key for the identification of the investigated taxa based on seed characters is provided.  相似文献   

15.
The allelopathic effects of neo-clerodane diterpenes, isolated from Teucrium chamaedrys (L.), have been evaluated on the seed germination and seedling growth of four coexisting Mediterranean species (Dactylis hispanica, Petrorhagia velutina, Phleum subulatum and Petrorhagia saxifraga) and two cosmopolitan weeds (Amaranthus retroflexus and Avena fatua). All of the structures have been elucidated on the basis of their spectroscopic features. The bioassays data, analyzed by principal component analysis, showed more negative effects on weeds respect to coexisting species. Moreover D. hispanica, P. velutina, P. subulatum showed both stimulating or inhibiting effects depending on the type of metabolite and the concentration used in the test.  相似文献   

16.
17.
Data on the external morphology are reviewed and new information is provided about the structure of the first naupliar instar of Parthenopea subterranea Kossmann, a rare and poorly known species of rhizocephalan barnacles. The taxonomic position of P. subterranea, which has so far been uncertain, is discussed. A new family, Parthenopeidae fam. nov., is erected to include a single genus, Parthenopea, with a single species, P. subterranea. The distinctive characters of the new family are described.  相似文献   

18.
Ruellia nocturna , a large- and night-flowering shrub from Central Somalia is described and illustrated, and its relationship to other large-flowered species occurring in the area is discussed.  相似文献   

19.
Summary.  Passiflora longicuspis (Passifloraceae), a new, red, large-flowered species of Passiflora from French Guiana is described; its history, taxonomy, distribution, pollination ecology and cultivation are discussed.  相似文献   

20.
Hypotheses on the taxonomic status of two Bolivian Pristimantis with taxonomic problems are assessed by an integrative taxonomic approach that integrates three independent lines of evidence: external morphology, prezygotic reproductive barriers (advertisement calls) and reciprocal monophyly (phylogenetic analyses of partial 16S mtDNA sequences). Central Andean Bolivian populations previously assigned to either P. peruvianus or P. dundeei, and lowland Amazonian populations from southern Peru and northern Bolivia previously considered P. peruvianus do not correspond to these species. Indeed, multivariate analyses of qualitative and quantitative morphological and bioacoustic characters, and phylogenetic analyses support the hypothesis that they represent different, previously unknown, cryptic lineages. They are herein described as new species. The former is a sibling species of P. fenestratus that inhabits the Amazonian and semideciduous forests of the Andean foothills in central Bolivia. The latter is sibling to the Andean species P. danae and is parapatric to it in the Amazonian lowland forests and adjacent foothills of northern Bolivia, southern Peru and adjacent Brazil. Most species of Neotropical frogs, and especially Pristimantis, have been described by using external qualitative morphological characters only. An extended integrative taxonomic approach, as exemplified herein, may lead to the discovery of many other cryptic and sibling lineages that would increase the species numbers of tropical areas. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 97–122.  相似文献   

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