凤仙花属棒凤仙亚属(凤仙花科)植物花粉形态的分类学意义

棒凤仙亚属代表着凤仙花属最先分化出的一支,以多年生草本,多于5朵花的总状花序,侧生萼片4枚,3沟花粉,心皮四室且每室具1枚种子,果实棒锤状,种子椭圆形以及三沟花粉其极面观为三角形而区别于其它种类。该亚属主要分布于中国南部,少数种类辐射分布至华中和中南半岛地区。已有报道证实花粉的形态特征对凤仙花属植物的属下分类具有重要意义,但对棒凤仙亚属的种类少有涉及。为了进一步探讨该亚属花粉的形态特征及其分类学价值,该研究应用扫描电镜技术对国产棒凤仙亚属植物的14种以及凤仙花亚属的窄萼凤仙花的花粉进行了观察。结果表明：棒凤仙亚属的花粉以单粒存在,具3条萌发沟,辐射对称,极面观为三角形或三角状圆形,花粉粒外壁具均匀的网状纹饰,网脊平滑或具波状边缘,网眼中具不同密度的颗粒状突起。棒凤仙亚属的花粉形态与水角属的花粉形态相似,表现出了其原始性;其花粉形态特征与花部形态性状等相关性差,对该亚属的组级分类意义较小,但对于该亚属的种间界定具有重要意义;而其花粉的极面观形状、赤道面观形状以及网状纹饰等变异相对稳定,对于界定该亚属具有重要的分类学价值。     

Isolation and characterization of microsatellite loci for the Potentilla core group (Rosaceae) using 454 sequencing

Microsatellites are valuable markers for the analysis of genetic diversity, linkage mapping or genotyping. The limited availability of microsatellites for the genus Potentilla (Rosaceae) stipulated the isolation of markers from a representative (Potentilla pusilla Host) of the Potentilla core group that constitutes the most species‐rich evolutionary lineage within the genus. Thousand four hundred and seventy‐six simple sequence repeat (SSR) containing candidate sequences were isolated from a single‐type line using 454 sequencing. Seventy‐four functional microsatellite markers were developed from 200 sequences selected for suitable priming sites flanking microsatellite repeats referring to a 37% primer‐to‐marker conversion ratio. Seventy‐two markers were polymorphic. These numbers confirm the increased efficiency of pyrosequencing over traditional isolation techniques in the development of microsatellites. Amplification primer sequences and the sequences of corresponding target fragments are provided for all functional markers, and molecular polymorphisms estimated for four accessions of P. pusilla and among seven core group species represented by 14 individuals are reported. Cross‐species transferability ranged between 86.4% and 97.3% among the studied taxa, and 57, 11 and six of the selected primer pairs amplified fragments of expected size and number in seven, six and five of the species, respectively. Reproducibility of the molecular phenotypes was 97.0%, which was inferred using a replicate sample of P. pusilla.     

Species distinction in the “Potentilla pollen type” (Rosaceae) of NW Europe

Pollen grains of eight different species from the genera Comarum, Fragaria, Potentilla and Sibbaldia, usually considered as one type, the “Potentilla type”, were examined and morphological features making distinction possible are described     

Herb pollen representation in surface moss samples from mown meadows and pastures in western Norway

Grazed and mown vegetation types in western Norway were investigated with the aim of describing their modern pollen/vegetation relationships as an aid to the interpretation of fossil pollen diagrams. Pollen surface samples and vegetation data were obtained from 186 square metre plots within 39 different sites of 10×10 m. Scatter plots that show the relationship between pollen percentages and vegetation percentages are presented forTrifolium pratense-type,Trifolium rcpens-type,Lotus, Campanula-type,Succisa, Ranunculus acris-type,Cirsium-type, Asteraceae Cichorioideae,Achillea-type,Potentilla-type, Apiaceae,Rumex sect.Acetosa, Galium-type, Cyperaceae,Calluna, Plantago lanceolata and Poaceae. Pollen representation factors relative to Poaceae (R_rel) are calculated for 54 pollen taxa. Differences in the values from different geographical areas were found in the case of some taxa, due to either different genera or species being included in the pollen taxa and/or to the different representation of high pollen producers in the different regional vegetation types. Background pollen influences the estimates for taxa such asR. sect.Acetosa, P. lanceolata, Poaceae, Cyperaceae, andCalluna, and an extended R-value (ERV) model was used to investigate the magnitude of this pollen component. Groups of roughly similar pollen representation were identified and factors to convert pollen percentages to vegetation abundances are suggested.     

Pollen morphology of Stachys (Lamiaceae) in Iran and its systematic implication

Pollen grains of 30 taxa of the genus Stachys (29 spp. and one subsp.), representing 9 of the currently recognized sections and 1 species of the closely related genus Sideritis (Si. montana) distributed in Iran were examined by light and scanning electron microscopy. Twenty-eight taxa are studied for the first time under aspects of pollen morphology. The basic shape of the pollen grains in most taxa studied is prolate-spheroidal, but subprolate, spheroidal and oblate-spheroidal pollen grains can also be found in few species. The grains are usually tricolpate (the amb triangular), but also tetracolpate (the amb circular to more or less square) in some species (S. iberica, S. atherocalyx and Si. montana). The surface is microreticulate (the frequent type), reticulate, perforate, foveolate-psilate or foveolate. The lumina are separated by smooth or sinuate muri which make them polygonal, more or less rounded and elongate. Major pollen morphological features of the taxa studied are compared and discussed on the basis of taxonomical concepts. In some cases, these characters are useful in delimitation of formerly introduced sections while they mostly provide further characters in separating related species from each other. For example, all members of S. sect. Aucheriana are characterized by elongated lumina. Based on the oblate-spheroidal shape of its pollen as well as tetracolpate aperture type, the results of the present study confirm sect. Pontostachys as including S. angustifolia, S. iberica, S. sparsipilosa as well as S. atherocalyx. Our results also suggest that although some species like S. fruticolosa and S. lavandulifolia are morphologically well characterized, they cannot be separated from other species of Stachys based on pollen morphology.     

Genetic diversity and differentiation in narrow versus widespread taxa of Helianthemum (Cistaceae) in a hotspot: The role of geographic range,habitat, and reproductive traits

Unraveling the relationships between ecological, functional traits and genetic diversity of narrow endemic plants provide opportunities for understanding how evolutionary processes operate over local spatial scales and ultimately how diversity is created and maintained. To explore these aspects in Sierra Nevada, the core of the Mediterranean Betic‐Rifean hotspot, we have analyzed nuclear DNA microsatellite diversity and a set of biological and environmental factors (physicochemical soil parameters, floral traits, and community composition) in two strictly endemic taxa from dolomite outcrops of Sierra Nevada (Helianthemum pannosum and H. apenninum subsp. estevei) and two congeneric widespread taxa (H. cinereum subsp. rotundifolium and H. apenninum subsp. apenninum) that further belong to two different lineages (subgenera) of Helianthemum. We obtained rather unexpected results contrasting with the theory: (a) The narrow endemic taxa showed higher values of genetic diversity as well as higher average values of pollen production per flower and pollen‐to‐ovule ratio than their widespread relatives; and (b) the two taxa of subg. Helianthemum, with larger corollas, approach herkogamy and higher pollen production than the two taxa of subg. Plectolobum, displayed lower genetic diversity and higher values of inbreeding. Altogether, these results disclose how genetic diversity may be affected simultaneously by a large number of intrinsic and extrinsic factors, especially in Pleistocene glacial refugia in mountains where the spatial context harbors a great ecological heterogeneity. On the other hand, differences in mating system and the significant effect of the substrate profile, both being highly diverse in the genus Helianthemum, in the genetic variability illustrate about the importance of these two factors in the diversification and species differentiation of this paradigmatic genus in the Mediterranean and open the field to formulate and test new hypotheses of local adaptation, trait evolution, and habitat diversification.     

Evolution ofPeperomia (Piperaceae) in the Juan Fernandez Islands,Chile

Four species ofPeperomia (Piperaceae) occur in the Juan Fernandez Islands, Chile:P. berteroana, P. margaritifera, P. skottsbergii, andP. fernandeziana. The last species is found also in continental Chile, whereas the other three are endemic to the archipelago.Peperomia margaritifera is found only on the older island of Masatierra, whereasP. skottsbergii is confined to the younger island of Masafuera, andP. berteroana occurs on both islands. Phenetic analyses of mainland taxa suggest thatP. fernandeziana belongs to subg.Sphaerocarpidium whereas the endemic taxa form their own subg.Tildenidium connecting to subg.Tildenia. Cladistic analyses indicate thatP. margaritifera is the most primitive species in the archipelago and thatP. berteroana is the most derived, especially patristically. Chromosomally, the four species are all n = 22, which may be tetraploid on a base of x = 11. Sulfated flavones occur only inP. berteroana andP. skottsbergii, which are otherwise unknown for the family. Dispersal of propagules to the islands from the continent and between islands is believed to have been accomplished by birds.     

ITS sequences from nuclear rDNA suggest unexpected phylogenetic relationships between Euro-Mediterranean, East Asiatic and North American taxa ofQuercus (Fagaceae)

Nucleotide sequences from the internal transcribed spacer (ITS) regions of the 18S–26S nuclear ribosomal DNA have been studied from ten species ofQuercus (representing four subgenera),Castanea sativa andFagus sylvatica, as a preliminary molecular contribution to the still poorly understood systematics and evolution ofFagaceae. The resulting matrix has been used to calculate pair-wise sequence divergence indices and to construct a maximum parsimony tree forQuercus coding indels as a fifth state. Divergence is greater forQuercus vs.Fagus than forQuercus vs.Castanea. The tree for theQuercus taxa studied reveals two clearly divergent clades. In clade I the evergreen W MediterraneanQ. suber appears in a basal position as sister to more distal deciduous taxa, i.e. the E MediterraneanQ. macrolepis and the E AsiaticQ. acutissima (all formerly united as different sections under the apparently polyphyletic subg.Cerris), andQ. rubra (a representative of the N American subg.Erythrobalanus), forming a pair withQ. acutissima. In clade II the evergreen southeastern N AmericanQ. virginiana is basal and sister to the remaining three branches, i.e. a pair of evergreen Mediterranean taxa withQ. ilex andQ. coccifera (subg.Sclerophyllodrys), the deciduous but otherwise plesiomorphic SE European/SW AsiaticQ. cerris (type species of subg.Cerris), and the related but more apomorphic European pairQ. petraea andQ. robur (subg.Quercus). These results partly conflict with current taxonomic classification but are supported by some anatomical and morphological characters. They document polyphyletic lines from evergreen to deciduous taxa and suggest Tertiary transcontinental connections within the genus.     

Stigma morphology in Aylostera subg. Mediolobivia (Cactaceae) and its importance for systematic investigation

The stigma of 31 taxa of Aylostera (Cactaceae) was studied using environmental scanning electron microscopy. Seven stigma types could be defined, based on the degree of fusion of the stigmatic lobes and, when these are completely separated (types I and II), their orientation. Four types (types IV, V, VI and VII) are present only in Aylostera subg. Mediolobivia, two of which (types IV and VII) are species-specific. Stigma morphology was found to be a good diagnostic character in Aylostera subg. Mediolobivia, allowing in some cases to distinguish species that had been confused previously. The stigmatic types here defined seem apt to characterize natural groups within the subgenus and are useful as an aid for species identification and the characterization of new taxa.     

Pollen evolution and its taxonomic significance in Cuscuta (dodders, Convolvulaceae)

The pollen morphology of 148 taxa (135 species and 13 varieties) of the parasitic plant genus Cuscuta (dodders, Convolvulaceae) was examined using scanning electron microscopy. Six quantitative characters were coded using the gap-weighting method and optimized onto a consensus tree constructed from three large-scale molecular phylogenies of the genus based on nuclear internal transcribed spacer (ITS) and plastid trn-LF sequences. The results indicate that 3-zonocolpate pollen is ancestral, while grains with more colpi (up to eight) have evolved only in two major lineages of Cuscuta (subg. Monogynella and clade O of subg. Grammica). Complex morphological intergradations occur between species when their tectum is described using the traditional qualitative types—imperforate, perforate, and microreticulate. This continuous variation is better expressed quantitatively as “percent perforation,” namely the proportion of perforated area (puncta or lumina) from the total tectum surface. Tectum imperforatum is likely the ancestral condition, while pollen grains with increasingly larger perforation areas have evolved multiple times. The reticulated tectum, unknown in other Convolvulaceae, has evolved in Cuscuta only in two lineages (subg. Monogynella, and clade O of subg. Grammica). Overall, the morphology of pollen supports Cuscuta as a sister to either the “bifid-style” Convolvulaceae clade (Dicranostyloideae) or to one of the members of this clade. Pollen characters alone are insufficient to reconstruct phylogenetic relationships; however, palynological information is useful for the species-level taxonomy of Cuscuta.     

Giants and dwarfs: molecular phylogenies reveal multiple origins of annual spurges within Euphorbia subg. Esula

Euphorbia (Euphorbiaceae) comprises over 2150 species and is thus the second-largest genus of flowering plants. In Europe, it is represented by more than 100 species with highest diversity in the Mediterranean area; the majority of taxa belong to subgenus Esula Pers., including about 500 taxa. The few available phylogenetic studies yielded contrasting results regarding the monophyly of subg. Esula, and the phylogenetic relationships among its constituents remain poorly understood. We have sampled DNA sequences from the nuclear ribosomal internal transcribed spacer (ITS) and the plastid trnT-trnF region from about 100, predominantly European taxa of subg. Esula in order to infer its phylogenetic history. The plastid data support monophyly of subg. Esula whereas the ITS phylogeny, which is generally less resolved, is indecisive in this respect. Although some major clades have partly incongruent positions in the ITS and plastid phylogenies, the taxonomic content of the major terminal clades is congruent in both trees. As traditional sectional delimitations are largely not corroborated, an improved classification is proposed. Character state reconstruction illustrates that the annual life form developed independently several times in different clades of subgenus Esula from perennial ancestors, and that several morphological traits used in previous classifications of Euphorbia developed in parallel in different lineages.     

Diversity and evolution of pollen-ovule production in <Emphasis Type="Italic">Cuscuta</Emphasis> (dodders,Convolvulaceae) in relation to floral morphology

Cuscuta (dodder, Convolvulaceae) is a genus of about 200 species of obligate stem parasites with subcosmopolitan distribution. The diversity of pollen and ovule production was surveyed in 128 species and ten varieties. Taxa were assigned to Cruden’s mating system categories based on their pollen-ovule ratios. Variation and correlations among floral characters were analyzed using regression and ANOVA, while the mating system categories were subjected to a linear discriminant and canonical variates analysis to assess their cohesiveness. Our data strongly suggest that most Cuscuta species possess a wide range of mixed-mating systems. Whereas four ovules develop in each flower, pollen production varies over three orders of magnitude. Several Cuscuta taxa are highly outcrossing, but no species could be identified that are exclusively selfing. The transition from the one-style flowers of subg. Monogynella to the two-style flowers of subgenera Cuscuta and Grammica, and from simultaneous to sequential maturation of the two stigmas in the latter subgenus, has decreased the role of herkogamy as a facilitator of outcrossing. These evolutionary changes are associated with an increase of species richness in subgenus Cuscuta, and especially in subgenus Grammica. Morphological features were not individually found to have a strong correlation to the mating system, but in general, larger corollas and stigmas were associated with greater pollen-ovule ratios. Cuscuta presents some puzzling results when considered in light of the sex allocation theory, as only some infrageneric lineages demonstrate the predicted pollen size-number tradeoff, while Cuscuta gracillima complex (in subgenus Grammica) displays an unexpected negative relationship between pollen size and style length. The relationship between host range and mating system is discussed, prompting further research into the co-evolution of pollination systems and life history traits between parasites and their host species.     

Morphological variation in pollen grains of <Emphasis Type="Italic">Mucuna</Emphasis> (Leguminosae): new biogeographic and evolutionary patterns

Mucuna comprises 105 species with an overall pantropical distribution and is divided into three subgenera: M. subg. Mucuna, M. subg. Stizolobium and M. subg. Macrocarpa. Although phylogenetic studies have supported the occurrence of three main clades, evolutionary relationships among them are not fully resolved. The objective of this study was to examine pollen grain morphology from representatives of all three subgenera and map these onto the phylogenetic trees generated by analysis of other characters. Pollen grain surface, form, size, and aperture number were compared. A Bayesian inference tree using matK sequences was constructed. The results indicate that the representatives of M. subg. Macrocarpa have the smallest pollen grains in the genus (a synapomorphic character here identified for this subgenus) and that species of subgenus Mucuna (those with umbelliform inflorescences) have the largest pollen grains. Additional morphological diversity of the pollen grain surface was noted: reticulate and/or micro-reticulate (in all three subgenera), perforate, gemmate or verrucose (only in M. subg. Mucuna). For all studied taxa, the pollen grains are triaperturate, except for two species of M. subg. Mucuna, which have tetraperturate pollen. The phylogenetic tree obtained using the matK marker resolved M. subg. Stizolobium as the earliest diverging lineage in Mucuna. Based on this phylogeny, a reticulate ornamentation pattern of the pollen surface may represent the ancestral state for the genus, while the larger pollen size and the foraminate, gemmate, and verrucose ornamentations are derived characteristics within the genus. These putative derived ornamentations have been observed only in neotropical species.     

LEAF CROSS SECTIONS AND PHYTOGEOGRAPHY: A POTENT COMBINATION FOR IDENTIFYING MEMBERS OF FESTUCA SUBGG. FESTUCA AND LEUCOPOA (POACEAE), OCCURRING IN NORTH AMERICA

Icon-like diagrams are used to summarize the anatomical patterns observed in leaf cross sections of 30 taxa of Festuca subgg. Festuca and Leucopoa occurring in western North America. Measurements of four variables, notes on the degree of development and the position of sclerenchyma, along with distribution maps of 24 native taxa, are presented. Twenty-nine diagrams were created from the synthesis of at least ten leaf-section drawings based on five plants chosen from across the geographic range of each taxon (fewer suitable specimens were obtained for two taxa). A key based on data collected in this study allows identification of species in subg. Festuca. Geographic distribution is more reliable than leaf anatomy for separating taxa in subg. Leucopoa.     

PALYNOLOGY AND SYSTEMATICS OF CUPHEA (LYTHRACEAE). II. POLLEN MORPHOLOGY AND INFRAGENERIC CLASSIFICATION

Present taxonomic studies in Cuphea (Lythraceae) reveal that a broad spectrum of biosystematic data is required for an understanding of evolutionary relationships among this large and complex group of species. As part of these studies pollen data have proven to be of greater pragmatic value than is frequently true for more stenopalynous taxa. A survey is made of pollen types in 160 species of Cuphea with special reference to specific taxonomic problems, and a summary presented of points at which pollen data can profitably contribute to taxonomic revision of the genus.     

Disentangling the components of pollen limitation in a widespread herb with gametophytic self-incompatibility

Premise

Seed production is frequently limited by the receipt of insufficient or low-quality pollen, collectively termed “pollen limitation” (PL). In taxa with gametophytic self-incompatibility (GSI), incompatible pollen can germinate on stigmas but pollen tubes are arrested in styles. This allows for estimates of pollen performance before, during, and after self-recognition, as well as insight into the factors underlying pollen quality limitation in GSI taxa.

Methods

We scored pollen performance following self and outcross pollinations in Argentina anserina to identify the location of self-recognition and establish the relationship between pollen tubes and seed production. We then estimated quantity and quality components of PL from >3300 field-collected styles. We combined our results with other studies to test the prediction that low pollen quality, but not quantity, drives higher PL in self-incompatible (SI) taxa than in self-compatible taxa (SC).

Results

Self and outcross pollen germinated readily on stigmas, but 96% of germinated self-pollen was arrested during early tube elongation. Reproduction in the field was more limited by pollen quality than by quantity, and pollen failure near the location of self-recognition was a stronger barrier to fertilization than pollen germination. Across 26 taxa, SI species experienced stronger pollen quality, but not quantity, limitation than SC species.

Conclusions

Evaluating pollen performance at multiple points within pistils can elucidate potential causes of pollen quality limitation. The receipt of incompatible pollen inhibits fertilization success more than insufficient pollen receipt or poor pollen germination in A. anserina. Likewise, pollen quality limitation drives high overall PL in other SI taxa.     

Analysis of fatty acids,proteins and ethereal extract in honeybee pollen - Considerations of their floral origin

Chemical analysis was made of the ethereal extract, fatty acids, protein and sugars of corbicula pollen as these are specific characters selected by the honeybee from plant species as a source of pollen for the hive. This group of analyses was carried out using balls of monospecific pollen of the following individual taxa which represent more than 5% of the total pollen collected by the honeybee: Castanea sativa, Erica, Eucalyptus, Halimium alyssoides, Quercus robur, Raphanus raphanistrum, Rubus and Cytisus scoparius-type. The ethereal extract content was similar for the total pollen in all the hives. The percentage composition of fatty acids, both saturated and unsaturated and their diversity allowed the relationship between fatty acids and plant species to be found, which contributed to the final content in the hives. In this way tridecanoic acid was related with Cytisus scoparius-type; palmitoleic acid with Castanea sativa, Erica, Eucalyptus and Quercus robur; behenic acid with Rubus and Raphanus raphanistrum; and isopalmitic acid with Rubus. Until now isopalmitic acid has not been cited in other studies as a component of honeybee pollen. The fatty acid content of pollen has also proved to be useful in determining geographical origin of this product. The pollen was found to be rich in essential fatty acids of interest for human nourishment. The protein content was high in hives and in the pollen of the individual taxa, varied between the 29.6% and 14%. The fructose content was higher than glucose. It was noticeable that pollen of Rubus was highest in glucose (21%) and Castanea sativa in fructose (26.3%). Water content of corbicula pollen was below 10%.     

Pollen morphology of the East Asiatic genus Chelonopsis (Lamioideae: Lamiaceae) and allied genera,with reference to taxonomic implications and potential pollination ecology

Pollen grains of 15 taxa of the genus Chelonopsis (14 spp. and 1 variety) from China and Japan and 6 species of the closely related genera Bostrychanthera (1 species) and Gomphostemma (5 species) were examined by light and scanning electron microscopy. Of these, the pollen morphology of 18 taxa was studied for the first time. Pollen grains were found to be tricolpate with polar lengths of 20.8–30.0 μm and equatorial widths of 17.5–27.3 μm. The basic shape of the pollen in most taxa is subprolate or prolate-spheroidal, but spheroidal, subprolate-spheroidal, oblate-spheroidal, and prolate-subprolate grains are also found in some species. The surface is generally reticulate or suprareticulate in Chelonopsis and granulate in Bostrychanthera. In comparison with those of Chelonopsis and Bostrychanthera, the pollen grain surfaces of Gomphostemma are more diverse. In Chelonopsis, pollen is taxonomically useful at the sectional level, and some grains provide enough characters for species delimitation. The potential pollination ecology of cellular hairs on the anthers of Chelonopsis and Bostrychanthera is also briefly discussed.     

Isoenzyme variation in the generaPhaseolus andVigna (Fabaceae) in relation to their systematics: Aspartate aminotransferase and superoxide dismutase

Evolutionary variation of aspartate aminotransferase and superoxide dismutase isoenzymes in 14 wild and cultivated species ofPhaseolus andVigna has been studied by electrophoresis and isoelectric focusing in polyacrylamide gel. The American cultivated beans of the genusPhaseolus s. str.,P. vulgaris, P. coccineus, P. lunatus andP. acutifolius, form a homogeneous group with only minor isoenzyme variation. The genusVigna, on the contrary, proves to be heterogeneous in isozyme characters. Several clusters of taxa can be distinguished in close correspondence with modern treatments of the genus. The isoenzyme data support the inclusion of the Asian Azuki beans of subg.Ceratotropis inVigna, but argue against the transfer of the S. American speciesP. adenantha. The cowpea complexV. unguiculata s. lato of sect.Catiang forms an uniform and isolated group, distinct from other sections of subg.Vigna, and shows affinity toPhaseolus s. str. by some isoenzymes. It is suggested to removeV. unguiculata s. lato from subg.Vigna and to recognize it as a separate subg.Catiang (DC.)Jaaska & Jaaska, stat. nov.