Leaf flavonoid chemistry of Coreopsis (Compositae) section Palmatae

Examination of leaf flavonoids of all taxa ofCoreopsis sectionPalmatae revealed that most members synthesize an array of common flavone (mostly luteolin and apigenin) glycosides. Each diploid species or diploid member of a species is characterized by a particular ensemble of compounds. These taxa includeC. major, C. verticillata, C. pulchra, C. palmata, andC. tripteris. The latter species differs from all other taxa in producing flavonol (kaempferol and quercetin) glycosides and what appear to be 6-oxygenated compounds. Tetraploids ofC. verticillata exhibit the same flavonoids as diploid members of the species, thus flavonoid chemistry supports the hypothesis that they originated from diploids within the species. Certain populations of hexaploid and octoploidC. major are similar chemically to diploids, suggesting they also originated as intraspeciflc polyploids. Other populations of these polyploids exhibit a flavonoid profile which differs from the profile of the diploids, and this profile is nearly identical to the octoploidCoreopsis × delphinifolia. The latter taxon has been viewed by Smith (1976) and Mueller (1974) as an interspecific hybrid betweenC. verticillata andC. major and/orC. tripteris. Species-specific compounds from the former species occur inC. × delphinifolia but no compounds unique to either of the latter two species are discernable. Flavonoid chemistry is not useful in ascertaining whether either or both species have been involved withC. verticillata in producing plants referable toC. × delphinifolia. There is morphological intergradation between octoploidC. major andC. × delphinifolia, and all plants not appearing to be “pure”C. major exhibit a flavonoid chemistry likeC. × delphinifolia. All plants of sectionPalmatae considered to be alloploids (includingC. × delphinifolia) produce the same array of leaf flavonoids, including several “novel” compounds not expressed in the putative parental taxa. Two of the “novel” flavonoids are present in the geographically restricted diploidC. pulchra. The systematic and phylogentic significance of this is not readily apparent.     

Characterization of self-compatibility in sweet cherry varieties by crossing experiments and molecular genetic analysis

Self-compatibility is a major breeding objective in sweet cherry. The identification and characterization of new sources of self-compatibility will be useful for breeding and research purposes. In this work, self-compatibility of four local Spanish sweet cherry varieties was investigated by crossing experiments and molecular genetic analysis of two self-incompatibility loci. Crossing experiments included self- and cross-pollinations in the laboratory followed by microscopic observation of pollen tube growth and fruit set assay in the field. After crossing experiments, two accessions, ‘Son Miró’ and ‘Talegal Ahín’, were self-compatible while the other two were self-incompatible. Inheritance of S-locus and microsatellite EMPaS02 (linked to self-compatibility, Sc) were investigated in self-pollination progeny of both self-compatible genotypes. Results indicate that self-compatibility in ‘Talegal Ahín’ is similar to self-compatibility described in sweet cherry ‘Cristobalina’ and may be caused by the same mutation. That is a pollen part mutation not linked to the S-locus but linked to microsatellite EMPaS02 in cherry LG3. In ‘Son Miró’ self-compatibility seems more complex, affecting pollen and style function, and probably involving more than one mutation not described previously in sweet cherry. Together with ‘Cristobalina’, the newly described self-compatible varieties ‘Son Miró’ and ‘Talegal Ahín’ confirm the existence of unique self-compatible plant material in local germplasm from Spain that should be conserved and characterized for its use in breeding and research.     

Unravelling the mechanisms for plant survival on gypsum soils: an analysis of the chemical composition of gypsum plants from Turkey

Depending on their specificity to gypsum, plants can be classified as gypsophiles (gypsum exclusive) and gypsovags (non‐exclusive). The former may further be segregated into wide and narrow gypsophiles, depending on the breadth of their distribution area. Narrow gypsum endemics have a putative similar chemical composition to plants non‐exclusive to gypsum (i.e. gypsovags), which may indicate their similar ecological strategy as stress‐tolerant plant refugees on gypsum. However, this hypothesis awaits testing in different regions of the world. We compared the chemical composition of four narrow gypsum endemics, one widely distributed gypsophile and six gypsovags from Turkey. Further, we explored the plasticity in chemical composition of Turkish gypsovags growing on high‐ and low‐gypsum content soils. Differences were explored with multivariate analyses (RDA) and mixed models (REML). Narrow gypsum endemics segregated from gypsovags in their chemical composition according to RDAs (mainly due to higher K and ash content in the former). Nevertheless, differences were small and disappeared when different nutrients were analysed individually. All the gypsovags studied accumulated more S and ash when growing on high‐gypsum than on low‐gypsum soils. Similar to narrow gypsum endemics from other regions of the world, most local gypsum endemics from Turkey show a similar chemical composition to gypsovags. This may indicate a shared ecological strategy as stress‐tolerant plants not specifically adapted to gypsum. Nevertheless, the narrow gypsum endemic Gypsophila parva showed a chemical composition typical of gypsum specialists, indicating that various strategies are feasible within narrowly distributed gypsophiles.     

Systematic studies in sedum section ternata (Crassulaceae)

An investigation of flavonoid compounds, pollen grains, and seed coats of the four taxa of the genusSedum sectionTernata, S. nevii, S. glaucophyllum, S. pulchellum, andS. ternatum, was undertaken to resolve the taxonomic status ofS. glaucophyllum. Flavonoid compounds were tentatively identified utilizing UV spectroscopy and shift reagents. Both flavones and fla vonols, as apigenin, luteolin, quercetin, and kaempferol aglycones and glycosides, were detected. Pollen grains and seed coats were viewed and photographed with the aid of a scanning electron microscope. Pollen grains of all four taxa were uniformly tricolporate; interspecific variation was negligible. Seed coats of all four taxa differed significantly with respect to ornamentation. Phytochemical and morphological data both support the recognition ofS. glaucophyllum as a species distinct from S.nevii.     

白菜型油菜自交亲和性变异分析

对不同来源的85份白菜型油菜品种的自交亲和指数研究表明,白菜型油菜的自交亲和性存在较大幅度的变异,自交亲和指数在0．00～9．28之间,这种变异不仅存在于品种间,而且存在于品种内不同个体间。85份参试材料中,自交亲和指数小于1的有50个品种;35个品种自交亲和指数大于1,自交亲和指数在1．00～9．28之间,其中亲和指数大于4的材料有28、44、45、55x、75、119、123、139号品种等。依据自交亲和指数,可将参试材料分为4种类型:高自交亲和类型(自交亲和指数>4．00);自交亲和类型(自交亲和指数1．00～3．99);自交不亲和类型(0．00< 自交亲和指数<1．00);高自交不亲和类型(自交亲和指数=0．00)。自交亲和性因地区而异,一般西部地区的品种自交亲和性高于其它地区的品种。     

North American black-fruited hawthorns. I. Variation in floral construction,breeding system correlates,and their possible evolutionary significance inCrataegus sect.Douglasii London

Differences in the numbers of stamens and styles per flower are conspicuous features of variation in North American hawthorns (Crataegus L.). Variation in stamen number between individuals is discontinuous, with modes of approximately 20 and 10 (or fewer). In North American black-fruited sectionDouglasii Loudon the 10-stamen morphotype is exclusively polyploid, whereas the 20-stamen morphotype comprises both diploids and polyploids. Polyploidy is associated with apospory, self-fertility, and varying degrees of pollen sterility. Variation in stamen number may also be correlated with variation in distribution, phenology, leaf shape, and other features of floral morphology, leading to recognition of taxa at the specific or infraspecific level. Comparable variation in stamen number is virtually unknown in Eurasian hawthorns, as in the majority of flowering plants. In sectionDouglasii stamen number morphotypes have been recognized as either varieties or species; although correlations between stamen number and other features are not as straightforward as was previously surmised, the higher rank appears to be appropriate. These data on breeding system and morphological variation may be explainable in terms of hypotheses linking gametophytic apomixis, polyploidization, and optimal strategies for pollen dispersal.     

Chromosome numbers in Great Plains species of Penstemon (Scrophulariaceae)

Chromosome numbers are reported for 79 populations ofPenstemon representing 20 species. All but two species counted here are diploids. First counts are reported for seven taxa, all asn=8 or 2n=16.     

Population genetic structure of diploid sexual and polyploid apomictic hawthorns (Crataegus; Rosaceae) in the Pacific Northwest

Polyploidy and gametophytic apomixis are two important and associated processes in plants. Many hawthorn species are polyploids and can reproduce both sexually and apomictically. However, the population genetic structure of these species is poorly understood. Crataegus douglasii is represented exclusively by self-compatible tetraploid pseudogamous apomicts across North America, whereas Crataegus suksdorfii found in the Pacific Northwest is known to include self-incompatible diploid sexuals as well as polyploid apomicts. We compare population structure and genetic variability in these two closely related taxa using microsatellite and chloroplast sequence markers. Using 13 microsatellite loci located on four linkage groups, 251 alleles were detected in 239 individuals sampled from 15 localities. Within-population multilocus genotypic variation and molecular diversity are greatest in diploid sexuals and lowest in triploid apomicts. Apart from the isolation of eastern North American populations of C. douglasii , there is little evidence of isolation by distance in this taxon. Genetic diversity in western populations of C. douglasii suggests that gene flow is frequent, and that colonization and establishment are often successful. In contrast, local populations of C. suksdorfii are more markedly differentiated. Gene flow appears to be limited primarily by distance in diploids and by apomixis and self-compatibility in polyploids. We infer that apomixis and reproductive barriers between cytotypes are factors that reduce the frequency of gene flow among populations, and may ultimately lead to allopatric speciation in C. suksdorfii . Our findings shed light on evolution in woody plants that show heterogeneous ploidy levels and reproductive systems.     

A CYTOGEOGRAPHIC STUDY OF ERIOPHYLLUM LANATUM (COMPOSITAE,HELENIEAE)

Analysis of 368 plants derived from 239 natural populations showed that this taxonomically perplexing and wide-ranging species-complex consists of diploids (n = 8), tetraploids, hexaploids and octoploids. Microsporocytes were the source of most of the chromosome counts. Meiosis was basically regular. Multivalent formation was uncommon, but 11 % of all the plants examined had one or more full-sized extra chromosomes. The frequency of plants with extra chromosomes varied significantly among the taxa, from 0 (five varieties) to over 20 % (two varieties). Except in one instance, where one population yielded a diploid and a triploid, different ploidy levels were not found in the same population. The frequency of diploid, tetraploid, hexaploid and octoploid populations was, respectively, 71, 22, 4 and 2%. Variety obovatum appears to be exclusively diploid, and var. aphanactis exclusively tetraploid. Diploids and one or more polyploid levels occurred in the other taxa. No correlation was found between polyploidy and geological history, soils, topography or climate, nor were the polyploids more widely distributed than the diploids. Some of the polyploid populations seem to have been derived from inter-varietal hybridizations, but others do not. The complex has a “pillar” structure in which 10 diploid taxa support a three-level polyploid superstructure. The available evidence suggests that the major role of polyploidy here has been to stabilize the products of intra- and inter-varietal hybridizations.     

SEM analysis of leaf epicuticular waxes of Sedum section Gormania (Crassulaceae)

Epicuticular leaf waxes in the 12 taxa classified inSedum, sect.Gormania show variation in size, shape, and frequency. All of the taxa exhibit wax platelets, but the platelets in the three putative relicts (S. albomarginatum, S. moranii, S. oblanceolatum) are larger than those in related taxa, and those inS. paradisum are poorly developed. Interspecific hybrids tend to show wax patterns intermediate between those of their respective parents. Hypothetical hybrid origins for the four polyploid taxa in the section have been supported previously by morphological and reproductive data and are further clarified by leaf wax data.     

Revision of Verbesina section Verbesina (Asteraceae: Heliantheae)

A revisionary treatment of the insular CaribbeanVerbesina sectionVerbesina (formerly sectionHamulium) is provided. Four taxa (three species and one variety) are recognized.     

Genetic diversities of four little-known species of Malesherbia (Malesherbiaceae) endemic to the arid inter-Andean valleys of Peru

Few studies of genetic variation have been conducted on plants of the Pacific coastal desert and neighboring Andes of Peru, although the region has many endemic taxa. Enzyme electrophoresis was employed to examine allozyme diversities of four species of the family Malesher-biaceae, an endemic to the arid Andes and coastal desert. One population ofMalesherbia splendens and two ofM. tubulosa, both endemics of the department of Lima, one population ofM. weberbaueri var.weberbaueri, an endemic of the Andean department Huancavélica, and the two Lima populations ofM. scarlatiflora were studied. Fifteen loci were examined for all populations and an additional seven loci were resolved forM. weberbaueri andM. splendens. Malesherbia splendens, which is known from three populations, has a low mean number of alleles per locus (A), proportion of polymorphic loci (P), and expected heterozygosity (H_s) (A=1.214, P=0.214, H_s=0.057).Malesherbia weberbaueri (A=1.231, P=0.154, H_s=0.079) andM. scarlatiflora (A=1.364, P=0.273, H_t=0.083) both have average expected heterozygosities and relatively low mean numbers of alleles per locus and proportions of polymorphic loci. InM. tubulosa, all measures of genetic diversity are high in comparison with other endemics (A=1.818, P=0.364, H_t=0.206).Malesherbia tubulosa has high interpopulation differentiation, whereasM. scarlatiflora has low among-population diversity. The relatively low allozyme diversities, restricted habitats, narrow ranges ofM. splendens andM. weberbaueri, and the morphological similarities of all four species suggest that they evolved recently by founder events. Greater allozyme diversities inM. tubulosa could be attributable to its maintenance of larger populations in a greater variety of habitats.     

The taxonomy ofVaccinium sectionHemimyrtillus

In view of their awnless stamens and pseudo-10-loculed berries borne on short racemes several NE Asian species ofVaccinium (includingV. hirtum, V. smallii, V. versicolor, andV. yakushimense) were transferred toVaccinium sectionCyanococcus by Sleumer (1941). Subsequently, however, Stevens (1969) and Vander Kloet (1972, 1981) argued on the basis of further study that these taxa should be transferred instead to sectionHemimyrtillus. Phenetic analyses of data from representatives of sectionsCyanococcus andHemimyrtillus, including NE Asian taxa transferred by Sleumer, demonstrate the distinctness of the two sections and support the assignment of the NE Asian taxa to sectionHemimyrtillus. A revised taxonomic treatment and key to the species ofVaccinium sectionHemimyrtillus is provided.     

Data on chromosome numbers in Aster (Asteraceae), with comments on the status and relationships of certain North American species

Chromosome counts are presented for more than 250 populations ofAster representing 56 species and eight spontaneous interspecific hybrids. Species are listed according to the infrageneric classification system presented in the preceding paper which utilizes basic chromosome numbers as the pivotal diagnostic character. Fundamental to the classification is an ecological species concept. The list is augmented by a series of comments on field observations and on the examination of types. Six older names previously placed in synonymy or recognized at an inferior rank are reinstated at the species level:A. brachypholis, A.firmus, A. fragilis, A. longifolius, A. simmondsii andA. tardiflorus. Two taxa included as species in current manuals of the eastern North American flora are reduced in status to subspecies rank underA. cordifolius. Putative hybrid status is assigned to four taxa previously treated and originally published as species:A. × coerulescens (= A. praealtus × A. simplex, A. × interior (= A. simplex × A. tradescantii, A. × maccallae (= A. ciliolatus × A. subspicatus) and A. × subgeminatus (= A. ciliolatus × A. tardiflorus). With new data available, the basic chromosome number ofx = 8 has now been confirmed for all species ofAster sectionHeterophylli, except the Mexican A.coahuilensis.     

Breeding systems of the Paraguaná coastal plain plants, Venezuela.

Breeding systems were evaluated for 51 plant species according to life form, pollination system, vegetation type, and phenology, in the coastal plain of Paraguaná Peninsula, Venezuela. Sexual systems were no associated to life form, pollination system, vegetation type, and phenology. The frequency distribution of sexual system was 82.3% hermaphroditism, 15.6% monoecy, and 1.9% dioecy. All sexual systems had a peak during the lowest rainfall. Genetic system distribution was 64.8% self-compatibility (including partially self-compatibility) and 35.2% self-incompatibility. Among self-compatible species, 45.1% were autogamous (19.6% not autogamous). The genetic systems were associated significantly to: (1) plant life form: self-compatible species tend to be herbaceous and self-incompatible plants tend to be woody species; (2) vegetation type: self-compatible species were predominant in the three vegetation types, but in the mangrove the frequency of self-compatible and self-incompatibles was similar; and (3) pollination system: most of the self-compatible species were polyphilous. Mating systems: xenogamous and autogamous species were associated only with plant life forms. Xenogamous plants were mostly woody species and autogamous plants were mostly herbaceous species. The high incidence of hermaphroditism, self-compatibility, and autogamy are related to herbaceous life form, polyphilous pollination system, and climatic conditions, together the insularity of the Paraguaná peninsula.     

REPRODUCTIVE BIOLOGY OF A TROPICAL PALM SWAMP COMMUNITY IN THE VENEZUELAN LLANOS

The reproductive biology of a tropical palm swamp community, called morichal in the Venezuelan Central Llanos, was studied. Of the 128 woody and herbaceous species of plants recorded, 99 (77.34%) were hermaphrodites, 25 (19.53%) were monoecious, and four (3.13%) were dioecious. The morichal is characterized by a low number of species with obligate cross-fertilization. The frequencies of species with different breeding systems in a subsample of 26 species showed that eight (30.77%) were self-incompatible, 14 (53.85%) were self-compatible, and four (15.38%) were agamospermous. Ten of 14 self-compatible species were autogamous. Regardless of the self-incompatibility level estimated, seed and fruit set were greater in self-fertilized flowers than in hand-pollinated flowers in three of the nine self-incompatible species. These results are related to the facts that: 1) the relative isolation of the plant population limits the gene flow among similar communities and enforces the intrapopulation pollen flow; 2) the overlapping flowering patterns and infrequent and unspecialized pollinators may be enforcing self-compatibility and agamospermy; 3) self-compatibility is the rule among short-lived species in the morichal; and 4) three out of four agamospermous species are of the Melastomataceae family.     

Three new species of galium (rubiaceae) from Baja California

The species described as new are apparently narrow endemics, all belonging to that section ofGalium having fruits with long straight specialized hairs.Galium wigginsii andG. moranii are of the widespreadG. wrightii-G. parishii complex, whereasG. carterae is most like the rarely collectedG. oresbium Greenman of northeastern Mexico.