Mating System and Hybridization of the Cyanus triumfetti and C. montanus Groups (Asteraceae)

Mode of reproduction and presence of reproductive barriers were studied in two closely related members of the genus Cyanus: the C. triumfetti (diploid 2n?=?22) and C. montanus (tetraploid 2n?=?44) groups. Based on results from isolation and emasculation experiments, taxa of these groups can be considered allogamous with a low selfing rate (0.07 %–0.21 % of achenes developed after selfing). Taxa of the C. triumfetti group hybridize easily and produce viable progeny. Differences in the percentage of well-developed achenes per capitulum obtained from interspecific crosses between members of the C. triumfetti group suggested different levels of reproductive isolation. The percentage of well-developed achenes of most homoploid crosses was 3.47 %–8.87 %. Higher percentages of well-developed achenes were obtained from crosses between Eastern Carpathian C. pinnatifidus and Alpine C. triumfetti s. str. (18.36 % ; 26.56 %) and between geographically close taxa in Central Europe (C. dominii, C. strictus and ‘intermediate morphotype’; 12.75 % –17.60 %), which indicate their overall close relatedness. Crossing geographically remote C. strictus and C. triumfetti s. str. yielded no or only few (0.99 %) well-developed achenes, indicating an increased degree of incompatibility in allopatry. The success of heteroploid crosses between plants belonging to different groups was reduced (2.96 %) and suggested reproductive incompatibilities between ploidy levels. The progeny of heteroploid crosses comprised 63 % of triploids of presumable hybrid origin on tetraploid as well as diploid maternal plants. Another 15.22 % of progeny had the maternal cytotype, probably resulting from selfing. Low viability of heteroploid hybrids supports the existence of post-zygotic mechanisms.     

Anatomical studies of Carex cuchumatanensis,C. decidua,and C. hermannh (Cyperaceae) and comparisons with north American taxa of the C. acuta complex

Foliar anatomy and micromorphology of perigynia and achenes were investigated for three taxa of theCarex acuta complex of sect.Phacocystis Dumort. in Middle and South America. Anatomical characters appear to be conservative, and show little variation amongC. cuchumatanensis Standl. & Steyerm.,C. decidua F. Boott, andC. hermannii Cochrane. Leaves of all species are amphistomatous, with stomates and papillae on both epidermal surfaces, and have a single layer of bulliform cells but differ in the number of vascular bundles. Perigynia have epidermal cells with thin, convex, outer walls that are collapsed in dired specimens, and epidermal cells of achenes each have a single, rounded, nodulose silica-body with a basal platform. Anatomical data are useful in resolving the affinities among these species, and show that they are anatomically indistinguishable fromC. lenticularis Michx. These four New World endemics differe substantially fromC. nigra (L.) Reichard.     

CYTOGENETIC STUDIES IN CLARKIA,SECTION PRIMIGENIA. IV. A CYTOLOGICAL SURVEY OF CLARKIA GRACILIS

Clarkia gracilis (2n = 28) is an allotetraploid which combines genomes from two subsections of section Primigenia. Natural populations consist of plants homozygous for a single chromosome arrangement, which may differ from the arrangements in other populations by one or more reciprocal translocations. One arrangement, the “standard,” was widespread. Cytological observations on plants derived from crosses between populations of C. gracilis, and on triploid plants derived from crosses with C. amoena subsp. huntiana, one of the parents of the tetraploid, were used to determine the end arrangements present. Ten arrangements were identified, and it was found that the standard amoena subgenome of C. gracilis is identical in end arrangement to the previously defined standard arrangement of the diploid C. amoena. Hence a race of C. amoena with this arrangement was involved in the hybridization which gave rise to C. gracilis. Evidence was found that other arrangements of C. amoena have probably been introduced into C. gracilis by subsequent introgressive hybridization. Cytological differences, coupled with differences in morphology, ecology, and distribution indicate that C. gracilis should be subdivided into four subspecies instead of the three presently recognized.     

Comparative osteology of lotaks, Cyprinion kais and C. macrostomum (Cypriniformes, Cyprinidae), from Godarkhosh River, western Iran

Osteology of two cyprinid fishes, Cyprinion kais and C. macrostomum, from the Tigris-Euphrates basin was described and compared. Eight specimens of C. kais and ten specimens of C. macrostomum from Godarkhosh River (western Iran) were studied. The skeletal elements were prepared using clearing and softening methods and photographed. The differences between the two taxa include a deeper posterior position of the lower jaw with a much narrower labial surface, a longer last dorsal unbranched ray with weaker posterior serration, and a more embowed dentary, maxillary and premaxillary in C. kais. Based on these differences, the examined specimens of these two taxa could be easily distinguished.     

Response of two species of Indo-Pacific corals, Porites cylindrica and Stylophora pistillata, to short-term thermal stress: The host does matter in determining the tolerance of corals to bleaching

The role of both host and dinoflagellate symbionts was investigated in the response of reef-building corals to thermal stress in the light. Replicate coral nubbins of Stylophora pistillata and Porites cylindrica from the GBR were exposed to either 28 °C (control) or 32 °C for 5 days before being returned to an ambient reef temperature (28 °C). S. pistillata was found to contain either Symbiodinium genotype C1 or C8a, while P. cylindrica had type C15 based on ITS genotyping. Analysis of the quantum yield of photosystem (PS) II fluorescence of the symbionts in P. cylindrica showed that light-induced excitation pressure on the C15 Symbiodinium was significantly less, and the steady state quantum yield of PSII fluorescence at noon (ΔF/Fm′) greater, than that measured in C1/C8a Symbiodinium sp. from S. pistillata. Immunoblots of the PS II D1 protein were significantly lower in Symbiodinium from S. pistillata compared to those in P. cylindrica after exposure to thermal stress. The biochemical markers, heat-stress protein (HSP) 70 and superoxide dismutase (SOD), were significantly greater in P. cylindrica before the experiment, and both species of coral increased their biosynthesis of HSP 70 and SOD when exposed to thermal stress. Concentrations of MAAs, glycerol, and lipids were not significantly affected by thermal stress in these experiments, but DNA damage was greater in heat-stressed S. pistillata compared to P. cylindrica. There was minimal coral mucus, which accounts for up to half of the total energy budget of a coral and provides the first layer of defense for invading microbes, produced by S. pistillata after heat stress compared to P. cylindrica. It is concluded that P. cylindrica contains a heat resistant C15 Symbiodinium and critical host proteins are present at higher concentrations than observed for S. pistillata, the combination of which provides greater protection from bleaching conditions of high temperature in the light.     

CYTOGENETIC STUDIES IN CLARKIA,SECTION PRIMIGENIA. I. A CYTOLOGICAL SURVEY OF CLARKIA AMOENA

Snow , Richard . (U. California, Davis.) Cytogenetic studies in Clarkia, section Primigenia. I. A cytological survey of Clarkia amoena. Amer. Jour. Bot. 50(4): 337–348. Illus. 1963.—Clarkia amoena (2n = 14) shows great cytological diversity based on reciprocal translocations. About ½ the plants sampled were heterozygotes; in 2 of the subspecies the frequency was as high as ⅔. The metaphase configurations were varied, including rings of 4, 6, 8, 4 + 4, 6 + 4, and more unusual types forming a chain of 3 + a univalent or a chain of 4 + a univalent. The latter have only 13 chromosomes but are not true monosomies. Some plants with supernumerary chromosomes were found, in addition to a plant with only 12 chromosomes which was derived from a “monosomic” type. From crosses of various homozygous lines to a standard strain, it was found that the standard end arrangement of chromosomes occurs widely and commonly throughout the species. A minimum of 7 different end arrangements, giving a ring of 4 with the standard strain, and 1 giving a ring of 6, account for the chromosome pairing found in interstrain crosses. No doubt more would be found with further testing. Some of the translocations may be components of adaptive polymorphic systems, though there is no proof of this yet. No balanced lethal systems similar to those in the closely related genus Oenothera were found.     

Cardamine L. sect.Macrophyllum O. E.Schulz (Cruciferae Juss.) in the Asian Territory of the Soviet Union A morphological,anatomical and phylogenetical study with taxonomic revision

Based on the study of herbarium material, a critical taxonomic account has been provided onCardamine sect.Macrophyllum (Cruciferae) from the Asian territory of the Soviet Union. Different morphological characters were examined but special attention was paid to flowers, nectar glands, pollen grains, fruits and seeds, followed by the anatomical studies of fruits and seeds. 8 species have been recognized which are arranged in 2 subsections underCardamine sect.Macrophyllum viz. 1.Macrophyllae (C. leucantha, C. tomentella, C. macrophylla andC densiflora) and 2.Prorepentae (C. schinziana, C. yezoensis, C. amareaformis andC. prorepens). Phylogenetic trend also has been traced out suggesting preliminary centres of divergency and polymorphism of the treated taxa.     

Relationships among Cedrus libani, C. brevifolia and C. atlantica as revealed by the morphological and anatomical needle characters

The main aim of the present study was testing the value of the morphological and anatomical characteristics of the needles in distinguishing Cedrus atlantica, C. libani and C. brevifolia. Nine populations were sampled in their natural habit and 25 characters were used to describe the variation of the brachyblast needles and to analyze the differences between species. The results indicated that morphological and anatomical needle characters provide valuable tools in discrimination of the taxa. The scored differences were statistically significant, as revealed in the Tukey’s t test, discrimination analysis and hierarchical analysis of variation. The results support treating C. libani, C. atlantica and C. brevifolia as independent species.     

Taxonomic revision of the genus Cutleria proposing a new genus Mutimo to accommodate M. cylindricus (Cutleriaceae,Phaeophyceae)

Molecular phylogenetic analyses of representative Cutleria species using mitochondrial cox3, chloroplast psaA, psbA and rbcL gene sequences showed that C. cylindrica Okamura was not included in the clade composed of other Cutleria species including the generitype C. multifida (Turner) Greville and the related taxon Zanardinia typus (Nardo) P.C. Silva. Instead, C. cylindrica was sister to the clade composed of the two genera excluding C. cylindrica. Cutleria spp. have heteromophic life histories and their gametophytes are rather diverse in gross morphology, from compressed or cylindrical‐branched to fan‐shaped, whereas the sporophytes are rather similar. In contrast, the monotypic species Z. typus has an isomorphic life history and resembles fan‐shaped Cutleria in morphology. Morphological comparisons of these taxa revealed that C. cylindrica is morphologically distinct from other Cutleria spp. and Z. typus in having cylindrical gametophytes with multiseriate trichothallic filaments instead of uniseriate filaments (hairs) characteristic of Cutleriales (or Cutleriaceae, Tilopteridales), and in lacking rhizoidal filaments in the crustose sporophytes. Therefore, based on the molecular and morphological data, the establishment of a new genus Mutimo to accommodate C. cylindrica, and the new combination of M. cylindricus, is proposed.     

Phylogenetic conclusions from Giemsa banding and NOR staining in top onions (Liliaceae)

The chromosomes of different strains of the top or tree onion, ofAllium cepa andA. fistulosum, as well as of cloned progenies from reciprocal crosses between these two taxa have been studied by application of Feulgen- or aceto carmine-, Giemsa- and silver staining. It was possible to differentiate between the satellite chromosomes and 2–4 other chromosome pairs ofA. cepa andA. fistulosum. The phylogenetic origin of the top onions [A. ×proliferum (Moench)Schrad.] from hybridization ofA. cepa andA. fistulosum is substantiated, taking into consideration the variability in size and position of satellites and of active NORs.     

Individual relationship between aneuploidy of gill cells and growth rate in the cupped oysters Crassostrea angulata, C. gigas and their reciprocal hybrids

The Portuguese oyster, Crassostrea angulata, is taxonomically close to the Pacific oyster, C. gigas, but there are clear genetic and phenotypic differences between these taxa. Among those differences, the faster growth of C. gigas compared with C. angulata has often been observed in the field. Crosses between C. angulata and C. gigas were performed to investigate the relationship between growth variation and somatic aneuploidy at the individual level in the two taxa and their reciprocal hybrids. The different progenies were reared in Ria Formosa (Portugal) under standard farming conditions. Growth rate and survival were significantly higher in C. gigas than in C. angulata, and the hybrids showed intermediate performances. Significant differences were also observed in the proportion of aneuploid cells (PAC) and of missing chromosomes (PMC) between the two taxa, C. angulata showing the highest values. Intermediate values of PAC and PMC were observed in the hybrids, supporting additive genetic bases of these parameters. Our results also confirm the negative correlation between somatic aneuploidy and growth rate at the individual level, as previously reported in C. gigas.     

Physiological and behavioral control of heating and cooling rates in rubber boas, Charina bottae

1. We examined the ability of rubber boas (Charina bottae) to physiologically and behaviorally control their heating and cooling rates between 5 and 35 °C with constrained and unconstrained postural treatments.     

CYTOGENETIC STUDIES IN CLARKIA,SECTION PRIMIGENIA. II. A CYTOLOGICAL SURVEY OF CLARKIA ARCUATA AND CLARKIA LASSENENSIS

Clarkia arcuata and C. lassenensis are the 2 members of the subsection Flexicaules. Although closely related morphologically, they show very different patterns of chromosomal variability in nature. About 25% of the plants grown from wild seed of C. arcuata, a predominantly cross-pollinating species, were heterozygous for 1 or 2 translocations; such heterozygotes were found in 5 of the 9 populations sampled. An analysis of the chromosome pairing in intraspecific crosses indicated that at least 5 different translocations giving a ring of 4 with the “standard” strain, 2 giving a ring of 6, and 2 giving a ring of 8 are present in nature. No arrangement was found with widespread distribution, and it is impossible to say at present what might be the primitive arrangement of this species. One population was found to contain an inversion, a rearrangement which is very rare in Clarkia at the intraspecific level. In C. lassenensis, a predominantly self-pollinating species, only 6% (3 plants) of a sample of 53 were translocation heterozygotes, and these heterozygotes were found in only 2 of 13 populations. Intraspecific crosses indicated that one chromosome arrangement, the “standard,” was present throughout the species range.     

Morphological and molecular (RAPD) analyses confirm the hybrid origin of the diploid grassCalamagrostis longiseta var.longe-aristata (Gramineae)

To examine the hybrid origin of the diploid grassCalamagrostis longiseta var.longe-aristata, we performed morphometric and genetic analyses of this taxon and its putative parental taxa. The morphometric analyses revealed that, in general,C. longiseta var.longe-aristata is morphologically intermediate betweenC. longiseta var.longiseta andC. fauriei. Previous studies have reported that some hybrids exhibit transgressive characters but others do not; the latter is the case forC. longiseta var.longe-aristata. Their absence may be due to the ecological adaptation to environments intermediate between those inhabited by the putative parental taxa, and therefore the transgressive characters have not been selected. Nevertheless, there is no direct evidence for adaptive value of the characters examined in this study and only a small part of all characters potentially responsible for adaptation was investigated. An alternative hypothesis about the absence of transgressive characters inC. longiseta var.longe-aristata is that it is at an early stage of hybrid speciation. Random amplified polymorphic DNA (RAPD) analyses showed that individuals ofC. longiseta var.longe-aristata were placed in both of the clusters formed by each putative parental taxon. Greater genetic diversity was observed inC. longiseta var.longe-aristata than in its putative parental taxa. All here reported findings support the scenario thatC. longiseta var.longe-aristata is of hybrid origin, having evolved fromC. longiseta var.longiseta andC. fauriei.     

Morphological and ploidy level variation ofCentaurea phrygia agg. (Asteraceae) in the Czech Republic, Slovakia and Ukraine

Centaurea phrygia agg. was studied in part of Central Europe (Czech Republic, Slovakia and Ukraine) to evaluate its karyological and morphological variation. Three ploidy levels were found: diploid (C. pseudophrygia, C. stenolepis and several populations ofC. phrygia s.str.), tetraploid (C. oxylepis and several populations ofC. phrygia s.str.), and triploid (very rare, only single individuals). Only one taxon,C. phrygia s.str., comprises populations of two ploidy levels, but they seem to be geographically separated. Multivariate morphometric analysis confirmed the separation of the four taxa; the length and the width of appendages of middle involucral bracts, visibility of appendages of inner involucral bracts, the length and the width of an involucre, and the length/width ratio of middle cauline leaves are the most important discriminant characters. Several populations intermediate between two species (eitherC. pseudophrygia andC. stenolepis orC. oxylepis andC. phrygia s.str.) were found. Their possible origin from introgressive hybridization is discussed considering their morphology (intermediate between putative parental species), chromosome numbers (always the same as in putative parents), and distribution (both spatially and ecologically more or less intermediate between distribution ranges of putative parents). A determination key for the four studied species, including intermediates, is also presented.     

Floral and mating system divergence in secondary sympatry: testing an alternative hypothesis to reinforcement in Clarkia

Background and Aims

Reproductive character displacement (RCD) is often an important signature of reinforcement when partially cross-compatible taxa meet in secondary sympatry. In this study, floral evolution is examined during the Holocene range expansion of Clarkia xantiana subsp. parviflora from eastern Pleistocene refugia to a western zone of sympatry with its sister taxon, subsp. xantiana. Floral divergence between the two taxa is greater in sympatry than allopatry. The goal was to test an alternative hypothesis to reinforcement – that floral divergence of sympatric genotypes is simply a by-product of adaptation to pollination environments that differ between the allopatric and sympatric portions of the subspecies'' range.

Methods

Floral trait data from two common garden studies were used to examine floral divergence between sympatric and allopatric regions and among phylogeographically defined lineages. In natural populations of C. x. parviflora, the magnitude of pollen limitation and reproductive assurance were quantified across its west-to-east range. Potted sympatric and allopatric genotypes were also reciprocally translocated between geographical regions to distinguish between the effects of floral phenotype versus contrasting pollinator environments on reproductive ecology.

Key Results

Sympatric populations are considerably smaller flowered with reduced herkogamy. Pollen limitation and the reproductive assurance value of selfing are greater in sympatric than in allopatric populations. Most significantly, reciprocal translocation experiments showed these differences in reproductive ecology cannot be attributed to contrasting pollinator environments between the sympatric and allopatric regions, but instead reflect the effects of flower size on pollinator attraction.

Conclusions

Floral evolution occurred during the westward range expansion of parviflora, particularly in the zone of sympatry with xantiana. No evidence was found that strongly reduced flower size in sympatric parviflora (and RCD between parviflora and xantiana) is due to adaptation to limited pollinator availability. Rather, floral divergence appears to have been driven by other factors, such as interactions with congenerics in secondary sympatry.     

A biosystematic study of Pacific Northwestern blue-eyed grasses (Sisyrinchium,Iridaceae)

Thirteen species of blue-eyed grasses had been described for the Pacific Northwest prior to this study. Contemporary taxonomic treatments vary; some authors recognize several of the taxa as valid species, others recognize only one highly variable, widely distributed species. Work has been directed to achieve an understanding of the biological integrity of all previously described species within the northwest. Living plants from natural populations were utilized in controlled artificial hybridization experiments, analysis of breeding systems, and cytological investigations. Hybrids of intraand interspecific crosses were examined for pollen fertility, and investigated cytologically for meiotic behavior. Eight genetically compatible groups are indicated from these experiments. Additional information gained from cytological analysis, breeding systems, ecology, distribution, and morphological studies substantiates the recognition of each genetically compatible group at the specific level, including the new species,S. hitchcockii, from southern Oregon. The following taxa are recognized for the Pacific Northwest: tetraploids (n = 16)S. bellum S. Wats.,S. halophilum Greene,S. septentrionale E. P. Bicknell; octoploids (n = 32)S. idahoense E. P. Bicknell (including the vars.segetum,macounii, andoccidentale), andS. hitchcockii D. Henderson; duodecaploids (n = 48)S. idahoense E. P. Bicknell var.idahoense, S. littorale Greene,S. montanum Greene, andS. sarmentosum Suksd. ex Greene.     

Inheritance and linkage analysis of ten enzyme and blood protein loci in the Japanese brown frogRana japonica

In order to clarify the genetic linkage groups of the Japanese brown frogRana japonica, and compare them with those of other vertebrates, the inheritance of 10 enzyme and blood protein loci was examined in 267 offspring derived from 18 crosses using 10 males heterozygous at these loci. Most of the segregation tests exhibited no significant deviations from the expected normal Mendelian ratios. Of 32 pairs of loci tested for linkage, 29 pairs showed independent assortment in all crosses examined. In the three other locus pairs, betweenADH-1 andAlb, IDH-1 andHb-1, andLDH-B andMPI, all offspring analyzed were parental, and there were no recombinants. These three linkage groups comprising six loci were thus established inR. japonica, whereas no linkage between the other four loci,AAT-1, ADA, GPI, andPEP-A, was observed.     

Crop/Weed gene flow:Cucurbita argyrosperma Huber andC. fraterna L. H. Bailey (Cucurbitaceae)

A mixed population of Cucurbita at Vado El Mow in northern Tamaulipas, Mexico showed an anomalous pattern of fruit bitterness. Some domesticated plants (C. argyrosperma andC. moschata) expressed cucurbitacin bitterness whereas some sympatric free-living plants produced non-bitter fruits. This reversal of typical cucurbitacin expression suggested gene flow between crop and weed at the site. Isozyme analysis provided little insight as to taxa involved in gene exchange, although progeny from a single free-living plant carried IDH allozymes that are associated with Mexican landraces ofC. pepo. Synthetic hybridization revealed that fertile F, hybrids are produced from crosses involvingC. fraterna as the pistillate parent andC. argyrosperma as the staminate parent. Interspecific crop/weed hybrids can produce viable progeny upon self-pollination or backcrossingto either parent, andF₂ families display normal allozyme segregation. Hybrid fertility, as indicated by pollen stainability, increases in progeny produced by backcrossingfrom theC. argyrosperma parent. Interspecific hybridfertility represents a potential for crop/weed gene flow that would be realized under natural conditions if pollen flow occurs betweenC. fraterna andC. argyrosperma in the fields of Tamaulipas. Oligolectic “squash bees” (Teponapis), efficientCucurbita pollen vectors, are present at the site. Thus, it is likely that natural interspecific crop/weed hybridization has occurred at Vado El Moro and this might at least partially explain the anomalous distribution of fruit bitterness among extant populations at the site.