bluuebunny/crossref_metadata_2025 huggingface dataset:
Sexual expression and genetic diversity in populations of Cryptogramma crispa (Pteridaceae)
Authors: Pajaro´n Santiago , Pangua Emilia , Garci´a‐A´lvarez Lorena
Published: April 2006

The reproductive biology of Cryptogramma crispa, a tetraploid species with a broad circumboreal and alpine distribution, growing mainly in siliceous boulder fields and crevices, was studied in the laboratory by growing gametophytes in plates with both solidified agar media and sterilized soil. In addition, an electrophoretic study of isozymes was carried out on frond samples from five natural populations, as an additional source of evidence concerning the breeding system and the genetic structure of sporophyte populations. Populations throughout the Iberian range of the species were selected for this study, and a Scottish population was included to represent plants from outside our local area and ecology. The morphological development of gametophytes is of the Adiantum type. All multispore cultures developed into a bigametophytic system, consisting in most cases of male and female prothalli. This pattern of sexual expression provides evidence for outcrossing as the main breeding system in this species. Moreover, there is good evidence that the species possesses an antheridiogen system to promote outcrossing. The long time needed by gametophytes to produce gametangia, and afterwards to fertilize and produce sporophytes, might be the primary reason why so few young sporophytes are found in the wild. The values of the percentage of polymorphic loci and the similarity levels obtained from the isozyme analyses indicate a level of genetic variability that would be expected in an outcrossing species. All these characteristics are usually associated with diploid fern species rather than polyploid species.
Secretory structures on the leaf rachis of Caesalpinieae and Mimosoideae (Leguminosae): implications for the evolution of nectary glands
Authors: Pascal Laurence M. , Motte‐Florac Elisabeth F. , McKey Doyle B.
Published: April 2006

Cup‐ or sometimes slit‐shaped nectary glands on the rachis are a widespread trait in the legume subfamily Mimosoideae, especially in derived tribes. Their spotty occurrence in genera that appear to be basal has led to uncertainty about when in the mimosoid radiation this character evolved. Until now, specialized rachis glands were unknown in caesalpinioids thought to be related to ancestral mimosoids. We report here the occurrence of rachis glands in seven of the ten species of the Paleotropical genus Erythrophleum, a member of the Dimorphandra group of caesalpinioids thought to include the sister group(s) of mimosoids. The histological structure and location of Erythrophleum glands suggest homology with those of mimosoids; these glands are simpler structurally than rachis glands of any known mimosoid. The Erythrophleum glands differ from those of most mimosoids in the following respects: (1) they are smaller than glands of mimosoids; (2) the secretory surface is sunken in a pit capped by a small round pore rather than exposed on a broad concave or flat surface; (3) a smaller number of cells are involved in production and secretion of nectar; (4) vascular supply to the nectary is less extensive; and (5) mechanical support tissue (sclerenchyma) is less extensive and less organized. Rachis glands appear to be absent in the nine other genera included in the Dimorphandra group. We also report the occurrence of other secretory structures (patches of glandular trichomes) on the rachis of some Caesalpinieae and Mimoseae that lack specialized nectary glands and suggest that these patches of trichomes are primitive homologues of more organized glands. We discuss the significance of these glands and of the patches of trichomes for understanding relationships among primitive mimosoids and related caesalpinioids, and for understanding the origin of ant‐guard defenses typical of many mimosoids.
Phylogenetic systematics of the tribe Millettieae (Leguminosae) based on chloroplast trnK/matK sequences and its implications for evolutionary patterns in Papilionoideae
Authors: Hu Jer‐Ming , Lavin Matt , Wojciechowski Martin F. , Sanderson Michael J.
Published: April 2006

Phylogenetic relationships in the tribe Millettieae and allies in the subfamily Papilionoideae (Leguminosae) were reconstructed from chloroplast trnK/matK sequences. Sixty‐two accessions representing 57 traditionally recognized genera of Papilionoideae were sampled, including 27 samples from Millettieae. Phylogenies were constructed using maximum parsimony and are well resolved and supported by high bootstrap values. A well‐supported “core Millettieae” clade is recognized, comprising the four large genera Millettia, Lonchocarpus, Derris, and Tephrosia. Several other small genera of Millettieae are not in the core Millettieae clade. Platycyamus is grouped with Phaseoleae (in part). Ostryocarpus, Austrosteenisia, and Dalbergiella are neither in the core Millettieae or Phaseoleae clade. These taxa, along with core Millettieae and Phaseoleae, form a monophyletic sister group to Indigofereae. Cyclolobium and Poecilanthe are close to Brongniartieae. Callerya and Wisteria belong to a large clade that includes all the legumes that lack the inverted repeat in their chloroplast genome, which confirms previous rbcL and phytochrome gene family phylogenies. The evolutionary history of four characters was examined in Millettieae and allies: the presence of canavanine, inflorescence types, the dehiscence of pods, and the presence of winged pods. trnK/matK sequence analysis suggests that the presence of a pseudoraceme or pseudopanicle and the accumulation of nonprotein amino acids are phylogenetically informative for Millettieae and allies with only a few exceptions.
Genetic diversity and population structure of the serpentine endemicCalystegia collina(Convolvulaceae) in northern California
Authors: Wolf Amy T. , Howe Robert W. , Hamrick James L.
Published: April 2006

We used enzyme electrophoresis to evaluate genetic diversity in 32 populations ofCalystegia collina, a clonal plant species endemic to serpentine outcrops in northern California (USA). Of 34 loci examined 56% were polymorphic, but on average only 17% were polymorphic within local populations. Neither the total number of alleles nor the number of multilocus genotypes differed significantly between populations in small vs. large serpentine outcrops. Genetic and geographic distances between populations were positively correlated, but this relationship was not significantly affected by the isolation of serpentine outcrops. Populations were highly differentiated (Fst= 0.417) and little genetic variation was explained by geographic region or serpentine outcrop.

Observed heterozygosity within populations almost always exceeded Hardy‐Weinberg expectations. In many populations, all 30 sample ramets were uniformly heterozygous at one or more loci yet were genetically variable at other loci. These results imply that manyC. collinapopulations originate from one or a few genetic founders, with little recruitment from seeds. Genetic variation within uniformly heterozygous populations must be the product of multiple, closely related founders or somatic mutations within the population. We conclude that vegetative reproduction, perhaps coupled with somatic mutation, helps maintain genetic diversity in these isolated but long‐lived populations.
Pollinator‐mediated interactions between a pathogenic fungus, Uromyces pisi (Pucciniaceae), and its host plant,Euphorbia cyparissias (Euphorbiaceae)
Authors: Pfunder Monika , Roy Barbara A.
Published: April 2006

The plant Euphorbia cyparissias is commonly infected by rust fungi of the species complex Uromyces pisi. When infected, E. cyparissias is unable to flower, but instead is induced by the fungus to form pseudoflowers. Pseudoflowers are rosettes of yellow leaves upon which the fungus presents its gametes in a sweet‐smelling fungal nectar. We hypothesized that the fungi, as they are heterothallic, are dependent on insect visitation to cross‐fertilize their mating types. We confirmed that insects are required with an insect exclusion experiment. We further hypothesized that pseudoflowers of U. pisi interact with uninfected true host flowers through insects during their period of co‐“flowering” in early spring. We conducted artificial array experiments in the field to test whether the two species share insects and whether they influenced each other's insect visitation. Insects moved between true flowers and pseudoflowers, but true flowers received more visits over all. Pseudoflowers and true flowers did not influence each other's visitation rates in mixtures. However, shorter visits were observed on pseudoflowers in mixtures than monocultures, suggesting that true flowers might be competitors for pseudoflowers. Further experiments are needed to determine whether the similarity of pseudoflowers to true flowers is adaptive.
Phylogenetic relationships of Salix (Salicaceae) based on rbcL sequence data
Authors: Azuma Takayuki , Kajita Tadashi , Yokoyama Jun , Ohashi Hiroyoshi
Published: April 2006

Nucleotide sequences of the chloroplast‐encoded rbcL gene were used to examine phylogenetic relationships of the genus Salix together with other allied genera of the family Salicaceae. Phylogenetic analyses of rbcL sequences strongly suggest the monophyly of three commonly recognized genera (Chosenia, Salix, and Toisusu). Two monophyletic groups are recognized within the larger monophyletic group. They do not correspond with any infrageneric taxa proposed so far. With regard to character evolution, it is thought that the reduction of stamen number from more than two stamens to two might occur in at least three lineages and that fused bud scales evolved several times and/or the reverse evolution occurred from fused to free. Some types of pollen surfaces are considered to have evolved independently.
Plant cell biology in the new millennium: new tools and new insights
Authors: Blancaflor Elison B. , Gilroy Simon
Published: April 2006

The highly regulated structural components of the plant cell form the basis of its function. It is becoming increasingly recognized that cellular components are ordered into regulatory units ranging from the multienzyme complexes that allow metabolic channeling during primary metabolism to the “transducon” complexes of signal transduction elements that allow for the highly efficient transfer of information within the cell. Against this structural background the highly dynamic processes regulating cell function are played out. Recent technological advances in three areas have driven our understanding of the complexities of the structural and functional dynamics of the plant cell. First, microscope and digital camera technology has seen not only improvements in the resolution of the optics and sensitivity of detectors, but also the development of novel microscopy applications such as confocal and multiphoton microscopy. These technologies are allowing cell biologists to image the dynamics of living cells with unparalleled three‐dimensional resolution. The second advance has been in the availability of increasingly powerful and affordable computers. The computer control/analysis required for many of the new microscopy techniques was simply unavailable until recently. Third, there have been dramatic advances in the available probes to use with these new microscopy approaches. Thus the plant cell biologist now has available a vast array of fluorescent probes that will report cell parameters as diverse as the pH of the cytosol, the oxygen level in a tissue, or the dynamics of the cytoskeleton. The combination of these new approaches has led to an increasingly detailed picture of how plant cells regulate their activities.
High abscission rates of damaged expanding leaves: field evidence from seedlings of a Bornean rain forest tree
Authors: Blundell Arthur G. , Peart David R.
Published: April 2006

Herbivore damage is known to cause the premature loss of mature leaves. However, the effects of herbivory on abscission during the early stages of leaf development remain unexplored, even though herbivores frequently prefer unlignified, immature leaves. In a field experiment, we removed 50% of the tissue from leaves at various stages of development on seedlings of Shorea hopeifolia (Dipterocarpaceae), a dominant rain forest tree in Indonesian Borneo. Four weeks following simulated herbivory, >88% of unlignified expanding leaves had been abscised, compared to only 20% of fully expanded, unlignified leaves and 0% of recently lignified, mature leaves. In a separate experiment over 9 wk, simulated herbivory did not increase abscission rates of mature leaves, even when 75% of leaf tissue was removed. Because most (58%) of S. hopeifolia seedlings under natural conditions had lost 1% or less of the tissue from their mature leaves, herbivore damage probably has little effect on the abscission of mature leaves. In contrast, the tendency for damaged expanding leaves to abscise may explain why 49% of S. hopeifolia seedlings had already lost their youngest leaf. If similar patterns occur in other species, herbivore attacks on developing leaves may contribute substantially to both leaf loss and the cumulative impact of herbivory on the growth and survival of whole plants.
Water loss and viability inZizania(Poaceae) seeds during short‐term desiccation
Authors: Horne Francis R. , Kahn Ari
Published: April 2006

How Texas wild rice,Zizania texana, became isolated in the San Marcos River of Central Texas, hundreds of kilometres from other wild rice populations is not known.Zizaniaseeds are intolerant of short‐term desiccation. Seeds desiccated at 14% relative humidity (RH) and 75% RH do not survive after only 5–6 d and 2–3 wk of drying. Water loss is rapid and reaches a maximum at the time of seed death due to drying. And although allZizaniaseeds germinate well following a long, cold dormancy period,Z. texanaseeds readily germinate in the isothermic water (22°C) of the San Marcos River and Springs without an obligate, cold dormant period. Within 30–60 d of collection,Z. texanaseeds germinate in substantial numbers, unlike seeds ofZ. palustris, which require a long, cold dormant period. The Texas population ofZ. texanamay represent a relict population of a once more widely dispersed wild rice population, since the San Marcos springs probably have never gone dry.
Utility of 17 chloroplast genes for inferring the phylogeny of the basal angiosperms
Authors: Graham Sean W. , Olmstead Richard G.
Published: April 2006

Sequences from 14 slowly evolving chloroplast genes (including three highly conserved introns) were obtained for representative basal angiosperm and seed‐plant taxa, using novel primers described here. These data were combined with published sequences from atpB, rbcL, and newly obtained sequences from ndhF. Combined data from these 17 genes permit sturdy, well‐resolved inference of major aspects of basal angiosperm relationships, demonstrating that the new primers are valuable tools for sorting out the deepest events in flowering plant phylogeny. Sequences from the inverted repeat (IR) proved to be particularly reliable (low homoplasy, high retention index). Representatives of Cabomba and Illicium were the first two successive branches of the angiosperms in an initial sampling of 19 exemplar taxa. This result was strongly supported by bootstrap analysis and by two small insertion/deletion events in the slowly evolving introns. Several paleoherb groups (representatives of Piperales) formed a strongly supported clade with taxa representing core woody magnoliids (Laurales, Magnoliales, and Winteraceae). The monophyly of the sampled eudicots and monocots was also well supported. Analyses of three major partitions of the data showed many of the same clades and supported the rooting seen with all the data combined. While Amborella trichopoda was supported as the sister group of the remaining angiosperms when we added Amborella and Nymphaea odorata to the analysis, a strongly conflicting rooting was observed when Amborella alone was added.
Genetic diversity and structure of the narrow endemic Wyethia reticulata and its congener W. bolanderi (Asteraceae) using RAPD and allozyme techniques
Authors: Ayres Debra R. , Ryan Frederick J.
Published: April 2006

Wyethia reticulata is an edaphic endemic in the Sierra Nevada foothills. Its sympatric congener, W. bolanderi, is also restricted to the foothills, but has a north–south range of 275 km, compared to 14 km for W. reticulata. The goals of this study were to determine clonal diversity, population size, genetic variation, and spatial and generic structure for each species from paired populations in El Dorado County, California, using allozyme and RAPD (random amplified polymorphic DNA) methodologies. Wyethia reticulata, spreading by rhizomes, had populations dominated by a few large individuals, while W. bolanderi, with a basal caudex, had populations of a few hundred evenly sized individuals. Genetic analyses indicated that W. reticulata, compared to its congener, had somewhat less genetic diversity (HT: 0.28 vs. 0.38), had more of its genetic variation partitioned among populations (FST: 0.25 vs. 0.07), and showed a complete absence of inbreeding (FIS: −0.03 vs. 0.22). Population membership in accord with populations defined by geographical location resulted only when all markers were included in the analysis. Ecological limits on recruitment of genets appears to result in small population size in W. reticulata. Limited gene flow, drift within small populations, and sexual reproductive dominance of large clones result in the genetic divergence of populations in this species, while genetic diversity is maintained by the longevity of clones and outbreeding.
Conservation implications of genetic variation in three rare species endemic to Florida rosemary scrub
Authors: Dolan Rebecca W. , Yahr Rebecca , Menges Eric S. , Halfhill Matthew D.
Published: April 2006

Habitat conversion and fire suppression during the last 50 yr have greatly reduced and altered Florida scrub vegetation, resulting in threats to the persistence of its unique flora. As part of a larger conservation project, we investigated patterns of isozyme variation in three rare perennial scrub plants with overlapping ranges endemic to Florida rosemary scrub on the Lake Wales Ridge. All three species have low levels of genetic variation, comparable to or lower than those generally reported for rare plants with restricted geographic ranges.Liatris ohlingeraehas more than twice the expected heterozygosity of the other two species, with little population differentiation. In contrast,Hypericum cumulicolahas highly differentiated populations with little apparent interpopulation gene flow and heterozygote deficiencies indicative of inbreeding.Eryngium cuneifolium,the species with the narrowest range and fewest populations, has intermediate values for genetic parameters. Although the three species have narrow and overlapping geographic ranges and similar habitat specificity, we discuss how optimal conservation of each species differs.
Inhibition of seedling survival under Rhododendron maximum (Ericaceae): could allelopathy be a cause?
Authors: Nilsen Erik T. , Walker John F. , Miller Orson K. , Semones Shawn W. , Lei Thomas T. , Clinton Barton D.
Published: April 2006

In the southern Appalachian mountains a subcanopy species, Rhododendron maximum, inhibits the establishment and survival of canopy tree seedlings. One of the mechanisms by which seedlings could be inhibited is an allelopathic effect of decomposing litter or leachate from the canopy of R. maximum (R.m.) on seed germination, root elongation, or mycorrhizal colonization. The potential for allelopathy by R.m. was tested with two bioassay species (lettuce and cress), with seeds from four native tree species, and with three ectomycorrhizal fungi. Inhibitory influences of throughfall, fresh litter, and decomposed litter (organic layer) from forest with R.m. (+R.m. sites) were compared to similar extractions made from forest without R.m. (−R.m. sites). Throughfall and leachates of the organic layer from both +R.m. and −R.m. sites stimulated germination of the bioassay species above that of the distilled water control, to a similar extent. There was an inhibitory effect of leachates of litter from +R.m. sites on seed germination and root elongation rate of both bioassay species compared with that of litter from −R.m. sites. Native tree seed stratified in forest floor material from both forest types had a slightly higher seed germination rate compared with the control. A 2‐yr study of seed germination and seedling mortality of two tree species, Quercus rubra and Prunus serotina, in field plots showed no significant influence of litter or organic layer from either forest type. Incorporating R.m. leaf material into the growth medium in vitro depressed growth of one ectomycorrhizal species but did not affect two other species. Leaf material from other deciduous tree species depressed ectomycorrhizal growth to a similar or greater extent as leaf material from R.m. In conclusion, R.m. litter can have an allelopathic effect on seed germination and root elongation of bioassay species as well as some ectomycorrhizal species. However, this allelopathic affect is not manifest in field sites and is not likely to be an important cause for the inhibition of seedling survival within thickets of R.m.
Distribution and sequence analysis of the centromere‐associated repetitive element CEN38 of Sorghum bicolor (Poaceae)
Authors: Zwick M. S. , Islam‐Faridi M. N. , Zhang H. B. , Hodnett G. L. , Gomez M. I. , Kim J. S. , Price H. J. , Stelly D. M.
Published: April 2006

Fluorescence in situ hybridization (FISH) of a large‐insert genomic clone, BAC 22B2, previously suggested that Sorghum bicolor (2n = 20) has the tetraploid architecture AbAbBbBb. Here, we report on BAC 22B2 subclone pCEN38 (1047‐bp insert) as related to sorghum and sugarcane. Mitotic FISH of six different subclones of BAC 22B2 showed that pCEN38 produced the strongest specificity to the Ab subgenome and signal occurred primarily near centromeres. Southern blots of pCEN38 to 21 crop plants revealed a narrow taxonomic distribution. Meiotic metaphase I FISH positioned pCEN38 sequences near active centromeres. Pachytene FISH revealed that the distributions are trimodal in several Bb and possibly all sorghum chromosomes. DNA sequencing revealed that the pCEN38 fragment contains three tandemly repeated dimers (<280 bp) of the same sequence family found in sorghum clone pSau3A10, and that each dimer consists of two divergent monomers (<140 bp). Sequence comparisons revealed homology between the pCEN38 monomers and the SCEN 140 bp tandem repeat family of sugarcane. FISH of pCEN38 yielded signal in centromere regions of most but not all sugarcane chromosomes. Results suggest that sugarcane and sorghum share at least one ancestor harboring elements similar to pCEN38 and SCEN and that each species had an ancestor in which the repetitive element was weakly present or lacking.
Origin and relationships of the tarweed–silversword lineage (Compositae–Madiinae)
Authors: Baldwin Bruce G. , Wessa Bridget L.
Published: April 2006

Based on results from phylogenetic analyses of nuclear 18S–26S rDNA internal transcribed spacer (ITS) region sequences, we suggest that the monophyletic tarweed and silversword subtribe (Madiinae) is phylogenetically nested among epaleate, x = 19 species of helenioid Heliantheae. Strong bootstrap support (100%) was obtained for a sister‐group relationship between Madiinae and Arnica (including Mallotopus and Whitneya) in an analysis including representatives of recognized genera in a principally Californian clade (Madieae sensu Baldwin) identified from a phylogenetic investigation of Heliantheae s.l. (sensu lato) and Eupatorieae. In all minimum‐length trees, the robust lineage comprising Madiinae and Arnica (x = 19) is part of a larger clade that also comprises Eatonella s.s. (sensu stricto), Hulsea, and Venegasia, all with x = 19. The phylogenetic position of Madiinae within a group of genera based uniformly on x = 19 leads us to conclude that the modal numbers of n = 7 and n = 8 (and other numbers, as low as n = 4) in Madiinae are the results of extreme dysploidy. Among the x = 19 “arnicoid” taxa, the near‐universal characteristics of perenniality (except in the monotypic Eatonella s.s. and a minority of hulseas) and montane or high‐latitudinal occurrence (except in the monotypic Venegasia) lead us to suggest that the most recent common ancestor of the tarweeds (a principally annual group of seasonally dry, low‐elevation habitats) was probably a montane, herbaceous perennial resembling the unusual subalpine and alpine tarweeds constituting Raillardella s.s. (x = 17), an arnica‐like genus. In Madiinae, Raillardella s.s. may be plesiomorphic in habit, capitular and ecological characteristics, and high base chromosome number. Shifts to an annual habit and to low chromosome numbers in Madiinae have been followed by subsequent episodes of polyploidy and descending dysploidy. We conclude that genome evolution in Madiinae has been marked by wide swings in chromosome number that confuse identification of diploids and polyploids.
Outcrossing rate and inbreeding depression in the perennial yellow bush lupine, Lupinus arboreus (Fabaceae)
Authors: Kittelson Pamela M. , Maron John L.
Published: April 2006

Little is known about the breeding systems of perennial Lupinus species. We provide information about the breeding system of the perennial yellow bush lupine, Lupinus arboreus, specifically determining self‐compatibility, outcrossing rate, and level of inbreeding depression. Flowers are self‐compatible, but autonomous self‐fertilization rarely occurs; thus selfed seed are a product of facilitated selfing. Based on four isozyme loci from 34 maternal progeny arrays of seeds we estimated an outcrossing rate of 0.78. However, when we accounted for differential maturation of selfed seeds, the outcrossing rate at fertilization was lower, ∼0.64. Fitness and inbreeding depression of 11 selfed and outcrossed families were measured at four stages: seed maturation, seedling emergence, seedling survivorship, and growth at 12 wk. Cumulative inbreeding depression across all four life stages averaged 0.59, although variation existed between families for the magnitude of inbreeding depression. Inbreeding depression was not manifest uniformly across all four life stages. Outcrossed flowers produced twice as many seeds as selfed flowers, but the mean performance of selfed and outcrossed progeny was not different for emergence, seedling survivorship, and size at 12 wk. Counter to assumptions about this species, L. arboreus is both self‐compatible and outcrosses ∼78% of the time.
Petrofilaments in palynological preparations
Authors: Graham Alan , Wood Gordon D. , Elsik William C. , Speed Robert C.
Published: April 2006

Microscopic structures (petrofilaments) may develop during palynological laboratory processing procedures that are superficially similar to secondary wall thickenings and elaters. These filaments form from angular bodies that resemble fungal spores and resin bodies. The angular bodies are a type of hydrocarbon called asphaltene and extrude the filaments when compounds in the bodies react with solvents in the mounting medium. They may be misinterpreted as fossils and so are illustrated here for the first time in the published literature.
The relationship between xylem conduit diameter and cavitation caused by freezing
Authors: Davis Stephen D. , Sperry John S. , Hacke Uwe G.
Published: April 2006

The centrifuge method for measuring the resistance of xylem to cavitation by water stress was modified to also account for any additional cavitation that might occur from a freeze‐thaw cycle. A strong correlation was found between cavitation by freezing and mean conduit diameter. On the one extreme, a tracheid‐bearing conifer and diffuse‐porous angiosperms with small‐diameter vessels (mean diameter <30 μm) showed no freezing‐induced cavitation under modest water stress (xylem pressure = −0.5 MPa), whereas species with larger diameter vessels (mean >40 μm) were nearly completely cavitated under the same conditions. Species with intermediate mean diameters (30–40 μm) showed partial cavitation by freezing. These results are consistent with a critical diameter of 44 μm at or above which cavitation would occur by a freeze–thaw cycle at −0.5 MPa. As expected, vulnerability to cavitation by freezing was correlated with the hydraulic conductivity per stem transverse area. The results confirm and extend previous reports that small‐diameter conduits are relatively resistant to cavitation by freezing. It appears that the centrifuge method, modified to include freeze–thaw cycles, may be useful in separating the interactive effects of xylem pressure and freezing on cavitation.
Seed provisioning in gynodioeciousSilene acaulis (Caryophyllaceae)
Authors: Delph Lynda F. , Bailey Maia F. , Marr Deborah L.
Published: April 2006

In gynodioecious species, which contain females and hermaphrodites, the outcrossed seeds of females have been found to outperform the outcrossed seeds of hermaphrodites, in spite of the fact that their seeds are not larger in mass. Females do not make pollen. Hence the nutrients that hermaphrodites allocate to pollen, such as nitrogen, might be allocated to seeds by the females, such that individual seeds from females are better provisioned than those from hermaphrodites. Alternatively, females might make more seeds, rather than better provisioned seeds. We tested the hypothesis that seeds from females would be better provisioned for the gynodioecious species Silene acaulis, by comparing seed mass, embryo/endosperm mass, nitrogen and phosphorus content, and energy content for outcrossed seeds from females and hermaphrodites produced in a natural population. We also measured the proportion of flowers that set fruit in both morphs. Seeds from the two sexual morphs were not found to differ significantly for any of the measures of seed provisioning, with seeds from females containing either nonsignificantly less or equivalent amounts of each of the measures as compared to hermaphrodites. However, females set a significantly higher proportion of their flowers to fruit, as compared to hermaphrodites. These results indicate that females do not provision individual seeds more than hermaphrodites in S. acaulis, and alternative hypotheses will need to be examined to explain the difference in the performance of the seeds from the two sexual morphs.
Narrow hybrid zone between two subspecies of big sagebrush (ARTEMISIA TRIDENTATA: Asteraceae). IX. Elemental uptake and niche separation
Authors: Wang Han , McArthur E. Durant , Freeman D. Carl
Published: April 2006

The concentrations of selected elements and their biological absorption coefficients were determined for leaves from plants in native stands and reciprocal transplant gardens to determine whether niche differentiation occurs among the parental taxa and their hybrids in the big sagebrush hybrid zone in Utah. The bounded hybrid superiority model predicts such niche differentiation, while the ecologically neutral dynamic equilibrium model predicts complete niche overlap, at least in the vicinity of the hybrid zone. The concentrations of elements in the leaves of site‐indigenous sagebrush and the biological absorption coefficients differed significantly between the subspecies and between either parental taxon and hybrids. Within reciprocal transplant gardens, both the elemental concentrations and the biological absorption coefficients differed among the gardens and taxa. Significant genotype‐by‐environment interactions were observed for several essential elements. Niche differentiation was evident as correspondence analyses ordinated the parental taxa and hybrids into separate groups even when raised in the same garden. These findings support the ecologically based bounded hybrid superiority model and suggest that the big sagebrush parental taxa and their hybrids have adapted to their respective unique habitats.
Predispersal predation of an understory rainforest herb Aphelandra aurantiaca (Acanthaceae) in gaps and mature forest
Authors: Calvo‐Irabie´n Luz Mari´a , Islas‐Luna Angeles
Published: April 2006

The opening of a canopy gap at Los Tuxtlas rainforest has an impact on populations of the understory herb Aphelandra aurantiaca: the ratio of recruited seedlings per reproductive individual is 1:17 in mature forest vs. gaps. Predation occurring before seed dispersal seems a plausible explanation for this observed difference. In a field experiment, in which insecticide was applied to plants growing in gaps and mature forest, we evaluated the extent to which herbivore damage to flowers, fruits, and seeds reduces the number of seeds available for seedling establishment. Under natural conditions, ∼30% of the flowers and >70% of the capsules of A. aurantiaca showed herbivore damage, but its impact changed depending on the type of forest habitat. Flower and fruit herbivores caused more damage in closed forest than in gaps, and this difference was even bigger under the insecticide treatment. Insecticide effectiveness varied depending on the type of forest patch. The highest herbivore impact on seeds was found in the mature forest without insecticide treatment, where most seeds were destroyed. The percentages of seed damage reported here show that predispersal predation is limiting seedling recruitment, especially in mature forest. Other possible explanations might be differences in insect composition, densities, and behavior between gaps and mature forest.
The efficiency of Arabidopsis thaliana (Brassicaceae) root hairs in phosphorus acquisition
Authors: Bates Terence R. , Lynch Jonathan P.
Published: April 2006

Arabidopsis thaliana root hairs grow longer and denser in response to low‐phosphorus availability. In addition, plants with the root hair response acquire more phosphorus than mutants that have root hairs that do not respond to phosphorus limiting conditions. The purpose of this experiment was to determine the efficiency of root hairs in phosphorus acquisition at high‐ and low‐phosphorus availability. Root hair growth, root growth, root respiration, plant phosphorus uptake, and plant phosphorus content of 3‐wk‐old wild‐type Arabidopsis (WS) were compared to two root hair mutants (rhd6 and rhd2) under high (54 mmol/m3) and low (0.4 mmol/m3) phosphorus availability. A cost‐benefit analysis was constructed from the measurements to determine root hair efficiency. Under high‐phosphorus availability, root hairs did not have an effect on any of the parameters measured. Under low‐phosphorus availability, wild‐type Arabidopsis had greater total root surface area, shoot biomass, phosphorus per root length, and specific phosphorus uptake. The cost‐benefit analysis shows that under low phosphorus, wild‐type roots acquire more phosphorus for every unit of carbon respired or unit of phosphorus invested into the roots than the mutants. We conclude that the response of root hairs to low‐phosphorus availability is an efficient strategy for phosphorus acquisition.
New Approaches to Old Problems: The Well-Being of the Population of Russia from 1821 to 1910 as Measured by Physical Stature
Authors: Mironov Boris N.
Published: April 2006

Scholars generally agree on the relationship between the physical stature, or height, of children and adults, and their quality of life, or their biological status, including diet, illnesses, intensity and conditions of work, availability of medical care, living conditions, psychological well-being, climate, water, air, and other environmental factors that have impinged on their lives prior to the point at which their height is measured. Genetic factors have an important effect on individual height, but genetic distinctions lose their significance when masses of individuals are measured and average heights are compared. The same effect holds at the level of entire populations: differences in height are determined, not by ethnic or racial attributes, but by living conditions.
Making Sense of the Sensual in Pavel Florenskii's Aesthetics: The Dialectics of Finite Being
Authors: Hutchings Stephen C.
Published: April 2006

A boundary is not that at which something stops, but…that from which something begins its presencing.

—Martin Heidegger,Poetry, Language, Thought

Personhood is a living contradiction—between private and social, form and content, finite and infinite, freedom and fate. Personhood would be lost if the boundaries and the forms that contain it were to disappear, if it were to dissolve into cosmic infinity. But personhood would not be the image and likeness of God if it did not accommodate within itself infinite content.

—Nikolai Berdiaev,Filosofiia svobodnogo dukha

The aesthetic…is the first stirrings …of the body's long, inarticulate rebellion against the tyranny of the theoretical.

—Terry Eagleton,The Ideology of the Aesthetic
Singing on the Steppes for Stalin: Ivan Pyr'ev and the Kolkhoz Musical in Soviet Cinema
Authors: Taylor Richard
Published: April 2006

In his celebrated "secret speech" to the delegates to the Twentieth Party Congress in February 1956, Nikita Khrushchev singled out Soviet filmmakers for their part in establishing and maintaining Stalin's personality cult. Although not specifically mentioned by Khrushchev, one film has been generally identified as a prime example of the way in which those filmmakers "varnished the reality," particularly of the Soviet countryside during the Stalin period: Ivan Pyr'ev'sKubanskie kazaki(The Kuban cossacks) made in the film-famine year of 1949 and released in February 1950. But let us look at what Khrushchev actually said.
Historicism or Providentialism? Pushkin'sHistory of Pugachevin the Context of French Romantic Historiography
Authors: Dolinin Alexander
Published: April 2006

The evolution of Aleksandr Pushkin's ideology and poetics in the 1830s has long been the most controversial issue of Pushkin studies, the greatest stumbling block to biographers and literary critics. Grigorii Gukovskii's simple scheme, which construes Pushkin's "path" as a steady progression from romanticism toward realism and historicism, though not yet totally refuted, is gradually falling out of favor, for it ignores, contradicts, or misinterprets obvious "archaic," retrograde trends in Pushkin's late writings. Repudiating and subverting contemporaneous romantic codes, Pushkin, as a number of recent studies have shown, does not replace them with innovative prerealist or realist ones but tries to rejuvenate certain outdated eighteenth-century systems.
Afterword: The “Trade and … ” Conundrum—A Commentary
Authors: Steger Debra P.
Published: April 2006

The issue of whether and how the trading system should deal with social and economic policies not strictly within the ambit of the WTO has been with us at least since the inception of the GATT in 1947-1948. It is not a new question. The problem, however, has become even more vexing since the 1970s, as tariffs became less important in trading relationships and governments struggled to respond to a proliferation of nontariff barriers to trade. I will argue, in this Afterword, that the question is not whether the WTO should or should not deal with the “trade and … ” subjects—trade and environment, trade and public health, trade and labor rights, trade and human rights, trade and competition, trade and investment, and trade and intellectual property, to name a few. It already does and has done so, in many respects, since 1948. The question I would pose is this: how should these so-called nontrade subjects be dealt with within the WTO system? And who should define the scope of WTO recognition/cognizance of these subjects: WTO member governments (the “Members”) or the quasi-judicial bodies of the dispute settlement system (the panels and the Appellate Body)?
The Myth and Reality of Transboundary Environmental Impact Assessment
Authors: Knox John H.
Published: April 2006

The dominant story of transboundary environmental impact assessment in international law has the following elements: (1) customary international law prohibits transboundary pollution; (2) according to the classic version of this prohibition, contained in Principle 21 of the 1972 Stockholm Declaration, states must ensure that activities within their territory or under their control do not harm the environment beyond their territory; (3) to ensure that activities within their jurisdiction will not cause transboundary harm, states must assess the potential transboundary effects of the activities; and (4) to that end, states enter into international agreements requiring them to carry out transboundary environmental impact assessment (transboundary EIA) for activities that might cause transboundary harm.
Metaphor Is to Dostoevskii as Metonymy Is to Tolstoi
Authors: Curtis James M.
Published: April 2006

The terms metaphor and metonymy, as defined by Roman Jakobson, produce important insights when applied to the novels of Fedor Dostoevskii and Lev Tolstoi. The oeuvre of each novelist constitutes a remarkably consistent whole because it emanates from the creative unconscious, rather than from conscious thought processes. In Jakobson’s view, metaphor involves the “combination of heterogeneous elements”; such elements in Dostoevskii include contrasting styles, genres, and references to other art forms such as painting. Windows juxtapose interior and exterior space, as the reading of letters juxtaposes private to public communication. By contrast, metonymy involves the linking of similar elements. As a metonymical writer, Tolstoi tended to take the opposition between self and other that he inherited from the romantic tradition and transform it into a relationship between self and self. The purpose of his well-known device of estrangement is to create just such transformations. In courtship, the self-other relationship is that of man to woman; Tolstoi minimizes this relationship by avoiding all sincere expressions of desire that lead to marriage.
Genealogy, Class, and “Tribal Policy” in Soviet Turkmenistan, 1924-1934
Authors: Edgar Adrienne L.
Published: April 2006

This article focuses on Soviet policy toward genealogically defined identity groups in the Central Asian republic of Turkmenistan. For Soviet authorities, kinship loyalties were problematic chiefly because they hindered the emergence of class consciousness among the Turkmen. Soviet officials pursued two essentially contradictory policies in their attempt to eliminate “tribalism” in the Turkmen republic. First, they sought to undermine the economic basis of genealogical affiliation by dismantling the existing system of collective land tenure. Second, they devised a policy of “tribal parity”, which attempted to suppress kin-based conflict by guaranteeing fair and equal treatment for all genealogical groups. Instead of allowing class consciousness to supplant kinship loyalties, however, Soviet rule tended to increase the salience of distinctions based on genealogy. Because of the close linkage between genealogy and socioeconomic standing in Turkmenistan, Soviet attempts to foment class conflict inadvertently exacerbated descent group conflict.
Metaphors of Dictatorship and Democracy: Change in the Russian Political Lexicon and the Transformation of Russian Politics
Authors: Anderson Richard D.
Published: April 2006

Metaphors act as cues to social identities. Political discourse that communicates the distinctiveness of the rulers' identity sustains authoritarianism by cueing people to act as either oppressors or oppressed, while political discourse that cues identification by citizens with politicians promotes democracy by encouraging people to participate. In Politburo speeches from the era of Soviet authoritarianism, metaphors of size, superiority, distance, and subordination were abundant. These metaphors are suitable for emphasizing the separateness of politics from ordinary life and for communicating the inferiority of the populace. In Politburo speeches from the transition year 1989, these metaphors had already begun to decrease in frequency, while new metaphors, often borrowed from the discourse of international diplomacy, deconstructed the rulers' claims to continuing authority. In Russian political discourse from the first years of electoral politics, authoritarian metaphors decline even more sharply and are replaced by metaphors of choice and identification suitable for encouraging people to align themselves with electoral candidates.
Aleksandr Polezhaev and Remembrance of War in the Caucasus: Constructions of the Soldier as Victim
Authors: Layton Susan
Published: April 2006

And thus the whirligig of time brings in his revenges.

—Shakespeare,Twelfth Night

Paul Fussell'sThe Great War and Modern Memorywas a landmark in the study of literature's role in shaping a society's remembrance of war. Although Fussell's book is primarily devoted to famous British poets of World War I, he stimulates thinking about the general question of how any military conflict comes to exist in the minds of civilian readers. A fascinating aspect of this immense topic concerns the power of words in the absence of images. Before newsreels and television regularly exposed civilians to scenes of carnage, writers had to rely on language to "depict" things a reader had never witnessed and probably never would. A picture can serve as a powerful substitute for seeing a massacre, and just one may leave an indelible mark. But words alone lack the stunning immediacy of visual images, an argument we can trace back to Aristotle. Verbal "depiction" is only a metaphor, as Viktor Shklovskii stressed when he asserted (with reference to suicide) that "'Blood' in poetry is not bloody." Unlike some deconstructionists, Shklovskii was not fretting about how much reality bloodshed has "prior to verbal configurations." He pinpointed instead the emotional and aesthetic detachment of readers never threatened by violence.
A Mass for a Heretic? The Controversy over Lev Tolstoi's Burial
Authors: Kolstø Pál
Published: April 2006

When Lev Tolstoi emerged as a religious teacher in the 1880s, taking a sharply polemical stance against the Orthodox faith, the leadership of the Russian church groped for ways and means to stem the spread of the pernicious new heresy among the Russian public. The most ambitious but also the most disastrous attempt was made in 1901 when the synod promulgated an official pronouncement (poslanie) against him. This document, which created a worldwide scandal, was undertaken by the church itself and not, as has been widely assumed, at the instigation of the state authorities. In its poslanie the synod declared that Tolstoi could not receive an Orthodox burial unless he repented. This strategy badly backfired, since Tolstoi under no circumstances wanted such a burial and therefore made no move toward repentance. At the same time many Russians, including fervent believers, felt that the church itself with its requiem ban had sinned against the Christian injunction of all-embracing love. When Tolstoi died in 1910 and the burial issue became acute, the synod strenuously, but unsuccessfully, searched for a way out of its predicament.
Giles of Viterbo: A Reformer's Thought on Renaissance Rome
Authors: O'Malley John W.
Published: April 2006

Giles of Viterbo (Egidio da Viterbo, 1469-1532) has been receiving increasing attention as his place in early sixteenth-century intellectual and religious history becomes clearer: he combined a central and effective position in ecclesiastical administration with an active role in the leading scholarly and literary circles of the late Italian Renaissance. As prior general of the Augustinian friars from 1508 until 1518 he undertook from Rome a vigorous reform of the order. He was a trusted adviser of Pope Julius II, under whose powerful patronage he had been elected head of the Augustinians, and he enjoyed a very cordial relationship with the two Medici popes, Leo X and Clement VII, the former of whom created him a cardinal in 1517.