bluuebunny/crossref_metadata_2025 huggingface dataset:
Inbreeding depression in two species of Mimulus (Scrophulariaceae) with contrasting mating systems
Authors: Carr David E. , Dudash Michele R.
Published: January 2018

We examined the effect of self‐ and cross‐pollination on germination success, flowering probability, pollen and ovule production, survivorship, and adult aboveground biomass in two species of Mimulus with contrasting mating systems: the highly seifing M. micranthus and an outcrossing population of M. guttatus. Cross‐pollinations were performed both within and between populations in order to examine the scale at which the genetic load is distributed. We found significant inbreeding depression in M. guttatus in four of the six traits, with the highest inbreeding depression observed in biomass (68% and 69% based on within‐ and between‐population crosses, respectively) and lowest in ovule production (21% based on between‐population crosses only). M. micranthus displayed significant inbreeding depression in only two of the six traits examined. Again, we observed the highest inbreeding depression in biomass (47–60% based on within‐ and between‐population crosses, respectively), but both traits showing significant differences between self and outcross progeny expressed lower inbreeding depression than in M. guttatus. We detected no significant inbreeding depression for either pollen or ovule production in M. micranthus. An estimate of total inbreeding depression based on the multiplicative effects of all traits was also lower in M. micanthus than∗∗∗ in M. guttatus. Our results are consistent with the expected purging of genetic load in populations with high selfing rates. The absence of inbreeding depression in M. micranthus pollen and ovule production, two traits with strong links to fitness in a selfing annual, further suggests the important role of directional selection in determining the population's genetic load. Comparison of cross‐pollinations made within and between populations revealed little evidence of divergence of genetic load among the M. micranthus and M. guttatus populations examined.
The role of leaf and canopy‐level gas exchange in the replacement ofQuercus virginiana(Fagaceae) byJuniperus ashei(Cupressaceae) in semiarid savannas
Authors: Owens M. K.
Published: January 2018

Photosynthesis, transpiration, and leaf area distribution were sampled in matureQuercus virginianaandJuniperus asheitrees to determine the impact of leaf position on canopy‐level gas exchange, and how gas exchange patterns may affect the successful invasion ofQuercuscommunities byJ. ashei.Sampling was conducted monthly over a 2‐yr period in 12 canopy locations (three canopy layers and four cardinal directions). Photosynthetic and transpiration rates of both species were greatest in the upper canopy and decreased with canopy depth. Leaf photosynthetic and transpiration rates were significantly higher forQ. virginiana(4.1–6.7 μmol CO2·m−2·s−1and 1.1–2.1 mmol H2O·m−2·s−1) than forJ. ashei(2.1–2.8 μmol CO2·m−2·s−1and 0.7–1.0 mmol H2O·m−2·s−1) in every canopy level and direction. Leaves on the south and east sides of both species had higher gas exchange rates than leaves on the north and west sides. AlthoughQuercushad a greater mean canopy diameter thanJuniperus(31.3 vs. 27.7 m2),J. asheihad significantly greater leaf area (142 vs. 58 m2/tree). A simple model combining leaf area and gas exchange rates for different leaf positions demonstrated a significantly greater total canopy carbon dioxide uptake forJ. asheicompared toQ. virginiana(831 vs. 612 g CO2·tree−1·d−1, respectively). Total daily water loss was also greater forJuniperus(125 vs. 73 Ltree−1·d−1). Differences in leaf gas exchange rates were poor predictors of the relationship between the invasiveJ. asheiand the codominantQ. virginiana.Leaf area and leaf area distribution coupled with leaf gas exchange rates were necessary to demonstrate the higher overall competitive potential ofJ. ashei.
Sinapate esters provide greater UV‐B attenuation than flavonoids in Arabidopsis thaliana (Brassicaceae)
Authors: Sheahan John J.
Published: January 2018

Mutants affected in flavonoid (tt4) or sinapate ester (fah1) biosynthesis were used to assess the relative importance of these phenolic UV photoprotectants in Arabidopsis. Flavonoid and sinapate ester absorption was more specific for UV‐B than major nonphenolic chromophores in crude extracts. A new method of evaluating phenolic UV‐B attenuation was developed using fluorescence analysis. When excited by UV‐B, sinapate ester containing leaves and cotyledons had enhanced sinapate ester fluorescence and reduced chlorophyll fluorescence relative to those without sinapate esters. Although fluorescence analysis gave no evidence of UV‐B attenuation by flavonoids, enhanced chlorophyll and protein loss were observed upon UV‐B exposure in flavonoid‐deficient leaves, suggesting they have another mechanism of UV‐B protection. The hydroxycinnamates have been largely ignored as UV‐B attenuating pigments, and the results indicate that greater attention should be paid to their role in attenuating UV‐B.
Sapindales: molecular delimitation and infraordinal groups
Authors: Gadek Paul A. , Fernando Edwino S. , Quinn Christopher J. , Hoot Sara B. , Terrazas Teresa , Sheahan Mary C. , Chase Mark W.
Published: January 2018

An analysis of rbcL sequence data for representatives of families of putative sapindalean/rutalean affinity identified a robust clade of core “sapindalean” taxa that is sister to representatives of Malvales. The constitution of this clade approximates the broad concept of Sapindales (sensu Cronquist). Five lineages within the order are recognized: a “rutaceae” clade (Rutaceae, Cneoraceae, Ptaeroxylaceae, Simaroubaceae sensu stricto, and Meliaceae); a “sapindaceae” clade (Sapindaceae, Aceraceae, and Hippocastenaceae); Anacardiaceae plus Burseraceae; Kirkiaceae; and Zygophyllaceae pro parte. Relationships among these groups were only weakly resolved, but there was no support for the recognition of the two more narrowly defined orders, Rutales and Sapindales sensu stricto. Several families that have previously been allied to Sapindales or Rutales show no affinity to the core sapindalean taxa identified with the molecular data, and are excluded from the order: viz. Akaniaceae, Bretschneideraceae, Conneraceae, Coriariaceae, Melianthaceae, Meliosmaceae, Physenaceae, Rhabdodrendraceae, Sabiaceae, Staphyleaceae, Stylobasiaceae, Surianaceae, and Zygophyllaceae sensu stricto.
Ultrastructural features of chilling injury: injured cells and the early events during chilling of suspension‐cultured mung bean cells
Authors: Ishikawa Hiroko A.
Published: January 2018

The ultrastructure of cells of mung bean (Vigna radiata L. var. Wilczek) in suspension culture was studied during chilling. During such treatment, three kinds of injured cells were observed: swollen cells, cells with broken vacuolar membranes, and cells with shrunken plasma membranes. Swelling was observed from the early stages of chilling, and in most cells during chilling. The other two types of cells were observed at the late stages of chilling. At the early stage of chilling, whorls of rough endoplasmic reticulum that surrounded clear regions of cytoplasm were observed. At the same time, markedly rough vacuolar membranes, plastids and mitochondria with vacuoles, enlargement of Golgi vesicles, and dilation of the ER were seen. These changes preceded the swelling of cells. These ultrastructural features of chilling injury are discussed in terms of biochemical observations. The disruption of the vacuolar membrane and the shrinking of the plasma membrane are discussed in terms of destruction of the cytoskeleton.
High level of polymorphism and spatial structure in a selfing plant species,Medicago truncatula(Leguminosae), shown using RAPD markers
Authors: Bonnin Isabelle , Huguet Thierry , Gherardi Michele , Prosperi Jean‐Marie , Olivieri Isabelle
Published: January 2018

Using RAPD markers and one morphological marker, we studied the among‐ and within‐population structure in a selfing annual plant species,Medicago truncatulaGAERTN. About 200 individuals, sampled from four populations subdivided into three subpopulations each, were scored for 22 markers. It was found that the within‐population variance component accounted for 55% of the total variance, while the among‐population variance component accounted for 45%. Eighteen percent of the total variance was due to within‐population structure (i.e., among subpopulations). Thus, 37% of the total variance was within subpopulations. Using a multilocus approach, it was found that no multilocus genotype was common to two populations. Two of the four studied populations were composed of few (≤6) multilocus genotypes, whereas the other two had many (≥15) multilocus genotypes. In the most polymorphic population (37 genotypes), only one genotype was found to be common to two subpopulations. Resampling experiments show that, depending on the population, three to 16 polymorphic loci were necessary and sufficient to score all multilocus genotypes in the population. When these data are compared to published results, it appears that on some occasions, the number of genotypes per population of selfing species might be larger than would be expected from the sole consideration of effective population size. The large within‐subpopulation genetic variance observed in some populations could be explained by either small neighborhood sizes within subpopulations, or by outcrossing following migration through seed and/or pollen.
North American black‐fruited hawthorns. II. Floral development of 10‐ and 20‐stamen morphotypes inCrataegussectionDouglasii(Rosaceae: Maloideae)
Authors: Evans Rodger C. , Dickinson Timothy A.
Published: January 2018

CrataegussectionDouglasiiexhibits variation in stamen number per flower typical for the genus throughout North America. To understand the developmental basis for this variation we studied the early floral ontogeny of the three taxa in sectionDouglasii: C. douglasii(both Pacific northwest and the upper Great Lakes basin),C. rivularis, andC.suksdorfii. Crataegus suksdorfii, like all known diploidCrataegus, has ≈20 stamens; the two other taxa have ≈10 stamens, a condition associated only with polyploidy. In all taxa petal primordia and a whorl of five pairs of stamen primordia develop from five common primordia. The 10‐stamen∗∗∗ condition results from loss of two whorls of five stamens that are subsequently formed inC. suksdorfii.Loss of these two whorls in the 10‐stamen taxa is the result of neither a smaller floral apex at initiation, nor a smaller flower at anthesis. Stamen number variability, particularly inC. douglasiiandC. rivularis, is the result predominantly of fewer than two stamen primordia developing between adjacent petal primordia. Pollen production inC. douglasiiis half that inC. suksdorfiibecause of the reduction in stamen number. The results are presented and discussed in terms of morphogenetic explanations of meristic variation.
Pinus MUTOI (Pinaceae), a new species of permineralized seed cone from the upper Cretaceous of Hokkaido, Japan
Authors: Saiki Ken'ichi
Published: January 2018

Pinus mutoi is described as a new species on the basis of a permineralized seed cone from the Upper Cretaceous of Hokkaido, Japan. The cone is at least 20 cm long and up to 6 cm in diameter, consisting of a cone axis and numerous cone‐scale complexes that are arranged helically around the axis. Two winged seeds are borne on the adaxial surface of each ovuliferous scale. Each complex receives a single trace from the vascular cylinder of the cone axis. In the scale base, all the resin canals occur abaxially to the vascular strand. The spatulate bract of the fossil is unique to the specimen among the cones of both living and fossil Pinus. The central umbo, broad sclerotic cortex of cone axis, and absence of serotinous features of the fossil cone suggest affinity with the subsection Sylvestres of the section Pinus, subgenus Pinus. This is the first record of permineralized preserved Pinus cone from the Cretaceous of Eastern Eurasia.
Water relations and leaf chemistry of Chrysothamnus nauseosus ssp. consimilis (Asteraceae) and Sarcobatus vermiculatus (Chenopodiaceae)
Authors: Donovan Lisa A. , Richards James H. , Muller Matthew W.
Published: January 2018

At Mono Lake, California, we investigated field water relations, leaf and xylem chemistry, and gas exchange for two shrub species that commonly co‐occur on marginally saline soils, and have similar life histories and rooting patterns. Both species had highest root length densities close to the surface and have large tap roots that probably reach ground water at 3.4‐5.0 m on the study site. The species differed greatly in leaf water relations and leaf chemistry. Sarcobatus vermiculatus had a seasonal minimum predawn xylem pressure potential (ψpd) of ‐2.7 MPa and a midday potential (ψmd) of ‐4.1 MPa. These were significantly lower than for Chrysothamnus nauseosus, which had a minimum ψpd of ‐1.0 MPa and ψmd of ‐2.2 MPa. Sarcobatus had leaf Na of up to 9.1 % and K up to 2.7 % of dry mass, and these were significantly higher than for Chrysothamnus which had seasonal maxima of 0.4% leaf Na and 2.4 % leaf K. The molar ratios of leaf K/Na, Ca/Na, and Mg/Na were substantially lower for Sarcobatus than for Chrysothamnus. Xylem ionic contents indicated that both species excluded some Na at the root, but that Chrysothamnus was excluding much more than Sarcobatus. The higher Na content of Sarcobatus leaves was associated with greater leaf succulence, lower calculated osmotic potential, and lower xylem pressure potentials. Despite large differences in water relations and leaf chemistry, these species maintained similar diurnal patterns and rates of photosynthesis and stomatal conductance to water vapor diffusion. Sarcobatus ψpd may not reflect soil moisture availability due to root osmotic and hydraulic properties.
A comparison of the seed dormancy characteristics of Spartina patens and Spartina alterniflora (Poaceae)
Authors: Plyler Daniel B. , Proseus Timothy E.
Published: January 2018

Seed dormancy characteristics of Spartina alterniflora were delineated previously by Plyler and Carrick (American Journal of Botany, vol. 80, pp. 752–756, 1993). This study was undertaken in order to determine whether or not the dormancy characteristics of S. patens are similar. As in the previous study, the site of a dormancy mechanism was determined by assessing the germinability of surgically altered dormant seeds. Likewise, the effects of three growth‐regulating substances (abscisic acid, fusicoccin, and gibberellic acid), prechilling, and light were studied by assessing the germinability of appropriately treated dormant seeds. Surgical injury to the endosperm, and to a lesser extent the scutellum, produced significant germination in S. patens, whereas only injury to the scutellum produced germination in S. alterniflora. Exogenously applied abscisic acid was highly effective in maintaining dormancy in injured seeds of both species. Gibberellic acid and fusicoccin were ineffective in promoting germination in S. patens, but fusicoccin was highly effective in breaking dormancy in 5. alterniflora. Prechilling was effective in breaking dormancy in S. patens but not in S. alterniflora. In S. patens, treatments that broke dormancy were only successful when seeds were exposed to light during the germination period. It is concluded that the dissimilarities in the dormancy mechanisms may be manifestations of the different environmental adaptations these closely related species display.
Polyploids and their structural and PHYSIOLOGICAL CHARACTERISTICS RELATIVE TO WATER DEFICIT INBETULA PAPYRIFERA(Betulaceae)
Authors: Li Wan‐Liang , Berlyn Graeme P. , Ashton P. Mark S.
Published: January 2018

The morphology and leaf anatomy, water relations, gas exchange, and growth characteristics ofBetula papyriferaseedlings grown in a greenhouse representing three ploidy levels (diploids, pentaploids, and hexaploids) have been compared in an effort to understand the role of polyploidy in habitat differentiation and adaptation to water deficit. The polyploids are more tolerant of water deficit than their diploid relatives. The polyploids have fewer stomata per unit area and smaller stomatal indices than the diploids. They also have thicker upper and lower epidermis and more pubescence, which tend to reduce water loss. The polyploids have lower osmotic potential at saturation (p.sat) than corresponding diploids, suggesting they are more able to maintain turgor in the case of low tissue water potential than the diploids. The photosynthesis of the diploids is more sensitive to water deficit. A 2‐hr artificial water stress treatment caused complete cessation of photosynthesis in the diploids. They are more drought‐avoiding than the polyploids as evidenced by closing their stomata to limit water loss at a relatively higher tissue water potential (‐1.425 MPa). The pentaploids and hexaploids maintained, although to a small extent, photosynthesis when their tissue water potentials dropped to ‐1.86 MPa and ‐2.07 MPa, respectively.
Environmentally induced nuclear 2C DNA content instability in Helianthus annuus (Asteraceae)
Authors: Johnston J. Spencer , Jensen Andrea , Czeschin Don G. , Price H. James
Published: January 2018

Experiments were conducted to detect developmental and environmental factors that influence nuclear DNA content in H. annuus inbred lines RHA 271 and RHA 299. DNA content (2C) was determined by laser flow cytometry of nuclei isolated from the first leaf pair of seedlings grown in a greenhouse and in growth chambers. DNA content of greenhouse grown seedlings was highly variable, ranging from 3.2 to 8.0 pg for RHA 299 and 5.2 to 8.2 pg for RHA 271. DNA content only weakly correlated to the position of the achene in the head from which the seedlings derived, and not at all to the position of the head on the plant. Experimentally varied environmental parameters of heat stress and water deficit, phosphate fertilizer levels in the substrate, and pH had little or no effect on the DNA content of seedlings. Seedlings grown with increased levels of substrate nitrogen in the form of NH4NO3 showed a significant increase in the mean DNA content. Plants grown in one of two types of growth chambers possessed less variability in DNA content, 6.2–8.4 pg for RHA 299 and 6.8–7.4 pg for RHA 271. Plants grown in a second growth chamber were highly variable with DNA content ranging from 3.0 to 8.6 pg for RHA 299 and 3.0 to 7.8 pg for RHA 271. Measurable physical differences between the growth chambers were irradiance level and the ratio of red to far red light. The hypothesis is presented that DNA stability of sunflowers is influenced by light quantity and/or quality.
Heterospecific pollen transfer between sympatric species in a midsuccessional old‐field community
Authors: McLernon Susan M. , Murphy Stephen D. , Aarssen Lonnie W.
Published: January 2018

The cumulative (season‐long) incidence of heterospecific pollen transfer (HPT) was examined using nine sympatric species in a midsuccessional old field. Inflorescences were collected weekly during the flowering season, and the proportion of foreign pollen/stigma was recorded. Flowering phenologies of sympatric species and ovule and seed counts of study species were also recorded. Heterospecific pollen was detected on some stigmas of each species. Medicago sativa (Fabaceae) received the most foreign pollen; in some cases, all of the grains on a stigma were heterospecific. Lotus corniculatus (Fabaceae) received the least amount of foreign pollen; the incidence of heterospecific pollen was near zero in most cases. The mean and range of foreign pollen received varied by as much as an order of magnitude between species. The six species with zygomorphic flowers, all Fabaceae, received more heterospecific pollen than the three species with actinomorphic flowers, Potentilla recta and P. simplex (Rosaceae) and Ranunculus acris (Ranunculaceae). This probably reflects a bias because our data were analyzed on a cumulative basis and the Fabaceae had longer flowering phenologies. HPT was not correlated with the species' relative abundance within the community. Proportion of foreign pollen received varied temporally within species, and this variation generally was not related to phenology of any sympatric taxa or the species' own phenology. Pollen grain diameter was positively related to levels of foreign pollen received by species. This might be caused by poor adhesion of large pollen grains to small stigmatic papillae or if generalist pollinators carrying large amounts of heterospecific pollen visit the large‐grained species and specialists with little foreign pollen visit the small‐grained species. The large proportions of heterospecific pollen on stigmas of many species indicate that HPT occurs frequently in the community we studied and the implications may include reduced seed set because of occlusion by foreign grains. As yet, however, it is unclear how important a factor HPT is in mediating pollen limitation of reproductive success.
The influence of extrafloral nectaries on parasitism of an insect herbivore
Authors: Pemberton Robert W. , Lee Jang‐Hoon
Published: January 2018

The extrafloral nectaries of many plants promote ant defense against insect herbivores. We examined the influence of extrafloral nectaries on the levels of parasitism of a generalist insect herbivore, the gypsy moth (Lymantria dispar L.). Larvae and pupae of the moth were collected from trees with and without extrafloral nectaries growing in the same forests in South Korea and reared to evaluate parasitism. More parasitism occurred on plants with extrafloral nectaries in seven of the nine season‐long collections at the six sites and in four out of five collecting periods. Parasitism was higher on the four main genera of plants with extrafloral nectaries than on any of five main genera of plants without extrafloral nectaries. There was no difference in parasitoid richness; nine species occurred in each group, eight of which were the same. There was a positive and almost significant correlation between the abundance of plants with extrafloral nectaries and the parasitism of gypsy moth at the sites. Extrafloral nectaries may reduce herbivory by inducing more parasitism of the insect herbivores that attack plants bearing the glands.
Vessels in Brasenia (Cabombaceae): New perspectives on vessel origin in primary XYLEM OF ANGIOSPERMS
Authors: Schneider Edward L. , Carlquist Sherwin
Published: January 2018

Studies by means of scanning electron microscope (SEM) of primary xylem of Nymphaeaceae have revealed diversity in vessels and rudimentary expressions of pore formation on end walls of vessel elements. A similar situation is true in Cabombaceae. In Brasenia schreberi, vessels occur not only in roots but also in rhizomes. Vessels in roots have lignified helical or annular bands only at the ends of the vessel elements; central portions of the elements have diminished versions of the thickenings, lacking borders and lignification—a configuration hitherto unreported for vascular plants. This may be the first demonstrated instance of a midpoint in reduction of tracheary tissue in relation to the aquatic habitat. Perforation plates in roots consist of a series of pores of various sizes in primary wall areas between the lignified bands; pores are fewer in the perforation plates of tracheary elements of rhizomes. Vessels in Brasenia likely illustrate early stages in vessel origin. Because the patterns of vessel structure now available by means of SEM are so different from those hitherto figured for primary xylem of dicotyledons currently placed in basal portions of cladograms, we are extending our studies to primary xylem of other vascular plants likely to show incipient stages of vessel evolution. Evidence now available forces us to envision vessel origin in angiosperms in terms of formation of numerous pores on end walls, rather than elimination of entire pit membranes at the outset, and this poses new questions about the nature of conduction and embolism spread in species with porose end walls.
Early inflorescence and floral development in Zea mays land race Chapalote (Poaceae)
Authors: Sundberg Marshall D. , Orr Alan R.
Published: January 2018

Tassel and ear primordia were collected from greenhouse‐grown specimens of the Mexican maize landrace Chapalote and prepared for scanning electron microscopic (SEM) examination. Measurements of inflorescence apices and spikelet pair primordia (spp) were made from SEM micrographs. Correlation of inflorescence apex diameter with number of spikelet ranks showed no significant difference between tassels and ears, except at the two‐rank level where the ear apical meristem had a significantly smaller diameter than corresponding two‐ranked tassels. Within individual inflorescences, spp in different ranks enlarged at comparable rates, although the rates from one ear to the next along the stem differed. In both tassels and ears, spp divide to form paired sessile and pedicellate spikelet primordia when the spp is 150 μm wide; ear axes are significantly thicker than tassel axes at the time of bifurcation. The similarities in growth between ear and tassel primordia lend further support to the hypothesis that both the maize tassel and ear are derived from a common inflorescence pattern, a pattern shared with teosinte. Inflorescence primordial growth also suggests that a key character difference between teosinte and maize, distichous vs. polystichous arrangement of spikelets, may be related to size of the apical dome and/or rate of primordium production by the apical meristem. There appears to be more than a single morphological event in the shift from vegetative to reproductive growth. The evocation of axillary buds (ears) is independent of, and temporally separated from, the transition to flowering at the primary shoot apex (tassel).
Patterns of genetic variability within and among populations of wild radish, Raphanus raphanistrum (Brassicaceae)
Authors: Kercher Suzanne , Conner Jeffrey K.
Published: January 2018

The genetic structure of populations is an important determinant of the evolutionary potential of a species. Colonizing plants tend to be characterized by low within‐ and high among‐population variability. Genetic differentiation of both floral traits and isozymes was studied in six populations of wild radish (Raphanus raphanistrum). Evidence for differentiation in both sets of traits was found, but patterns of differentiation of floral traits did not coincide with isozyme differentiation. Contrary to most colonizing species, wild radish showed high within‐ and only moderate among‐population variability at isozyme loci. In addition, levels of differentiation did not correspond to geographic distance between the populations. These results are likely due at least in part to the self‐incompatibility system of this species, long‐distance movement of large numbers of wild radish seeds by humans, and introgression from cultivated radish (R. sativus).
Revegetation patterns and seedbank structure on abandoned pastures in northern Japan
Authors: Tsuyuzaki Shiro , Kanda Fusayuki
Published: January 2018

To compare revegetation patterns between native and exotic species on abandoned pastures in northern Japan, we surveyed the vegetation structure and the seedbank using a flotation technique in 140 1 1 m plots. Previously introduced grasses such as Poa pratensis, Phleum pratense, and Dactylis glomerata were abundant 20 yr after the pasture abandonment, while Sasa senanensis, native shrub species, regenerated from propagation that had spread from the surrounding forests. S. senanensis shrublands and P. pratensis/P. pratense grasslands established on deep soils while D. glomerata grasslands established on shallow soils. Trees rarely became established on abandoned pastures. The seed density in the seedbank, representing 19 species, ranged from 542 to 2957 seeds/m2. The dominant species in the vegetation (P. pratensis, Trifolium repens, and Rumex acetosella) were also common in the seedbank, whereas Cerastium holosteoides var. angustifolium, Chenopodium album var. centrorubrum, and Erigeron canadensis were widespread in the seedbank but did not occur in the extant vegetation. S. senanensis regenerated by vegetative propagation, and P. pratensis and P. pratense developed a seedbank. We concluded that for native species, particularly S. senanensis, vegetative reproduction has an important role on revegetation rather than regeneration from the seedbank, and the dwarf bamboo may be a keystone species in the ecosystems.
Why is there variation in mean seed size among plants within single populations? test of the fertilization efficiency hypothesis
Authors: Sakai Satoki , Sakai Akiko
Published: January 2018

We tested the fertilization efficiency hypothesis, which attempts to explain mean seed size variation among plants within single populations, by comparing the patterns of seed size variation between chasmogamous (CH) flowers and cleistogamous (CL) flowers in Impatiens noli‐tangere and Viola grypoceras, respectively. The fertilization efficiency hypothesis predicts that larger plants produce larger seeds if the number of pollen grains captured by a plant increases with increased allocation of resources to its attractive structures (e.g., corolla and nectar), but with diminishing gains. Thus, seed size should depend on plant size in seeds from CH flowers because of the diminishing gains of capturing pollen in these flowers, whereas seed size should not depend on plant size in seeds from CL flowers because CL flowers need not capture outcross pollen. We found significant positive correlations between mean seed size per plant and plant size for seeds from CH flowers in both species. However, there was no significant positive correlation between these two factors for seeds from CL flowers of both species. The results of the present investigations were thus consistent with the fertilization efficiency hypothesis.
piRNA‐19128 regulates spermatogenesis by silencing of KIT in chicken
Authors: Guo Qixin , Xu Lu , Bi Yulin , Qiu Lingling , Chen Yin , Kong Lingling , Pan Rui , Chang Guobin
Published: January 2018

Spermatogenesis is a complex process. Some studies have shown that Piwi‐interacting RNAs (piRNAs) play an important role in spermatogenesis. To verify the evaluate between piRNAs and PIWI proteins in chicken and its possible role in spermatogenesis and reproductive stem cell proliferation and differentiation, we performed immunoprecipitation and deep sequencing analyses and determined the expression profiles of small RNAs in primordial germ cells (PGCs), spermatogonial stem cells (SSCs), spermatogonia (Sa) cells, and spermatozoa. Length analysis showed that piRNAs bound to PIWIL1 mainly contained 23‐30 nt. Base preference analysis showed “1U‐10A”; moreover, base preference of piRNAs was obvious in all of germline cells. Here we reported the TE family of gallus gallus, and targeted by piRNA. Target gene of piRNA annotation enrichment analysis identified candidate genes KIT, SRC, WNT4, and HMGB2. Kyoto Encyclopedia of Genes and Genomes analysis showed that these genes were associated with steroid hormone biosynthesis, Notch signaling pathway, and melanogenesis. These results indicate that chicken piRNAs perform important regulatory roles during spermatogenesis similar to mice piRNAs. Chicken piRNAs interacted with PIWI proteins and regulated spermatogenesis and germ cell proliferation and differentiation. Further, we observed a negative correlation between piRNA‐19128 and KIT expression. Results of dual‐luciferase reporter assay confirmed that piRNA‐19128 directly interacted with KIT, suggesting that it plays a key role in the regulation spermatogenesis by inhibiting KIT expression. Thus, the present study provides information on the length and base preference of chicken piRNAs and suggests that piRNA‐19128 regulates spermatogenesis in chicken by silencing KIT.
Jolkinolide B inhibits glycolysis by downregulating hexokinase 2 expression through inactivating the Akt/mTOR pathway in non‐small cell lung cancer cells
Authors: Gao Xiang , Han Han
Published: January 2018

Jolkinolide B (JB), a bioactive compound isolated from herbal medicine, has been found to inhibit tumor growth by altering glycolysis. However, whether glycolysis is influenced by JB in non‐small cell lung cancer (NSCLC) cells and the mechanism remain unknown. The aim of the present study was to evaluate the effect of JB on the glycolysis in NSCLC cells and the underlying molecular mechanism. The results showed that JB treatment inhibited cell viability of A549 and H1299 cells in a concentration‐dependent manner. JB reduced the glucose consumption, lactate production, and HK2 expression. The expressions of p‐Akt and p‐mTOR were also decreased by JB treatment. Knockdown of HK2 reduced glucose consumption and lactate production. Inhibition of the Akt/mTOR pathway decreased HK2 expression and inhibited glycolysis. In conclusion, the results indicated that JB inhibits glycolysis by down‐regulating HK2 expression through inactivating the Akt/mTOR pathway in NSCLC cells, suggesting that JB might be a potential therapeutic agent for the treatment of NSCLC.
Effects of insulin on transcriptional response and permeability in an in vitro model of human blood‐brain barrier
Authors: Kuai Ziyu , Xu Yan , Zhao Qi , Liu Jie , Guan Shanshan , Qiao Yongbo , Gong Xin , Nie Jiaojiao , Li Pengju , Liu Dongni , Xing Yifan , Li Huiwen , Sun Zixiao , Wang Wenqi , Ning Chunan , Shi Yuhua , Kong Wei , Shan Yaming
Published: January 2018

Alzheimer's disease (AD) is the most prevalent form of dementia worldwide and is an emerging global epidemic. Active and passive immune therapies targeting beta amyloid (Aβ) have shown very limited evidence in human studies of clinical benefits from these approaches. Epidemiological studies have shown that subjects with type 2 diabetes (T2D) are at higher risk of developing AD. However, whether and how these two conditions are causally linked is unknown. With the purpose of confirming the relationship between T2D and AD, this study specifically focused on effects of insulin in an in vitro model of the human blood‐brain barrier (BBB) and on potential mechanisms of action in the treatment of AD. By using a series of assays to establish a BBB model, we demonstrated that insulin treatment alone could induce the increase of brain endothelial barrier properties. The transcriptional response of hCMEC/D3 cells to activation with different concentrations of insulin was determined by RT‐PCR, and expression levels of genes involved in the control of barrier permeability, including inter‐brain endothelial junctions, integrin‐focal adhesions complexes, and transporter system, were found to be altered by the treatment. Notably, the influence of insulin on expression of the ATP‐binding cassette (ABC) transporter which contributes to the clearance of Aβ was investigated. Insulin up‐regulated adherens junction and tight junction transmembrane proteins, as well as the ABC transporter. By treatment with insulin, the models have major advantages: it is fast, it has low cost, it is fit for considerable samples, and its conditions are under control.
FTO reduces mitochondria and promotes hepatic fat accumulation through RNA demethylation
Authors: Kang Huifang , Zhang Zhiwang , Yu Lin , Li Yixing , Liang Mingzhen , Zhou Lei
Published: January 2018

Fat mass and obesity‐associated protein (FTO) is a RNA demethylase, whether FTO regulates fat metabolism through its demethylation is unclear. The results of this study confirmed that N6‐methyladenosine (m6A) is associated with fat accumulation both in vivo and in vitro. The data showed that FTO down‐regulated m6A levels, decreased mitochondrial content, and increased triglyceride (TG) deposition. However, an FTO (R316A) mutant lacking demethylation activity could not regulate mitochondria and TG content, indicating that FTO affects mitochondrial content and fat metabolism by modulating m6A levels in hepatocytes. In addition, the regulatory roles of cycloleucine (methylation inhibitor) and betaine (methyl donor) could regulate m6A levels and fat deposition. This work clarified that the demethylation function of FTO plays an essential role in the fat metabolism of hepatocytes and links the epigenetic modification of RNA with fat deposition, thereby providing a new target (m6A) for regulation of hepatic fat metabolism.
Ethylene epoxidation over supported silver catalysts – influence of catalyst pretreatment on conversion and selectivity
Authors: Aho Atte , Eränen Kari , Lemus‐Yegres Lived J , Voss Bodil , Gabrielsson Anders , Salmi Tapio , Murzin Dmitry Yu
Published: January 2018

BACKGROUND

Ethylene oxide is a key intermediate in the chemical industry. It is produced through catalytic epoxidation of ethylene. Significant economic benefits can be achieved by small improvements in catalyst activity and selectivity. The aim of this work was to study how different preparation methods and pretreatments affect the catalyst performance under industrially relevant reaction conditions. The influence of pretreatment strategy on the selectivity and reaction temperature was for the first time investigated at a constant ethylene conversion of 7%.

RESULTS

Epoxidation of ethylene to ethylene oxide was studied over a range of silver catalysts which were prepared with different thermal treatments. The influence of catalyst preparation method and catalyst pretreatment strategy on the catalytic performance was investigated. It was found that calcination resulted in lower ethylene conversion compared with pre‐drying. In the latter case an induction period was observed, absent for the calcined catalyst. This induction period can be eliminated by oxidative or reductive pretreatment of the catalyst.

CONCLUSIONS

The most promising pretreatment strategy was carried out by first treating the catalyst with 1 ppm of DCE for 5 h at 230 °C followed by overnight pre‐treatment in 20% ethylene at 250 °C. With this pretreatment it was possible to achieve a target ethylene conversion of 7% at 232.6 °C with a selectivity to ethylene oxide of 82.1%. © 2018 Society of Chemical Industry
Comparative anatomy of the clasper of the subfamily Potamotrygoninae (Chondrichthyes: Myliobatiformes)
Authors: de Moreira Renan A. , Loboda Thiago S. , de Carvalho Marcelo R.
Published: January 2018

Claspers of stingrays (Myliobatiformes) are poorly documented in comparison to claspers of skates, with our knowledge restricted mainly to external morphological characters and skeletal components included in descriptions of new species; more encompassing morphological comparative analyses are lacking. Concerning potamotrygonins, clasper morphology has been described for a handful of species, but without elucidating their variation and systematic potential. The present article analyzed clasper structures in all genera of the subfamily Potamotrygoninae (Potamotrygon, Paratrygon, Plesiotrygon, and Heliotrygon), which were compared to the clasper of Styracura and some dasyatid genera. Potamotrygon shows some morphometric variation among the species analyzed. Anatomically, we found variation mainly in the dorsal terminal 1 and accessory terminal 1 cartilages, which are considered diagnostic among potamotrygonin genera; external morphological structures did not present significant differences among potamotrygonins.
Exploring the Effects of Creativity Training on Creative Performance and Creative Self‐Efficacy: Evidence from a Longitudinal Study
Authors: Meinel Martin , Wagner Timm F. , Baccarella Christian V. , Voigt Kai‐Ingo
Published: January 2018

In organizations and educational institutions, creativity trainings are the preferred approach to enhancing individual creative abilities. However, three issues regarding these trainings still remain largely unsolved. First, the question of how long‐lasting creativity training effects are has not been sufficiently answered so far. Second, the question arises whether all participants benefit from such trainings equally in terms of their creative performance (CP). Third, an increasing number of studies have shown that creativity trainings may also be able to increase participants' creative self‐efficacy (CSE), that is, the confidence in one's own creativity. Other studies, however, did not find evidence for this effect. Therefore, this article aims to address these issues by analyzing data from three measurement waves. Results reveal that participants' CP increased during the training and decreased only slightly 4 weeks after the training. Additionally, we found an effect of diminishing training returns in that the higher a participant's CP before the training the lower the training effect was. In contrast to most prior literature, we found no support for an effect of creativity training on participants' CSE. We discuss these findings and offer implications for both theory and practice. Finally, we state this study's limitations and derive avenues for further research.
American beech leaf‐litter leachate chemistry: Effects of geography and phenophase
Authors: Hudson Janice E. , Levia Delphis F. , Wheeler Kathryn I. , Winters Catherine G. , Vaughan Matthew C. H. , Chace Jameson F. , Sleeper Ryan
Published: January 2018

The decomposition of broadleaved tree leaves can contribute a substantial amount of energy to forested watersheds via dissolved organic matter (DOM), nutrients, and biological activity. Less is known about how these inputs may vary within a single tree species that is known to have two genetically distinct and geographically separate populations, or how these inputs may change throughout autumn senescence and abscission. It is often implicitly assumed that intraspecific differences in leaf‐litter leachate chemistry do not significantly differ geographically. We analyzed the morphological and chemical leaf traits and leachates from Fagus grandifolia (American beech) leaves (n = 360) during three phenophases: fresh green leaves, senescing leaves, and fallen leaves. During each phenophase, leaves were collected from four sites along a geographic transect stretching from Vermont to North Carolina (over 1400 km), with two sites representing each genetic population and differing climatic conditions. Leachates were analyzed for routine solutes and nutrients, as well as fluorescent and UV‐visible absorbance indices. Amounts of macro‐ and micronutrients were highly variable among sites and phenophases but tended to be lowest during the fallen‐leaf phase, while measured fluorescence and absorbance indices tended to increase during the senescing‐leaf phase and plateau. Results suggest significant differences in leached nutrients among sites, and optical properties and nutrients among phenophases. Aromaticity and molecular weight of DOM in leachates was generally low, and aromaticity and humification of leachates both increased over time with leaf age. These results also suggest that geographically (or genetically) separate populations of the same species do not experience senescence in the same way and that implicit assumptions of intraspecific uniformity of leaf‐litter leachate chemistry for a given tree species may be invalid.
The role of megatides and relative sea level in controlling the deglaciation of the British–Irish and Fennoscandian ice sheets
Authors: Scourse J. D. , Ward S. L. , Wainwright A. , Bradley S. L. , Uehara K.
Published: January 2018

Key external forcing factors have been proposed to explain the collapse of ice sheets, including atmospheric and ocean temperatures, subglacial topography, relative sea level and tidal amplitudes. For past ice sheets it has not hitherto been possible to separate relative sea level and tidal amplitudes from the other controls to analyse their influence on deglaciation style and rate. Here we isolate the relative sea level and tidal amplitude controls on key ice stream sectors of the last British–Irish and Fennoscandian ice sheets using published glacial isostatic adjustment models, combined with a new and previously published palaeotidal models for the NE Atlantic since the Last Glacial Maximum (22 ka BP). Relative sea level and tidal amplitude data are combined into a sea surface elevation index for each ice stream sector demonstrating that these controls were potentially important drivers of deglaciation in the western British Irish Ice Sheet ice stream sectors. In contrast, the Norwegian Channel Ice Stream was characterized by falling relative sea level and small tidal amplitudes during most of the deglaciation. As these simulations provide a basis for observational field testing we propose a means of identifying the significance of sea level and tidal amplitudes in ice sheet collapse.
Citrus species and hybrids depicted by near‐ and mid‐infrared spectroscopy
Authors: Páscoa Ricardo NMJ , Moreira Silvana , Lopes João A , Sousa Clara
Published: January 2018

BACKGROUND

Citrus trees are among the most cultivated plants in the world, with a high economic impact. The wide sexual compatibility among relatives gave rise to a large number of hybrids that are difficult to discriminate. This work sought to explore the ability of infrared spectroscopy to discriminate among Citrus species and/or hybrids and to contribute to the elucidation of its relatedness.

RESULTS

Adult leaves of 18 distinct Citrus plants were included in this work. Near‐ and mid‐infrared (NIR and FTIR) spectra were acquired from leaves after harvesting and a drying period of 1 month. Spectra were modelled by principal component analysis and partial least squares discriminant analysis. Both techniques revealed a high discrimination potential (78.5–95.9%), being the best results achieved with NIR spectroscopy and air‐dried leaves (95.9%).

CONCLUSION

Infrared spectroscopy was able to successfully discriminate several Citrus species and/or hybrids. Our results contributed also to enhance insights regarding the studied Citrus species and/or hybrids. Despite the benefit of including additional samples, the results herein obtained clearly pointed infrared spectroscopy as a reliable technique for Citrus species and/or hybrid discrimination. © 2018 Society of Chemical Industry
Near‐infrared reflectance spectroscopy calibrations for assessment of oil, phenols, glucosinolates and fatty acid content in the intact seeds of oilseed Brassica species
Authors: Sen Rahul , Sharma Sanjula , Kaur Gurpreet , Banga Surinder S
Published: January 2018

BACKGROUND

Very few near‐infrared reflectance spectroscopy (NIRS) calibration models are available for non‐destructive estimation of seed quality traits in Brassica juncea. Those that are available also fail to adequately discern variation for oleic acid (C18:1), linolenic (C18:3) fatty acids, meal glucosinolates and phenols. We report the development of a new NIRS calibration equation that is expected to fill the gaps in the existing NIRS equations.

RESULTS

Calibrations were based on the reference values of important quality traits estimated from a purposely selected germplasm set comprising 240 genotypes of B. juncea and 193 of B. napus. We were able to develop optimal NIRS‐based calibration models for oil, phenols, glucosinolates, oleic acid, linoleic acid and erucic acid for B. juncea and B. napus. Correlation coefficients (RSQ) of the external validations appeared greater than 0.7 for the majority of traits, such as oil (0.766, 0.865), phenols (0.821, 0.915), glucosinolates (0.951, 0.986), oleic acid (0.814. 0.810), linoleic acid (0.974, 0.781) and erucic acid (0.963, 0.943) for B. juncea and B. napus, respectively.

CONCLUSION

The results demonstrate the robust predictive power of the developed calibration models for rapid estimation of many quality traits in intact rapeseed‐mustard seeds which will assist plant breeders in effective screening and selection of lines in quality improvement breeding programmes. © 2018 Society of Chemical Industry