bluuebunny/crossref_metadata_2025_split huggingface dataset:
MECHANISMS OF ALUMINUM TOLERANCE IN TRITICUM AESTIVUM L. (WHEAT). I. DIFFERENTIAL PH INDUCED BY WINTER CULTIVARS IN NUTRIENT SOLUTIONS
Authors: Taylor Gregory J. , Foy Charles D. 
Published: January 2018

Twenty winter cultivars of Triticum aestivum L. (wheat) were grown in solution culture with and without aluminum (Al) (74 μM, 2.0 mg L‐1) for 14 days. Exposure to Al increased root growth of the most tolerant cultivar, while both root and shoot growth were depressed in all other cultivars. On the basis of a root tolerance index (RTI = weight of roots grown with Al/weight of roots grown without Al), cultivar tolerance to Al ranged 9‐fold, from 0.13 ± 0.01 to 1.16 ± 0.10. Symptoms of Al toxicity were most evident on roots. Aluminum‐affected roots were relatively short and thick and had numerous undeveloped laterals. Leaves of some cultivars showed chlorosis resembling iron deficiency, and others showed purple stems typical of phosphate deficiency.Plants of all cultivars grown with and without Al depressed the pH of nutrient solutions, presumably until NH4+ was depleted, at which point the pH increased. Cultivar tolerance, expressed both as the root tolerance index and a shoot tolerance index, was negatively correlated with the negative log of the mean hydrogen ion (H+) concentration, the minimum pH, and the slope of the pH decline, each calculated from pH data collected during the first 9 days of the experimental period before any sharp rises in pH occurred. These results are consistent with the hypothesis that the Al tolerance of a given cultivar is a function of its ability to resist acidification of the nutrient solution and hence to limit the solubility and toxicity of Al.
MECHANISMS OF ALUMINUM TOLERANCE IN TRITICUM AESTIVUM L. (WHEAT). II. DIFFERENTIAL PH INDUCED BY SPRING CULTIVARS IN NUTRIENT SOLUTIONS
Authors: Taylor Gregory J. , Foy Charles D. 
Published: January 2018

Twenty spring cultivars of Triticum aestivum L. (wheat) were grown in solution culture with and without aluminum (Al) (74 μM, 2.0 mg L‐1) for 14 days. Root growth and shoot growth were depressed in all cultivars grown with Al; however, symptoms of Al toxicity were most evident on roots. Based on a root tolerance index (RTI = weight of roots grown with Al/weight of roots grown without Al), cultivar tolerance ranged from 0.18 ± 0.02 to 0.85 ± 0.03. Aluminum‐affected roots were relatively short, thick, and had numerous undeveloped laterals. Leaves of some cultivars showed chlorosis resembling iron deficiency and others showed purple stems typical of phosphate deficiency.Plants of all cultivars induced a progressive decline in nutrient solution pH from the outset of the experiment until Days 10–14. After this initial period, some cultivars rapidly increased solution pH, while others continued to depress solution pH throughout the experiment. Cultivar tolerance expressed as the RTI was negatively correlated with the negative log of the mean hydrogen ion (H+) concentration, the minimum pH, and the slope of the pH decline, each calculated from pH data collected during the first 9 days of the experimental period before any sharp rises in pH. The relationship between solution pH and Al tolerance was similar to that reported previously for winter cultivars of T. aestivum, suggesting that the Al tolerance of a given cultivar is a function of its ability to resist acidification of the nutrient solution and hence to limit the solubility and toxicity of Al.
ULTRASTRUCTURE OF NICOTIANA ALATA POLLEN, ITS GERMINATION AND EARLY TUBE FORMATION
Authors: Cresti M. , Ciampolini F. , Mulcahy D. L. M. , Mulcahy G. 
Published: January 2018

Both internal anatomy and external morphology of the mature pollen grain of Nicotiana alata have been studied, together with pollen activation and tube emergence and its cytological zonation.A peculiar feature of mature pollen is the occurrence in the vegetative cell cytoplasm of a large quantity of stacked cisterns of rough endoplasmic reticulum, which then dissociate during pollen activation.Pollen tube emergence generally occurs 2 hr 30 min after hydration, while cytological zonation is complete 4 hr 30 min after hydration when the first callosic plug is formed.
EFFECT OF DENSITY ON SECONDARY SEX CHARACTERISTICS AND SEX RATIO IN SILENE ALBA (CARYOPHYLLACEAE)
Authors: Doust J. Lovett , O'Brien G. , Doust L. Lovett 
Published: January 2018

A field survey of plant and flower sex ratio and secondary sex characteristics was made in Silene alba. Female‐biased plant sex ratios were found, as seems typical for the species. Sex ratio distribution correlated with a gradient of soil moisture (with the more moist area having a more female‐biased ratio) and with changes in the density of Silene (intermediate and higher density areas having greater female bias). The floral sex ratio was significantly female‐biased only at the site that was most female‐biased in terms of plant sex ratio. Otherwise the population of flowers was significantly male‐biased. Male and female plants harvested from the field differed in secondary sexual characteristics. Males had more flowers and invested proportionately more biomass in leaf, but less in root, stem and reproductive tissue than did females. Although both males and females were larger in terms of total dry weight at the moist site, males produced more flowers at the driest (high density) site. Here the female bias in plant sex ratio was intermediate, but the floral sex ratio was significantly male‐biased.A glasshouse experiment was performed in which plants were grown at four densities. Density significantly influenced plant survivorship and the probability of flowering, and increased female bias in the pots, but it did not affect patterns of biomass allocation in flowering plants. Patterns of male and female biomass allocation did not differ in the experiment, except in terms of reproductive allocation (greater in females) and allocation to leaf, greater in males, but only at the lowest density. This work urges caution in interpreting differences between males and females in the field as secondary sex characteristics, since we find such properties to be overlapping under experimental conditions. It supports the idea that males and females of a species may sustain different reproductive output under differing conditions.
ASPECTS OF THE MYCORRHIZAL ECOLOGY OF PRAIRIE DROPSEED, SPOROBOLUS HETEROLEPIS (POACEAE)
Authors: Ebbers Bert C. , Anderson Roger C. , Liberta Anthony E. 
Published: January 2018

Vesicular‐arbuscular mycorrhizal (VAM) fungal colonization of prairie dropseed and rhizosphere spore abundance were sampled seasonally at two sites in Illinois. At Goose Lake Prairie (GLP), Gaussian ordination of 49 vegetation stands, using plant cover data for 40 species, assigned stands x‐vector values and ordered them along a soil moisture‐nutrient gradient. Prairie dropseed cover data plotted over ordered stands yielded a significant Gaussian curve across a relatively narrow gradient segment. In contrast, colonization and spore abundance had significant negative linear correlations with stand x‐vector values that decreased from the drier, low‐nutrient portion of the gradient to the wetter, high‐nutrient sector. Variation in spore abundance suggested that no VAM fungal species responded to environmental gradient conditions in a manner similar to that of prairie dropseed. The differential responses of host and VAM mycobionts across the gradient suggest that their respective success may be partially independently determined or limited by different parameters. Also, the generally ubiquitous VAM fungal distributions suggest that the host may be more sensitive to gradient conditions than its mycobiont associates.Colonization and spore abundance at GLP were significantly negatively correlated with available Ca and Mg, and pH. Spore abundance was significantly positively correlated with available K. Neither colonization nor spore abundance were significantly correlated with available P, total N, or organic matter. Seasonally, patterns of VAM colonization and rhizosphere spore abundance varied, having significant positive correlations at GLP and Weston Cemetery Prairie (WCP) in some seasons but not others.In general, colonization levels were highest in fall 1983 for GLP and fall 1984 for WCP. For 1984, increasing colonization was observed from spring (WCP) or summer (GLP) to fall.
GENETIC AND MATERNAL EFFECTS ON SEEDLING CHARACTERS OF SOLIDAGO ALTISSIMA (COMPOSITAE)
Authors: Weis Arthur E. , Hollenbach Heidi G. , Abrahamson Warren G. 
Published: January 2018

The relative contributions of genetic and maternal factors to phenotypic variation were studied in seedlings of the clonal herb Solidago altissima L. Pairwise crosses were made to establish 19 full‐sibships. Because crosses were reciprocal, each parent served as seed parent to half its offspring and as pollen parent to the other half. For 18 characters, genetic variation was estimated from the between sibship variance and maternal variation from the variance between maternal groups within sibships. Early in the growing season, maternal effects exerted strong influence over variation in leaf and stem dimensions, while genetic influences were weak or absent. At the end of the season genetic influences on leaf and stem dimensions, relative biomass allocation between stem and leaves, and the propensity to flower were significant but maternal effects were not. However, both genetic and maternal influences were found on the number and lengths of new rhizomes.Phenotypic, genetic, and maternal correlation matrices were examined through principal component analysis for trade‐offs among vegetative growth, clonal expansion and floral reproduction which could constrain the evolution of life history patterns. At the phenotypic level, seedlings with strong vegetative growth produced more and longer rhizomes, and were more likely to flower. Genetically, correlations among these functions were weak or absent. Strong maternal contributions to seedling vegetative growth correlated positively with the number and length of rhizomes. Thus, no trade‐offs acting during the seedling stage were found. However, there were indications of a genetically influenced trade‐off between the number of rhizomes produced in the seedling year with the size of the ramets produced in the second year.
EFFECTS OF HYBRIDIZATION AND INBREEDING ON FITNESS IN PHLOX
Authors: Levin Donald A. , Bulinska‐Radomska Zophia 
Published: January 2018

The effects of interpopulation hybridization, and self‐fertilization and immigration on fitness in Phlox drummondii were analyzed in 5 natural field sites. Germination rates, survivorship to flowering, fecundity, and net reproductive rates (Ro) were determined for planted populations of natives, hybrids, aliens, and the products of one and two generations of self‐fertilization.At all sites, seed germination was 36% for natives, 35% for hybrids and 28% for aliens. Survivorship for natives was 50%, compared to 49% for hybrids and 41% for aliens. The mean fecundity was 34, 35, and 39 seeds per plant for natives, hybrids, and aliens, respectively. The Ro of natives averaged 5.2 vs. 6.4 for hybrids and 4.2 aliens. At all the sites, germination averaged 25% for self‐1 plants and 19% for self‐2 plants compared to 24% for open‐pollinated controls. Survivorship progressed from 50% in the controls to 46% in self‐1 and 44% in self‐2 plants. Seed production per plant averaged 35% in the control vs. 32% in the self‐1 and 25% in the self‐2 plants. The mean Ro of the control was 3.8 vs. 3.3 in the self‐1 and 2.14 in the self‐2 plants. Our results demonstrate that the genetic variable may have a substantial effect on plant fitness in the field.
DIOECISM AND ITS CORRELATES IN THE CAPE FLORA OF SOUTH AFRICA
Authors: Steiner Kim E. 
Published: January 2018

Floral sexuality is characterized for the flora of the Cape region of South Africa. Among angiosperms (N = 8,497), monostylous hermaphroditism constitutes the largest proportion of species with 77.7%, followed by gynomonoecism (7.1%), dioecism (6.6%), andromonoecism (4.0%), monoecism (2.6%), heterostylous hermaphroditism (1.9%), polygamomonoecism (0.01%) and polygamodioecism (0.01%).The incidence of dioecism is significantly higher (P < 0.001) at the species level for two smaller floras within the Cape flora that consist mostly of species‐rich fynbos vegetation (Cape of Good Hope Nature Reserve: 11.6% [N = 1,349], Cape Hangklip: 9.7% [N = 1,046]). The relatively high incidence of dioecism in all three floras compared to other temperate floras is due to the large number of Restionaceae species. Excluding these rush‐like plants, dioecism at the species level is only 3.0% for the Cape flora, 4.2% for the Cape Hangklip flora and 3.6% for the Cape of Good Hope flora. At the generic level there are no significant differences in the incidence of dioecism between the three floras.Among dioecious species and genera in the Cape flora, there is a higher than expected incidence of wind pollination, fleshy fruits and nonwoodiness when each variable is analyzed independently. The association between nonwoodiness and dioecy has not been reported for other floras and is due to the large proportion of nonwoody wind‐pollinated Restionaceae. If this family is excluded from the analysis, dioecy becomes associated with biotic pollination, fleshy fruits, and woodiness.Interactions among the variables themselves as well as with dioecism indicate the need for a joint analysis of the variables. At the genus level, analyses reveal the following: 1) There is a higher than expected incidence of wind pollination among dioecious plants with dry fruits. If the Restionaceae are excluded from the analysis, wind pollination is more common than expected only for woody plants with dry fruits. 2) Dioecious plants that are biotically pollinated have a significantly higher incidence of fleshy fruits than expected. 3) Dioecious plants with dry fruits that are biotically pollinated have a higher than expected incidence of woodiness. If the Restionaceae are excluded from the analysis, woodiness is more common than expected among both nonwind and wind‐pollinated dioecious genera.
LIFE HISTORY AND SEED DISPERSAL OF THE SHORT‐LIVED CHAPARRAL SHRUB DENDROMECON RIGIDA (PAPAVERACEAE)
Authors: Bullock Stephen H. 
Published: January 2018

The natural history of the short‐lived, fire‐following shrub Dendromecon rigida Benth. was studied with emphasis on reproductive output and the consequences of seed dispersal, by intensive study of one population and comparisons with several others.

In 16 populations throughout California, mean seed weight ranged from 10 to 16 mg, and was not correlated with rainfall, elevation or latitude. Seed number per fruit ranged from 3 to 11. Adult populations ranged in size up to several million, but each was probably even‐aged, established after recent disturbance. Seed‐dispersing ants were found at all localities.
Reproduction began one year after establishment. Precocious reproduction did not increase mortality; rather, longer‐lived plants were more fecund at all ages.
The percentage of the population reproducing and fruit number in the most fecund plants were directly related to rainfall in the preceding six months, regardless of plant age. Reproduction also differed according to topographic position.
Mean life expectancy of one‐year‐old plants was about six years, and only 5% survived to age 10 years. Intraspecific density effects were not apparent. Seed longevity probably exceeds adult longevity by a factor of five or ten.
The fruits are explosive and secondary dispersal is by gravity and ants. The ants are attracted to a caruncle which represents 14% of the propagule's caloric content. In the intensive study area ants removed more seeds from more sites than did vertebrate seed predators. Pogonomyrmex subnitidus developed large nests on open sites on ridges, and thus provided uphill (even interdrainage) dispersal; it discarded seeds on the soil surface, free to roll but open to predation. Camponotus species had fewer foragers but many small nests in well‐covered sites, and discarded the seeds in underground refuse galleries. Dispersal thus affects exposure to predation, the microsite of germination, conspecific aggregation, and position in the mosaic patterns of topography and fire.
DROUGHT AND THE EVOLUTION OF FLOWERING TIME IN DESERT ANNUALS
Authors: Fox Gordon A. 
Published: January 2018

Drought is often thought to stimulate flowering in desert, and sometimes in mesic, annuals. I review experimental studies of the effect of drought on flowering time in both desert and mesic annuals. No convincing experimental evidence presently exists that drought stimulates flowering in any annual plant; some experimental results suggest the opposite. The design and analysis of flowering time studies are also reviewed; most extant studies have serious flaws. Thus, a convincing demonstration of drought‐stimulated flowering will require carefully designed and analyzed experiments.In light of these results, I examine several ways in which drought may affect the ecology and evolution of flowering time in desert annuals, and suggest directions for research. Several mechanisms probably contribute to phenotypic variation in flowering time and size, including water and nutrient limitation, competition, and variation in seed size and germination time. Phenotypic effects of seed traits suggest that seed and flowering time traits may not evolve independently of one another. Water stress during reproduction can influence seed traits; such maternal effects can influence the outcome of selection both on seed traits and on flowering time. The multivariate character of flowering time evolution suggests that genetic and phenotypic correlations among these traits may present important constraints on the evolution of flowering time.
MONOPLASTIDIC CELL DIVISION IN LOWER LAND PLANTS
Authors: Brown Roy C. , Lemmon Betty E. 
Published: January 2018

In many bryophytes and vascular cryptogams mitosis and/or meiosis takes place in cells containing a single plastid. In monoplastidic cell division plastid polarity assures that nuclear and plastid division are infallibly coordinated. The two major components of plastid polarity are morphogenetic plastid migration and microtubule organization at the plastids. Before nuclear division the plastid migrates to a position intersecting the future division plane. This morphogenetic migration is a reliable marker of division polarity in cells with and without a preprophase band of microtubules (PPB). The PPB, which predicts the future division plane before mitosis, is a characteristic feature of land plants and its insertion into the cytokinetic apparatus marks the evolution of a cortical microtubule system and a commitment to meristematic growth. Microtubule systems associated with plastid division, the axial microtubule system (AMS) in mitosis and the quadripolar microtubule system (QMS) in meiosis, contribute to predictive positioning of plastids and participate directly in spindle ontogeny. Division polarity in monoplastidic sporocytes is remarkable in that division sites are selected prior to the two successive nuclear divisions of meiosis. Plastid arrangement prior to meiosis determines the future spore domains in monoplastidic sporocytes, whereas in polyplastidic sporocytes the spore nuclei play a major role in claiming cytoplasmic domains. It is hypothesized that predivision microtubule systems associated with monoplastidic cell division are early forming components of the mitotic apparatus that serve to orient the spindle and insure equal apportionment of nucleus and plastids.“Can it be supposed that cytoplasm would be intrusted with so important a task as the preparation of a chloroplast for each of the four nuclei that are later to preside over the spores before there is any indication that such nuclear division is to take place?”Bradley Moore Davis, 1899
MicroRNA hsa‐let‐7b suppresses the odonto/osteogenic differentiation capacity of stem cells from apical papilla by targeting MMP1
Authors: Wang Yanqiu , Pang Xiyao , Wu Jintao , Jin Lin , Yu Yan , Gobin Romila , Yu Jinhua 
Published: January 2018

AbstractMicroRNA let‐7 family acts as the key regulator of the differentiation of mesenchymal stem cells (MSCs). However, the influence of let‐7b on biological characteristics of stem cells from apical papilla (SCAPs) is still controversial. In this study, the expression of hsa‐let‐7b was obviously downregulated during the osteogenic differentiation of SCAPs. SCAPs were then infected with hsa‐let‐7b or hsa‐let‐7b inhibitor lentiviruses. The proliferation ability was determined by CCK‐8 and flow cytometry. The odonto/osteogenic differentiation capacity was analyzed by alkaline phosphatase (ALP) activity, alizarin red staining, Western blot assay, and real‐time RT‐PCR. Bioinformatics analysis was used to screen out the target of hsa‐let‐7b and the target relationship was confirmed by dual luciferase reporter assay. Hsa‐let‐7b was of no influence on the proliferation of SCAPs. Interferential expression of hsa‐let‐7b increased the ALP activity as well as the formation of calcified nodules of SCAPs. Moreover, the mRNA levels of osteoblastic markers (ALP, RUNX2, OSX, OPN, and OCN) were upregulated while the protein levels of DSPP, ALP, RUNX2, OSX, OPN, and OCN also increased considerably. Conversely, overexpression of hsa‐let‐7b inhibited the odonto/osteogenic differentiation capacity of SCAPs. Bioinformatics analysis revealed a putative binding site of hsa‐let‐7b in the matrix metalloproteinase 1 (MMP1) 3′‐untranslated region (3′‐UTR). Dual luciferase reporter assay confirmed that hsa‐let‐7b targets MMP1. The odonto/osteogenic differentiation ability of SCAPs ascended after repression of hsa‐let‐7b, which was then reversed after co‐transfection with siMMP1. Together, hsa‐let‐7b can suppress the odonto/osteogenic differentiation capacity of SCAPs by targeting MMP1.
Retracted: Long non‐coding RNA XIST promotes osteosarcoma progression by targeting YAP via miR‐195‐5p
Authors: Yang Chao , Wu Ke , Wang Shan , Wei Guanghui 
Published: January 2018

AbstractThe lncRNA XIST (X inactive‐specific transcript) is an oncogenic lncRNA that is present in various malignant tumors; however, its role and molecular mechanisms in osteosarcoma (OS) progression remain unclear. In the current study, 40 pairs of OS tissues and matched adjacent non‐tumor tissues were collected. qRT‐PCR was conducted to investigate the differences in XIST expression in tissues and OS cell lines. The proliferation, invasion, and EMT status of OS cells after transfection were assessed with WST‐1 assays, Transwell assays, and Western blot analysis, respectively. Whether miR‐195‐5p was a direct downstream target of XIST was verified by both bioinformatics target gene prediction and dual‐luciferase report analysis. A mouse model was established to evaluate tumor proliferation in vivo. Our results demonstrated that XIST expression was significantly upregulated in OS tissues and cell lines and negatively correlated with clinical prognosis. XIST knockdown inhibited cancer cell proliferation and invasion in vitro, inhibited the EMT of OS cells in vitro, and suppressed subcutaneous tumor growth in vivo. Further analysis demonstrated that XIST regulated YAP expression by functioning as a competing endogenous RNA that sponged miR‐195‐5p in OS cells. XIST directly interacted with miR‐195‐5p and decreased the binding of miR‐195‐5p to the YAP 3′UTR, which suppressed the degradation of YAP mRNA by miR‐195‐5p. In conclusion, this work demonstrates that lncRNA XIST enhances OS cancer cell proliferation and invasion in part through the miR‐195‐5p/YAP pathway. Therefore, lncRNA XIST might be a promising therapeutic target for OS.