Rubra

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Rubra

  • f. rubra
  • festuca rubra
  • haliotis rubra
  • q. rubra
  • quercus rubra


  • Selected Abstracts


    Treatment of Striae Rubra and Striae Alba With the 585-nm Pulsed-Dye Laser

    DERMATOLOGIC SURGERY, Issue 4 2003
    Gloria P. Jimeénez MD
    BACKGROUND The treatment of striae distensae has recently been reported with various lasers such as the 585-nm pulsed dye laser. At lower fluences (2.0 to 4.0 J/cm2), this laser has been purported to increase the amount of collagen in the extracellular matrix. OBJECTIVE To determine whether the 585-nm pulsed dye laser is effective in both striae rubra and striae alba after two treatments and, in addition, to determine whether there is a net effect on collagen density in treated samples. METHODS Twenty patients (skin types II to VI) with either striae rubra (9) or striae alba (11) were treated at baseline and at week 6. The total length of the study was 12 weeks. Untreated striae on the same patient were used as control subjects. Striae clinical parameters such as color and area were measured before the first and after the last treatment by an independent examiner using a visual analog scale. A hydroxyproline assay was used to measure collagen changes in two of the striae quantitatively. RESULTS The 585 nm had a moderate beneficial effect in reducing the degree of erythema in striae rubra. There was no apparent clinical change on striae alba. Total collagen per gram of dry weight of sampled tissue increased in striae treated with pulsed dye laser versus control subjects. CONCLUSION We recommend the use of the 585-nm pulsed dye laser for striae rubra in patients skin types II to IV. Extreme caution or avoidance should be observed in pulsed dye laser treatments for patients with phototypes V to VI even with the use of low fluences. Tissue collagen changes measured may be an early change, which precedes significant clinical improvement. [source]


    High-speed separation and characterization of major constituents in Radix Paeoniae Rubra by fast high-performance liquid chromatography coupled with diode-array detection and time-of-flight mass spectrometry

    RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 1 2009
    E-Hu Liu
    A fast high-performance liquid chromatography (HPLC) method coupled with diode-array detection (DAD) and electrospray ionization time-of-flight mass spectrometry (ESI-TOFMS) has been developed for rapid separation and sensitive identification of major constituents in Radix Paeoniae Rubra (RPR). The total analysis time on a short column packed with 1.8-µm porous particles was about 20,min without a loss in resolution, six times faster than the performance of a conventional column analysis (115,min). The MS fragmentation behavior and structural characterization of major compounds in RPR were investigated here for the first time. The targets were rapidly screened from RPR matrix using a narrow mass window of 0.01,Da to restructure extracted ion chromatograms. Accurate mass measurements (less than 5,ppm error) for both the deprotonated molecule and characteristic fragment ions represent reliable identification criteria for these compounds in complex matrices with similar if not even better performance compared with tandem mass spectrometry. A total of 26 components were screened and identified in RPR including 11 monoterpene glycosides, 11 galloyl glucoses and 4 other phenolic compounds. From the point of time savings, resolving power, accurate mass measurement capability and full spectral sensitivity, the established fast HPLC/DAD/TOFMS method turns out to be a highly useful technique to identify constituents in complex herbal medicines. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Potential Effects of Passenger Pigeon Flocks on the Structure and Composition of Presettlement Forests of Eastern North America

    CONSERVATION BIOLOGY, Issue 6 2003
    JOSHUA W. ELLSWORTH
    We suggest that the activities of roosting and nesting Passenger Pigeons caused widespread, frequent disturbances in presettlement eastern forests through tree limb and stem breakage and nutrient deposition from pigeon excrement. We suspect that the deposition of fine fuels resulting from such disturbances may have influenced fire intensity and frequency in presettlement forests. Further, we propose that consumption of vast quantities of acorns by pigeons during the spring breeding season may partially explain the dominance of white oak (Quercus alba) throughout much of the presettlement north-central hardwoods region. Consequently, the pigeon's extinction may have facilitated the increase and expansion of northern red oak (Quercus rubra) during the twentieth century. Although it is difficult to accurately quantify how physical and chemical disturbances and mast consumption by Passenger Pigeon flocks affected forest ecology, we suspect they shaped landscape structure and species composition in eastern forests prior to the twentieth century. We believe their impact should be accounted for in estimates of the range of natural variability of conditions in eastern hardwood forests. Resumen:,Consideramos los posibles efectos que pudieron haber tenido parvadas de Palomas Migratorias (Ectopistes migratorius) sobre el régimen de perturbación y la composición de especies de bosques en Norte América oriental antes de la colonización. Sugerimos que las actividades de perchado y anidación de las palomas causaron perturbaciones frecuentes y extensas en los bosques orientales antes de la colonización por medio de la ruptura de ramas y tallos de árboles y la deposición de nutrientes del excremento de las palomas. Sospechamos que la deposición de combustibles resultantes de tales perturbaciones pudo haber influido en la intensidad y frecuencia de incendios forestales. Más aún, proponemos que el consumo de grandes cantidades de bellotas por las palomas en la primavera puede parcialmente explicar la dominancia de roble blanco (Quercus alba) en muchos de los bosques nor-orientales. En consecuencia, la extinción de la paloma pudo haber facilitado el incremento y expansión del roble rojo (Quercus rubra) durante el siglo veinte. Aunque es difícil cuantificar con precisión como las perturbaciones físicas y químicas y el consumo masivo por parvadas de palomas migratorias afectaron a la ecología forestal, sospechamos que modelaron la estructura del paisaje y la composición de especies en los bosques orientales antes del siglo veinte. Creemos que su impacto debería ser considerado cuando se hacen estimaciones del rango de variabilidad natural de las condiciones en bosques orientales de maderas duras. [source]


    Treatment of Striae Rubra and Striae Alba With the 585-nm Pulsed-Dye Laser

    DERMATOLOGIC SURGERY, Issue 4 2003
    Gloria P. Jimeénez MD
    BACKGROUND The treatment of striae distensae has recently been reported with various lasers such as the 585-nm pulsed dye laser. At lower fluences (2.0 to 4.0 J/cm2), this laser has been purported to increase the amount of collagen in the extracellular matrix. OBJECTIVE To determine whether the 585-nm pulsed dye laser is effective in both striae rubra and striae alba after two treatments and, in addition, to determine whether there is a net effect on collagen density in treated samples. METHODS Twenty patients (skin types II to VI) with either striae rubra (9) or striae alba (11) were treated at baseline and at week 6. The total length of the study was 12 weeks. Untreated striae on the same patient were used as control subjects. Striae clinical parameters such as color and area were measured before the first and after the last treatment by an independent examiner using a visual analog scale. A hydroxyproline assay was used to measure collagen changes in two of the striae quantitatively. RESULTS The 585 nm had a moderate beneficial effect in reducing the degree of erythema in striae rubra. There was no apparent clinical change on striae alba. Total collagen per gram of dry weight of sampled tissue increased in striae treated with pulsed dye laser versus control subjects. CONCLUSION We recommend the use of the 585-nm pulsed dye laser for striae rubra in patients skin types II to IV. Extreme caution or avoidance should be observed in pulsed dye laser treatments for patients with phototypes V to VI even with the use of low fluences. Tissue collagen changes measured may be an early change, which precedes significant clinical improvement. [source]


    Variation in the abundance of fungal endophytes in fescue grasses along altitudinal and grazing gradients

    ECOGRAPHY, Issue 3 2007
    Gustaf Granath
    Epichloë festucae, a common fungal symbiont of the genus Festuca (family Poaceae), can provide its host plant with protection against herbivores. However, infection might also be associated with a cost to its host plant. We examined the distribution of Epichloë festucae infection in natural populations of three fescue grasses, Festuca rubra, F. ovina and F. vivipara, on mountains in northern Sweden to determine whether infection frequency varied with reindeer Rangifertarandus grazing pressure and altitude. Two differently-scaled approaches were used: 1) infection frequency was measured at a local scale along ten elevational transects within a ca 400 km2 area and 2) infection frequency was measured on a regional scale along elevational transects on 17 mountains classified as having a history of high or low reindeer grazing pressure. Mean infection frequencies in F. rubra were 10% (vegetative tillers at a local scale), and 23% (flowering culms at a regional scale), and in F. ovina they were 13% (local scale) and 15% (regional scale). Endophyte infection frequency in F. vivipara, was, on average, 12% (local scale) and 37% (regional scale). In F. rubra, infection decreased significantly with increasing altitude at both the local and regional scale, and was positively correlated with grazing pressure. In F. ovina, an opposite trend was found at the regional scale: infection frequency increased significantly with increasing altitude, while no discernible distribution pattern was observed at the local scale. No elevational trends were observed in infection of F. vivipara. These patterns in the distribution of endophyte-infected grasses in non-agricultural ecosystems may be explained by both biotic (grazing) and abiotic factors (altitude). Differences in ecology and life history of the studied grass species may also be of importance for the different results observed among species. [source]


    Local host ant specificity of Phengaris (Maculinea) teleius butterfly, an obligatory social parasite of Myrmica ants

    ECOLOGICAL ENTOMOLOGY, Issue 5 2010
    MAGDALENA WITEK
    1. Phengaris butterflies are obligatory social parasites of Myrmica ants. Early research suggested that there is a different Myrmica host species for each of the five European Phengaris social parasites, but more recent studies have shown that this was an oversimplification. 2. The pattern of host ant specificity within a Phengaris teleius metapopulation from southern Poland is reported. A combination of studying the frequency distribution of Phengaris occurrence and morphometrics on adult butterflies were used to test whether use of different host species is reflected in larval development. 3. Phengaris teleius larvae were found to survive in colonies of four Myrmica species: M. scabrinodis, M. rubra, M. ruginodis, and M. rugulosa. Myrmica scabrinodis was the most abundant species under the host plant but the percentage of infested nests was similar to other host ant species at two sites and lower in comparison to nests of M. rubra and M. ruginodis at the other two sites. Morphometric measurements of adult butterflies reared by wild colonies of M. scabrinodis and M. ruginodis showed that wing size and number of wing spots were slightly greater for adults eclosing from nests of M. ruginodis. 4. Our results suggest that P. teleius in the populations studied is less specialised than previously suggested. The results are consistent with the hypothesis that P. teleius is expected to be the least specific of the European Phengaris species, as it has the largest and best defended fourth-instar caterpillars and, as a predatory species, it spends less time in the central larval chambers of the host colonies. The fact that individuals reared by M. ruginodis had wider hind wings may suggest that P. teleius had better access to resources in M. ruginodis than in M. scabrinodis colonies. [source]


    The effect of organic acids on base cation leaching from the forest floor under six North American tree species

    EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2001
    F. A. Dijkstra
    Summary Organic acidity and its degree of neutralization in the forest floor can have large consequences for base cation leaching under different tree species. We investigated the effect of organic acids on base cation leaching from the forest floor under six common North American tree species. Forest floor samples were analysed for exchangeable cations and forest floor solutions for cations, anions, simple organic acids and acidic properties. Citric and lactic acid were the most common of the acids under all species. Malonic acid was found mainly under Tsuga canadensis (hemlock) and Fagus grandifolia (beech). The organic acids were positively correlated with dissolved organic carbon and contributed significantly to the organic acidity of the solution (up to 26%). Forest floor solutions under Tsuga canadensis contained the most dissolved C and the most weak acidity among the six tree species. Under Tsuga canadensis we also found significant amounts of strong acidity caused by deposition of sulphuric acid from the atmosphere and by strong organic acids. Base cation exchange was the most important mechanism by which acidity was neutralized. Organic acids in solution from Tsuga canadensis, Fagus grandifolia, Acer rubrum (red maple) and Quercus rubra (red oak) were hardly neutralized while much more organic acidity was neutralized for Acer saccharum (sugar maple) and Fraxinus americana (white ash). We conclude that quantity, nature and degree of neutralization of organic acids differ among the different tree species. While the potential for base cation leaching with organic acids from the forest floor is greatest under Tsuga canadensis, actual leaching with organic anions is greatest under Acer saccharum and Fraxinus americana under which the forest floor contains more exchangeable cations than does the strongly acidified forest floor under Tsuga canadensis. [source]


    Neutrophil gelatinase-associated lipocalin is a marker for dysregulated keratinocyte differentiation in human skin

    EXPERIMENTAL DERMATOLOGY, Issue 6 2002
    Lotus Mallbris
    Abstract: Neutrophil gelatinase-associated lipocalin (NGAL) is a 25-kDa protein initially isolated from the specific granules of human neutrophils. It is a member of the highly heterogeneous lipocalin protein family, which shares a common tertiary structure. Its synthesis is induced in gastrointestinal epithelium in association with inflammation and malignancy. To gain insight into its potential role in other epithelia we have investigated the expression of NGAL in human skin embryonic development, in normal adult skin, and in skin associated with inflammation and neoplastic transformation. In the present study we report that the embryonic expression of NGAL appears to be regulated in a spatio-temporal pattern. It was induced in the interfollicular epidermis at 20,24 weeks of gestational age but thereafter progressively receded towards the hair follicles. In normal adult skin, NGAL was detected solely in association with hair follicles. However, strong induction of NGAL in the epidermis was seen in a variety of skin disorders characterized by dysregulated epithelial differentiation such as psoriasis, pityriasis rubra and squamous cell carcinoma. In these tissues production of NGAL was confined to spatially distinct subpopulations of keratinocytes underlying areas of parakeratosis, whereas skin samples lacking parakeratotic epithelium such as lichen ruber planus, acute contact eczema and basal cell carcinoma were negative for NGAL. Consistent with being a marker for disturbed terminal differentiation, NGAL immunoreactivity showed an inverse pattern when compared with that of the differentiation marker filaggrin. The biologic functions of NGAL in epithelia are not fully known, although an immunomodulatory role in host defense has been proposed. In addition, the transient interfollicular NGAL expression during skin embryogenesis along with the induction of NGAL in adult parakeratotic epidermis suggests it play a role in epithelial differentiation pathways. [source]


    Relative susceptibility of oaks to seven species of Phytophthora isolated from oak forest soils

    FOREST PATHOLOGY, Issue 6 2008
    Y. Balci
    Summary Isolates of Phytophthora cambivora, P. cinnamomi, P. citricola, P. europaea, P. quercetorum and two unidentified species were tested for their pathogenicity to eastern US oak species by root and stem inoculations. Experiments were conducted during two different periods and included 1-, 2- and 20-year-old oaks grown under greenhouse and field conditions. Species of Phytophthora were pathogenic in varying degrees to the oak species tested. All species were pathogenic to fine and taproots of at least one oak species. The fine root damage caused by the species of Phytophthora ranged from 9 to 55% when compared to the controls. Roots were more susceptible during the fall inoculation period than the summer. With exception of Phytophthora sp1 and P. quercina -like, all species of Phytophthora were pathogenic to oak stems with P. cinnamomi and P. citricola being the most aggressive. Quercus montana and Q. rubra were the most susceptible oak species to stem inoculation. Lesion sizes were considerably larger when 20-year-old trees were inoculated. Generally, no significant differences in lesion sizes were detected in greenhouse tests when the summer and fall inoculation periods were compared. However, on 2-year-old field-grown seedlings, lesion sizes were considerably smaller or not significantly different from controls during the fall inoculation period, suggesting lower, late season temperatures may restrict lesion development. [source]


    Foliar susceptibility of eastern oak species to Phytophthora infection

    FOREST PATHOLOGY, Issue 5 2008
    Y. Balci
    Summary Seven different Phytophthora species were used to test the foliar susceptibility of the common eastern US oak species and understory plants to Phytophthora infection. The Phytophthora species employed were Phytophthora cambivora, Phytophthora cinnamomi, Phytophthora citricola, Phytophthora europaea, Phytophthora quercetorum, Phytophthora quercina -like and Phytophthora sp1. Inoculation of detached-leaves with agar plugs containing mycelia of Phytophthora provided an estimate of their relative susceptibility. Lesions were always greater when foliage was wounded and young. On deciduous plants, lesion sizes were considerably reduced with the increasing foliar age, although with evergreen plants lesion sizes remained similar regardless of foliar age when more aggressive isolates were tested. Infections seldom resulted when foliage was not wounded. With young and mature foliage, P. citricola usually produced the largest lesions. Young foliage of Quercus rubra was the most susceptible to infection followed by Castanea dentata for both wounded and non-wounded inoculations. Mature foliage of Hamamelis virginiana, Kalmia latifolia and Quercus alba were the most susceptible to wound and non-wound inoculations. [source]


    Hosts and distribution of Collybia fusipes in France and factors related to the disease's severity

    FOREST PATHOLOGY, Issue 1 2002
    D. PIOU
    Using data collected by two different observation networks, it was possible to clarify the distribution of Collybia fusipes in France. It is frequently found in the western and northern parts of France, mainly on Quercus rubra and Quercus robur, and to a somewhat lesser extent on Quercus petraea. When the relative areas covered by these species are compared, it is evident that Q. rubra is much the most susceptible of the three species. The fungus has been less frequently reported in the south-eastern quarter of France, where Quercus ilex and Quercus pubescens are the dominant species. Complementary observations carried out at the National Arboretum of Les Barres indicate that a large number of oak species are susceptible to infection by this fungus, particularly those in the subgenus Erythrobalanus. These observations are discussed with reference to reports of this fungus throughout Europe. In a Q. rubra stand, fruit-body clumps were monitored and root damage was assessed on 73 final-crop trees and 40 codominant trees. The results suggest that C. fusipes does not preferentially infect weakened trees. Both the severity of root damage and the number of fruit-body clumps increased with increasing depth to signs of waterlogging. Répartition et hôtes de Collybia fusipes en France et facteurs de gravité de la maladie D'après les données collectées par deux réseaux de surveillance distincts, la répartition de Collybia fusipes en France a été précisée. Le champignon est fréquent dans les moitiés ouest et nord du pays, principalement sur Quercus rubra et Q. robur, et dans une moindre mesure sur Q. petraea. Quand on considère la surface relative occupée par ces espèces, il apparaît évident que Q. rubra est le plus sensible. Il a été moins souvent signalé dans le quart sud-est oùQ. ilex et Q. pubescens sont dominants. Des observations complémentaires réalisées à l'Arboretum National des Barres indiquent qu'un grand nombre d'espèces de chênes sont susceptibles d'être attaquées par ce champignon, particulièrement celles du sous-genre Erythrobalanus. Ces observations sont discutées et comparées avec les données disponibles en Europe. L'apparition des carpophores a été suivie dans un peuplement de Q. rubra, et les dégâts aux racines ont étéévalués sur 73 arbres de place et 40 arbres codominants. Les résultats indiquent que C. fusipes n'infecte pas plus gravement les arbres affaiblis. Le degré d'hydromorphie influence significativement l'importance des dégâts racinaires ainsi que le nombre de carpophores produits. Cette étude confirme que C. fusipes se développe préférentiellement dans les sites où l'hydromorphie n'est pas trop sévère. Wirtspflanzen und Verbreitung von Collybia fusipes in Frankreich sowie mit der Krankheitsintensität assoziierte Umweltfaktoren Mit Hilfe der Daten von zwei unterschiedlichen Beobachtungsnetzwerken konnte die Verbreitung von Collybia fusipes in Frankreich präzisiert werden. Der Pilz ist im Westen und Norden des Landes häufig auf Quercus rubra und Quercus robur zu finden, etwas weniger häufig auf Quercus petraea. Beim Vergleich der von diesen Arten bestockten Flächen wird deutlich, dass Q. rubra die anfälligste der drei Eichenarten ist. Im südöstlichen Teil Frankreichs, wo Quercus ilex und Quercus pubescens dominieren, wurde der Pilz weniger häufig nachgewiesen. Ergänzende Beobachtungen im Arboretum National des Barres ergaben, dass zahlreiche Eichenarten gegen C. fusipes anfällig sind, insbesondere die des Subgenus Erythrobalanus. Diese Ergebnisse werden im Vergleich mit der aus Europa über diesen Pilz verfügbaren Literatur diskutiert. In einem Q. rubra, Bestand wurde das Auftreten von Fruchtkörpern und von Wurzelschäden an 73 herrschenden und 40 mitherrschenden Bäumen registriert. Die Ergebnisse zeigen, dass C. fusipes geschwächte Bäume nicht bevorzugt befällt. Sowohl die Intensität der Wurzelschäden als auch die Anzahl der Fruchtkörper erhöhte sich mit zunehmender Tiefe der Anzeichen für Staunässe im Bodenprofil. [source]


    Relationship between presence of basidiomes, above-ground symptoms and root infection by Collybia fusipes in oaks

    FOREST PATHOLOGY, Issue 1 2000
    B. Marçis
    Summary Collybia fusipes is a common cause of root rot on oak in the north of France. Collybia fusipes basidiomes can be as frequent on oaks in stands where no decline of the trees occurs compared with stands where the decline is chronic. This might be explained by differences in the amount of roots damaged by the parasite. To test that hypothesis, 430 oak trees, Quercus petraea, Quercus robur and Quercus rubra, located in six forests were selected. Half of them showed C. fusipes basidiomes at the trunk base. The association between presence of basidiomes and decline of affected trees depended on the forest. The level of infection of each tree by C. fusipes, as well as the crown appearance, the tree height : diameter at breast height ratio, age and sapwood width were determined. The presence of C. fusipes basidiomes was always associated with significant root infections. The crowns of the trees deteriorated with increasing level of root infection and the decline was severe only when the root damage was heavy. Although the decline of trees that were heavily damaged by C. fusipes was severe in some of the stands, in others, it was only mild, and so the differences in tree decline between the stands could not be attributed solely to differences in root infection severity. Trees damaged by C. fusipes seemed not to be subjected to more competition than their undamaged neighbour as reflected by a similar tree height: diameter at breast height ratio. [source]


    Rapid detection of fungal endophytes in grasses for large-scale studies

    FUNCTIONAL ECOLOGY, Issue 4 2006
    S. KOH
    Summary 1Standard visual screening methods for determining the qualitative and quantitative presence of fungal endophytes are too time-consuming for large-scale ecological studies. 2We investigated whether commercially available immunoblot kits, using monoclonal antibody techniques and designed for rapid-screening of the presence of Neotyphodium endophytes in fresh samples of the pasture grasses Festuca arundinacea and Lolium perenne, could be used for Neotyphodium detection using other grasses and preserved samples. We also determined whether immunoblot kits could provide quantitative information about the amount of Neotyphodium in the grass. 3The kits accurately detected endophyte presence in F. rubra, F. ovina, F. pratensis and F. altaica, in both preserved samples (dried and fixed), including 12-year-old stored, dried samples of F. rubra. 4Endophytes were detected in 7-day-old seedlings of Lolium perenne, 3 days (30%) earlier than previously recognized. 5The intensity of the coloured tissue prints on scanned immunoblot cards was significantly positively correlated with hyphal density, demonstrating a previously unrecognized accurate quantitative application. 6These findings greatly reduce logistical barriers to large-scale field research into the broader ecological significance of Neotyphodium in temperate and arctic grasses in non-agricultural ecosystems (particularly in remote areas) and suggest potential for estimating historical infection rates using stored and herbarium specimens. [source]


    Impact of elevated carbon dioxide on the rhizosphere communities of Carex arenaria and Festuca rubra

    GLOBAL CHANGE BIOLOGY, Issue 11 2007
    BARBARA DRIGO
    Abstract The increase in atmospheric carbon dioxide (CO2) levels is predicted to stimulate plant carbon (C) fixation, potentially influencing the size, structure and function of micro- and mesofaunal communities inhabiting the rhizosphere. To assess the effects of increased atmospheric CO2 on bacterial, fungal and nematode communities in the rhizosphere, Carex arenaria (a nonmycorrhizal plant species) and Festuca rubra (a mycorrhizal plant species) were grown in three dune soils under controlled soil temperature and moisture conditions, while subjecting the aboveground compartment to defined atmospheric conditions differing in CO2 concentrations (350 and 700 ,L L,1). Real-time polymerase chain reaction (PCR) and PCR-denaturing gradient gel electrophoresis methods were used to examine effects on the size and structure of rhizosphere communities. Multivariate analysis of community profiles showed that bacteria were most affected by elevated CO2, and fungi and nematodes to a lesser extent. The influence of elevated CO2 was plant dependent, with the mycorrhizal plant (F. rubra) exerting a greater influence on bacterial and fungal communities. Biomarker data indicated that arbuscular mycorrhizal fungi (AMF) may play an important role in the observed soil community responses. Effects of elevated CO2 were also soil dependent, with greater influence observed in the more organic-rich soils, which also supported higher levels of AMF colonization. These results indicate that responses of soil-borne communities to elevated CO2 are different for bacteria, fungi and nematodes and dependent on the plant type and soil nutrient availability. [source]


    Studying spatial and temporal dynamics of sward structure at low stocking densities: the use of an extended rising-plate-meter method

    GRASS & FORAGE SCIENCE, Issue 4 2003
    O. Correll
    Abstract An extended rising-plate-meter method was used to study the spatial and temporal variability of the sward structure of extensively managed pastures over a grazing season. Two treatments of a long-term grazing experiment with heifers were investigated: extensive continuous grazing (EG) with a target sward height of 10 cm and intensive continuous grazing (IG) with a target sward height of 5 cm. Compressed sward height and related herbage mass (HM), dominant plant species and stage of development of phenology were determined at weekly or twice weekly intervals at fixed measuring points. The results demonstrated a strong variability in sward height and HM, especially on the EG treatment. The botanical composition of the standing herbage differed between treatments and between patches of different heights within the same treatment. In areas with a short sward, the herbage was predominantly composed of Agrostis capillaris, Festuca rubra and Trifolium repens. It was more evenly composed and also included taller growing species, such as Alopecurus pratensis and Galium mollugo, in areas with a tall sward. The area potentially available for reproductive development was high in the EG treatment and low in the IG treatment. The method employed proved suitable to provide a detailed description of the dynamics of the sward structure. [source]


    The effect of Calluna vulgaris cover on the performance and intake of ewes grazing hill pastures in northern Spain

    GRASS & FORAGE SCIENCE, Issue 4 2000
    K. Osoro
    The effect of the proportion of Calluna vulgaris cover on diet composition, intake and performance of sheep grazing hill vegetation communities in northern Spain is examined. A total of 591 non-lactating Gallega ewes grazed for five consecutive grazing seasons (June to September) on replicated plots of hill pastures (1700 m.a.s.l.) composed principally of Festuca, Agrostis, Nardus and Calluna spp. but with different proportions of Calluna vulgaris cover, either 0·3 (C0·3) or 0·7 (C0·7) of the total area. In 1 year, twenty-eight ewes suckling single lambs also grazed the plots. The mean stocking density over the 5 years was 8·7 ewes ha,1. On treatment C0·3, daily liveweight gains (33 g d,1) of non-lactating ewes were significantly (P < 0·001) greater than on treatment C0·7 (12 g d,1). Likewise in lactating ewes the difference in mean daily liveweight change was 40 g d,1 (,5 vs. ,45 g d,1 for C0·3 and C0·7 treatments respectively; P < 0·001). Liveweight gains of lambs were only 80,100 g d,1 from June to August and lambs only maintained live weight during August and September. The effect of lactational status on liveweight changes was not significant. Liveweight gains of non-lactating ewes increased significantly (P < 0·001) from the first to the last year of the experiment on both treatments. The composition of the diet was significantly affected by treatment (P < 0·001), with a higher proportion of grass species on the C0·3 treatment and a higher digestibility of the diet in the first half of the grazing season (P < 0·001). The proportion of C. vulgaris in the diet was significantly (P < 0·001) higher on the C0·7 treatment and increased significantly (P < 0·001) from July to September on both treatments. There were no significant differences in the composition of the diet selected by lactating and non-lactating ewes. The results demonstrate that on hill vegetation communities, in which the grass components (Festuca rubra, Agrostis capillaris, and Nardus stricta) cover at least 0·3 of the area and on which the preferred grass component (Festuca and Agrostis spp.) is maintained at a sward height of at least 2·5 cm, non-lactating ewes can increase their live weight and body condition, but this increase is influenced by the proportion and quantity of species of grass in the diet, which is affected in turn by the species of grass available and their nutritive quality. However, ewes suckling lambs were not able to maintain their live weight and body condition except when Calluna cover was 0·3 and grass height was more than 3·5 cm. It is concluded that these indigenous vegetation communities can be used in sheep production systems to complement the use of improved pastures at other times of year. In particular, they can be utilized during the non-lactating period (summer) to increase body condition before the beginning of the mating period in autumn. [source]


    Die Blattanatomie eines schnell und eines langsam wachsenden Grases in Abhängigkeit von der Stickstoffversorgung

    JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2001
    G. Schulte auf'm Erley
    Leaf anatomy of a fast- and a slow-growing grass as dependent on nitrogen supply The grass species Lolium perenne and Festuca rubra, originating from habitats with differing N-availability, differ in their relative growth rate. This is mainly caused by the higher specific leaf area of L. perenne compared to F. rubra. The leaf anatomy of both species was further investigated. The species were raised in growth chambers under high and low N-supply. The higher specific leaf area of L. perenne (27 mm2 mg,1) in relation to F. rubra (14 mm2 mg,1) was mainly caused by a lower leaf density (0.23 vs. 0.33 mg mm,3). The level of N-supply influenced both leaf density and leaf thickness. The leaf volume of L. perenne comprised higher fractions of epidermis and lower fractions of mesophyll and intercellular space compared to F. rubra. However, the discrepancy in leaf density between the species could not be explained by anatomical differences. Under low N-supply, the leaves of both species had higher amounts of vascular bundles and fibre cells and lower amounts of intercellular space, which partly explained the higher density of the leaves. It is concluded, that thinner cell walls and higher amounts of cytoplasm cause the higher specific leaf area of L. perenne. Die Grasarten Lolium perenne und Festuca rubra, die auf Standorten mit unterschiedlicher N-Verfügbarkeit beheimatet sind, unterscheiden sich in ihrer relativen Wachstumsrate. Der Hauptgrund dafür liegt in der höheren spezifischen Blattfläche von L. perenne gegenüber F. rubra. Von beiden Arten wurde die Blattanatomie näher untersucht, nachdem sie in Klimakammern unter einer hohen und einer niedrigen N-Versorgungsstufe angezogen worden waren. Es zeigte sich, daß sich die höhere spezifische Blattfläche von L. perenne (27 mm2 mg,1) gegenüber F. rubra (14 mm2 mg,1) auf eine niedrigere Blattdichte zurückführen ließ (0,23 gegenüber 0,33 mg mm,3). Die Höhe der N-Versorgung beeinflußte sowohl die Blattdichte als auch die Blattdicke. Die Blätter von L. perenne hatten gegenüber denen von F. rubra höhere Volumenanteile an Epidermis und geringere Anteile an Mesophyll und Interzellularen. Die Unterschiede in der Blattdichte zwischen den Spezies ließen sich hierdurch nicht erklären. Unter niedriger N-Versorgung hatten die Blätter beider Arten höhere Anteile an Leit- und Faserbündeln und weniger Interzellularraum, was die höhere Blattdichte unter niedriger N-Versorgung teilweise erklärt. Es wird gefolgert, daß insgesamt dünnere Zellwände und mehr Cytoplasma die höhere spezifische Blattfläche von L. perenne verursachen. [source]


    Intraspecific genetic analysis of the summer tanager Piranga rubra: implications for species limits and conservation

    JOURNAL OF AVIAN BIOLOGY, Issue 1 2007
    Tiffany M. Shepherd
    The summer tanager Piranga rubra is a Neotropical migrant that has experienced noted declines in the southwestern United States caused by extensive habitat loss of native riparian woodlands. This species is composed of two morphologically and behaviorally distinct taxa that traditionally have been recognized as subspecies, each occupying unique habitats in the southern part of North America. Genetic analyses of intraspecific variation are important in studies of threatened or endangered species because they can indicate whether smaller management units exist below the species level and they also provide estimates of within population variability. Using a mitochondrial DNA marker, the intraspecific genetic variation of this species is explored to determine whether the morphologically and behaviorally distinct subspecies are also genetically unique. By using traditional phylogenetic methods and building haplotype networks, results from this study indicate that the subspecies represent two phylogenetic species and should be managed as separate units. In addition, the level of gene flow among geographically isolated populations of the western subspecies is explored using Nested Clade Phylogeographic Analysis and population genetic tests. These analyses show that populations are genetically diverse and that haplotypes are shared across populations. Newly colonized populations are as diverse as older populations. This suggests that as habitat degrades in traditional breeding areas of the summer tanager, if suitable habitat elsewhere becomes available for new populations, these new colonies should be genetically diverse. [source]


    Assessing spatial variation in browsing history by means of fraying scars

    JOURNAL OF BIOGEOGRAPHY, Issue 6 2004
    Bruno Vila
    Abstract Aim, We used fraying scars to understand spatial variation in browsing history. Information on browsing history is an essential background in studies on the long-term effect of deer browsing on the flora and fauna and of its variation in space. Location, We focused on two small neighbouring islands of Haida Gwaii (British Columbia, Canada), Reef Island and South-Skedans Island, colonized by introduced black-tailed deer (Odocoileus hemionus sitkensis). Methods, We searched for sites where trees with fraying scars were clustered. We studied the trees that deer selected (species, size) and the characteristics of scars (number, position, size). Using a cross-dating procedure, we dated fraying scars with dendrochronology, obtaining an accurate estimate of the year the scar was formed. Results, On Reef Island, Thuja plicata was the tree species chosen for fraying. On South-Skedans Island, where Thuja plicata is missing, deer chose Salix sp. and Alnus rubra. Deer chose only trees with a circumference of less than 50 cm. About two to three fraying scars were recorded per tree. All of them extended between 30,40 and 70,80 cm from the ground and were between 5 and 6 cm in width. On Reef Island, 95% of the scars were formed during the last 50 years. On South-Skedans Island, 95% were formed over the last 10 years. Age distribution of scars showed a constant increase of the number of scars over time. It indicated that deer had colonized Reef Island 53 years prior to this study but were absent or rare on South-Skedans Island until 13 years prior to this study. Main conclusions, These results indicate different colonization dates and thus different length of browsing histories for the islands studied and provide the historical background necessary to analyse the involvement of deer in the current differences in the flora and fauna observed between islands. [source]


    Vegetation and disturbance history of a rare dwarf pitch pine community in western New England, USA

    JOURNAL OF BIOGEOGRAPHY, Issue 10-11 2002
    Glenn Motzkin
    Abstract Aim, This study documents the vegetation history and age-structure of a rare, ridgetop dwarf pine,oak community and compares the dynamics of this unusual vegetation with similar dwarf pine communities found elsewhere in the north-eastern United States (US). Location, The study area is located on the summit of Mt Everett in the Taconic Mountains of south-western Berkshire County, Massachusetts, USA (42°06,N 73°26,W). Methods, Vegetation composition, tree age-structure, physical site characteristics, and evidence of fire and other disturbances were determined for twelve 15 × 15 m plots in dwarf pine,oak vegetation and two plots in oak forests on the summit. Age-structure analyses, tree-ring patterns, and historical records of human and natural disturbance were used to investigate the long-term history and dynamics of the summit vegetation. Results, The summit of Mt Everett has been dominated by dwarf pines (1,3 m tall) and ericaceous shrubs similar to the modern vegetation throughout the historical period; there is no evidence that tall-stature forests occurred on the site at any point in the past few centuries. The summit supports uneven-aged stands; pitch pine (Pinus rigida) recruitment began in the 1830s and occurred in every decade since the 1860s. Average pitch pine age is seventy-eight with a range of 12,170 years. Red oak (Quercus rubra) and red maple (Acer rubrum) increased in importance in the twentieth century, with most stems establishing from 1940 to 1980. Pitch pine radial growth rates averaged <0.5 mm year,1 while red oak and red maple averaged 1.0 and 0.8 mm year,1, respectively. In some areas, hardwoods have overtopped pitch pines, apparently resulting in pitch pine mortality. Whereas most dwarf pitch pine communities occur on sites that burn frequently and have a high degree of cone serotiny, we found no evidence of recent fires or cone serotiny. Small amounts of macroscopic charcoal that we documented may have resulted from fires in the pre-European or early historical periods. Conclusions, Harsh edaphic conditions and chronic low-level disturbances on the summit, including frequent winter storms, have apparently contributed to the establishment, long-term persistence, and slow radial growth of dwarf pitch pines on Mt Everett. The ability of dwarf pines to persist on a site in the absence of frequent fire is highly unusual among North-eastern barrens and has not been well-incorporated into previous conceptual ecological models of these communities. Our results suggest that even among North-eastern barrens, the summit of Mt Everett is characterized by highly unusual vegetation and dynamics. The site has long been recognized as regionally significant and should be afforded the strictest conservation protection. With no evident history of human disturbance or recent fire, there is no apparent need for immediate active management of the site. [source]


    Environmental stresses mediate endophyte,grass interactions in a boreal archipelago

    JOURNAL OF ECOLOGY, Issue 2 2010
    Nora M. Saona
    Summary 1.,Both evolutionary theory and empirical evidence from agricultural research support the view that asexual, vertically transmitted fungal endophytes are typically plant mutualists that develop high infection frequencies within host grass populations. In contrast, endophyte,grass interactions in natural ecosystems are more variable, spanning the range from mutualism to antagonism and comparatively little is known about their range of response to environmental stress. 2.,We examined patterns in endophyte prevalence and endophyte,grass interactions across nutrient and grazing (from Greylag and Canada geese) gradients in 15 sites with different soil moisture levels in 13 island populations of the widespread grass Festuca rubra in a boreal archipelago in Sweden. 3.,In the field, endophyte prevalence levels were generally low (range = 10,53%) compared with those reported from agricultural systems. Under mesic-moist conditions endophyte prevalence was constantly low (mean prevalence = 15%) and was not affected by grazing pressure or nutrient availability. In contrast, under conditions of drought, endophyte prevalence increased from 10% to 53% with increasing nutrient availability and increasing grazing pressure. 4.,In the field, we measured the production of flowering culms, as a proxy for host fitness, to determine how endophyte-infected plants differed from uninfected plants. At dry sites, endophyte infection did not affect flowering culm production. In contrast, at mesic-moist sites production of flowering culms in endophyte-infected plants increased with the covarying effects of increasing nutrient availability and grazing pressure, indicating that the interaction switched from antagonistic to mutualistic. 5.,A concurrent glasshouse experiment showed that in most situations, the host appears to incur some costs for harbouring endophytes. Uninfected grasses generally outperformed infected grasses (antagonistic interaction), while infected grasses outperformed uninfected grasses (mutualistic interaction) only in dry, nutrient-rich conditions. Nutrient and water addition affected tiller production, leaf number and leaf length differently, suggesting that tillers responded with different strategies. This emphasizes that several response variables are needed to evaluate the interaction. 6.,Synthesis. This study found complex patterns in endophyte prevalence that were not always correlated with culm production. These contrasting patterns suggest that the direction and strength of selection on infected plants is highly variable and depends upon a suite of interacting environmental variables that may fluctuate in the intensity of their impact, during the course of the host life cycle. [source]


    Year-to-year variation in plant competition in a mountain grassland

    JOURNAL OF ECOLOGY, Issue 1 2003
    Herben
    Summary 1We used a series of removal experiments to examine how species response to competition and climatic differences varied in three different years. We tested the interaction between removal of the dominant grass species, Festuca rubra, and year-to-year environmental variation in a mown mountain grassland. 2In each year, we quantified shoot frequency and above-ground biomass of all remaining plant species. Above-ground responses were tested both by analysis of covariance and by redundancy analysis with randomization tests of changes in total species composition. 3Analysis of above-ground biomass data showed that other species compensated for the removal of F. rubra biomass within 2 years and that the response in total biomass of the community did not differ among years in which the experiment was started. 4Multivariate tests showed that species composition changed as a result of the removal; grass biomass and frequency increased more than that of dicotyledons. However, response of species composition to removal of F. rubra was significantly different between onset years. Specific conditions in individual years thus affect the competitive ability of individual species in a non-additive way. 5Our results indicate that the year-to-year variation at the site has the potential to affect species coexistence and richness. As a consequence, year-to-year variation of climatic parameters may be an important driving factor in community dynamics and should be taken into account in studies of ecosystem response to climate. [source]


    The relationship between growth and mortality for seven co-occurring tree species in the southern Appalachian Mountains

    JOURNAL OF ECOLOGY, Issue 4 2002
    Peter H. Wyckoff
    Summary 1Slow growth is associated with high mortality risk for trees, but few data exist to assess interspecific differences in the relationship between growth and mortality. Here we compare low growth tolerance for seven co-occurring species in the southern Appalachian Mountains: Acer rubrum, Betula lenta, Cornus florida, Liriodendron tulipifera, Quercus prinus, Quercus rubra and Robinia pseudo-acacia. 2For all species, mortality was greater for understorey individuals than for canopy trees. Species varied widely in the length of growth decline prior to death, ranging from 6 years for L. tulipifera to more than 12 years for Q. rubra. 3Growth-mortality functions differ among species, but we found little evidence of a trade-off between tolerance of slow growth and an ability to show rapid growth in high light conditions. 4A. rubrum stands out in its ability both to grow rapidly and to tolerate slow growth, suggesting that its density may increase at our study site as in other parts of the eastern United States. In contrast, C. florida shows high mortality (15% per annum) as a result of infection with dogwood anthracnose. 5We modified a forest simulation model, LINKAGES (which assumes that all species have the same ability to tolerate slow growth), to include our functions relating growth and mortality. The modified model gives radically altered predictions, reinforcing the need to rethink and re-parameterize existing computer models with field data. [source]


    PHYSICO-CHEMICAL ANALYSES, SENSORY EVALUATION AND POTENTIAL OF MINIMAL PROCESSING OF PEJIBAYE (BACTRIS GASIPAES) COMPARED TO MASCARENES PALMS

    JOURNAL OF FOOD QUALITY, Issue 2010
    J. JOAS
    ABSTRACT A palm species native of South America, pejibaye (Bactris gasipaes), was recently introduced in Reunion Island in an attempt to diversify its agriculture. Morphological analyses highlighted the agronomic advantages of pejibaye including a high weight-to-harvest-date ratio compared to three mascarenes palm species. Sensory analyses by a trained panel allowed the elaboration of sensory profiles of the four palms tested. Ranking test done by 120 consumers revealed that pejibaye was preferred to the Mascarenes palms at the 5% level of significance and triangle test showed that Acanthophoenix rubra (red palm), the most cultivated species for the local market, was significantly different from pejibaje at the 1% level. Phenolic profiles revealed that pejibaye differed from the other species by a peak absorbing at 272 nm and weak polyphenol oxidase activities. As no browning reaction was observed in fresh cut pejibaye, this palm could be used for minimal processing (local and export market). PRACTICAL APPLICATIONS Sensorial characteristics of fresh hearts of palm are different of those of canned heart of palm, and fresh heart palms are generally preferred by consumers. However, the marketing of fresh palm is limited by the high level of oxidation of most of palm species. The high stability of pejibaye after cutting and its slow rate of oxidation offer the possibility of minimal processing, without special additives. So the packaging in wrapped trays of this palm, cut and stored at low temperature opens up new perspectives, ensuring sensorial quality of a "fresh" product with a shelf life allowing a controlled management of market supply. [source]


    Pulsed Electric Field Processing of Beer: Microbial, Sensory, and Quality Analyses

    JOURNAL OF FOOD SCIENCE, Issue 8 2004
    G.A. Evrendilek
    ABSTRACT: In this study, pulsed electric field (PEF) treatment of beer, effectiveness of PEF treatment on microbial inactivation, effects of PEF treatment on sensory properties, and detection of electrode material migration were explored. Beer samples were treated by PEF for the inactivation of natural flora and inoculated cultures of Saccaromyces uvarum, Rhodotorula rubra, Lactobacillus plantarum, Pediococcus damnosus, and Bacillus subtilis. Inactivation induced by the PEF treatment was 0.5, 4.1, 4.3, 4.7, 5.8, and 4.8 log10 colony-forming units/mL in the above microorganisms, respectively (P < 0.05). There was a significant increase in the amount of Cr, Zn, Fe, and Mn ions in the beer samples after PEF treatment (P < 0.05) leading to a statistically significant degradation in flavor and mouth feel. Further studies are needed to optimize electrode materials and PEF treatment to minimize or eliminate this degradation. [source]


    Intensity and Importance of Competition for a Grass (Festuca rubra) and a Legume (Trifolium pratense) Vary with Environmental Changes

    JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 12 2008
    Junyan Zhang
    Abstract How plant competition varies across environmental gradients has been a long debate among ecologists. We conducted a growth chamber experiment to determine the intensity and importance of competition for plants grown in changed environmental conditions. Festuca rubra and Trifolium pratense were grown in monoculture and in two- and/or three-species mixtures under three environmental treatments. The measured competitive variations in terms of growth (height and biomass) were species-dependent. Competition intensity for Festuca increased with decreased productivity, whilst competition importance displayed a humpback response. However, significant response was detected in neither competition intensity nor importance for Trifolium. Intensity and importance of competition followed different response patterns, suggesting that they may not be correlated along an environmental gradient. The biological and physiological variables of plants play an important role to determine the interspecific competition associated with competition intensity and importance. However, the competitive feature can be modified by multiple environmental changes which may increase or hinder how competitive a plant is. [source]


    EVIDENCE FOR LATERAL TRANSFER OF AN IE INTRON BETWEEN FUNGAL AND RED ALGAL SMALL SUBUNIT RRNA GENES,

    JOURNAL OF PHYCOLOGY, Issue 2 2005
    Kirsten M. Müller
    A previous study of the North American biogeography of the red algal genus Hildenbrandia noted the presence of group I introns in the nuclear small subunit (SSU) rRNA gene of the marine species H. rubra (Sommerf.) Menegh. Group IC1 introns have been previously reported at positions 516 and 1506 in the nuclear SSU RNA genes in the Bangiales and Hildenbrandiales. However, the presence of an unclassified intron at position 989 in a collection of H. rubra from British Columbia was noted. This intron is a member of the IE subclass and is the first report of this intron type in the red algae. Phylogenetic analyses of the intron sequences revealed a close relationship between this IE intron inserted at position 989 and similar fungal IE introns in positions 989 and 1199. The 989 IE introns formed a moderately to well-supported clade, whereas the 1199 IE introns are weakly supported. Unique structural helices in the P13 domain of the 989 and 1199 IE introns also point to a close relationship between these two clades and provide further evidence for the value of secondary structural characteristics in identifying homologous introns in evolutionarily divergent organisms. The absence of the 989 IE intron in all other red algal nuclear SSU rRNA genes suggests that it is unlikely that this intron was vertically inherited from the common ancestor of the red algal and fungal lineages but rather is the result of lateral transfer between fungal and red algal nuclear SSU rRNA genes. [source]


    SYSTEMATICS OF THE HILDENBRANDIALES (RHODOPHYTA): GENE SEQUENCE AND MORPHOMETRIC ANALYSES OF GLOBAL COLLECTIONS,

    JOURNAL OF PHYCOLOGY, Issue 2 2003
    Alison R. Sherwood
    Fifty-seven collections of marine and freshwater Hildenbrandia from North America, South America, Europe, and Africa were compared with 21 type and historically important specimens using multivariate morphometrics. Additionally, phylogenetic analyses of 48 specimens of Hildenbrandia and two specimens of Apophlaea were carried out based on sequences of the rbcL chloroplast gene and the nuclear 18S rRNA gene. Morphometric analyses based on vegetative cell and filament dimensions distinguished two groups of freshwater Hildenbrandia specimens, the first corresponding to those collections from North America and the Philippines and the second to those from Europe and the Canary Islands. The first group had smaller mean cell and filament dimensions (cells 4.0 × 4.4 ,m, filaments 46.5 ,m) and corresponded to H. angolensis, whereas the second group had larger mean dimensions (cells 5.8 × 6.6 ,m, filaments 55.3 ,m) and represented H. rivularis. Marine specimens were morphometrically distinguishable into two groups based on tetrasporangial division pattern as well as other thallus characters. However, measurements and character determinations of some type specimens differed greatly from the original descriptions, and thus further work to determine the stability of these characters is required. Phylogenetic reconstruction based on the 18S rRNA gene and rbcL gene sequence data generally demonstrated separation of the marine and freshwater forms of Hildenbrandia, with some marine taxa forming monophyletic groups (e.g. H. lecannellieri and H. occidentalis) and others forming paraphyletic groups (e.g. H. rubra). The two specimens of Apophlaea formed a monophyletic group within the paraphyletic genus Hildenbrandia. [source]


    Ergovaline occurrence in grasses infected by fungal endophytes of semi-arid pastures in Spain

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 4 2003
    Beatriz R Vazquez de Aldana
    Abstract Ergovaline is a mycotoxin produced by fungal endophytes belonging to Neotyphodium and Epichloë spp in several host grass species. Owing to the production of this alkaloid, the ingestion of endophyte-infected grasses causes toxicosis in grazing animals. The aim of this work was to determine if ergovaline is produced in several grasses (Agrostis castellana Boiss and Reuter, Brachypodium phoenicoides (L) Roemer and Schultes, Dactylis glomerata L, Festuca arundinacea Schreb, Festuca arundinacea Schreb subsp fenas (Lag) Arcangeli, Festuca ovina L, Festuca rubra L, Holcus lanatus L and Lolium perenne L) infected by fungal endophytes in ,dehesa' pastures in Spain. Forage and seed samples of several ecotypes of these grass species were analysed for their ergovaline content by HPLC with fluorescence detection. The ergovaline content ranged between 0.03 and 0.85,µg,g,1 in forage and 0.28 and 3.17,µg,g,1 in seed samples of F arundinacea, between 0.00 and 0.08,µg,g,1 in forage and 0.02 and 0.19,µg,g,1 in seed samples of F rubra, between 0.00 and 0.02,µg,g,1 in forage samples of H lanatus, and was 0.11,µg,g,1 in one ecotype of F ovina. All nine ecotypes of F rubra had ergovaline in seed samples, but in three ecotypes the alkaloid was not detected in forage samples. No ergovaline was detected in the other four endophyte-infected grasses analysed. The ergovaline content should be considered as an anti-quality parameter to be measured when the nutritional quality of these pastures is evaluated. © 2003 Society of Chemical Industry [source]


    Factors influencing anthocyanin content in red cabbage (Brassica oleracea var capitata L f rubra (L) Thell)

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2002
    Roberta Piccaglia
    Abstract In North and Central Italy an experiment was conducted for two consecutive years to optimise the anthocyanin yield of red cabbage. Two hybrids (,Roxy' and ,Gradur') were grown under a factorial combination of increasing rates of potassium sulphate (0, 50, 100,kg K ha,1) and superphosphate (0, 39, 78,kg P ha,1) applied before planting. Cabbages were transplanted at the beginning of August and harvested in winter. Anthocyanins were extracted from cabbage heads with HCl in methanol (1% v/v solution) and quantified by absorption spectrophotometry at 530,nm. Results showed that red cabbage can give high yields of anthocyanins (more than 90,kg,ha,1) which are characterised by strong acylation and therefore, presumably, by good stability. However, differences over sites and years were marked. In the first year, yields in North Italy were reduced by a heavy infection of soft rot disease. The choice of variety, linked to a different anthocyanin content in the heads, appeared to be the major factor for a successful crop. P and K fertilisation had only a small influence. On clay soils in Central Italy the highest rates of both elements had a negative effect on the anthocyanin concentration in cabbage heads. © 2002 Society of Chemical Industry [source]