The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform

James R Ehleringer - One of the best experts on this subject based on the ideXlab platform.

  • Ecological correlates of seed mass variation in Phoradendron juniperinum, a xylem-tapping mistletoe
    Oecologia, 1991
    Co-Authors: Todd E Dawson, James R Ehleringer
    Abstract:

    We investigated several ecological correlates of seed mass variation in the hemiparasitic, xylemtapping mistletoe, Phoradendron juniperinum . Mean seed mass varied two-fold among plants between the ages of 4 and 14 years old and was positively correlated with parental plant age. Both the standard deviation and the coefficient of variation in mean seed mass decreased with increasing plant age demonstrating that, on average, younger plants produced seed with more variable mass. Nitrogen concentrations (mg nitrogen per gram of seed) of both the seed and “fruit” (pericarp) were not correlated with mass or the age of the parent plant from which the seed was taken. However, the nitrogen content per seed (mg nitrogen per seed) was positively correlated with the mean seed dry mass and the age of the seed parent, suggesting that the carbon to nitrogen ratio of individual seeds remained relatively constant as seed mass increased and plants grew older. Seed germination ranged between 20% and 86% and was positively correlated with mass and parental plant age. Heavier seeds (seeds from older plants) also had the highest root radicle growth rates. Furthermore, the final root radicle length after 76 d of growth was positively correlated with seed dry mass. When grown on a medium containing an extract prepared from the host plant foliage, all seeds showed lower germination, grew more slowly and had shorter overall root radicles, but had significantly greater development of the haustorial “disks” (the holdfast which forms the host-parasite junction in Phoradendron ) than seeds grown on a control medium. Our results suggest that, on average, seeds of greater mass produced by older plants have a greater total resource pool per propagule (fruit + seed). This resource pool may be important in conferring a greater potential for dispersal (fruit), survival, colonization, and establishment.

  • age structure of Phoradendron juniperinum viscaceae a xylem tapping mistletoe inferences from a non destructive morphological index of age
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, Edward J King, James R Ehleringer
    Abstract:

    We report a nondestructive index of age based on the branching structure of the mistletoe Phoradendron juniperinum and correlate it with an independent determination of age based on anatomical studies

  • AGE STRUCTURE OF Phoradendron JUNIPERINUM (VISCACEAE), A XYLEM‐TAPPING MISTLETOE: INFERENCES FROM A NON‐DESTRUCTIVE MORPHOLOGICAL INDEX OF AGE
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, Edward J King, James R Ehleringer
    Abstract:

    We report a nondestructive index of age based on the branching structure of the mistletoe Phoradendron juniperinum and correlate it with an independent determination of age based on anatomical studies

  • sex ratio and reproductive variation in the mistletoe Phoradendron juniperinum viscaceae
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, James R Ehleringer, John D Marshall
    Abstract:

    We addressed the following questions : what is the sex ratio in this population of P. juniperinum? Do males and females allocate biomass equally to reproduction? Do the sexes exhibit similar age distribution patterns? Are the sexes evenly distributed across the same locations on the bost? and Do female mistletoes predominate in locations expected to be most favorable to their carbon balance?

  • SEX‐RATIO AND REPRODUCTIVE VARIATION IN THE MISTLETOE Phoradendron JUNIPERINUM (VISCACEAE)
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, James R Ehleringer, John D Marshall
    Abstract:

    We addressed the following questions : what is the sex ratio in this population of P. juniperinum? Do males and females allocate biomass equally to reproduction? Do the sexes exhibit similar age distribution patterns? Are the sexes evenly distributed across the same locations on the bost? and Do female mistletoes predominate in locations expected to be most favorable to their carbon balance?

Todd E Dawson - One of the best experts on this subject based on the ideXlab platform.

  • Ecological correlates of seed mass variation in Phoradendron juniperinum, a xylem-tapping mistletoe
    Oecologia, 1991
    Co-Authors: Todd E Dawson, James R Ehleringer
    Abstract:

    We investigated several ecological correlates of seed mass variation in the hemiparasitic, xylemtapping mistletoe, Phoradendron juniperinum . Mean seed mass varied two-fold among plants between the ages of 4 and 14 years old and was positively correlated with parental plant age. Both the standard deviation and the coefficient of variation in mean seed mass decreased with increasing plant age demonstrating that, on average, younger plants produced seed with more variable mass. Nitrogen concentrations (mg nitrogen per gram of seed) of both the seed and “fruit” (pericarp) were not correlated with mass or the age of the parent plant from which the seed was taken. However, the nitrogen content per seed (mg nitrogen per seed) was positively correlated with the mean seed dry mass and the age of the seed parent, suggesting that the carbon to nitrogen ratio of individual seeds remained relatively constant as seed mass increased and plants grew older. Seed germination ranged between 20% and 86% and was positively correlated with mass and parental plant age. Heavier seeds (seeds from older plants) also had the highest root radicle growth rates. Furthermore, the final root radicle length after 76 d of growth was positively correlated with seed dry mass. When grown on a medium containing an extract prepared from the host plant foliage, all seeds showed lower germination, grew more slowly and had shorter overall root radicles, but had significantly greater development of the haustorial “disks” (the holdfast which forms the host-parasite junction in Phoradendron ) than seeds grown on a control medium. Our results suggest that, on average, seeds of greater mass produced by older plants have a greater total resource pool per propagule (fruit + seed). This resource pool may be important in conferring a greater potential for dispersal (fruit), survival, colonization, and establishment.

  • age structure of Phoradendron juniperinum viscaceae a xylem tapping mistletoe inferences from a non destructive morphological index of age
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, Edward J King, James R Ehleringer
    Abstract:

    We report a nondestructive index of age based on the branching structure of the mistletoe Phoradendron juniperinum and correlate it with an independent determination of age based on anatomical studies

  • AGE STRUCTURE OF Phoradendron JUNIPERINUM (VISCACEAE), A XYLEM‐TAPPING MISTLETOE: INFERENCES FROM A NON‐DESTRUCTIVE MORPHOLOGICAL INDEX OF AGE
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, Edward J King, James R Ehleringer
    Abstract:

    We report a nondestructive index of age based on the branching structure of the mistletoe Phoradendron juniperinum and correlate it with an independent determination of age based on anatomical studies

  • sex ratio and reproductive variation in the mistletoe Phoradendron juniperinum viscaceae
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, James R Ehleringer, John D Marshall
    Abstract:

    We addressed the following questions : what is the sex ratio in this population of P. juniperinum? Do males and females allocate biomass equally to reproduction? Do the sexes exhibit similar age distribution patterns? Are the sexes evenly distributed across the same locations on the bost? and Do female mistletoes predominate in locations expected to be most favorable to their carbon balance?

  • SEX‐RATIO AND REPRODUCTIVE VARIATION IN THE MISTLETOE Phoradendron JUNIPERINUM (VISCACEAE)
    American Journal of Botany, 1990
    Co-Authors: Todd E Dawson, James R Ehleringer, John D Marshall
    Abstract:

    We addressed the following questions : what is the sex ratio in this population of P. juniperinum? Do males and females allocate biomass equally to reproduction? Do the sexes exhibit similar age distribution patterns? Are the sexes evenly distributed across the same locations on the bost? and Do female mistletoes predominate in locations expected to be most favorable to their carbon balance?

David D Haines - One of the best experts on this subject based on the ideXlab platform.

  • solvent effects on phytochemical constituent profiles and antioxidant activities using four different extraction formulations for analysis of bucida buceras l and Phoradendron californicum
    BMC Research Notes, 2015
    Co-Authors: Simon Bernard Ilokiassanga, Lidianys Maria Lewislujan, Claudia Lizeth Laraespinoza, Armida A Gilsalido, Daniela Fernandezangulo, Jose Luis Rubiopino, David D Haines
    Abstract:

    Background The present investigation evaluated 4 different solvent compositions for their relative capacity to extract total phenolic and total flavonoid (TF) components of the leaves, trunks, and stems of Bucida buceras L. (Combretaceae), and the stems of Phoradendron californicum (Viscaceae), plus mesquite and oak species endemic to the Southwestern United States, northern Mexico, and tropical regions of Central and South America, as well as to profile the composition of these plant materials and to measure their antioxidant capacity.

  • Solvent effects on phytochemical constituent profiles and antioxidant activities, using four different extraction formulations for analysis of Bucida buceras L. and Phoradendron californicum
    BMC Research Notes, 2015
    Co-Authors: Simon B. Iloki-assanga, Lidianys M. Lewis-luján, Claudia L. Lara-espinoza, Armida A. Gil-salido, Daniela Fernandez-angulo, Jose L. Rubio-pino, David D Haines
    Abstract:

    Background The present investigation evaluated 4 different solvent compositions for their relative capacity to extract total phenolic and total flavonoid (TF) components of the leaves, trunks, and stems of Bucida buceras L. (Combretaceae), and the stems of Phoradendron californicum (Viscaceae), plus mesquite and oak species endemic to the Southwestern United States, northern Mexico, and tropical regions of Central and South America, as well as to profile the composition of these plant materials and to measure their antioxidant capacity. Methods The total phenolic content of plant material used in the present investigation was measured using the Folin–Ciocalteau assay. Total flavonoids were assayed by AlCl_3 and 2,4-dinitrophenylhydrazin colorimetry. Nitroblue tetrazolium was utilized for scavenging of superoxide anion, and in vitro antioxidant activity was evaluated using the 2, 2-diphenyl-1-picrylhydrazyl and Ferric Reducing/Antioxidant Power assays. Results Phytochemical screening of each plant extract evaluated revealed the following major results: (1) No evidence of alkaloids for each of the extraction phases tested was detected in the hexanic, ethanolic, or aqueous phases of Bucida buceras and Phoradendron californicum (oak and mesquite); (2) Analysis of the hexane phase of B. buceras and P. californicum (mesquite) extracts revealed the presence of carotenes, triterpenes/steroids, and lactonic groups; (3) Analysis of the ethanol and aqueous extraction phases for both plants revealed the presence of a diverse range of compounds, including tripterpenes/steroids, lactonics groups, saponins, phenols/tannins, amines and/or amino acids, and flavonoids/anthocyanins; and (4) The highest total phenolic and flavonoid content were observed in P. californicum (oak): 523.886 ± 51.457 µg GAE/mg extract and 409.651 ± 23.091 µg/mg of extract for methanol and aqueous fractions, respectively. The highest flavonoid content was 237.273 ± 21.250 µg PNE/mg extract in the acetone extract of Bucida buceras stems; while the flavonol content (260.685 ± 23.031 µg CE/mg extract) was higher in the ethanol extract of P. californicum (oak). The acetone extract of B. buceras trunk extract showed the highest levels of DPPH radical-scavenging activity (IC_50 = 4.136 ± 0.446 µg/mL) and reducing power (4928.392 ± 281.427 µM AAE/mg extract). The highest superoxide radical scavenging activity (IC_50) was 55.249 ± 9.829 µg/mL, observed in acetone extracts of B. buceras leaves. Conclusions The results of the present investigation demonstrated the effects of extraction solvent on phenolic and flavonoid content yield—and antioxidant activities by Bucida buceras and Phoradendron californicum . The present investigation further revealed that Bucida buceras exhibited optimal antioxidant capacity when acetone was used as extraction solvent; and the highest yield of phenols and flavonoids were obtained from the P. californicum oak, using methanol and aqueous solvents, respectively.

John D Marshall - One of the best experts on this subject based on the ideXlab platform.

Jorge Luiz Waechter - One of the best experts on this subject based on the ideXlab platform.

  • generic identity of Phoradendron rusbyi viscaceae and a new record for argentina
    Darwiniana (Argentina) Num.1 Vol.50, 2015
    Co-Authors: Greta Aline Dettke, Jorge Luiz Waechter
    Abstract:

    During a review of herbaria in Argentina we found a specimen of Phoradendron rusbyi, which represents the third collection of the species and a new record for the flora of Argentina. This species is a little aphyllous plant, being a member of the group of hyperparasitic mistletoes, and was found in a mixed collection, parasitizing Phoradendron bathyoryctum. A morphological description of the species is provided, and its inclusion in Phoradendron confirmed.

  • Phoradendron argentinum viscaceae new mistletoe for the brazilian flora and its general distribution in south america
    Darwiniana (Argentina) Num.1 Vol.49, 2015
    Co-Authors: Greta Aline Dettke, Luis F P Lima, Jorge Luiz Waechter
    Abstract:

    The first collection of the mistletoe Phoradendron argentinum (Viscaceae) for the Brazilian flora is reported. A brief description, a key including the taxonomically closest species, photographs and a distribution map of the species are given. Lectotype of P. argentinum is here designated.

  • estudo taxonomico das ervas de passarinho da regiao sul do brasil ii viscaceae Phoradendron
    Rodriguésia - Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, 2014
    Co-Authors: Greta Aline Dettke, Jorge Luiz Waechter
    Abstract:

    Phoradendron e um genero neotropical com ca. 230 especies e no Brasil ocorrem ca. 60 especies distribuidas em todos os dominios fitogeograficos. O objetivo deste trabalho foi realizar o estudo taxonomico de Phoradendron na Regiao Sul do Brasil. Foram confirmadas 21 especies: P. argentinum , P. bathyoryctum , P. berteroanum , P. burkartii , P. chrysocladon , P. coriaceum , P. craspedophyllum , P. crassifolium , P. dipterum , P. ensifolium , P. habrostachyum , P. hexastichum , P. holoxanthum , P. inaequidentatum , P. mucronatum , P. obtusissimum , P. pellucidullum , P. perrottetii , P. piperoides , P. quadrangulare e P. undulatum . Um nome e restabelecido ( P. burkartii ) e nove sao propostos como sinonimos ( P. affine , P. falcifrons , P. interruptum , P. liga , P. lindemanii , P. linearifolium , P. pachyneuron , P. paraguari e P. reductum ). O lectotipo de P. reductum e designado. E apresentada uma chave de identificacao para as especies do Sul do Brasil, bem como descricoes, comentarios taxonomicos, informacoes sobre a distribuicao geografica, hospedeiros, fenologia e ilustracoes para cada especie. Taxonomic study of mistletoes from South Brazil: II. Viscaceae (Phoradendron)  Abstract Phoradendron is a Neotropical genus with c. 230 species. In Brazil c. 60 species occur, distributed in all major phytogeographic domains. The aim of this work was the taxonomic study of Phoradendron in southern Brazil. Twenty-one species were confirmed, namely P. argentinum , P. bathyoryctum , P. berteroanum , P. burkartii , P. chrysocladon , P. coriaceum , P. craspedophyllum , P. crassifolium , P. dipterum , P. ensifolium , P. habrostachyum , P. hexastichum , P. holoxanthum , P. inaequidentatum , P. mucronatum , P. obtusissimum , P. pellucidullum , P. perrottetii , P. piperoides , P. quadrangulare and P. undulatum . One name is reestablished ( P. burkartii ) and nine are proposed as synonyms ( P. affine , P. falcifrons , P. interruptum , P. liga , P. lindemanii , P. linearifolium , P. pachyneuron , P. paraguari and P. reductum ). The lectotype of P. reductum is designated. An identification key to the southern Brazilian species is provided, as well as morphological descriptions, taxonomic comments, information on geographic distribution, hosts and phenology, and illustrations for each species.

  • identidad generica de Phoradendron rusbyi viscaceae y un nuevo registro para argentina
    Darwiniana nueva serie, 2012
    Co-Authors: Greta Aline Dettke, Jorge Luiz Waechter
    Abstract:

    During a review of herbaria in Argentina we found a specimen of Phoradendron rusbyi , which represents the third collection of the species and a new record for the flora of Argentina. This species is a little aphyllous plant, being a member of the group of hyperparasitic mistletoes, and was found in a mixed collection, parasitizing Phoradendron bathyoryctum . A morphological description of the species is provided, and its inclusion in Phoradendron confirmed.

  • generic identity of Phoradendron rusbyi viscaceae and a new record for argentina
    Darwiniana, 2012
    Co-Authors: Greta Aline Dettke, Jorge Luiz Waechter
    Abstract:

    Dettke, G. A. & J. L. Waechter. 2012. Generic identity of Phoradendron rusbyi (Viscaceae) and a new record for Argentina. Darwiniana50(1): 154-156. During a review of herbaria in Argentina we found a specimen of Phoradendron rusbyi, which represents the third collection of the species and a new record for the flora of Argentina. This species is a little aphyllous plant, being a member of the group of hyperparasitic mistletoes, and was found in a mixed collection, parasitizing Phoradendron bathyoryctum. A morphological description of the spe- cies is provided, and its inclusion in Phoradendronconfirmed.