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Rachel A Levin - One of the best experts on this subject based on the ideXlab platform.

  • pisonia calafia Nyctaginaceae species nova from the baja california peninsula mexico
    Acta Botanica Mexicana, 2012
    Co-Authors: Rachel A Levin
    Abstract:

    Pisonia is a primarily American genus, distributed mainly in subtropical to tropical regions. In this paper a new species, Pisonia calafia, is described and ...

  • pisonia calafia Nyctaginaceae especie nueva de la peninsula de baja california mexico
    Acta Botanica Mexicana, 2012
    Co-Authors: Rachel A Levin
    Abstract:

    Pisonia  is a primarily American genus, distributed mainly in subtropical to tropical regions. In this paper a new species,  Pisonia calafia,  is described and documented. This species occurs as a small population on a coastal strand in the Cape Region of the Baja California Peninsula. The main characteristics that differentiate  P. calafia  from the rest of  Pisonia  is the lack of sulci and glands in the fruit. In addition to the new species description, we discuss the evolutionary affinities of this new taxon based on phylogenetic analysis of nrITS sequence data. The known population is limited to a few dozen individuals, now seriously endangered by the ongoing development of tourism projects.

  • the systematic utility of floral and vegetative fragrance in two genera of Nyctaginaceae
    Systematic Biology, 2003
    Co-Authors: Rachel A Levin, Lucinda A Mcdade, Robert A Raguso
    Abstract:

    We examined relationships between fragrance and phylogeny using a number of approaches to coding fragrance data and comparing the hierarchical information in fragrance data with the phylogenetic signal in a DNA sequence data set. We first used distance analyses to determine which coding method(s) best distinguishes species while grouping conspecifics. Results suggest that interspecific differences in fragrance composition were maximized by coding as presence/absence of fragrance compounds and biosynthetic pathways rather than when quantitative information was also included. Useful systematic information came from both compounds and pathways and from fragrance emitted by both floral and vegetative tissues. The coding methods that emerged from the distance analyses as best distinguishing species were then adapted for use in phylogenetic analysis. Although hierarchical signal among fragrance data sets was congruent, this signal was highly incongruent with the phylogenetic signal in the DNA sequence data. Notably, topologies inferred from fragrance data sets were congruent with the DNA topology only in the most distal portions (e.g., sister group pairs or closely related species that had similar fragrance profiles were often recovered by analyses of fragrance). Examination of consistency and retention indices for individual fragrance compounds and pathways as optimized onto one of the most-parsimonious trees inferred from DNA data revealed that although most compounds were homoplastic, some compounds were perfectly congruent with the DNA phylogeny. In particular, compounds and pathways found in a few taxa were less homoplastic than those found in many taxa. Pathways that synthesize few volatiles also seem to have lower homoplasy than those that produce many. Although fragrance data as a whole may not be useful in phylogeny reconstruction, these data can provide additional support for clades reconstructed with other types of characters. Factors other than phylogeny, including pollinator interactions, also likely influence fragrance composition. (Acleisanthes; character coding; four o'clocks; fragrance; Mirabilis; phylogenetics; scent; volatiles.)

  • taxonomic status of acleisanthes selinocarpus and ammocodon Nyctaginaceae
    Novon a journal of botanical nomenclature from the Missouri Botanical Garden, 2002
    Co-Authors: Rachel A Levin
    Abstract:

    Recent molecular and morphological studies suggest that neither Acleisanthes nor Selinocarpus (Nyctaginaceae) are monophyletic as currently circumscribed. Further, these data provide no basis for continued recognition of the monotypic genus Ammocodon as separate from these other two genera. Therefore, all 8 Selinocarpus species and the monospecific Ammocodon are transferred to Acleisanthes; 3 additional Selinocarpus species are reduced to synonymy. The genus Acleisanthes is now composed of 16 species, distributed primarily in the Chihuahuan Desert of North America. Diagnostic features of Acleisanthes include an herbaceous or woody perennial habit in arid environments, and the presence of both cleistogamous and chasmogamous flowers often simultaneously on an individual plant. Further, flowers are usually axillary and subtended by 1 to 4 subulate bracts, with chasmogamous flowers frequently white or yellow and funnelform to salverform.

  • fragrance chemistry and pollinator affinities in Nyctaginaceae
    Phytochemistry, 2001
    Co-Authors: Rachel A Levin, Robert A Raguso, Lucinda A Mcdade
    Abstract:

    Abstract We present results of dynamic head-space collections and GC–MS analyses of floral and vegetative fragrances for 20 species in three genera of Nyctaginaceae: Acleisanthes, Mirabilis and Selinocarpus. Most of the species included in this study are either hawkmoth or noctuid moth-pollinated. A wide variety of compounds were observed, including mono- and sesquiterpenoids, aromatics (both benzenoids and phenylpropanoids), aliphatic compounds, lactones, and nitrogen-bearing compounds. Intraspecific variation in fragrance profiles was significantly lower than interspecific variation. Each species had a unique blend of volatiles, and the fragrance of many species contained species-specific compounds. The fragrance profiles presented here are generally consistent with previous studies of fragrance in a variety of moth-pollinated angiosperms.

S J Siebert - One of the best experts on this subject based on the ideXlab platform.

  • a taxonomic revision of boerhavia Nyctaginaceae in southern africa
    South African Journal of Botany, 2013
    Co-Authors: M Struwig, S J Siebert
    Abstract:

    Abstract The genus Boerhavia in southern Africa is revised. Eight species and one infraspecific taxon are recognized for the Flora of Southern Africa region, with Boerhavia orbicularifolia Struwig described as new. Four of the species are indigenous, with three endemic to semi-arid parts of Namibia and north-western South Africa. The eight species can be distinguished from one another by the shape and indumentum of the anthocarp. The majority of taxa have no edaphic preferences but Boerhavia repens subsp. repens is associated with high Mg levels. This is a first attempt at a comprehensive taxonomic revision for the genus in southern Africa, and includes a key to the species, complete nomenclature, and a description of all the infrageneric taxa. Taxon accounts are supplemented with geographical distribution records, notes on the ecology, soil preferences and known traditional uses.

  • pollen morphology of members of southern african boerhavia and commicarpus Nyctaginaceae
    Bothalia, 2013
    Co-Authors: M Struwig, S J Siebert, A Jordaan
    Abstract:

    In southern Africa, Boerhavia L. and Commicarpus Standl. are the most species-rich genera of the Nyctaginaceae. Hitherto, the pollen morphology of only three southern African species of each of these genera has been described. A palynological study of the remaining species is therefore necessary to complete the information for the taxa. The pollen morphology of sixteen species was studied with light, scanning electron and transmission electron microscopy. Pollen grains of Boerhavia and Commicarpus are uniform in shape and sculpturing. Grains are spheroidal and pantoporate, and the tectum tubuliferous and spinulose. Pollen grains of the Boerhavia are 52–91 μm in diameter and those of Commicarpus 52–129 μm. Spinules in both genera are 1–5 μm long. Pore plates have one or two spinules. In both genera the exine is 3.5–11.5 μm thick, the tectum 0.9–3.9 μm thick and the collumellae 0.6–2.8 μm long. Foot layers are 0.9–5.1 μm thick and the endexine is barely visible. Size variation of the pollen grain, pore diameter and exine thickness overlap and cannot be used to distinguish between the two genera or the individual species.

  • a taxonomic revision of commicarpus Nyctaginaceae in southern africa
    South African Journal of Botany, 2013
    Co-Authors: M Struwig, S J Siebert
    Abstract:

    The Research Directorate, Unit for Environmental Sciences andManagement of theNorth-WestUniversity and the South African Biosystematics Initiative (SABI)

  • anatomy of the southern african boerhavia and commicarpus species Nyctaginaceae
    Bangladesh Journal of Plant Taxonomy, 2011
    Co-Authors: M Struwig, Anine Jordaan, S J Siebert
    Abstract:

    The Nyctaginaceae in southern Africa is represented by five genera of which Boerhavia L. and Commicarpus Standl. are the most species-rich. Stem, leaf and anthocarp material was collected in situ and examined with a scanning electron microscope and a light microscope. The anatomy of the leaf and anthocarp proved diagnostic at the generic level, but was uniform amongst the species of each genus. Kranz anatomy occurs around the minor veins in the leaves of Boerhavia , but in Commicarpus the minor veins are surrounded by large parenchyma cells. The anthocarp of Boerhavia has five ribs or three wings, with sclerenchyma within the ribs and the area between the ribs, whereas Commicarpus has ten ribs with sclerenchyma only present within the ribs. The number of chlorenchyma rows in the stems could be diagnostic and the outline of the sclerenchyma bundles in the anthocarp could divide the Commicarpus species into two groups, but more research needs to be done on these characters. Keywords: Stem; Leaf; Anthocarp; Trichomes; Kranz anatomy; Light microscopy. DOI: http://dx.doi.org/10.3329/bjpt.v18i2.9297 Bangladesh J. Plant Taxon. 18 (2): 105-115, 2011 (December)

  • anatomical adaptations of boerhavia l and commicarpus standl Nyctaginaceae for survival in arid environments of namibia
    Acta Biologica Cracoviensia Series Botanica, 2011
    Co-Authors: M Struwig, Anine Jordaan, S J Siebert
    Abstract:

    Members of the Nyctaginaceae Jussieu. are distributed throughout southern Africa. Eight species of the family occur naturally in arid parts of Namibia. These species have acquired the ability to survive and reproduce in these dry conditions. They are xerophytes, which have been described as drought evaders, avoiders, and drought-tolerant. In the Nyctaginaceae, Boerhavia deserticola, B. hereroensis, Commicarpus helenae and C. squarrosus are thought to be drought avoiders. In this study we investigated their stem, leaf and anthocarp anatomy for adaptations to arid environments. The results indicated that the four species are avoiders, with modifications of the trichomes, secretions, crystals, secondary growth, Kranz mesophyll, water storage cells, tannins, mucilage, inner and outer stomatal ledges, large-diameter xylem vessels, and the presence of sclerenchyma in their stems, leaves and anthocarps. These adaptations enable the plants to tolerate arid conditions, conserve water and maintain a high photosynthetic rate, and aid seed dispersal.

M Struwig - One of the best experts on this subject based on the ideXlab platform.

  • a taxonomic revision of boerhavia Nyctaginaceae in southern africa
    South African Journal of Botany, 2013
    Co-Authors: M Struwig, S J Siebert
    Abstract:

    Abstract The genus Boerhavia in southern Africa is revised. Eight species and one infraspecific taxon are recognized for the Flora of Southern Africa region, with Boerhavia orbicularifolia Struwig described as new. Four of the species are indigenous, with three endemic to semi-arid parts of Namibia and north-western South Africa. The eight species can be distinguished from one another by the shape and indumentum of the anthocarp. The majority of taxa have no edaphic preferences but Boerhavia repens subsp. repens is associated with high Mg levels. This is a first attempt at a comprehensive taxonomic revision for the genus in southern Africa, and includes a key to the species, complete nomenclature, and a description of all the infrageneric taxa. Taxon accounts are supplemented with geographical distribution records, notes on the ecology, soil preferences and known traditional uses.

  • pollen morphology of members of southern african boerhavia and commicarpus Nyctaginaceae
    Bothalia, 2013
    Co-Authors: M Struwig, S J Siebert, A Jordaan
    Abstract:

    In southern Africa, Boerhavia L. and Commicarpus Standl. are the most species-rich genera of the Nyctaginaceae. Hitherto, the pollen morphology of only three southern African species of each of these genera has been described. A palynological study of the remaining species is therefore necessary to complete the information for the taxa. The pollen morphology of sixteen species was studied with light, scanning electron and transmission electron microscopy. Pollen grains of Boerhavia and Commicarpus are uniform in shape and sculpturing. Grains are spheroidal and pantoporate, and the tectum tubuliferous and spinulose. Pollen grains of the Boerhavia are 52–91 μm in diameter and those of Commicarpus 52–129 μm. Spinules in both genera are 1–5 μm long. Pore plates have one or two spinules. In both genera the exine is 3.5–11.5 μm thick, the tectum 0.9–3.9 μm thick and the collumellae 0.6–2.8 μm long. Foot layers are 0.9–5.1 μm thick and the endexine is barely visible. Size variation of the pollen grain, pore diameter and exine thickness overlap and cannot be used to distinguish between the two genera or the individual species.

  • a taxonomic revision of commicarpus Nyctaginaceae in southern africa
    South African Journal of Botany, 2013
    Co-Authors: M Struwig, S J Siebert
    Abstract:

    The Research Directorate, Unit for Environmental Sciences andManagement of theNorth-WestUniversity and the South African Biosystematics Initiative (SABI)

  • anatomy of the southern african boerhavia and commicarpus species Nyctaginaceae
    Bangladesh Journal of Plant Taxonomy, 2011
    Co-Authors: M Struwig, Anine Jordaan, S J Siebert
    Abstract:

    The Nyctaginaceae in southern Africa is represented by five genera of which Boerhavia L. and Commicarpus Standl. are the most species-rich. Stem, leaf and anthocarp material was collected in situ and examined with a scanning electron microscope and a light microscope. The anatomy of the leaf and anthocarp proved diagnostic at the generic level, but was uniform amongst the species of each genus. Kranz anatomy occurs around the minor veins in the leaves of Boerhavia , but in Commicarpus the minor veins are surrounded by large parenchyma cells. The anthocarp of Boerhavia has five ribs or three wings, with sclerenchyma within the ribs and the area between the ribs, whereas Commicarpus has ten ribs with sclerenchyma only present within the ribs. The number of chlorenchyma rows in the stems could be diagnostic and the outline of the sclerenchyma bundles in the anthocarp could divide the Commicarpus species into two groups, but more research needs to be done on these characters. Keywords: Stem; Leaf; Anthocarp; Trichomes; Kranz anatomy; Light microscopy. DOI: http://dx.doi.org/10.3329/bjpt.v18i2.9297 Bangladesh J. Plant Taxon. 18 (2): 105-115, 2011 (December)

  • anatomical adaptations of boerhavia l and commicarpus standl Nyctaginaceae for survival in arid environments of namibia
    Acta Biologica Cracoviensia Series Botanica, 2011
    Co-Authors: M Struwig, Anine Jordaan, S J Siebert
    Abstract:

    Members of the Nyctaginaceae Jussieu. are distributed throughout southern Africa. Eight species of the family occur naturally in arid parts of Namibia. These species have acquired the ability to survive and reproduce in these dry conditions. They are xerophytes, which have been described as drought evaders, avoiders, and drought-tolerant. In the Nyctaginaceae, Boerhavia deserticola, B. hereroensis, Commicarpus helenae and C. squarrosus are thought to be drought avoiders. In this study we investigated their stem, leaf and anthocarp anatomy for adaptations to arid environments. The results indicated that the four species are avoiders, with modifications of the trichomes, secretions, crystals, secondary growth, Kranz mesophyll, water storage cells, tannins, mucilage, inner and outer stomatal ledges, large-diameter xylem vessels, and the presence of sclerenchyma in their stems, leaves and anthocarps. These adaptations enable the plants to tolerate arid conditions, conserve water and maintain a high photosynthetic rate, and aid seed dispersal.

Valeria Cid Maia - One of the best experts on this subject based on the ideXlab platform.

Maria Arlene Pessoa Da Silva - One of the best experts on this subject based on the ideXlab platform.

  • phytotoxic activity of guapira graciliflora Nyctaginaceae on weeds
    Journal of Animal Science, 2020
    Co-Authors: Allana Silva Rodrigues, Josa Weverton Almeida Bezerra, Viviane Bezerra Da Silva, Adrielle Rodrigues Costa, Felicidade Caroline Rodrigues, Karina Vieiralves Linhares, Janete De Souza Bezerra, Marcos Aura Lio Figueiredo Dos Santos, Maria Arlene Pessoa Da Silva
    Abstract:

    The plants produce a variety of compounds that are not directly associated with their growth and are derived from their secondary metabolisms. Such compounds can be used in the formulation of bioherbicides, in the control of weeds. Among the chemical groups that most present allelopathic actions are the phenolic compounds which are present the flavonoids. A species rich in such compounds is Guapira graciliflora , which allows hypothesizing that it may present phytotoxic action. In this way, the objective of this research was to evaluate its phytotoxic action on the germination and growth of Cenchrus echinatus and Calotropis procera . For this purpose, aqueous extracts were prepared from fruits and leaves and applied to seeds of the species mentioned above. Pre and post germinative parameters were measured. Our results show that the extracts can retard the growth of the roots of C. echinatus and C. procera in a significant way ( p <0.05), however it is not able to interfere in the number of germinated seeds or germinated seeds speed. The mechanisms of action of the allelochemicals may be related to inhibition of specific PSII sites or reduction of chlorophyll content. Guapira graciliflora presents allelochemicals in the constitution of its leaves and its fruits that affect the growth of the initial structures of C. echinatus and C. procera , with potential to be used as bioherbicides in the control of these weeds.

  • Phytotoxic Activity of Guapira graciliflora (Nyctaginaceae) on Weeds
    Journal of Animal Science, 2020
    Co-Authors: Allana Silva Rodrigues, Viviane Bezerra Da Silva, Adrielle Rodrigues Costa, Felicidade Caroline Rodrigues, Karina Vieiralves Linhares, Janete De Souza Bezerra, José Weverton Almeida Bezerra, Marcos Aurélio Figueiredo Dos Santos, Maria Arlene Pessoa Da Silva
    Abstract:

    The plants produce a variety of compounds that are not directly associated with their growth and are derived from their secondary metabolisms. Such compounds can be used in the formulation of bioherbicides, in the control of weeds. Among the chemical groups that most present allelopathic actions are the phenolic compounds which are present the flavonoids. A species rich in such compounds is Guapira graciliflora , which allows hypothesizing that it may present phytotoxic action. In this way, the objective of this research was to evaluate its phytotoxic action on the germination and growth of Cenchrus echinatus and Calotropis procera . For this purpose, aqueous extracts were prepared from fruits and leaves and applied to seeds of the species mentioned above. Pre and post germinative parameters were measured. Our results show that the extracts can retard the growth of the roots of C. echinatus and C. procera in a significant way ( p