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Peter C. Boyce - One of the best experts on this subject based on the ideXlab platform.

Timothy R. Sexton - One of the best experts on this subject based on the ideXlab platform.

  • Crassulacean acid metabolism in the ZZ plant, Zamioculcas zamiifolia (Araceae).
    American journal of botany, 2007
    Co-Authors: Joseph A. M. Holtum, Klaus Winter, Mark A. Weeks, Timothy R. Sexton
    Abstract:

    Zamioculcas zamiifolia (Araceae), a terrestrial East African aroid, with two defining attributes of crassulacean acid metabolism (CAM) (net CO2 uptake in the dark and diel fluctuations of titratable acidity) is the only CAM plant described within the Araceae, a mainly tropical taxon that contains the second largest number of epiphytes of any vascular plant family. Within the Alismatales, the order to which the Araceae belong, Z. zamiifolia is the only documented nonaquatic CAM species. Zamioculcas zamiifolia has weak CAM that is upregulated in response to water stress. In well-watered plants, day–night fluctuations in titratable acidity were 2.5 lmol H þ � (g fresh mass) � 1 , and net CO2 uptake in the dark contributed less than 1% to daily carbon gain. Following 10 d of water stress, net CO2 uptake in the light fell 94% and net CO2 uptake in the dark increased 7.5-fold, such that its contribution increased to 19% of daily carbon gain. Following rewatering, dark CO2 uptake returned to within 5% of prestressed levels. We postulate that CAM assists survival of Z. zamiifolia by reducing water loss and maintaining carbon gain during seasonal droughts characteristic of its natural habitat.

Susanne S. Renner - One of the best experts on this subject based on the ideXlab platform.

  • The evolution of pollinator-plant interaction types in the Araceae.
    Evolution; international journal of organic evolution, 2013
    Co-Authors: Marion Chartier, Marc Gibernau, Susanne S. Renner
    Abstract:

    Most plant–pollinator interactions are mutualistic, involving rewards provided by flowers or inflorescences to pollinators. Antagonistic plant–pollinator interactions, in which flowers offer no rewards, are rare and concentrated in a few families including Araceae. In the latter, they involve trapping of pollinators, which are released loaded with pollen but unrewarded. To understand the evolution of such systems, we compiled data on the pollinators and types of interactions, and coded 21 characters, including interaction type, pollinator order, and 19 floral traits. A phylogenetic framework comes from a matrix of plastid and new nuclear DNA sequences for 135 species from 119 genera (5342 nucleotides). The ancestral pollination interaction in Araceae was reconstructed as probably rewarding albeit with low confidence because information is available for only 56 of the 120–130 genera. Bayesian stochastic trait mapping showed that spadix zonation, presence of an appendix, and flower sexuality were correlated with pollination interaction type. In the Araceae, having unisexual flowers appears to have provided the morphological precondition for the evolution of traps. Compared with the frequency of shifts between deceptive and rewarding pollination systems in orchids, our results indicate less lability in the Araceae, probably because of morphologically and sexually more specialized inflorescences.

  • The evolution of pollinator/plant interaction types in the Araceae.
    Evolution international journal of organic evolution, 2013
    Co-Authors: Marion Chartier, Marc Gibernau, Susanne S. Renner
    Abstract:

    Most plant–pollinator interactions are mutualistic, involving rewards provided by flowers or inflorescences to pollinators. Antagonistic plant–pollinator interactions, in which flowers offer no rewards, are rare and concentrated in a few families including Araceae. In the latter, they involve trapping of pollinators, which are released loaded with pollen but unrewarded. To understand the evolution of such systems, we compiled data on the pollinators and types of interactions, and coded 21 characters, including interaction type, pollinator order, and 19 floral traits. A phylogenetic framework comes from a matrix of plastid and new nuclear DNA sequences for 135 species from 119 genera (5342 nucleotides). The ancestral pollination interaction in Araceae was reconstructed as probably rewarding albeit with low confidence because information is available for only 56 of the 120–130 genera. Bayesian stochastic trait mapping showed that spadix zonation, presence of an appendix, and flower sexuality were correlated with pollination interaction type. In the Araceae, having unisexual flowers appears to have provided the morphological precondition for the evolution of traps. Compared with the frequency of shifts between deceptive and rewarding pollination systems in orchids, our results indicate less lability in the Araceae, probably because of morphologically and sexually more specialized inflorescences.

  • global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils
    New Phytologist, 2012
    Co-Authors: Lars Nauheimer, Dirk Metzler, Susanne S. Renner
    Abstract:

    Summary • The family Araceae (3790 species, 117 genera) has one of the oldest fossil records among angiosperms. Ecologically, members of this family range from free-floating aquatics (Pistia and Lemna) to tropical epiphytes. Here, we infer some of the macroevolutionary processes that have led to the worldwide range of this family and test how the inclusion of fossil (formerly occupied) geographical ranges affects biogeographical reconstructions. • Using a complete genus-level phylogeny from plastid sequences and outgroups representing the 13 other Alismatales families, we estimate divergence times by applying different clock models and reconstruct range shifts under different models of past continental connectivity, with or without the incorporation of fossil locations. • Araceae began to diversify in the Early Cretaceous (when the breakup of Pangea was in its final stages), and all eight subfamilies existed before the K ⁄ T boundary. Early lineages persist in Laurasia, with several relatively recent entries into Africa, South America, South-East Asia and Australia. • Water-associated habitats appear to be ancestral in the family, and DNA substitution rates are especially high in free-floating Araceae. Past distributions inferred when fossils are included differ in nontrivial ways from those without fossils. Our complete genus-level time-scale for the Araceae may prove to be useful for ecological and physiological studies.

  • reevaluation of the cox1 group i intron in Araceae and angiosperms indicates a history dominated by loss rather than horizontal transfer
    Molecular Biology and Evolution, 2008
    Co-Authors: Natalie Cusimano, Libing Zhang, Susanne S. Renner
    Abstract:

    The origin and modes of transmission of introns remain matters of much debate. Previous studies of the group I intron in the angiosperm cox1 gene inferred frequent angiosperm-to-angiosperm horizontal transmission of the intron from apparent incongruence between intron phylogenies and angiosperm phylogenies, patchy distribution of the intron among angiosperms, and differences between cox1 exonic coconversion tracts (the first 22 nt downstream of where the intron inserted). We analyzed the cox1 gene in 179 angiosperms, 110 of them containing the intron (intron+) and 69 lacking it (intron-). Our taxon sampling in Araceae is especially dense to test hypotheses about vertical and horizontal intron transmission put forward by Cho and Palmer (1999. Multiple acquisitions via horizontal transfer of a group I intron in the mitochondrial coxl gene during evolution of the Araceae family. Mol Biol Evol. 16:1155–1165). Maximum likelihood trees of Araceae cox1 introns, and also of all angiosperm cox1 introns, are largely congruent with known phylogenetic relationships in these taxa. The exceptions can be explained by low signal in the intron and long-branch attraction among a few taxa with high mitochondrial substitution rates. Analysis of the 179 coconversion tracts reveals 20 types of tracts (11 of them only found in single species, all involving silent substitutions). The distribution of these tracts on the angiosperm phylogeny shows a common ancestral type, characterizing most intron+ and some intron- angiosperms, and several derivative tract types arising from gradual back mutation of the coconverted nucleotides. Molecular clock dating of small intron+ and intron- sister clades suggests that coconversion tracts have persisted for 70 Myr in Araceae, whose cox1 sequences evolve comparatively slowly. Sequence similarity among the 110 introns ranges from 91% to identical, whereas putative homologs from fungi are highly different, but sampling in fungi is still sparse. Together, these results suggest that the cox1 intron entered angiosperms once, has largely or entirely been transmitted vertically, and has been lost numerous times, with coconversion tract footprints providing unreliable signal of former intron presence.

Y W Sin - One of the best experts on this subject based on the ideXlab platform.

  • molecular phylogeny of tribe schismatoglottideae Araceae based on two plastid markers and recognition of a new tribe philonotieae from the neotropics
    Taxon, 2010
    Co-Authors: Peter C. Boyce, Y W Sin, Othman Ahmad S, Chui Pin Leaw
    Abstract:

    Tribe Schismatoglottideae comprises one large genus, Schismatoglottis, and six small ‘satellite’ genera. A combined molecular phylogenetic analysis of matK, the 3′ portion of the trnK intron, and trnL-F sequence data was carried out on 77 taxa representing all genera in the tribe, all informal groups in Schismatoglottis, together with sister tribe Cryptocoryneae, and outgroups from Araceae. Analyses of combined datasets with parsimony, maximum likelihood, and Bayesian methods revealed tribe Schismatoglottideae to be a polyphyletic assemblage. Neotropical Schismatoglottis is shown to be sister to the palaeotropical Schismatoglottideae + Cryptocoryneae. Schismatoglottis acuminatissima is a sister clade to the rest of the Schismatoglottideae. Palaeotropical Schismatoglottis is unsupported as a monophyletic genus. A new neotropical tribe of Araceae, Philonotieae S.Y. Wong & P.C. Boyce, sister to Cryptocoryneae + palaeotropical Schismatoglottideae, is proposed.

Thomas B. Croat - One of the best experts on this subject based on the ideXlab platform.

  • Complete Chloroplast Genomes of Anthurium huixtlense and Pothos scandens (Pothoideae, Araceae): Unique Inverted Repeat Expansion and Contraction Affect Rate of Evolution
    Journal of Molecular Evolution, 2020
    Co-Authors: Claudia L. Henriquez, Thomas B. Croat, Furrukh Mehmood, Monica M. Carlsen, Madiha Islam, Mohammad Tahir Waheed, Peter Poczai, Ibrar Ahmed
    Abstract:

    The subfamily Pothoideae belongs to the ecologically important plant family Araceae. Here, we report the chloroplast genomes of two species of the subfamily Pothoideae: Anthurium huixtlense (size: 163,116 bp) and Pothos scandens (size: 164,719 bp). The chloroplast genome of P. scandens showed unique contraction and expansion of inverted repeats (IRs), thereby increasing the size of the large single-copy region (LSC: 102,956 bp) and decreasing the size of the small single-copy region (SSC: 6779 bp). This led to duplication of many single-copy genes due to transfer to IR regions from the small single-copy (SSC) region, whereas some duplicate genes became single copy due to transfer to large single-copy regions. The rate of evolution of protein-coding genes was affected by the contraction and expansion of IRs; we found higher mutation rates for genes that exist in single-copy regions as compared to those in IRs. We found a 2.3-fold increase of oligonucleotide repeats in P. scandens when compared with A. huixtlense , whereas amino acid frequency and codon usage revealed similarities. The ratio of transition to transversion mutations was 2.26 in P. scandens and 2.12 in A. huixtlense . Transversion mutations mostly translated in non-synonymous substitutions. The phylogenetic inference of the limited species showed the monophyly of the Araceae subfamilies. Our study provides insight into the molecular evolution of chloroplast genomes in the subfamily Pothoideae and family Araceae.

  • A new species of Anthurium (Araceae) from Ecuador
    Phytotaxa, 2015
    Co-Authors: Thomas B. Croat, Carmen Ulloa Ulloa, Efraín Freire
    Abstract:

    Anthurium sect. Belolonchium (Araceae) is defined and characterized.  One new species of sect. Belolonchium , namely A. yanacochense Croat, C.Ulloa & E.Freire from Pichincha province, Ecuador, is described as new and compared with related species.

  • Two new species of Alocasia (Araceae, Colocasieae) from Vietnam
    Willdenowia, 2013
    Co-Authors: Van Du Nguyen, Thomas B. Croat, Hong Truong Luu, Chang Young Lee, Joongku Lee, Rogier P. J. De Kok
    Abstract:

    Abstract Nguyen V. D., Croat T. B., Luu H. T., Lee C. Y., Lee J. & de Kok R.: Two new species of Alocasia (Araceae, Colocasieae) from Vietnam. — Willdenowia 43: 293–299. December 2013. — ISSN 0511-9618; © 2013 BGBM Berlin-Dahlem. Stable URL: http://dx.doi.org/10.3372/wi.43.43209 Two new species, Alocasia evrardii and A. vietnamensis (Araceae, Colocasieae), are described and illustrated from Vietnam. Although A. evrardii was described previously by Gagnepain in 1942, also with a historical record from Cambodia, its name was not validly published. A key to the species of Alocasia in Cambodia, Laos, and Vietnam is provided.

  • Interactive web-taxonomy for the Araceae: www.cate-Araceae.org
    Blumea - Biodiversity Evolution and Biogeography of Plants, 2009
    Co-Authors: A. Haigh, Thomas B. Croat, Peter C. Boyce, Simon J Mayo, Josef Bogner, L. Reynolds, M. Mora Pinto, L. Lay, Benjamin R. Clark, C. Kostelac
    Abstract:

    CATE (Creating a Taxonomic E-science) is a pilot project funded by the UK Natural Environment Research Council (NERC) to test a model of internet taxonomy which aims to construct and maintain online a full descriptive taxonomic revision as a collective enterprise carried out by the specialist taxonomic community. The software application includes the functionality to allow taxonomists to make contributions and proposals for change that are passed for peer review to an editorial and moderating body drawn from the taxonomic community. The model is being tested on the Hawkmoths (Sphingidae) and Aroid (Araceae) families. The paper describes the aims of the project and current progress on the Araceae e-revision.

  • Validation of the Name Anthurium nutibarense (Araceae)
    Novon: A Journal for Botanical Nomenclature, 2008
    Co-Authors: Thomas B. Croat
    Abstract:

    The new species Anthurium nutibarense Croat (Araceae) from Colombia was published invalidly in 2005, not specifically designating the location of the holotype. This oversight is corrected with the validation of the name Anthurium nutibarense Croat.