DOCSLIB.ORG

Ronsheim-And-Bever-2000.Pdf

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Ronsheim-And-Bever-2000.Pdf American Journal of Botany 87(12): 1769±1777. 2000. GENETIC VARIATION AND EVOLUTIONARY TRADE-OFFS FOR SEXUAL AND ASEXUAL REPRODUCTIVE MODES IN ALLIUM VINEALE (LILIACEAE)1 MARGARET L. RONSHEIM2,3 AND JAMES D. BEVER4,5 2Department of Biology, Box 513, Vassar College, 124 Raymond Avenue, Poughkeepsie, New York 12604-0513 USA; and 4Department of Biology, Indiana University, Bloomington, Indiana 47405 USA Populations of Allium vineale commonly include individuals with very different allocation patterns to three modes of reproduction: sexual ¯owers, aerially produced asexual bulbils, and belowground asexual offsets. If selection is currently acting to maintain these different allocation patterns there must be a genetic basis for variation in allocation to these three reproductive modes. In addition, negative genetic correlations between reproductive traits would imply evolutionary trade-offs among reproductive strategies. We eval- uated the heritability of these allocation patterns by growing 16 clones from a single population in the greenhouse at two levels of fertilization. Bulb mass and the mass and number of bulbils, offsets, and ¯owers were used as response variables, in addition to the proportion allocated to each reproductive mode. We found evidence of substantial heritable variation in allocation to sexual reproduction and in allocation within the two modes of asexual reproduction, indicating high sensitivity of these allocation patterns to natural selection. We also found evidence of strong negative genetic correlations between bulbil and ¯ower traits, as well as between bulbil and offset traits, with one group of genotypes allocating greater resources to aerial asexual bulbils and the second group allocating more resources to belowground asexual offsets and aerial ¯owers. Phenotypic plasticity in allocation to above- vs. belowground asexual reproduction and sexual vs. asexual aerial reproduction was limited, indicating that plants are unlikely to change reproductive mode in response to nutrient availability. Together, then, we have demonstrated strong heritability for, and trade-offs in, the reproductive allocation patterns within this plant population. Key words: Allium vineale; genetic correlations; heritability; life history traits; Liliaceae; multiple reproductive modes; trade- offs. Diverse modes of reproduction are often maintained within tion of beaked to unbeaked achenes at lower plant density species and within single plant populations. For example, plant (Baker and O'Dowd, 1982). In general, higher light and nu- species can produce combinations of chasmogamous and cleis- trient levels increase the proportion of chasmogamous to cleis- togamous ¯owers (e.g., Impatiens, Schemske, 1978; Danthon- togamous ¯owers (e.g., Schemske, 1978; Trapp and Hendrix, ia spicata, Clay, 1982; Viola mirabilis, Mattila and Salonen, 1988; Le Corff, 1993; but see Mattila and Salonen, 1995). In 1995), aerial and subterranean seeds (e.g., Amphicarpum pur- Amphicarpum purshii, aerial reproduction occurs under higher shii, Cheplick and Quinn, 1988; Amphicarpaea bracteata, resource availability, while subterranean seeds are produced at Trapp and Hendrix, 1988; see Cheplick, 1987, for a review), all resource levels (Cheplick and Quinn, 1982). Selection seeds and ramets (e.g., Tussilago farfara, Ogden, 1974; Fra- would favor such phenotypic plasticity if different propagule garia virginiana, Holler and Abrahamson, 1977), as well as types are favored when environmental conditions change heteromorphic aerial achenes (e.g., Hypochoeris glabra, Baker (Schoen and Lloyd, 1984; Loehle, 1987). and O'Dowd, 1982; Heterosperma pinnatum, Venable and In order for natural selection to currently operate to maintain Burquez, 1989). Adaptive explanations for the maintenance of these diverse reproductive strategies and phenotypic plasticity this diversity posit trade-offs among alternate components of in allocation patterns, the variation in reproductive mode must ®tness. For example, some propagule types may be favored in have a genetic basis. In fact, the response of a population competitive situations near the parent, while others may serve depends not only on the availability of genetic variation, but a role in dispersal (Schoen and Lloyd, 1984; Venable, 1985). also on the existence of genetic correlations between traits Different advantages may also exist for producing sexual vs. (Reznick, 1985). In particular, negative genetic correlations be- asexual progeny, as sexual progeny may be favored in the tween life history traits suggest trade-offs in reproductive strat- presence of pathogens or changing environments, and asexual egies (Falconer, 1981; Stearns, 1992), as selection for in- progeny may be favored in static environments. creased allocation to one trait will cause a decrease in allo- In addition, genotypes are known to vary their allocation to cation to the other. different modes of reproduction with environmental change. In general, reproductive traits have lower heritabilities than Allocation to vegetative and sexual reproduction changes with morphological traits (Mousseau and Roff, 1987), but signi®- plant density in several species (e.g., Ogden, 1974; Abraham- cant genetic variation in allocation to different reproductive son, 1975; Holler and Abrahamson, 1977; for a review see modes has been demonstrated (e.g., cleistogamy vs. chasmo- Loehle, 1987). Hypochoeris glabra produces a higher propor- gamy, Clay, 1982; proportion of achene morphs, Venable and Burquez, 1989; allocation to aerial seeds, Cheplick and Quinn, 1 Manuscript received 22 June 1999; revision accepted 29 February 2000. 1988). Negative genetic correlations, which indicate trade-offs The authors thank Kathy Mills, Sarah Cross, and Shawn White and ac- among life history traits, have also been detected. For exam- knowledge support from USDA grants 92-37101-7461 and 94-37101-0354 and NSF grant DEB 9996221. ple, Law (1979) found a negative correlation between ®rst- 2 Author for correspondence (e-mail: [email protected]). and second-year reproduction in Poa annua, and Campbell 3 e-mail: [email protected]. (1997) observed a negative correlation between corolla width, 1769 1770 AMERICAN JOURNAL OF BOTANY [Vol. 87 which affects pollen export rates and potentially male ®tness, and others that do produce ¯owers have low seed set, measurement of heri- and net female ®tness. However, not all species demonstrate tability through maternal or paternal contributions would be dif®cult and not trade-offs in life history strategies (see Stearns, 1992, for a representative of the natural population. Instead, we have measured the broad- review). For example, Cain et al. (1995) found no evidence sense or clonal heritabilities and correlations by using the aerially produced for genetic trade-offs among ®ve reproductive traits in Trifo- asexual bulbils to replicate genotypes. This approach has the obvious limi- lium repens, and Weis, Hollenbach, and Abrahamson (1987) tation that we are not able to separate the additive genetic variance compo- found only indirect evidence for a trade-off between sexual nents from the dominance, epistatic, or maternal components. Furthermore, and asexual reproduction in Solidago altissima. In addition, in sampling the population we were not able to include individuals that pro- the presence of trade-offs may be dependent on resource avail- duce in¯orescences with ¯owers and no bulbils (a small minority in this pop- ability, with stronger allocation trade-offs present when nutri- ulation), which may reduce the genetic variation that we measure. We also ents are more limiting (e.g., Reznick, 1985; Biere, 1995; purposefully collected bulbils from two groups of individuals: one that pro- duced some ¯owers and a second that produced only bulbils. This resulted in Schlichting and Pigliucci, 1998) a higher representation in our study than in the ®eld of individuals that pro- Our study organism, Allium vineale, has three modes of re- duce both ¯owers and bulbils in their in¯orescence, and may in¯ate our es- production, each with its own implications for genetic vari- timate of genetic variance. While these sampling dif®culties reduce the rele- ability, dispersal, dormancy, and probability of successful es- vance of our measured values of heritabilities and genetic correlations to the tablishment. Two of the modes are asexual in nature, one being population of their origin, these estimates are still valuable to address the aboveground (bulbils), the other belowground (offsets). Sex- issue of the evolutionary potential within Allium populations in general. ually produced aerial seeds are the third type of propagule. In this experiment we determined the reproductive allocation of replicates Within one population, it is possible to ®nd individuals that of 16 different genotypes when grown in two fertilization regimes. Infruc- are reproducing solely asexually, as well as individuals that tescences were collected in September 1993 from 16 different plants at a ®eld are reproducing both sexually and asexually, in varying pro- site in Durham, North Carolina (for details of the ®eld site, see Fowler, 1978; portions. To determine whether there is genetic variation in Fowler and Antonovics, 1981). Each of the parents was considered a separate allocation to these three reproductive modes and to test for genotype, for a total of 16 genotypes. A range of infructescence phenotypes trade-offs between sexual and asexual reproduction in Allium was included, varying from all bulbils
Load more

Recommended publications
  • Guide to the Flora of the Carolinas, Virginia, and Georgia, Working Draft of 17 March 2004 -- LILIACEAE
    Guide to the Flora of the Carolinas, Virginia, and Georgia, Working Draft of 17 March 2004 -- LILIACEAE LILIACEAE de Jussieu 1789 (Lily Family) (also see AGAVACEAE, ALLIACEAE, ALSTROEMERIACEAE, AMARYLLIDACEAE, ASPARAGACEAE, COLCHICACEAE, HEMEROCALLIDACEAE, HOSTACEAE, HYACINTHACEAE, HYPOXIDACEAE, MELANTHIACEAE, NARTHECIACEAE, RUSCACEAE, SMILACACEAE, THEMIDACEAE, TOFIELDIACEAE) As here interpreted narrowly, the Liliaceae constitutes about 11 genera and 550 species, of the Northern Hemisphere. There has been much recent investigation and re-interpretation of evidence regarding the upper-level taxonomy of the Liliales, with strong suggestions that the broad Liliaceae recognized by Cronquist (1981) is artificial and polyphyletic. Cronquist (1993) himself concurs, at least to a degree: "we still await a comprehensive reorganization of the lilies into several families more comparable to other recognized families of angiosperms." Dahlgren & Clifford (1982) and Dahlgren, Clifford, & Yeo (1985) synthesized an early phase in the modern revolution of monocot taxonomy. Since then, additional research, especially molecular (Duvall et al. 1993, Chase et al. 1993, Bogler & Simpson 1995, and many others), has strongly validated the general lines (and many details) of Dahlgren's arrangement. The most recent synthesis (Kubitzki 1998a) is followed as the basis for familial and generic taxonomy of the lilies and their relatives (see summary below). References: Angiosperm Phylogeny Group (1998, 2003); Tamura in Kubitzki (1998a). Our “liliaceous” genera (members of orders placed in the Lilianae) are therefore divided as shown below, largely following Kubitzki (1998a) and some more recent molecular analyses. ALISMATALES TOFIELDIACEAE: Pleea, Tofieldia. LILIALES ALSTROEMERIACEAE: Alstroemeria COLCHICACEAE: Colchicum, Uvularia. LILIACEAE: Clintonia, Erythronium, Lilium, Medeola, Prosartes, Streptopus, Tricyrtis, Tulipa. MELANTHIACEAE: Amianthium, Anticlea, Chamaelirium, Helonias, Melanthium, Schoenocaulon, Stenanthium, Veratrum, Toxicoscordion, Trillium, Xerophyllum, Zigadenus.
    [Show full text]
  • The Vascular Plants of Massachusetts
    The Vascular Plants of Massachusetts: The Vascular Plants of Massachusetts: A County Checklist • First Revision Melissa Dow Cullina, Bryan Connolly, Bruce Sorrie and Paul Somers Somers Bruce Sorrie and Paul Connolly, Bryan Cullina, Melissa Dow Revision • First A County Checklist Plants of Massachusetts: Vascular The A County Checklist First Revision Melissa Dow Cullina, Bryan Connolly, Bruce Sorrie and Paul Somers Massachusetts Natural Heritage & Endangered Species Program Massachusetts Division of Fisheries and Wildlife Natural Heritage & Endangered Species Program The Natural Heritage & Endangered Species Program (NHESP), part of the Massachusetts Division of Fisheries and Wildlife, is one of the programs forming the Natural Heritage network. NHESP is responsible for the conservation and protection of hundreds of species that are not hunted, fished, trapped, or commercially harvested in the state. The Program's highest priority is protecting the 176 species of vertebrate and invertebrate animals and 259 species of native plants that are officially listed as Endangered, Threatened or of Special Concern in Massachusetts. Endangered species conservation in Massachusetts depends on you! A major source of funding for the protection of rare and endangered species comes from voluntary donations on state income tax forms. Contributions go to the Natural Heritage & Endangered Species Fund, which provides a portion of the operating budget for the Natural Heritage & Endangered Species Program. NHESP protects rare species through biological inventory,
    [Show full text]
  • Coreopsideae Daniel J
    Chapter42 Coreopsideae Daniel J. Crawford, Mes! n Tadesse, Mark E. Mort, "ebecca T. Kimball and Christopher P. "andle HISTORICAL OVERVIEW AND PHYLOGENY In a cladistic analysis of morphological features of Heliantheae by Karis (1993), Coreopsidinae were reported Morphological data to be an ingroup within Heliantheae s.l. The group was A synthesis and analysis of the systematic information on represented in the analysis by Isostigma, Chrysanthellum, tribe Heliantheae was provided by Stuessy (1977a) with Cosmos, and Coreopsis. In a subsequent paper (Karis and indications of “three main evolutionary lines” within "yding 1994), the treatment of Coreopsidinae was the the tribe. He recognized ! fteen subtribes and, of these, same as the one provided above except for the follow- Coreopsidinae along with Fitchiinae, are considered ing: Diodontium, which was placed in synonymy with as constituting the third and smallest natural grouping Glossocardia by "obinson (1981), was reinstated following within the tribe. Coreopsidinae, including 31 genera, the work of Veldkamp and Kre# er (1991), who also rele- were divided into seven informal groups. Turner and gated Glossogyne and Guerreroia as synonyms of Glossocardia, Powell (1977), in the same work, proposed the new tribe but raised Glossogyne sect. Trionicinia to generic rank; Coreopsideae Turner & Powell but did not describe it. Eryngiophyllum was placed as a synonym of Chrysanthellum Their basis for the new tribe appears to be ! nding a suit- following the work of Turner (1988); Fitchia, which was able place for subtribe Jaumeinae. They suggested that the placed in Fitchiinae by "obinson (1981), was returned previously recognized genera of Jaumeinae ( Jaumea and to Coreopsidinae; Guardiola was left as an unassigned Venegasia) could be related to Coreopsidinae or to some Heliantheae; Guizotia and Staurochlamys were placed in members of Senecioneae.
    [Show full text]
  • New Insights on Bidens Herzogii (Coreopsideae, Asteraceae), an Endemic Species from the Cerrado Biogeographic Province in Bolivia
    Ecología en Bolivia 52(1): 21-32. Mayo 2017. ISSN 1605-2528. New insights on Bidens herzogii (Coreopsideae, Asteraceae), an endemic species from the Cerrado biogeographic province in Bolivia Novedades en el conocimiento de Bidens herzogii (Coreopsideae, Asteraceae), una especie endémica de la provincia biogeográfica del Cerrado en Bolivia Arturo Castro-Castro1, Georgina Vargas-Amado2, José J. Castañeda-Nava3, Mollie Harker1, Fernando Santacruz-Ruvalcaba3 & Aarón Rodríguez2,* 1 Cátedras CONACYT – Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional, Unidad Durango (CIIDIR-Durango), Instituto Politécnico Nacional. 2 Herbario Luz María Villarreal de Puga (IBUG), Instituto de Botánica, Departamento de Botánica y Zoología, Universidad de Guadalajara. Apartado postal 1-139, Zapopan 45101, Jalisco, México. *Author for correspondence: [email protected] 3 Laboratorio de Cultivo de Tejidos, Departamento de Producción Agrícola, Universidad de Guadalajara. Apartado postal 1-139, Zapopan 45101, Jalisco, México. Abstract The morphological limits among some Coreopsideae genera in the Asteraceae family are complex. An example is Bidens herzogii, a taxon first described as a member of the genus Cosmos, but recently transferred to Bidens. The species is endemic to Eastern Bolivia and it grows on the Cerrado biogeographic province. Recently collected specimens, analysis of herbarium specimens, and revisions of literature lead us to propose new data on morphological description and a chromosome counts for the species, a tetraploid, where x = 12, 2n = 48. Lastly, we provide data on geographic distribution and niche modeling of B. herzogii to predict areas of endemism in Eastern Bolivia. This area is already known for this pattern of endemism, and the evidence generated can be used to direct conservation efforts.
    [Show full text]
  • Vascular Plants and a Brief History of the Kiowa and Rita Blanca National Grasslands
    United States Department of Agriculture Vascular Plants and a Brief Forest Service Rocky Mountain History of the Kiowa and Rita Research Station General Technical Report Blanca National Grasslands RMRS-GTR-233 December 2009 Donald L. Hazlett, Michael H. Schiebout, and Paulette L. Ford Hazlett, Donald L.; Schiebout, Michael H.; and Ford, Paulette L. 2009. Vascular plants and a brief history of the Kiowa and Rita Blanca National Grasslands. Gen. Tech. Rep. RMRS- GTR-233. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 44 p. Abstract Administered by the USDA Forest Service, the Kiowa and Rita Blanca National Grasslands occupy 230,000 acres of public land extending from northeastern New Mexico into the panhandles of Oklahoma and Texas. A mosaic of topographic features including canyons, plateaus, rolling grasslands and outcrops supports a diverse flora. Eight hundred twenty six (826) species of vascular plant species representing 81 plant families are known to occur on or near these public lands. This report includes a history of the area; ethnobotanical information; an introductory overview of the area including its climate, geology, vegetation, habitats, fauna, and ecological history; and a plant survey and information about the rare, poisonous, and exotic species from the area. A vascular plant checklist of 816 vascular plant taxa in the appendix includes scientific and common names, habitat types, and general distribution data for each species. This list is based on extensive plant collections and available herbarium collections. Authors Donald L. Hazlett is an ethnobotanist, Director of New World Plants and People consulting, and a research associate at the Denver Botanic Gardens, Denver, CO.
    [Show full text]
  • Antonio José Cavanilles (1745-1804)
    ANTONIO JOSÉ CAVANILLES (1745-1804) Segundo centenario de la muerte de un gran botánico ANTONIO JOSÉ CAVANILLES (1745-1804) Segundo centenario de la muerte de un gran botánico Valencia Real Sociedad Económica de Amigos del País 2004 1. Dalia (cultivar de Dahlia pinnata Cav.). Según el sistema internacional de clasificación, pertenece al grupo “flor semicactus”. 2. Rosa (Rosa x centifolia L.). 3. Amapola (Papaver rhoeas L.). Variedad de flor doble. 4. Tulipán (variedad de jardín de Tulipa gesneriana L.) 5. Áster de China (Callistephus chinensis L.) = Nees (Aster chinensis L.), variedad de flor doble. 6. Jazmín oloroso (Jasminum odoratissimum L.). 7. Adormidera (Papaver somniferum L.). Variedad de jardín. 8. Crisantemo (Chysanthemum x indicum L.). 9. Clavel (Dianthus caryophyllus L.). 10. Perpetua (Helichrysum italicum (Roth) G. Don = Gnaphalium italicum Roth.). 11. Hortensia (Hydrangea macrophylla (Thunb.) (Ser. = Viburnum macrophyllum Thunb.) 12. Fucsia (Fuchsia fulgens DC.). Identificación y esquema por María José López Terrada. Edita: Real Sociedad Económica de Amigos del País Valencia, 2004 ISBN: 84-482-3874-5 Depósito legal: V. 4.381 - 2004 Artes Gráficas Soler, S. L. - La Olivereta, 28 - 46018 Valencia ÍNDICE Presentación de Francisco R. Oltra Climent. Director de la Real Socie- dad Económica de Amigos del País de Valencia ........................... 1 La obra de Cavanilles en la “Económica”, de Manuel Portolés i Sanz. Coordinador por la Real Sociedad Económica de Amigos del País de Valencia de “2004: año de Cavanilles” ...................................... 3 Botànic Cavanilles per sempre, de Francisco Tomás Vert. Rector de la Universitat de València ........................................................ 5 Palabras de Rafael Blasco Castany. Conseller de Territorio y Vivienda de la Generalitat Valenciana .....................................................
    [Show full text]
  • Flora Montiberica 28: 3-22 (XII-2004)
    FLORA MONTIBERICA Publicación periódica especializada en trabajos sobre la flora del Sistema Ibérico Vol. 28 Valencia, XII-2004 FLORA MONTIBERICA Publicación independiente sobre temas relacionados con la flora de la Cordillera Ibérica (plantas vasculares). Edición en Internet: http://www.floramontiberica.org Editor y Redactor general: Gonzalo Mateo Sanz. Jardín Botánico. Universidad de Valencia. C/ Quart, 80. E-46008-Valencia. Redactores adjuntos: Cristina Torres Gómez y Javier Fabado Alós Comisión Asesora: Antoni Aguilella Palasí (Valencia) Juan A. Alejandre Sáenz (Vitoria) Vicente J. Arán Redó (Madrid) Manuel Benito Crespo Villalba (Alicante) José María de Jaime Lorén (Valencia) Emilio Laguna Lumbreras (Valencia) Pedro Montserrat Recoder (Jaca) Depósito Legal: V-5097-1995 ISSN: 1138-5952 Imprime: MOLINER-40 (GÓMEZ COLL, S.L.) Tel./Fax 390 3735 - Burjasot (Valencia). Portada: Phlomis crinita Cav., procedente dela cuesta de Barig (Valen- cia), localidad clásica cavanillesiana. Flora Montiberica 28: 3-22 (XII-2004) SOBRE LOS GÉNEROS DESCRITOS POR CAVANILLES. Emilio LAGUNA LUMBRERAS (1) Generalitat Valenciana. Conselleria de Territorio y Vivienda. Servicio de Conservación y Gestión de la Biodiversidad. Arquitecto Alfaro, 39. E-46011. Valencia. [email protected] ABSTRACT: A provisory list of vascular plant genera established by A. J. Cava- nilles is given. Cavanilles created at least 100 new genera, 54 of them being in current use. These genera have been used to generate the name of 2 orders, 10 families, 7 sub- families, 16 tribes and 9 subtribes; at least 1 order (Calycerales) and 5 families (Calyce- raceae, Cobaeaceae, Epacridaceae, Eucryphyaceae and Oleandraceae) are generally accepted and under current use. Most of these taxa belong to the tropical and subtropical flora.
    [Show full text]
  • Using ITS Sequences Suggests Lability in Reproductive Characters
    MOLECULAR PHYLOGENETICS AND EVOLUTION Molecular Phylogenetics and Evolution 33 (2004) 127–139 www.elsevier.com/locate/ympev Phylogeny of Coreopsideae (Asteraceae) using ITS sequences suggests lability in reproductive characters Rebecca T. Kimballa,*, Daniel J. Crawfordb a Department of Zoology, University of Florida, P.O. Box 118525, Gainesville, FL 32611-8525, USA b Department of Ecology and Evolutionary Biology, The Natural History Museum and Biodiversity Research Center, University of Kansas, Lawrence, KS 66045-2106, USA Received 3 November 2003; revised 14 April 2004 Available online 7 July 2004 Abstract Relationships among the 21 genera within the tribe Coreopsideae (Asteraceae) remain poorly resolved despite phylogenetic stud- ies using morphological and anatomical traits. Recent molecular phylogenies have also indicated that some Coreopsideae genera are not monophyletic. We used internal transcribed spacer (ITS) sequences from representatives of 19 genera, as well as all major lin- eages in those genera that are not monophyletic, to examine phylogenetic relationships within this group. To examine the affects of alignment and method of analysis on our conclusions, we obtained alignments using five different parameters and analyzed all five alignments with distance, parsimony, and Bayesian methods. The method of analysis had a larger impact on relationships than did alignments, although different analytical methods gave very similar results. Although not all relationships could be resolved, a num- ber of well-supported lineages were found, some in conflict with earlier hypotheses. We did not find monophyly in Bidens, Coreopsis, and Coreocarpus, though other genera were monophyletic for the taxa we included. Morphological and anatomical traits which have been used previously to resolve phylogenetic relationships in this group were mapped onto the well-supported nodes of the ITS phy- logeny.
    [Show full text]
  • The Importance of the Intensity and Frequency of Perturbations on the Germination Delay
    The importance of the intensity and frequency of perturbations on the germination delay Alfonso Garmendia , Luis Garmendia , Adela Salvador Department of Agro-forest Ecosystems, Mediterranean Agro-forest Institute, Technical University of Valencia, E.T.S.M.R.E. (U.P.V.), Av. Blasco Ibatiez 21, 46010 Valencia, Spain Department of Programming and Computing Systems, Complutense University of Madrid, Juan del Rosal 8, 28040 Madrid, Spain Department of Applied Mathematics, Technical University of Madrid, E.T.S.I. Caminos, Ciudad Universitaria sin. 28040 Madrid, Spain Abstract An iterative model is developed to evaluate the reproductive strategies of plants in environments with different frequencies and intensities of disturbance. Two extreme reproductive strategies are compared: the "homocarpic" strategy, in which all the seeds germinate the following spring, without dormancy, and the "heterocarpic" strategy, whereby, each year, half of the existing seeds germinate. It is observed that this sort of heterocarpy is beneficial in environments with strong perturbations, in which a high percentage of the population dies. However, the frequency of such perturbations does not cause changes in the advan­ tage of one strategy over the other. The results suggest that the intensity of the disturbance is much more important than the frequency. Keywords: Heterocarpy; Homocarpy; Germination strategy; Perturbation; Disturbance; Dormancy 1. Introduction This paper is the first part of a theoretical study about the evolution of heterocarpy in dis­ turbed environments. The model tested the relative importance of intensity and frequency of disturbance to reproductive strategies of plants in variable environments. It has considered the transient dynamics and the patterns of two population co-existence, with two contrasting reproductive strategies.
    [Show full text]
  • Checklist of the Washington Baltimore Area
    Annotated Checklist of the Vascular Plants of the Washington - Baltimore Area Part I Ferns, Fern Allies, Gymnosperms, and Dicotyledons by Stanwyn G. Shetler and Sylvia Stone Orli Department of Botany National Museum of Natural History 2000 Department of Botany, National Museum of Natural History Smithsonian Institution, Washington, DC 20560-0166 ii iii PREFACE The better part of a century has elapsed since A. S. Hitchcock and Paul C. Standley published their succinct manual in 1919 for the identification of the vascular flora in the Washington, DC, area. A comparable new manual has long been needed. As with their work, such a manual should be produced through a collaborative effort of the region’s botanists and other experts. The Annotated Checklist is offered as a first step, in the hope that it will spark and facilitate that effort. In preparing this checklist, Shetler has been responsible for the taxonomy and nomenclature and Orli for the database. We have chosen to distribute the first part in preliminary form, so that it can be used, criticized, and revised while it is current and the second part (Monocotyledons) is still in progress. Additions, corrections, and comments are welcome. We hope that our checklist will stimulate a new wave of fieldwork to check on the current status of the local flora relative to what is reported here. When Part II is finished, the two parts will be combined into a single publication. We also maintain a Web site for the Flora of the Washington-Baltimore Area, and the database can be searched there (http://www.nmnh.si.edu/botany/projects/dcflora).
    [Show full text]
  • Annotated Checklist of the Vascular Plant Flora of Grand Canyon-Parashant National Monument Phase II Report
    Annotated Checklist of the Vascular Plant Flora of Grand Canyon-Parashant National Monument Phase II Report By Dr. Terri Hildebrand Southern Utah University, Cedar City, UT and Dr. Walter Fertig Moenave Botanical Consulting, Kanab, UT Colorado Plateau Cooperative Ecosystems Studies Unit Agreement # H1200-09-0005 1 May 2012 Prepared for Grand Canyon-Parashant National Monument Southern Utah University National Park Service Mojave Network TABLE OF CONTENTS Page # Introduction . 4 Study Area . 6 History and Setting . 6 Geology and Associated Ecoregions . 6 Soils and Climate . 7 Vegetation . 10 Previous Botanical Studies . 11 Methods . 17 Results . 21 Discussion . 28 Conclusions . 32 Acknowledgments . 33 Literature Cited . 34 Figures Figure 1. Location of Grand Canyon-Parashant National Monument in northern Arizona . 5 Figure 2. Ecoregions and 2010-2011 collection sites in Grand Canyon-Parashant National Monument in northern Arizona . 8 Figure 3. Soil types and 2010-2011 collection sites in Grand Canyon-Parashant National Monument in northern Arizona . 9 Figure 4. Increase in the number of plant taxa confirmed as present in Grand Canyon- Parashant National Monument by decade, 1900-2011 . 13 Figure 5. Southern Utah University students enrolled in the 2010 Plant Anatomy and Diversity course that collected during the 30 August 2010 experiential learning event . 18 Figure 6. 2010-2011 collection sites and transportation routes in Grand Canyon-Parashant National Monument in northern Arizona . 22 2 TABLE OF CONTENTS Page # Tables Table 1. Chronology of plant-collecting efforts at Grand Canyon-Parashant National Monument . 14 Table 2. Data fields in the annotated checklist of the flora of Grand Canyon-Parashant National Monument (Appendices A, B, C, and D) .
    [Show full text]
  • HARVEST BRODIAEA Is 5-25 Cm Tall
    capsule. The 3-5 basal leaves are linear and the scape HARVEST BRODIAEA is 5-25 cm tall. Brodiaea coronaria (Salisb.) Distribution Engl. This plant was a greater California Central Valley plant symbol = BRCO3 plant at one time extending in vast numbers across the Sacramento and San Joaquin valleys. Due to Contributed By: USDA, NRCS, National Plant Data overgrazing, farming, and urban development this Center plant is becoming rare. It is also found in northwestern California, the central and northern Sierra Nevada, the Cascade Range and British Columbia at an elevational range from 0 to 1600 m. The plant is found in multiple plant community types including valley grassland, foothill woodland, mixed conifer forests, and volcanic mesas. Establishment If possible, obtain the seed and corms from local sources near where they will be planted, to maintain genetic diversity of harvest brodiaea and for the best adaptation to local conditions. Some plant nurseries may label their corms and seeds according to geographic source. If planting flowering-size corms, Alfred Brousseau they can be directly planted outside. Plant the corms Brother Eric Vogel, St. Mary's College in the fall in full sun. The less crowded the more the @ CalPhotos corms will offset. Plant them 2 to 4 inches apart and 4 inches deep. A well-drained soil that is light and Alternate Names loose will produce bigger corms. Water and weed Indian potato, topoderos, walla, crown brodiaea the patch regularly and protect it from small and large mammals, insects, and birds. Keep the ground Uses slightly damp. If given too much water the corms Ethnobotanic: Corms were gathered with a wooden will rot.
    [Show full text]