DOCSLIB.ORG

Physiological Adaptations

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Physiological Adaptations Glime, J. M. 2017. Water Relations: Physiological Adaptations. Chapt. 7-5. In: Glime, J. M. Bryophyte Ecology. Volume 1. 7-5-1 Physiological Ecology. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. Last updated 7 March 2017 and available at <http://digitalcommons.mtu.edu/bryophyte-ecology/>. CHAPTER 7-5 WATER RELATIONS: PHYSIOLOGICAL ADAPTATIONS TABLE OF CONTENTS Water Relations on Land.....................................................................................................................................7-5-2 Drought Tolerance vs Avoidance........................................................................................................................7-5-3 Desiccation Tolerance..................................................................................................................................7-5-4 Desiccation Avoidance ................................................................................................................................7-5-9 Life Cycle and Life Strategy Adaptations...........................................................................................................7-5-9 Seasonal Changes..............................................................................................................................................7-5-11 Physiological Adaptations.................................................................................................................................7-5-14 Mode of Conduction..................................................................................................................................7-5-16 Osmotic Potential and Turgor....................................................................................................................7-5-21 Water Content.....................................................................................................................................7-5-24 Water-logging.....................................................................................................................................7-5-26 Inducible vs Constitutive Desiccation Tolerance.......................................................................................7-5-26 Hardening...........................................................................................................................................7-5-28 Desiccation-induced Changes ....................................................................................................................7-5-28 Cell Contents.......................................................................................................................................7-5-30 Chloroplast Responses........................................................................................................................7-5-31 Photosynthesis....................................................................................................................................7-5-31 Mitochondria.......................................................................................................................................7-5-32 Nuclei..................................................................................................................................................7-5-32 Vacuoles and Vesicles........................................................................................................................7-5-32 Membranes.........................................................................................................................................7-5-32 Plasmolysis.........................................................................................................................................7-5-33 Liverworts...........................................................................................................................................7-5-33 Summary ...........................................................................................................................................................7-5-34 Acknowledgments.............................................................................................................................................7-5-34 Literature Cited .................................................................................................................................................7-5-34 7-5-2 Chapter 7-5: Water Relations: Physiological Adaptations CHAPTER 7-5 WATER RELATIONS: PHYSIOLOGICAL ADAPTATIONS Figure 1. Riccia cavernosa, a thallose liverwort that dries out during drought and recovers in the fall when rain returns. Photo by Jan-Peter Frahm, with permission. Water Relations on Land Proctor (2014) points out that one of the basic needs of relative ease with which genes can be moved into them or bryophytes is that of coping with the intermittent knocked out of them and their expressions be observed. availability of water. To this end, poikilohydry is efficient And both bryophyte and fern gametophytes exhibit at the small scale of a bryophyte, whereas endohydry is desiccation tolerance, whereas this ability is rare among more beneficial for the large tracheophytes. sporophytic seed plants (Watkins et al. 2007). Long live Physiological adaptations relate on one end to the the gametophytes! Even the lichens seem to have less morphology and on the other to the biochemistry. desiccation tolerance than the bryophytes (Green et al. Although we have recognized morphological characters for 2011). a very long time, few have actually been tested Oliver et al. (2000) hypothesized that for experimentally on a large scale for their adaptive value in photosynthetic plants to move onto land, desiccation altering physiology. The biochemical adaptations, on the tolerance was crucial. Using species of "resurrection other hand, constitute a new and emerging field of plants" from both bryophytes and tracheophytes, Fisher bryology, one that coincides closely with physiology of (2008) concluded that desiccation tolerance arose among tracheophytes. By using the more easily studied propagules as a means of survival. In bryophytes, nearly bryophytes, we have gained the possibility of better every part is a potential propagule in most species. For understanding of the physiology of tracheophytes. This example, Maheu (1902) found that the moss Tortula unusual interest in bryophytes is largely because of the muralis (Figure 2) would regenerate protonemata after Chapter 7-5: Water Relations: Physiological Adaptations 7-5-3 being stored dry for 14 years. Physiological adaptations water-stressed and the plant itself has become dry; it suffers may permit the bryophyte to retain water or to recover from dehydration of all its metabolic systems. Such vegetative loss of water, and to change its strategies with the seasons desiccation tolerance is rare among tracheophytes, with few or the climate. species withstanding vegetative desiccation: 60-70 species of fern and fern allies and 60 species of angiosperms (Oliver et al. 2000). Instead, most tracheophytes survive through reproductive structures. Bryophytes (and lichens), on the other hand, exhibit vegetative desiccation tolerance as well as through reproductive structures (Kappen & Valladares 1999; Proctor et al. 2007). Figure 2. Tortula muralis, a moss species that can survive drought as protonemata. Photo by Christophe Quintin, through Figure 3. Grimmia pulvinata, a drought tolerator growing Creative Commons. on concrete. Photo with permission from Botany Department Alpert (2000) presented two main puzzles from the website, University of British Columbia, Canada, with observed habitat patterns of desiccation-tolerant plants. permission. "What are the mechanisms by which plants tolerate For sake of clarity, let us consider drought to be a desiccation?" and "Why are desiccation-tolerant plants not condition of the environment and desiccation to be a more ecologically widespread?" There appear to be condition of the plant, in this case the bryophyte. For multiple mechanisms of tolerance, including protection tracheophytes, drought in the environment nearly always from oxidants and loss of normal configuration of causes desiccation in the plant, but for bryophytes, this may macromolecules during dehydration. Alpert suggests that not so often be the case. their inability to occupy a wide ecological range is due to Using that terminology, drought tolerance can be their inability to maintain a cumulative positive carbon accomplished in two ways: desiccation tolerance and balance during their repeated wet/dry cycles and the desiccation avoidance. Desiccation avoidance is the tradeoffs between desiccation tolerance and growth rate. ability to prevent desiccation from occurring within the plant or the ability to go into a dormant stage during Drought Tolerance vs Avoidance periods of low water availability; it is often characterized As clear as the two words tolerance and avoidance by plants that die and leave stress-tolerant diaspores (any may seem, they can lead to confusion because of structures that become detached from parent plant and differences in perspective. During (1979) tells us that gives rise to new individuals) that will grow the next drought tolerance is the ability to survive and maintain season. Note the use of the word stage here, not state. For activity despite a lack of water in the environment. Proctor bryophytes, spores and gemmae provide dormant stages, (2000) gives a more physiological
Load more

Recommended publications
  • Accumulation Characteristics of Some Elements in the Moss Polytrichum Commune (Bryophytes) Based on XRF Spectrometry
    Journal of Environmental Protection, 2013, 4, 522-528 http://dx.doi.org/10.4236/jep.2013.46061 Published Online June 2013 (http://www.scirp.org/journal/jep) Accumulation Characteristics of Some Elements in the Moss Polytrichum commune (Bryophytes) Based on XRF Spectrometry Rudolf Šoltés, Eva Gregušková Institute of High Mountains Biology, University of Žilina, Tatranská Javorina, Slovakia. Email: [email protected], [email protected] Received February 18th, 2013; revised March 21st, 2013; accepted April 19th, 2013 Copyright © 2013 Rudolf Šoltés, Eva Gregušková. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Bryophytes are broadly used as bioindicators. However, the internal distribution of accumulated elements in the moss tissue is little known. Sampling was carried out in The West Carpathians, Slovakia, in autumn 2012. Seven replicates have been used. The samples were analyzed by XRF Spectrometer Delta Classic. S, Pb, K, Ca, Cr, Mn, Fe, Cu, Rb, Sr, Mo, Ba and Zn were determined. For ordination analysis we used principal component analysis, statistical graphics system STATISTICA have been used for the correlation analysis and for analysis of variance. Results show that sulphur, zinc, chromium, manganese, molybdenum, kalcium and copper are preferentially accumulated in the capsula. While lead favors gametophyte, potassium and strontium prefer accumulation in sporophyte. Iron significantly accumulates in the more-year segments, while zinc in the stems. Copper, chromium and sulphur are accumulated preferentially in The Fatra Mts. Keywords: Bioindication; Polytrichum commune; The West Carpathians; Elemental Accumulation; XRF Spectrometry 1.
    [Show full text]
  • Polytrichaceae – Hair Cap Moss Family
    POLYTRICHACEAE – HAIR CAP MOSS FAMILY Plant: moss (tend to be larger and more noticeable than most mosses) Stem: mostly erect Root: rhizoids (no root) Leaves: mostly narrowly lanceolate (although quite variable), spirally arranged on stem, lamellae along leaf nerves, often with toothed leaf margins, leaves sharp pointed, most have a hyaline basal sheath Flowers: dioecious; gametophyte (leafy) with sporophyte born at tip of gametophyte (gametophyte generation dimorphic); sporophtyte – setea often long and solitary, capsule 2 to 6 angled (shape variable), calyptra usually of matted or felted hair, single row of (16?) 32 or 64 teeth on peristome Fruit: Other: forms mats or patches; common throughout NA and CAN (not found in some southwest states); prefers acidic conditions Genera: 22+ genera *** species descriptions are general - for full ID see professional texts for full descriptions (sometimes microscopic details are necessary) WARNING – family descriptions are only a layman’s guide and should not be used as definitive POLYTRICHACEAE – HAIR CAP MOSS FAMILY Common Hair Cap [Polytrichum] Moss; Polytrichum commune Hedw. A Polytrichum (Hair Cap) Moss; Polytrichum piliferum Hedw. Common Hair Cap [Polytrichum] Moss Polytrichum commune Hedw. Polytrichaceae (Hair Cap Moss Family) Oak Openings Metropark, Lucas County, Ohio Notes: antheridia (male) rossettes greenish yellow; seta yellowish brown to red, calyptra of yellowish to brownish hair, capsule rectangular to somewhat cubic; leaves erect to spreading, tips recurved, finely toothed from base to tip, large clasping sheath, awn short; plants medium to tall, in mats or clumps in moist areas; most of NA and CAN except some southwestern states ; spring [V Max Brown, 2009] A Polytrichum (Hair Cap) Moss Polytrichum piliferum Hedw.
    [Show full text]
  • Species List For: Labarque Creek CA 750 Species Jefferson County Date Participants Location 4/19/2006 Nels Holmberg Plant Survey
    Species List for: LaBarque Creek CA 750 Species Jefferson County Date Participants Location 4/19/2006 Nels Holmberg Plant Survey 5/15/2006 Nels Holmberg Plant Survey 5/16/2006 Nels Holmberg, George Yatskievych, and Rex Plant Survey Hill 5/22/2006 Nels Holmberg and WGNSS Botany Group Plant Survey 5/6/2006 Nels Holmberg Plant Survey Multiple Visits Nels Holmberg, John Atwood and Others LaBarque Creek Watershed - Bryophytes Bryophte List compiled by Nels Holmberg Multiple Visits Nels Holmberg and Many WGNSS and MONPS LaBarque Creek Watershed - Vascular Plants visits from 2005 to 2016 Vascular Plant List compiled by Nels Holmberg Species Name (Synonym) Common Name Family COFC COFW Acalypha monococca (A. gracilescens var. monococca) one-seeded mercury Euphorbiaceae 3 5 Acalypha rhomboidea rhombic copperleaf Euphorbiaceae 1 3 Acalypha virginica Virginia copperleaf Euphorbiaceae 2 3 Acer negundo var. undetermined box elder Sapindaceae 1 0 Acer rubrum var. undetermined red maple Sapindaceae 5 0 Acer saccharinum silver maple Sapindaceae 2 -3 Acer saccharum var. undetermined sugar maple Sapindaceae 5 3 Achillea millefolium yarrow Asteraceae/Anthemideae 1 3 Actaea pachypoda white baneberry Ranunculaceae 8 5 Adiantum pedatum var. pedatum northern maidenhair fern Pteridaceae Fern/Ally 6 1 Agalinis gattingeri (Gerardia) rough-stemmed gerardia Orobanchaceae 7 5 Agalinis tenuifolia (Gerardia, A. tenuifolia var. common gerardia Orobanchaceae 4 -3 macrophylla) Ageratina altissima var. altissima (Eupatorium rugosum) white snakeroot Asteraceae/Eupatorieae 2 3 Agrimonia parviflora swamp agrimony Rosaceae 5 -1 Agrimonia pubescens downy agrimony Rosaceae 4 5 Agrimonia rostellata woodland agrimony Rosaceae 4 3 Agrostis elliottiana awned bent grass Poaceae/Aveneae 3 5 * Agrostis gigantea redtop Poaceae/Aveneae 0 -3 Agrostis perennans upland bent Poaceae/Aveneae 3 1 Allium canadense var.
    [Show full text]
  • Household and Personal Uses
    Glime, J. M. 2017. Household and Personal Uses. Chapt. 1-1. In: Glime, J. M. Bryophyte Ecology. Volume 5. Uses. Ebook sponsored 1-1-1 by Michigan Technological University and the International Association of Bryologists. Last updated 5 October 2017 and available at <http://digitalcommons.mtu.edu/bryophyte-ecology/>. CHAPTER 1 HOUSEHOLD AND PERSONAL USES TABLE OF CONTENTS Household Uses...................................................................................................................................................1-1-2 Furnishings...................................................................................................................................................1-1-4 Padding and Absorption...............................................................................................................................1-1-5 Mattresses.............................................................................................................................................1-1-6 Shower Mat...........................................................................................................................................1-1-7 Urinal Absorption.................................................................................................................................1-1-8 Cleaning.......................................................................................................................................................1-1-8 Brushes and Brooms.............................................................................................................................1-1-8
    [Show full text]
  • Addendum to the Guide to the Natural Communities of the Delaware Estuary
    ADDENDUM TO THE UIDE TO THE ATURAL OMMUNITIES G N C OF THE DELAWARE ESTUARY SEPTEMBER0 2009 Citation: Largay, E. and L. Sneddon. 2009. Addendum to the Guide to the Ecological Systems and Vegetation Communities of the Delaware Estuary. NatureServe. Arlington, Virginia. Partnership for the Delaware Estuary, Report #09-XX. 112 pp. PDE Report No. 09-XX Copyright © 2009 NatureServe COVER PHOTOS Top L: Overwash Dunes, photo from Delaware Natural Heritage Program Top R: Coastal Plain Muck Pondshore, photo by Kathleen Strakosch Walz, New Jersey Natural Heritage Program Bottom L: Dry Oak Hickory Forest, photo by Tony Davis, Pennsylvania Natural Heritage Program Bottom R: Inland Dune and Ridge Forest/Woodland, Kathleen Strakosch Walz, New Jersey Natural Heritage Program ADDENDUM TO THE GUIDE TO THE NATURAL COMMUNITIES OF THE DELAWARE ESTUARY Ery Largay Lesley Sneddon September 2009 Acknowledgements: This work was made possible through funding from the Delaware Estuary Program (EPA 320 Funding). Kristin Snow and Mary Russo from NatureServe provided essential data management services to develop this report and report format. Robert Coxe and Bill McAvoy from the Delaware Natural Heritage Program, Kathleen Strakosch Walz from the New Jersey Natural Heritage Program, Tony Davis from the Pennsylvania Natural Heritage Program, Linda Kelly and Karl Anderson, independent botanists, provided ecological expertise, energy and insight. Mark Anderson and Charles Ferree from The Nature Conservancy developed ecological systems maps to accompany this work. Danielle Kreeger, Laura Whalen, and Martha-Maxwell Doyle from the Partnership for the Delaware Estuary provided support and guidance throughout this project. We thank everyone who helped us with this effort.
    [Show full text]
  • Cytotoxic and Antiviral Compounds from Bryophytes and Inedible Fungi
    Journal of Pre-Clinical and Clinical Research, 2013, Vol 7, No 2, 73-85 ORIGINAL ARTICLE www.jpccr.eu Cytotoxic and Antiviral Compounds from Bryophytes and Inedible Fungi Yoshinori Asakawa1, Agnieszka Ludwiczuk1,2, Toshihiro Hashimoto1 1 Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, Japan 2 Department of Pharmacognosy with Medicinal Plants Laboratory, Medical University of Lublin, Poland Asakawa Y, Ludwiczuk A, Hashimoto T. Cytotoxic and Antiviral Compounds from Bryophytes and Inedible Fungi. J Pre-Clin Clin Res. 2013; 7(2): 73–85. Abstract Over several hundred new compounds have been isolated from the bryophytes and more than 40 new carbon skeletal terpenoids and aromatic compounds found in this class. Most of liverworts elaborate characteristic odiferous, pungent and bitter tasting compounds many of which show, antimicrobial, antifungal, antiviral, allergenic contact dermatitis, cytotoxic, insecticidal, anti-HIV, superoxide anion radical release, plant growth regulatory, neurotrophic, NO production inhibitory, muscle relaxing, antiobesity, piscicidal and nematocidal activity. Several inedible mushrooms produce spider female pheromones, strong antioxidant, or cytotoxic compounds. The present paper concerns with the isolation of terpenoids, aromatic compounds and acetogenins from several bryophytes and inedible fungi and their cytotoxic and antiviral activity. Key words bryophytes, inedible fungi, terpenoids, bis-bibenzyls; cytotoxicity, antiviral activity 1. CHEMIcaL CONSTITUENTS OF BRYOPHYTES 1.1 Introduction The bryophytes are found everywhere in the world except in the sea. They grow on wet soil or rock, the trunk of trees, in lake, river and even in Antarctic island. The bryophytes are placed taxonomically between algae (Fig. 1) and pteridophytes (Fig. 2); there are approximately 24,000 species in the world.
    [Show full text]
  • Volume 1, Chapter 7-4A: Water Relations: Leaf Strategies-Structural
    Glime, J. M. 2017. Water Relations: Leaf Strategies – Structural. Chapt. 7-4a. In: Glime, J. M. Bryophyte Ecology. Volume 1. 7-4a-1 Physiological Ecology. Ebook sponsored by Michigan Technological University and the International Association of Bryologists. Last updated 17 July 2020 and available at <http://digitalcommons.mtu.edu/bryophyte-ecology/>. CHAPTER 7-4a WATER RELATIONS: LEAF STRATEGIES – STRUCTURAL TABLE OF CONTENTS Overlapping Leaves .......................................................................................................................................... 7-4a-4 Leaves Curving or Twisting upon Drying ......................................................................................................... 7-4a-5 Thickened Leaf.................................................................................................................................................. 7-4a-5 Concave Leaves ................................................................................................................................................ 7-4a-7 Cucullate Leaves ............................................................................................................................................. 7-4a-10 Plications ......................................................................................................................................................... 7-4a-10 Revolute and Involute Margins ......................................................................................................................
    [Show full text]
  • 8. POLYTRICHACEAE Schwägrichen
    8. POLYTRICHACEAE Schwägrichen Gary L. Smith Merrill Plants small, medium to large, densely to loosely caespitose or scattered among other bryophytes, rarely with individual plants scattered on a persistent protonema. Stems erect, acrocarpous, from a ± developed underground rhizome, simple or rarely branched, bracteate proximally, grading gradually or abruptly to mature leaves. Leaves various, with a chartaceous, sheathing base and a divergent, firm-textured blade (polytrichoid), or the whole leaf membranous and sheath not or weakly differentiated, the blade rarely transversely undulate, crisped and contorted when dry; adaxial surface of blade with numerous closely packed longitudinal photosynthetic lamellae across most of the blade, the marginal lamina narrow, or the lamellae restricted to the costa, flanked by a broad, 1 (rarely 2)-stratose lamina, rarely with abaxial lamellae; margins 1(–3)-stratose, entire, denticulate, serrate, or toothed (in Atrichum bordered by linear, thick- walled cells); costa narrow in basal portion, in the blade abruptly broadened and diffuse, smooth or toothed adaxially, rarely with abaxial lamellae, in cross section with a prominent arc of large diameter guide cells and an abaxial stereid band; lamellae entire, finely serrulate, crenulate, or coarsely serrate, the free margin smooth or cuticular-papillose, the marginal cells in cross-section undifferentiated or sharply distinct in size and/or shape from those beneath; transition in areolation from sheath to blade gradual or abrupt, with “hinge-tissue” at the shoulders (except Atrichum and Psilopilum); cells of back of costa (or cells of the membranous lamina) typically in longitudinal rows, ± isodiametric to transversely elongate-hexagonal. Vegetative reproduction none, or by proliferation of an underground rhizome.
    [Show full text]
  • Conservation Assessment for Creeping Snowberry (Gaultheria Hispidula)
    Conservation Assessment for Creeping snowberry (Gaultheria hispidula) Photo; Mike Hays USDA Forest Service, Eastern Region Prepared by: Michael Hays, Botanist Allegheny National Forest September 2001 This document is undergoing peer review, comments welcome. This Conservation Assessment was prepared to compile the published and unpublished information on the subject taxon or community; or this document was prepared by another organization and provides information to serve as a Conservation Assessment for the Eastern Region of the Forest Service. It does not represent a management decision by the U.S. Forest Service. Though the best scientific information available was used and subject experts were consulted in preparation of this document, it is expected that new information will arise. In the spirit of continuous learning and adaptive management, if you have information that will assist in conserving the subject taxon, please contact the Eastern Region of the Forest Service Threatened and Endangered Species Program at 310 Wisconsin Avenue, Suite 580 Milwaukee, Wisconsin 53203. TABLE OF CONTENTS LIST OF FIGURES .......................................................................................................... 1 SUMMARY ....................................................................................................................... 2 INTRODUCTION/OBJECTIVES .................................................................................. 2 NOMENCLATURE AND TAXONOMY......................................................................
    [Show full text]
  • Fungal Biomass Associated with the Phyllosphere of Bryophytes and Vascular Plants
    mycological research 113 (2009) 1254–1260 journal homepage: www.elsevier.com/locate/mycres Fungal biomass associated with the phyllosphere of bryophytes and vascular plants M. L. DAVEYa,b,*, L. NYBAKKENa,1, H. KAUSERUDb, M. OHLSONa aDepartment of Ecology and Natural Resource Management, Norwegian University of Life Sciences, PO Box 5003, 1432 A˚ s, Norway bMicrobial Evolution Research Group, Department of Biology, University of Oslo, PO Box 1066, Blindern, N-0316 Oslo, Norway article info abstract Article history: Little is known about the amount of fungal biomass in the phyllosphere of bryophytes Received 24 April 2009 compared to higher plants. In this study, fungal biomass associated with the phyllosphere Received in revised form of three bryophytes (Hylocomium splendens, Pleurozium schreberi, Polytrichum commune) and 31 July 2009 three vascular plants (Avenella flexuosa, Gymnocarpium dryopteris, Vaccinium myrtillus) was Accepted 4 August 2009 investigated using ergosterol content as a proxy for fungal biomass. Phyllosphere fungi ac- Available online 12 August 2009 counted for 0.2–4.0 % of the dry mass of moss gametophytes, representing the first estima- Corresponding Editor: tion of fungal biomass associated with bryophytes. Significantly more fungal biomass was John W. G. Cairney associated with the phyllosphere of bryophytes than co-occurring vascular plants. The er- gosterol present in moss gametophytic tissues differed significantly between species, while Keywords: the ergosterol present in vascular plant leaf tissues did not. The photosynthetic tissues of Bryophytes mosses had less associated fungal biomass than their senescent tissues, and the magni- Endophytes tude of this difference varied in a species-specific manner. The fungal biomass associated Epiphytes with the vascular plants studied varied significantly between localities, while that of Ergosterol mosses did not.
    [Show full text]
  • Water Transport and Gas Exchange in the Non-Vascular Plant Dendroligotrichum Dendroides (Brid
    Gayana Bot. 68(1): 89-92, 2011. Comunicación breve ISSN 0016-5301 Water transport and gas exchange in the non-vascular plant Dendroligotrichum dendroides (Brid. ex Hedw.) Broth. (Polytrichaceae, Bryophyta) Transporte de agua e intercambio de gases en la planta no vascular Dendroligotrichum dendroides (Brid. ex Hedw.) Broth. (Polytrichaceae, Bryophyta) CRISTIAN ATALA Laboratorio de Anatomía Funcional de Plantas, Departamento de Ciencia y Tecnología Vegetal (DCTV), Universidad de Concepción Campus Los Ángeles, Juan Antonio Coloma 0201, Los Ángeles, Chile. [email protected] RESUMEN Se midió la conductancia hidráulica específi ca (Ks) y el intercambio de gases en individuos de D. dendroides (Polytrichaceae, Musci). Ks fue más alta que en algunas coníferas y comparable con algunas angiospermas leñosas, pero la fotosíntesis (Amax) fue relativamente baja. Los resultados muestran que una planta no vascular puede alcanzar altos valores de Ks, sugiriendo un funcionamiento “vascular” similar a las traqueófi tas. INTRODUCTION Mosses are non-vascular plants, generally short, and lacking There is a positive relationship between hydraulic specialized vascular tissue. They are poikilohydric, meaning conductance and carbon gain (Meinzer & Grantz 1990, they are strongly dependent on environmental moisture Sperry & Pockman 1993, Hubbard et al. 2001). The (Proctor 1981). Mosses belonging to the Polytrichaceae photosynthesis rate in some mosses is lower than in most present a conductive tissue analogous to xylem, and some vascular plants (Brodribb et al. 2007), with the exception species can reach 60 cm to ca. 1 m height. Several species of of Polytrichum commune Hedw. that reach values similar to the Polytrichaceae have been studied regarding the anatomy gimnosperms (Brodribb et al.
    [Show full text]
  • Conservation Assessment for Schistostega Pennata (Hedw.) Web. & Mohr
    Conservation Assessment For Schistostega pennata (Hedw.) Web. & Mohr. P hoto by M. Hutten October 27, 2005 Judith A. Harpel Ph.D. and Richard Helliwell USDA Forest Service, Region 6 and USDI Bureau of Land Management, Oregon and Washington Updated by Camille Duncan in February 2010 (Update added Appendix 2: Photos) 1 Disclaimer This Conservation Assessment was prepared to compile the published and unpublished information on the Schistostega pennata. It does not represent a management decision by the U.S. Forest Service or Bureau of Land Management. Though the best scientific information available was used and subject experts were consulted in preparation of this document, it is expected that new information will arise. In the spirit of continuous learning and adaptive management, if you have information that will assist in conserving the subject taxon, please contact the interagency Special Status/Sensitive Species Conservation Planning Coordinator in the Portland, Oregon Forest Service/Bureau of Land Management Offices via the website www.or.blm.gov/isssp/. 2 Executive Summary Species and Taxonomic Group Schistostega pennata (Hedw.) Web. & Mohr., Bryophyte Management Status Schistostega pennata is listed as Sensitive on the Region 6 U.S. Forest Service (R6) Sensitive Species List, and is considered a Bureau Assessment species in Oregon by the Oregon-Washington Bureau of Land Management (http://www.or.blm.gov/isssp/). In Oregon this species is ranked as S2, List 2 by the Oregon Natural Heritage Program (http://oregonstate.edu/ornhic/data/nonvasc.html) and is ranked as S2 by the Washington Natural Heritage Program (htt://www.dnr.wa.gov/nhp/refdesk/lists/plantrnk.html).
    [Show full text]