DOCSLIB.ORG

Gametogenesis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gametogenesis Glime, J. M. 2017. Ecophysiology of Development: Gametogenesis. Chapt. 5-8. In: Glime, J. M. Bryophyte Ecology. Volume 1. 5-8-1 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 5-8 ECOPHYSIOLOGY OF DEVELOPMENT: GAMETOGENESIS TABLE OF CONTENTS Definition ............................................................................................................................................................ 5-8-2 Developmental Stages ......................................................................................................................................... 5-8-2 Environmental Factors ........................................................................................................................................ 5-8-2 Water Availability ........................................................................................................................................ 5-8-2 Gametangium Developmental Need for Water ..................................................................................... 5-8-3 Swimming Sperm ................................................................................................................................. 5-8-3 Paraphyses ............................................................................................................................................ 5-8-6 Photoperiod and Light Intensity ................................................................................................................... 5-8-6 Nutrients ..................................................................................................................................................... 5-8-12 pH............................................................................................................................................................... 5-8-14 Temperature ............................................................................................................................................... 5-8-15 Environmental Signalling Interactions ....................................................................................................... 5-8-15 Hormones .......................................................................................................................................................... 5-8-16 Environmental Hormone Interactions ........................................................................................................ 5-8-17 Sugars ................................................................................................................................................................ 5-8-17 Overall Physiology ............................................................................................................................................ 5-8-17 Color Changes ................................................................................................................................................... 5-8-18 Delay of Gametogenesis.................................................................................................................................... 5-8-18 Male vs Female ................................................................................................................................................. 5-8-19 Differential Survival .................................................................................................................................. 5-8-20 Bisexual Gametangial Differentiation ........................................................................................................ 5-8-21 Hormonal Regulation of Gender ................................................................................................................ 5-8-21 Dwarf Males ............................................................................................................................................... 5-8-22 Different Controls ...................................................................................................................................... 5-8-22 Numbers of Gametangia ............................................................................................................................ 5-8-24 Gender Recognition .......................................................................................................................................... 5-8-24 Fertilization ....................................................................................................................................................... 5-8-25 Self-incompatibility ................................................................................................................................... 5-8-25 Geographic and Habitat Relationships .............................................................................................................. 5-8-27 Tradeoffs – Cost of Reproduction ..................................................................................................................... 5-8-30 Summary ........................................................................................................................................................... 5-8-31 Acknowledgments ............................................................................................................................................. 5-8-32 Literature Cited ................................................................................................................................................. 5-8-32 5-8-2 Ecophysiology of Development: Gametogenesis CHAPTER 5-8 ECOPHYSIOLOGY OF DEVELOPMENT: GAMETOGENESIS Figure 1. Antheridial splash cups of Polytrichum juniperinum. Photo by Janice Glime. Definition Gametogenesis – the development of gametes (genesis stages, it produces a stalk, then the two-sided apical cell means origin) is the essential process leading to sexual gains a third cutting face and the archegonium develops reproduction. In bryophytes, gametes are produced by from this cell. The antheridial development is similar to mitotic division of tissue within multicellular structures, the that of other mosses. This chapter will examine the antheridia (male) and archegonia (female), collectively interaction of hormones and the environment as they known as gametangia. The location of these structures on influence this development. the mosses is the basis for dividing the mosses into two large groups, the acrocarpous mosses that produce Environmental Factors archegonia at the tips of upright stems, and the The timing of the induction of gametangia is a critical pleurocarpous mosses that produce archegonia on side function in the life cycle of bryophytes. For sexual branches of a generally horizontal stem. The differences in reproduction to be successful, gametangia must form at a location of these archegonia can present differences in the time when they can survive and they must mature at a time ease with which the sperm can reach the archegonium, and when it is safe and sufficient water is present for the sperm hence reach the egg. to reach the egg. This timing is controlled by external Developmental Stages signals in the environment, and this is interpreted internally through such controls as hormones and nutrient levels. Lal and Bhandari (1968) described the developmental stages of the sex organs of the moss Physcomitrium Water Availability carpathicum. The archegonium begins its development in Gametogenesis (development of gametes) must be a manner similar to that of the antheridium. In these early timed in such a way as to take advantage of the most Chapter 5-8: Ecophysiology of Development: Gametogenesis 5-8-3 critical need in fertilization – water. Because sperm in Sphagnum (Figure 4) provides a good example of bryophytes must swim to the archegonium, adequate water effect of water on gametangial maturation. Sundberg is critical, but too much water or rapidly flowing water may (2002) studied nine sites in Sweden for six years, during dilute or carry off the sperm and make directional which the nine most abundant species produced capsules. movement toward the archegonium all but impossible. In Capsule production related most to moisture regime of the fact, timing of moss reproduction, whether a response to previous summer, with more precipitation resulting in more day length or temperature or other environmental stimulus, capsules. This presumably relates to success of is often related to the season of proper moisture. Since gametangial formation. Capsule success in wetter pits gametangial initiation can occur several (or many) months related positively to spring precipitation in the same year as prior to the actual time of fertilization, environmental cues capsule production, suggesting it was also important for other than moisture must trigger the process. It is therefore fertilization success. Further discussion of timing of an expected consequence that different species within a reproduction with moisture availability is in the phenology genus respond to different environmental cues for chapter. gametogenesis, permitting them to live in different habitats. And even within species, populations can differ widely (Clarke & Greene 1970). But for many bryophytes, water is an important signal for gemetangia to develop, perhaps because it permits the gametophyte to be active and
Load more

Recommended publications
  • Fungi-Rhizopus
    Characters of Fungi Some of the most important characters of fungi are as follows: 1. Occurrence 2. Thallus organization 3. Different forms of mycelium 4. Cell structure 5. Nutrition 6. Heterothallism and Homothallism 7. Reproduction 8. Classification of Fungi. 1. Occurrence: Fungi are cosmopolitan and occur in air, water soil and on plants and animals. They prefer to grow in warm and humid places. Hence, we keep food in the refrigerator to prevent bacterial and fungal infestation. 2. Thallus organization: Except some unicellular forms (e.g. yeasts, Synchytrium), the fungal body is a thallus called mycelium. The mycelium is an interwoven mass of thread-like hyphae (Sing, hypha). Hyphae may be septate (with cross wall) and aseptate (without cross wall). Some fungi are dimorphic that found as both unicellular and mycelial forms e.g. Candida albicans. 3. Different forms of mycelium: (a) Plectenchyma (fungal tissue): In a fungal mycelium, hyphae organized loosely or compactly woven to form a tissue called plectenchyma. It is two types: i. Prosenchyma or Prosoplectenchyma: In these fungal tissue hyphae are loosely interwoven lying more or less parallel to each other. ii. Pseudoparenchyma or paraplectenchyma: In these fungal tissue hyphae are compactly interwoven looking like a parenchyma in cross-section. (b) Sclerotia (Gr. Skleros=haid): These are hard dormant bodies consist of compact hyphae protected by external thickened hyphae. Each Sclerotium germinates into a mycelium, on return of favourable condition, e.g., Penicillium. (c) Rhizomorphs: They are root-like compactly interwoven hyphae with distinct growing tip. They help in absorption and perennation (to tide over the unfavourable periods), e.g., Armillaria mellea.
    [Show full text]
  • Checklist of the Liverworts and Hornworts of the Interior Highlands of North America in Arkansas, Illinois, Missouri and Oklahoma
    Checklist of the Liverworts and Hornworts of the Interior Highlands of North America In Arkansas, Illinois, Missouri and Oklahoma Stephen L. Timme T. M. Sperry Herbarium ‐ Biology Pittsburg State University Pittsburg, Kansas 66762 and 3 Bowness Lane Bella Vista, AR 72714 [email protected] Paul Redfearn, Jr. 5238 Downey Ave. Independence, MO 64055 Introduction Since the last publication of a checklist of liverworts and hornworts of the Interior Highlands (1997)), many new county and state records have been reported. To make the checklist useful, it was necessary to update it since its last posting. The map of the Interior Highlands of North America that appears in Redfearn (1983) does not include the very southeast corner of Kansas. However, the Springfield Plateau encompasses some 88 square kilometers of this corner of the state and includes limestone and some sandstone and shale outcrops. The vegetation is typical Ozarkian flora, dominated by oak and hickory. This checklist includes liverworts and hornworts collected from Cherokee County, Kansas. Most of what is known for the area is the result of collections by R. McGregor published in 1955. The majority of his collections are deposited in the herbarium at the New York Botanical Garden (NY). This checklist only includes the region defined as the Interior Highlands of North America. This includes the Springfield Plateau, Salem Plateau, St. Francois Mountains, Boston Mountains, Arkansas Valley, Ouachita Mountains and Ozark Hills. It encompasses much of southern Missouri south of the Missouri River, southwest Illinois; most of Arkansas except the Mississippi Lowlands and the Coastal Plain, the extreme southeastern corner of Kansas, and eastern Oklahoma (Fig.
    [Show full text]
  • Classifications of Fungi
    Chapter 24 | Fungi 675 Sexual Reproduction Sexual reproduction introduces genetic variation into a population of fungi. In fungi, sexual reproduction often occurs in response to adverse environmental conditions. During sexual reproduction, two mating types are produced. When both mating types are present in the same mycelium, it is called homothallic, or self-fertile. Heterothallic mycelia require two different, but compatible, mycelia to reproduce sexually. Although there are many variations in fungal sexual reproduction, all include the following three stages (Figure 24.8). First, during plasmogamy (literally, “marriage or union of cytoplasm”), two haploid cells fuse, leading to a dikaryotic stage where two haploid nuclei coexist in a single cell. During karyogamy (“nuclear marriage”), the haploid nuclei fuse to form a diploid zygote nucleus. Finally, meiosis takes place in the gametangia (singular, gametangium) organs, in which gametes of different mating types are generated. At this stage, spores are disseminated into the environment. Review the characteristics of fungi by visiting this interactive site (http://openstaxcollege.org/l/ fungi_kingdom) from Wisconsin-online. 24.2 | Classifications of Fungi By the end of this section, you will be able to do the following: • Identify fungi and place them into the five major phyla according to current classification • Describe each phylum in terms of major representative species and patterns of reproduction The kingdom Fungi contains five major phyla that were established according to their mode of sexual reproduction or using molecular data. Polyphyletic, unrelated fungi that reproduce without a sexual cycle, were once placed for convenience in a sixth group, the Deuteromycota, called a “form phylum,” because superficially they appeared to be similar.
    [Show full text]
  • The Gemma of （Marchantiaceae, Marchantiophyta）
    蘚苔類研究（Bryol. Res.） 12（1）: 1‒5, July 2019 The gemma of Marchantia pinnata （Marchantiaceae, Marchantiophyta） Tian-Xiong Zheng and Masaki Shimamura Laboratory of Plant Taxonomy and Ecology, Graduate School of Integrated Sciences for Life, Hiroshima University, 1‒3‒1 Kagamiyama, Higashihiroshima-shi, Hiroshima 739‒8526, Japan Abstract. The novel morphology of gemma in Marchantia pinnata Steph., an endemic species to east Asia, is reported for the first time. The outer shape of gemma is gourd-like with maximum width ca. 250 µm and length ca. 350 µm. The surface is not smooth due to the swelling of the cells. The margin of gemmae is never entire due to mammillose and with several papillae on marginal cells. The two apical notches have no mucilage hairs. These morphologies are widely different from those of a com- mon species, M. polymorpha subsp. ruderalis with larger and nearly circular in outer shape, entire margin and mucilage hairs in notches. Morphological characters of gemmae might be useful for the identification of Marchantia species. Key words: Marchantiaceae, Marchantia pinnata, gemma, mucilage hair 鄭天雄・嶋村正樹：ヒトデゼニゴケの無性芽（〒739‒8526 広島県東広島市鏡山1‒3‒1 広島大学大学院 統合生命科学研究科 植物分類・生態学研究室） 東アジア固有種であるヒトデゼニゴケ Marchantia pinnata Steph. の無性芽の形態について報告する． ヒトデゼニゴケの無性芽は，ひょうたん型の外形を持ち，長さと幅の最大値はそれぞれ350 µm，250 µm 程度，二つのノッチには粘液毛がない．また，無性芽の縁の細胞は円錐状のマミラを持ち，パピラが散 在する．これらの形態は，ほぼ円形でより大きな外形を持ち，縁が全縁，ノッチに粘液毛を有するゼニ ゴケの無性芽とは明らかに異なる．ゼニゴケ属における無性芽の形態の多様性は，種を識別するための 有用な形質として扱えるかもしれない． gemmae is multicellular discoid structure with two Introduction laterally placed apical notches. The central part is several cells thick and becomes gradually thinner to- The asexual reproduction propagule, organ gem- ward the unistratose margin（Shimamura 2016）. mae shows the high morphological diversity for each Marchantia pinnana Steph., an endemic species of taxon of liverworts.
    [Show full text]
  • From Southern Africa. 1. the Genus Dumortiera and D. Hirsuta; the Genus Lunularia and L
    Bothalia 23,1: 4 9 -5 7 (1993) Studies in the Marchantiales (Hepaticae) from southern Africa. 1. The genus Dumortiera and D. hirsuta; the genus Lunularia and L. cruciata S.M. PEROLD* Keywords: Dumortiera, D. hirsuta, Dumortieroideae, Hepaticae, Lunularia, L cruciata. Lunulariaceae, Marchantiaceae, Marchantiales, taxonomy, southern Africa, Wiesnerellaceae ABSTRACT The genera Dumortiera (Dumortieroideae, Marchantiaceae) and Lunularia (Lunulariaceae), are briefly discussed. Each genus is represented in southern Africa by only one subcosmopolitan species, D. hirsuta (Swartz) Nees and L. cruciata (L.) Dum. ex Lindberg respectively. UITTREKSEL Die genusse Dumortiera (Dumortieroideae, Marchantiaceae) en Lunularia (Lunulariaceae) word kortliks bespreek. In suidelike Afrika word elke genus verteenwoordig deur slegs een halfkosmopolitiese spesie, D. hirsuta (Swartz) Nees en L. cruciata (L.) Dum. ex Lindberg onderskeidelik. DUMORTIERA Nees Monoicous or dioicous. Antheridia sunken in subses­ sile disciform receptacles, which are fringed with bristles Dumortiera Nees ab Esenbeck in Reinwardt, Blume and borne singly at apex of thallus on short bifurrowed & Nees ab Esenbeck, Hepaticae Javanicae, Nova Acta stalk. Archegonia in groups of 8—16 in saccate, fleshy Academiae Caesareae Leopoldina-Carolinae Germanicae involucres, on lower surface of 6—8-lobed disciform Naturae Curiosorum XII: 410 (1824); Gottsche et al.: 542 receptacle with marginal sinuses dorsally, raised on stalk (1846); Schiffner: 35 (1893); Stephani: 222 (1899); Sim: with two rhizoidal furrows; after fertilization and 25 (1926); Muller: 394 (1951-1958); S. Amell: 52 (1963); maturation, each involucre generally containing a single Hassel de Men^ndez: 182 (1963). Type species: Dumor­ sporophyte consisting of foot, seta and capsule; capsule tiera hirsuta (Swartz) Nees. wall unistratose, with annular thickenings, dehiscing irre­ gularly.
    [Show full text]
  • Ordovician Land Plants and Fungi from Douglas Dam, Tennessee
    PROOF The Palaeobotanist 68(2019): 1–33 The Palaeobotanist 68(2019): xxx–xxx 0031–0174/2019 0031–0174/2019 Ordovician land plants and fungi from Douglas Dam, Tennessee GREGORY J. RETALLACK Department of Earth Sciences, University of Oregon, Eugene, OR 97403, USA. *Email: gregr@uoregon. edu (Received 09 September, 2019; revised version accepted 15 December, 2019) ABSTRACT The Palaeobotanist 68(1–2): Retallack GJ 2019. Ordovician land plants and fungi from Douglas Dam, Tennessee. The Palaeobotanist 68(1–2): xxx–xxx. 1–33. Ordovician land plants have long been suspected from indirect evidence of fossil spores, plant fragments, carbon isotopic studies, and paleosols, but now can be visualized from plant compressions in a Middle Ordovician (Darriwilian or 460 Ma) sinkhole at Douglas Dam, Tennessee, U. S. A. Five bryophyte clades and two fungal clades are represented: hornwort (Casterlorum crispum, new form genus and species), liverwort (Cestites mirabilis Caster & Brooks), balloonwort (Janegraya sibylla, new form genus and species), peat moss (Dollyphyton boucotii, new form genus and species), harsh moss (Edwardsiphyton ovatum, new form genus and species), endomycorrhiza (Palaeoglomus strotheri, new species) and lichen (Prototaxites honeggeri, new species). The Douglas Dam Lagerstätte is a benchmark assemblage of early plants and fungi on land. Ordovician plant diversity now supports the idea that life on land had increased terrestrial weathering to induce the Great Ordovician Biodiversification Event in the sea and latest Ordovician (Hirnantian)
    [Show full text]
  • The Use of Dna Barcoding to Address Major Taxonomic Problems for Rare British Bryophytes
    THE USE OF DNA BARCODING TO ADDRESS MAJOR TAXONOMIC PROBLEMS FOR RARE BRITISH BRYOPHYTES FINAL REVISED REPORT FEBRUARY 2013 David Bell David Long Pete Hollingsworth Royal Botanic Garden Edinburgh With major contribution from D.T. Holyoak (Bryum) CONTENTS 1. Executive summary……………………………………………………………… 3 2. Introduction……………………………………………………………………… 4 3. Methods 3.1 Sampling……………………………………………………………….. 6 3.2 DNA extraction & sequencing…………………………………………. 7 3.3 Data analysis…………………………………………………………… 9 4. Results 4.1 Sequencing success…………………………………………………….. 9 4.2 Species accounts 4.2.1 Atrichum angustatum ………………………………………… 10 4.2.2 Barbilophozia kunzeana ………………………………………13 4.2.3 Bryum spp……………………………………………………. 16 4.2.4 Cephaloziella spp…………………………………………….. 26 4.2.5 Ceratodon conicus …………………………………………… 29 4.2.6 Ditrichum cornubicum & D. plumbicola …………………….. 32 4.2.7 Ephemerum cohaerens ……………………………………….. 36 4.2.8 Eurhynchiastrum pulchellum ………………………………… 36 4.2.9 Leiocolea rutheana …………………………………………... 39 4.2.10 Marsupella profunda ……………………………………….. 42 4.2.11 Orthotrichum pallens & O. pumilum ……………………….. 45 4.2.12 Pallavicinia lyellii …………………………………………... 48 4.2.13 Rhytidiadelphus subpinnatus ……………………………….. 49 4.2.14 Riccia bifurca & R. canaliculata ………………………........ 51 4.2.15 Sphaerocarpos texanus ……………………………………... 54 4.2.16 Sphagnum balticum ………………………………………… 57 4.2.17 Thamnobryum angustifolium & T. cataractarum …………... 60 4.2.18 Tortula freibergii …………………………………………… 62 5. Conclusions……………………………………………………………………… 65 6. Dissemination of results…………………………………………………………
    [Show full text]
  • L-Myo-Inositol-1-Phosphate Synthase from Bryophytes: 245 Purification and Characterization of the Enzyme from Lunularia Cruciata (L.) Dum
    2009 BRAZILIAN SOCIETY OF PLANT PHYSIOLOGY DOI 00.0000/S00000-000-0000-0 RESEARCH ARTICLE L- myo-Inositol-1-phosphate synthase from bryophytes: purification and characterization of the enzyme from Lunularia cruciata (L.) Dum. Dhani Raj Chhetri1*, Sachina Yonzone1, Sanjeeta Tamang1 and Asok Kumar Mukherjee2 1 Plant Physiology and Biochemistry Laboratory, Post Graduate Department of Botany, Darjeeling Government College, Darjeeling-734 101, WB, India. 2 Department of Biotechnology, Bengal College of Engineering and Technology Bidhan Nagar, Durgapur-713 212, WB, India. * Corresponding author. Post box No. 79, Darjeeling-H.P.O., Darjeeling-734 101, WB, India; e-mail: [email protected] Received: 07 January 2009; Accepted: 28 October 2009. ABSTRACT L-myo-inositol-1-phosphate synthase (MIPS; EC: 5.5.1.4) catalyzes the conversion of D-glucose-6-phosphate to 1L-myo-inositol- 1-phosphate, the rate limiting step in the biosynthesis of all inositol containing compounds. Myo-inositol and its derivatives are implicated in membrane biogenesis, cell signaling, salinity stress tolerance and a number of other metabolic reactions in different organisms. This enzyme has been reported from a number of bacteria, fungi, plants and animals. In the present study some bryophytes available in the Eastern Himalaya have been screened for free myo-inositol content. It is seen that Bryum coronatum, a bryopsid shows the highest content of free myo-inositol among the species screened. Subsequently , the enzyme MIPS has been partially purified to the tune of about 70 fold with approximately 18% recovery form the reproductive part bearing gametophytes of Lunularia cruciata. The L. cruciata synthase specifically utilized D-glucose-6-phosphate and NAD+ as its substrate and co-factor respectively.
    [Show full text]
  • Of Mount Sibayak North Sumatra, Indonesia Marchantia
    BIOTROPIA Vol. 20 No. 2, 2013: 73 - 80 DOI: 10.11598/btb.2013.20.2.3 THE LIVERWORT GENUS MARCHANTIA (MARCHANTIACEAE) OF MOUNT SIBAYAK NORTH SUMATRA, INDONESIA ETTI SARTINA SIREGAR1,2 , NUNIK S. ARIYANTI 3 , and SRI S.TJITROSOEDIRDJO3,4 1 Plant Biology Graduate Program, Graduate School, Bogor Agricultural University, IPB-Campus Darmaga, Bogor, Indonesia 2University of Sumatra Utara, Medan, Indonesia 3Department of Biology, Faculty of Mathematics and Natural Sciences, Bogor Agricultural University, IPB-Campus Darmaga, Bogor Indonesia 4 SEAMEO BIOTROP, Jl. Raya Tajur km 6, Bogor, Indonesia Received 21 January 2013/Accepted 02 July 2013 ABSTRACT Knowledge on the liverworts (Marchantiophyta) flora of Sumatra is very scanty including that of genusMarchantia (Marchantiaceae). This study was conducted to explore the diversity of Marchantia in Mount Sibayak North Sumatra, Indonesia. Altogether, seven species of Marchantia are found in Mount Sibayak North Sumatra, of which five are previously known (Marchantia acaulis , M. emarginata , M. geminata , M. paleacea , and M. treubii ), while one is as new species record (M. polymorpha ) for Sumatra, and one species has not been identified ( Marchantia sp. ). An identification key to the species of Marchantia from Sumatra is provided. Key words: Liverwort,Marchantia , Marchantiaceae, Mount Sibayak, North Sumatra INTRODUCTION Marchantia L. is one of the largest genera in the liverworts order Marchantiales. This genus is represented by 36 species found in the world (Bischler-Causse 1998). In Indonesia especially Sumatra, the floristic work onMarchantia is still very scarce. Herzog (1943) in his study of liverworts from Sumatra, recorded three species of Marchantia,namely M. emarginata , M. mucilaginosa and M.
    [Show full text]
  • 16. Plants.Pptx
    2/27/11 Class announcements Simulation #3-#5 – Class results 1. Next Friday – HW5. Diffusion homework due. Available at GAE homeworks link 2. Next Friday’s GAE – bring 2 calculators for each circle 4 group. Particles past Concentration gradient = ΔC (Particle number) Δx (Distance of 4 circles) Fick’s First Law of Diffusion Simulation #6 – Class results ΔC area J = -D J Δx Not enough Δx e.g., a membrane data for 80 s J = flux (“diffusion rate”) D = diffusion coefficient ΔC = concentration difference Δx = distance € (Negative sign means down the gradient, but biologists often drop Two (of many) possibilities include: the sign.) 1) t is directly proportional to x (the plot of t vs. x is a straight line) 2) t is directly proportional to x squared (the plot is parabolic) 1 2/27/11 Movement of small diffusible molecules 2 Fick’s Second Law of Diffusion For example, glucose - 2 ∂C ∂ C ( x) = D molecular weight: 180 Da Δ 2 t = t x -6 2 ∂ ∂ diffusion coefficient: 7.0 x 10 cm /sec 2D Einstein’s solution - “time-to-diffuse equation” Distance (Δx) Time (t) Typical Structure 10 nm 100 ns Cell membrane 2 (Δx) 1 µm 1 ms Bacteria € t = 10 µm 100 ms€ Eukaryotic cell HELP ME, 2D 207! 300 µm 1.5 min Sea urchin embryo t = time 1 mm 16.6 min Volvox Δx = mean distance traveled D = diffusion coefficient 2 cm 4.6 days Human heart wall 10 cm 82.7 days Squid giant axon Adapted from www.npl.co.uk/educate-+-explore/beginners-guides-posters/einstein-and-blackboard€ The Evolution of Plants - They Made the Land Green The “easy” life of an aquatic alga • Bathed in nutrients
    [Show full text]
  • Evolution and Networks in Ancient and Widespread Symbioses Between Mucoromycotina and Liverworts
    This is a repository copy of Evolution and networks in ancient and widespread symbioses between Mucoromycotina and liverworts. White Rose Research Online URL for this paper: http://eprints.whiterose.ac.uk/150867/ Version: Published Version Article: Rimington, WR, Pressel, S, Duckett, JG et al. (2 more authors) (2019) Evolution and networks in ancient and widespread symbioses between Mucoromycotina and liverworts. Mycorrhiza, 29 (6). pp. 551-565. ISSN 0940-6360 https://doi.org/10.1007/s00572-019-00918-x Reuse This article is distributed under the terms of the Creative Commons Attribution (CC BY) licence. This licence allows you to distribute, remix, tweak, and build upon the work, even commercially, as long as you credit the authors for the original work. More information and the full terms of the licence here: https://creativecommons.org/licenses/ Takedown If you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing [email protected] including the URL of the record and the reason for the withdrawal request. [email protected] https://eprints.whiterose.ac.uk/ Mycorrhiza (2019) 29:551–565 https://doi.org/10.1007/s00572-019-00918-x ORIGINAL ARTICLE Evolution and networks in ancient and widespread symbioses between Mucoromycotina and liverworts William R. Rimington1,2,3 & Silvia Pressel2 & Jeffrey G. Duckett2 & Katie J. Field4 & Martin I. Bidartondo1,3 Received: 29 May 2019 /Accepted: 13 September 2019 /Published online: 13 November 2019 # The Author(s) 2019 Abstract Like the majority of land plants, liverworts regularly form intimate symbioses with arbuscular mycorrhizal fungi (Glomeromycotina).
    [Show full text]
  • Evidence for Equal Size Cell Divisions During Gametogenesis in a Marine Green Alga Monostroma Angicava
    www.nature.com/scientificreports OPEN Evidence for equal size cell divisions during gametogenesis in a marine green alga Monostroma Received: 18 March 2015 Accepted: 03 August 2015 angicava Published: 03 September 2015 Tatsuya Togashi1, Yusuke Horinouchi1, Hironobu Sasaki2 & Jin Yoshimura1,3,4 In cell divisions, relative size of daughter cells should play fundamental roles in gametogenesis and embryogenesis. Differences in gamete size between the two mating types underlie sexual selection. Size of daughter cells is a key factor to regulate cell divisions during cleavage. In cleavage, the form of cell divisions (equal/unequal in size) determines the developmental fate of each blastomere. However, strict validation of the form of cell divisions is rarely demonstrated. We cannot distinguish between equal and unequal cell divisions by analysing only the mean size of daughter cells, because their means can be the same. In contrast, the dispersion of daughter cell size depends on the forms of cell divisions. Based on this, we show that gametogenesis in the marine green alga, Monostroma angicava, exhibits equal size cell divisions. The variance and the mean of gamete size (volume) of each mating type measured agree closely with the prediction from synchronized equal size cell divisions. Gamete size actually takes only discrete values here. This is a key theoretical assumption made to explain the diversified evolution of isogamy and anisogamy in marine green algae. Our results suggest that germ cells adopt equal size cell divisions during gametogenesis. Differences in sperm and egg size are evident in many animals and land plants1. However, variable mat- ing systems are also found in green algal taxa: 1) isogamy, where gamete sizes are identical between the two mating types, 2) slight anisogamy, where the sizes of male and female gametes are slightly different, and 3) marked anisogamy, where their sizes are markedly different2,3.
    [Show full text]