DOCSLIB.ORG

New Insights and Evolutionary Significance of the Megasporangiate Strobilus of Minostrobus Chaohuensis (Lycopsida) from the Upper Devonian of South China

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
New Insights and Evolutionary Significance of the Megasporangiate Strobilus of Minostrobus Chaohuensis (Lycopsida) from the Upper Devonian of South China See discussions, stats, and author profiles for this publication at: http://www.researchgate.net/publication/256850881 New insights and evolutionary significance of the megasporangiate strobilus of Minostrobus chaohuensis (Lycopsida) from the Upper Devonian of South China ARTICLE in REVIEW OF PALAEOBOTANY AND PALYNOLOGY · MARCH 2013 Impact Factor: 1.94 · DOI: 10.1016/j.revpalbo.2012.11.007 CITATIONS READS 4 104 4 AUTHORS, INCLUDING: Meicen Meng Deming Wang Chinese Academy of Geological Sciences Peking University 12 PUBLICATIONS 18 CITATIONS 46 PUBLICATIONS 293 CITATIONS SEE PROFILE SEE PROFILE Jinzhuang Xue Peking University 39 PUBLICATIONS 167 CITATIONS SEE PROFILE Available from: Jinzhuang Xue Retrieved on: 12 October 2015 Review of Palaeobotany and Palynology 190 (2013) 20–40 Contents lists available at SciVerse ScienceDirect Review of Palaeobotany and Palynology journal homepage: www.elsevier.com/locate/revpalbo Research paper New insights and evolutionary significance of the megasporangiate strobilus of Minostrobus chaohuensis (Lycopsida) from the Upper Devonian of South China Meicen Meng, Deming Wang ⁎, Jinzhuang Xue, Xiao Zhu Key Laboratory of Orogenic Belts and Crustal Evolution, Department of Geology, Peking University, No. 5 Yiheyuan Road, Haidian District, Beijing 100871, China article info abstract Article history: Heterosporous lycopsids with monosporangiate strobili are highly diverse in the Carboniferous, but their early Received 16 June 2012 evolution is poorly understood. The Late Devonian Minostrobus chaohuensis was included in this plant group, Received in revised form 3 November 2012 but features of the strobili were unclear in detail. Permineralized material of M. chaohuensis was sectioned and Accepted 5 November 2012 ground in series to reveal details of megasporangiate strobili. The megasporophylls are smooth and borne in a Available online 5 December 2012 2/9 helical phyllotaxy. The megasporophyll consists of a pedicel which bears a keel and alations, lamina and heel. The alations extend horizontally and then bend upward to surround the sporangial base. A single megaspo- Keywords: Isoёtales sensu lato rangium with a subarchesporial pad is inserted onto the sporophyll pedicel through a narrow attachment. Each Lagenicula sporangium contains four Lagenicula-type spiny megaspores that may be of variable size. On the basis of these Late Devonian new fertile traits, M. chaohuensis is assigned to the Isoёtales sensu lato. This plant is proved to be monosporangiate, megasporangiate strobilus and thus Devonian lycopsids are shown for the first time to have possessed megasporangiate strobili. It is confirmed Minostrobus that phylogenetically advanced heterosporous lycopsids with monosporangiate strobili had evolved by the Late monosporangiate-strobilus lycopsid Devonian. The type of alations and size variation of the four megaspores per sporangium indicate that Minostrobus may represent an evolutionary form in transition toward the Carboniferous isoёtaleans with monosporic megasporangia more fully enclosed by alations. Evidence suggests a free megaspore dispersal mechanism in M. chaohuensis. © 2012 Elsevier B.V. All rights reserved. 1. Introduction (Wang et al., 2003b)andMinostrobus (Wang et al., 2012), but further evidence from strobili is required to confirm the monosporangiate As one of the earlier lineages of land plants, the lycopsids nature of the latter two genera. Both groups of heterosporous lycopsids, appeared by the Late Silurian–Early Devonian, and attained maxi- those with bisporangiate or with monosporangiate strobili, usually in mum diversity and significance in the Carboniferous and evolved arborescent habit, were the most conspicuous plants of the Carboniferous till now (Phillips, 1979; Gensel and Andrews, 1984; Stewart and landscape (Taylor et al., 2009). Rothwell, 1993). Heterospory in lycopsids, one of the most impor- Minostrobus chaohuensis was established by Wang (2001), on the tant evolutionary innovations, was first encountered in Middle basis of material from the Upper Devonian–Lower Carboniferous Devonian taxa with bisporangiate strobili (a single strobilus containing Wutung (Wutong) Formation, at Shizikou Section, Chaohu District, both mega- and microspores), i.e., Mixostrobilus Senkevitsch et al. Anhui Province of China. He described the morphological characters (1993) and Yuguangia Hao et al. (2007). Heterosporous lycopsids with of the strobili containing megaspores, and observed the megaspores monosporangiate strobili (separate strobili containing either mega- or and xylem of strobilar axes by scanning electron microscope microspores) are proposed by cladistic analysis to be the most derived (SEM). Recently, Wang et al. (2012) reported the sterile axes, and clade (Bateman, 1992; Bateman et al., 1992; DiMichele and Bateman, megasporangiate and microsporangiate strobili of this plant, from 1996; Xue, 2011). This monosporangiate-strobilus clade is known material collected near the type locality. However, they gave no from only three representatives in the Late Devonian, i.e., Lepidostrobus further description of the megasporangiate strobili. We have since Brongniart (Wang et al., 2003a), Sublepidodendron (Nathorst) Hirmer obtained numerous well-preserved specimens of permineralized megasporangiate strobili from the same formation and district, but from the Fenghuangshan Section. New data allow the megasporangiate strobilus of Minostrobus to be compared with the ⁎ Corresponding author at: Department of Geology, Peking University, No. 5 Yiheyuan strobili of related heterosporous lycopsids of Devonian and Road, Haidian District, Beijing 100871, China. Tel.: +86 10 62761095; fax: +86 10 Carboniferous age, to confirm the systematic position and verify the 62751187. fi E-mail addresses: [email protected] (M. Meng), [email protected] monosporangiate character, to discuss the evolutionary signi cance, (D. Wang), [email protected] (J. Xue), loofl[email protected] (X. Zhu). and to interpret the megaspore dispersal mechanism of Minostrobus. 0034-6667/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.revpalbo.2012.11.007 M. Meng et al. / Review of Palaeobotany and Palynology 190 (2013) 20–40 21 Fig. 1. Map showing fossil localities of Minostrobus chaohuensis. 2. Material and methods for examination under transmitted light. All specimens and slides are housed at Department of Geology, Peking University, China. To describe About 200 specimens were obtained from the Wutong Formation, the strobilus, we adopt the terminology used by Bateman et al. (1992). Fenghuangshan Section in Chaohu City, Anhui Province, South China. This section (31°37′51″Nand117°50′54″E) is located southwest of the Shizikou Section (31°38′08″N and 117°51′08″E) from which 3. Systematics Minostrobus chaohuensis was reported by Wang (2001), and northeast of another section (31°37′42″Nand117°50′43″E) where Wang et al. Class: Lycopsida Pichi-Sermolli 1958. (2012) collected additional material of this plant (Fig. 1). The Wutong Order: Isoёtales sensu lato Meyen 1987. Formation consists of the Guanshan and Leigutai members, in ascend- Suborder: Dichostrobiles DiMichele and Bateman 1996. ing order. According to Hou and Qi (2006), the middle part of the Family: Incertae sedis. Leigutai Member in Chaohu District consists of lower and upper clay Genus: Minostrobus Wang 2001 emend. Wang et al. 2012 emend. layers intercalated with quartz sandstone; these two clay layers are Emended diagnosis: (Emended and additional generic characters characterized by latest Devonian spore and plant assemblage and earli- are in brackets) [Monosporangiate-strobilus lycopsid.] Aerial axes multi- est Carboniferous invertebrate assemblage, respectively. Strobili of dichotomous. Leaf persistent, with single mid-vein. Megasporangiate M. chaohuensis in the current study came from the gray-black mudstone and microsporangiate strobili [possibly] monoecious. Single spherical to of the lower clay layer, and are thus latest Famennian in age. On the elliptical sporangium inserted to adaxial side of sporophyll with smooth basis of stratigraphic data and fossil assemblages provided by Wang margin and pointed apex. [Megasporophylls attached to strobilar axis at (2001) (see his Fig. 2), we suggest that his collection is from the lower approximately right angles, borne in clockwise helix, consisting of pedicel clay layer of the Leigutai Member, at Shizikou Section. Material with alations and keel, heel, and upturned lamina. Megasporangium described in Wang et al. (2012) was from the Leigutai Member and connected to sporophyll by narrow attachment, with sporangial base also dated as Famennian. surrounded by alations. Sporangial wall comprising one layer of columnar Under a dissecting microscope, the strobili were prepared with steel cells. Subarchesporial pad along inner surface of sporangial wall.] Each needles. Two strobili have been permineralized by limonite, others by megasporangium with four [Lagenicula-type megaspores bearing spiny carbonate. Plant tissues and structures (e.g., the leaf epidermis, walls ornamentation]. Axis with solid exarch primary xylem. Protoxylem con- of sporangium and megaspore, and (possible) the outer cortex and vas- fined to ridges at periphery of primary xylem strands. Metaxylem cular xylem of strobilar axis) are preserved as black carbonaceous seg- tracheids bearing Williamson's striations. ments. Permineralized strobili, strobilar axes and clusters of sporangia were embedded in epoxy resin, and sectioned at
Load more

Recommended publications
  • Variation in Sex Expression in Canada Yew (Taxus Canadensis) Author(S): Taber D
    Variation in Sex Expression in Canada Yew (Taxus canadensis) Author(s): Taber D. Allison Source: American Journal of Botany, Vol. 78, No. 4 (Apr., 1991), pp. 569-578 Published by: Botanical Society of America Stable URL: http://www.jstor.org/stable/2445266 . Accessed: 23/08/2011 15:56 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Botanical Society of America is collaborating with JSTOR to digitize, preserve and extend access to American Journal of Botany. http://www.jstor.org AmericanJournal of Botany 78(4): 569-578. 1991. VARIATION IN SEX EXPRESSION IN CANADA YEW (TAXUS CANADENSIS)1 TABER D. ALLISON2 JamesFord Bell Museumof Natural History and Departmentof Ecology and BehavioralBiology, Universityof Minnesota, Minneapolis, Minnesota 55455 Sex expressionwas measuredin severalCanada yew (Taxus canadensisMarsh.) populations of theApostle Islands of Wisconsinand southeasternMinnesota to determinethe extent of variationwithin and among populations. Sex expression was recorded qualitatively (monoecious, male,or female) and quantitatively (by male to female strobilus ratios or standardized phenotypic gender).No discernibletrends in differencesin sex expressionamong populations or habitats wererecorded. Trends in sexexpression of individuals within populations were complex. Small yewstended to be maleor, if monoecious, had female-biasedstrobilus ratios.
    [Show full text]
  • Earliest Record of Megaphylls and Leafy Structures, and Their Initial Diversification
    Review Geology August 2013 Vol.58 No.23: 27842793 doi: 10.1007/s11434-013-5799-x Earliest record of megaphylls and leafy structures, and their initial diversification HAO ShouGang* & XUE JinZhuang Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China Received January 14, 2013; accepted February 26, 2013; published online April 10, 2013 Evolutionary changes in the structure of leaves have had far-reaching effects on the anatomy and physiology of vascular plants, resulting in morphological diversity and species expansion. People have long been interested in the question of the nature of the morphology of early leaves and how they were attained. At least five lineages of euphyllophytes can be recognized among the Early Devonian fossil plants (Pragian age, ca. 410 Ma ago) of South China. Their different leaf precursors or “branch-leaf com- plexes” are believed to foreshadow true megaphylls with different venation patterns and configurations, indicating that multiple origins of megaphylls had occurred by the Early Devonian, much earlier than has previously been recognized. In addition to megaphylls in euphyllophytes, the laminate leaf-like appendages (sporophylls or bracts) occurred independently in several dis- tantly related Early Devonian plant lineages, probably as a response to ecological factors such as high atmospheric CO2 concen- trations. This is a typical example of convergent evolution in early plants. Early Devonian, euphyllophyte, megaphyll, leaf-like appendage, branch-leaf complex Citation: Hao S G, Xue J Z. Earliest record of megaphylls and leafy structures, and their initial diversification. Chin Sci Bull, 2013, 58: 27842793, doi: 10.1007/s11434- 013-5799-x The origin and evolution of leaves in vascular plants was phology and evolutionary diversification of early leaves of one of the most important evolutionary events affecting the basal euphyllophytes remain enigmatic.
    [Show full text]
  • X. the Conifers and Ginkgo
    X. The Conifers and Ginkgo Now we turn our attention to the Coniferales, another great assemblage of seed plants. First let's compare the conifers with the cycads: Cycads Conifers few apical meristems per plant many apical meristems per plant leaves pinnately divided leaves undivided wood manoxylic wood pycnoxylic seeds borne on megaphylls seeds borne on stems We should also remember that these two groups have a lot in common. To begin with, they are both groups of woody seed plants. They are united by a small set of derived features: 1) the basic structure of the stele (a eustele or a sympodium, two words for the same thing) and no leaf gaps 2) the design of the apical meristem (many initials, subtended by a slowly dividing group of cells called the central mother zone) 3) the design of the tracheids (circular-bordered pits with a torus) We have three new seed plant orders to examine this week: A. Cordaitales This is yet another plant group from the coal forest. (Find it on the Peabody mural!) The best-known genus, Cordaites, is a tree with pycnoxylic wood bearing leaves up to about a foot and a half long and four inches wide. In addition, these trees bore sporangia (micro- and mega-) in strobili in the axils of these big leaves. The megasporangia were enclosed in ovules. Look at fossils of leaves and pollen-bearing shoots of Cordaites. The large, many-veined megaphylls are ancestral to modern pine needles; the shoots are ancestral to pollen-bearing strobili of modern conifers. 67 B.
    [Show full text]
  • Seasonal Growth of the Female Strobilus in Pinus Radiata
    No. 1 15 SEASONAL GROWTH OF THE FEMALE STROBILUS IN PINUS RADIATA G. B. SWEET and M. P. BOLLMANN Forest Research Institute, New Zealand Forest Service, Rotorua (Received for publication 12 November, 1970) ABSTRACT Growth of female strobili of Pinus radiata D. Don from central North Island of New Zealand is described and illustrated with photographs. The two-and-a-half year period from strobilus emergence until cone maturity comprises a seasonal period of growth in which pollination occurs, a second period of seasonal growth in which fertilisation occurs, and finally a period of cone maturation. The periods of rapid growth do not appear to result directly from either pollination or fertilisation, and the seasonal growth periods have some similarity to those of vegetative growth. The time taken to reach cone maturity in P. radiata (a closed-cone pine) is six months longer than that frequently described for other species of Pinus. INTRODUCTION The general pattern of female strobilus development in Pinus is well documented (e.g., Ferguson, 1904; Stanley, 1958; Sarvas, 1962). Broadly, a total period of two-and- a-half years is involved, leading through from strobilus determination one summer, to anthesis the following spring, to fertilisation late in the subsequent spring and finally to maturation the succeeding autumn. Seed production in Pinus radiata D. Don apparently follows within general limits the typical pattern for Pinus, but few details have been published either of its strobilus or its ovule development. As part of a comprehensive study of the processes leading to seed production in this species, material was collected in 1968 and 1969 to enable details of strobilus development to be determined.
    [Show full text]
  • Perfectly Ginkgo Is Variability Reproductive Considerable, Only
    Variability of the female reproductive organs in Ginkgo biloba L. by W.K.H. Karstens (Botanical Laboratory, University of Leyden). Introduction. In 1915 Worsdell signed: "The object of botanical investigation, in whatever should be far department, to determine, as as possible, the inter- relationship of the various facts which are accumulated and them arrange and has for accordingly; not merely, as so long been the custom, to pile them in chaotic heap." This is often the facts have been in quite true; only too piled a chaotic This been with heap. has the case investigations on the nature of the both female and in reproductive organs, male, Ginkgo biloba. An extenuating circumstance, however, is the great variability in the afore- said organs; so great a variability indeed that one hesitates to tackle the for fear that it will be still than subject, appear to greater was previously supposed. It is to state perfectly unnecessary once more that Ginkgo is a very remarkable tree, less known is the fact that the variability in the female reproductive organs is very considerable, not only in one plant at one but in relation time moment, to too. It makes a difference, whether a Ginkgo tree is young or old. So great is the variability that quite common variations have been termed "abnormalities". Material. From a number of trees seeds were obtained. In the first place the tree in the Botanic Garden of Leyden has to be mentioned. From this tree planted in 1850, a large number of seeds has been collected in 1940 seeds the by Jonkheer W.
    [Show full text]
  • L14 Ferns & Allies (Lecture Slides)
    3/22/20 I. Intro to "Ferns & Fern Allies" A. Types L14: Ferns & Fern Allies BIOL 153/L Black Hills State Univ. Ramseys 1. Lycophytes 1. Lycophytes short w/ microphylls + strobili; • Club moss: resemble tiny conifers (strobilus = club) gametophytes photosynthetic, or not; oldest vascular lineage • Spike moss: mostly tropical; some from dry places widespread, not diverse Club moss Spike moss 1 3/22/20 2. Ferns many sporophyte forms; heart-shaped gametophyte; frond from rhizome widespread, diverse Ferns 3. Horsetails Horsetails jointed stem with silica; tiny whorled leaves; stems branched or naked Northern Hemisphere, not diverse I. Intro to "Ferns & Fern Allies" Red Algae B. Evolutionary relationships "Green Algae" "Bryophytes" "Ferns Land & Fern Allies" Plants Gymnosperms & Angiosperms 2 3/22/20 Clubmoss I. Intro to "Ferns & Fern Allies" Spike moss C. Dominance of sporophyte Ferns Horsetails largest, most persistent stage is sporophyte I. Intro to "Ferns & Fern Allies" I. Intro to "Ferns & Fern Allies" C. Dominance of sporophyte D. Life in terrestrial environment 1. Adaptations present 1. Adaptations present embryo + stomata vascular tissue + roots embryo + stomata vascular tissue + roots (sporophyte only) (sporophyte only) 2. Adaptations absent wood, pollen, seeds flowers + fruits 3 3/22/20 1. Homosporous vs. heterosporous 1. Homosporous vs. heterosporous homosporous: producing one type of spore homosporous: producing one type of spore gametophyte bisexual gametophyte bisexual heterosporous: producing two types of spores gametophyte male or female II. Structures and terminology 2. Spore vs. microspore/megaspore A. Reproductive spores are produced by.... homosporous plants 2. Spore vs. microspore/megaspore 3. Sporangia and sporophyll spores are produced by.... sporangia: structures in which spores produced homosporous plants microspores and megaspores are produced by..
    [Show full text]
  • Reproductive Morphology of Lycopodium and Selaginella I
    12 Laboratory 6 - Reproductive Morphology of Lycopodium and Selaginella I. Lycopodium A. Morphology of Lycopodium strobili and subgenera 1. Subgenus Huperzia (old Urostachya) Observe herbarium and preserved specimens of the following species of Lycopodium, subgenus Huperzia (ref. Gifford and Foster, p. 123), as available: Lycopodium lucidulum L. selago L. reflexum L. alopecuroides All of these species show strobili which are not compact and merely represent fertile areas of the stem. Arrange these specimens in typological order, if possible, starting with the least specialized strobilar organization and proceeding to the most specialized. What vegetative features do these urostachyoid Lycopodium types have in common? Obtain pickled material of L. lucidulum if fresh strobili are not available. Locate the sporangium, the sporophyll and the shoot apex. Is a ligule present? Obtain and observe a prepared slide of the strobilus of L. lucidulum or L. selago. Describe the shape of the sporangium. Is the sporangium located on a stalk? Is the line of dehiscence obvious? Is it longitudinal or transverse? Carefully remove a single sporophyll from a plant and observe it under the dissecting microscope. Is the morphology of the sporophyll the same as that of a vegetative leaf? Is the phyllotaxis of the sporophylls similar to that of the vegetative leaf? Is the genus Lycopodium heterosporous or homosporous? 2. Subgenera Lycopodium, Diphasiastrum and Lycopodiella (old Rhopalostachya) Observe herbarium and preserved specimens of the following species of Lycopodium as available: L. annotinum L. cernuum L. clavatum L. complanatum L. inundatum L. obscurum L. pachystachyon These species exhibit strobili which are very distinct and not merely fertile, little-differentiated areas of the shoot.
    [Show full text]
  • The Flowering Plants We Come in the End to the Largest of All Vascular
    XI. Magnoliophyta: The Flowering Plants We come in the end to the largest of all vascular plant groups, the flowering plants. There are about 250,000 of them in about 415 families and 59 orders. Three features of flowering plants set them apart from all of the other vascular plants: 1) a folded and sealed leaf called the carpel, which encloses the ovules; 2) a highly reduced female gametophyte, of just eight nuclei in seven cells; and 3) double fertilization, that is the fusion of one sperm with an egg and a second sperm with a neighboring cell of the female gametophyte to yield a nutritive tissue called the endosperm. A. Apical Meristems Angiosperms share an unusual kind of meristem with the Gnetophyta (a group we will mention in lecture, but which won't be examined in lab). This meristem, called the tunica-corpus meristem, is well known to biology students because it figures prominently in introductory biology. However, not many divisions of vascular plants have this type of meristem. 1. Examine the prepared slides of Coleus apical meristems available in the lab. The tunica and corpus are visible at the very summit of the stem (the apical dome), along with the primordia (mounds of tissue destined to be leaves and buds). DIAGRAM the Coleus shoot. Label tunica, corpus, leaf primordia, bud primordia, and leaf trace. B. Variations in Vegetative Features of the Flowering Plants 1. Many different orders of flowering plants include species that are adapted to xeric (dry) environments. At some point during the lab have a look at the following: a.
    [Show full text]
  • The Floral Biology of the Magnoliaceae
    The floral biology of the Magnoliaceae The floral biology of the Magnoliaceae Leonard B. Thien l, Shoichi Kawano2, HiroshiAzuma2, Shane Latimer, Margaret S. DevalP, Sam Rosso4, Stella Elakovichs, Victor Rico Gray and David JobesI The family Magnoliaceae, a well defined group of trees or shrubs, is a component of the order Magnoliales (subclass Magnoliidae) distributed in temperate (four-fifths of the species) and tropical Asia from the Himalayas eastward to Japan and southeastward through the Malay Archipelago to the New Guinea area (see map, Takhtajan 1969; Law 1984). The remainder of ~e family is found in the Americas from temperate North America to Brazil, including the West Indies (Heywood 1978; Treseder 1978). Concepts of the reproductive biology of the family, however, are based primarily on studies of various species of Magnolia located in temperate regions of the world (Heiser 1962; Thien 1974; Yasukawa et aL 1992). The interaction of insects with flowers as pollinators is considered to be one of the major factors in the success and diversification of flowering plants (Stebbins 1981; Baker & Hurd 1968; Crepet & Friis 1987; Regal 1977). Early pollination studies of Magnolia (in European gardens) found beetles to be pollinators (Delphino 1875). Since Coleoptera and magnolias constitute old groups of organisms, the flower of Magnolia became a model of pollination for the "earliest flowering plants" (Eyde 1975; Endress 1990). The "mess and spoil" principle of pollination was applied particularly to beetles tramping around in Magnolia flowers (Faegri & van der PijI 1979). It was thought that "Higher pollinators, like bees, are "ill at eaSe in these large blossoms which have no guide structures (like a sman child in a big bed)", (Faegri & van der PijI1979).
    [Show full text]
  • Chapter 12 Biology of Non-Flowering Plants
    BOT 3015L (Outlaw/Sherdan/Aghoram); Page 1 of 8 Chapter 12 Biology of Non-Flowering Plants Objectives Overview of Non-Flowering Plants. Know the distinguishing characteristics of plants. Know the plant adaptations required for terrestrial life. Know the adaptations for terrestrial life displayed by angiosperms and how they are advantageous. Bryophytes. Distinguish bryophytes from green algae1 and from other plants. Understand the life cycle of Marchantia, a liverwort, and how it compares with the life cycle of higher plants e.g. gymnosperms and angiosperms. Know the structures of the bryophyte gametophyte and sporophyte and understand their function. Know the characteristics of peat moss. Seedless Vascular Plants. Understand the advantages of a vascular system for terrestrial life. Understand the limitations associated with not having a seed. Understand how homosporous and heterosporous life cycles differ. Gymnosperms. Know general features of gymnosperms. Understand the advantages of seeds and pollen for terrestrial life. Know the life cycle of gymnosperms. Understand how the structure of a gymnosperm leaf is adapted for terrestrial habitats. Comparing Angiosperm and Gymnosperm Reproduction. Understand the similarities and differences in reproduction of angiosperms and gymnosperms. Understand the differences in seed formation in gymnosperms and angiosperms. Understand the advantages that each has over the other in terrestrial habitats. Introduction to Non-flowering Plants Several lines of evidence indicate that plants (embryophytes) evolved from green algae. Plants, unlike green algae, are, in general, terrestrial and have evolved adaptations for terrestrial life. Terrestrial plants require adaptations to avoid desiccation, provide mechanical support, transport water and nutrients, transfer “male” gametes, and protect the zygote from desiccation and harsh conditions.
    [Show full text]
  • Factors Affecting the Number of Pollen Grains Per Male Strobilus in Japanese Cedar (Cryptomeria Japonica)
    plants Article Factors Affecting the Number of Pollen Grains per Male Strobilus in Japanese Cedar (Cryptomeria japonica) Hiroyuki Kakui 1 , Eriko Tsurisaki 2, Rei Shibata 2 and Yoshinari Moriguchi 1,* 1 Graduate School of Science and Technology, Niigata University, Niigata City, Niigata 950-2181, Japan; [email protected] 2 Faculty of Agriculture, Niigata University, Niigata City, Niigata 950-2181, Japan; [email protected] (E.T.); [email protected] (R.S.) * Correspondence: [email protected]; Tel.: +81-25-262-6861 Abstract: Japanese cedar (Cryptomeria japonica) is the most important timber species in Japan; however, its pollen is the primary cause of pollinosis in Japan. The total number of pollen grains produced by a single tree is determined by the number of male strobili (male flowers) and the number of pollen grains per male strobilus. While the number of male strobili is a visible and well-investigated trait, little is known about the number of pollen grains per male strobilus. We hypothesized that genetic and environmental factors affect the pollen number per male strobilus and explored the factors that affect pollen production and genetic variation among clones. We counted pollen numbers of 523 male strobili from 26 clones using a cell counter method that we recently developed. Piecewise Structural Equation Modeling (pSEM) revealed that the pollen number is mostly affected by genetic variation, male strobilus weight, and pollen size. Although we collected samples from locations with different environmental conditions, statistical modeling succeeded in predicting pollen numbers for different clones sampled from branches facing different directions.
    [Show full text]
  • Chapter 23: Plant Evolution Invading the Land
    Chapter 23: Plant Evolution Invading the Land • Cyanobacteria were probably the first to spread into and up freshwater streams • Later, green algae and fungi made the journey together • Every plant is descended from species of green algae Setting the Stage for Plants • Earth’s atmosphere was originally oxygen free • Ultraviolet radiation bombarded the surface • Photosynthetic cells produced oxygen and allowed formation of a protective ozone layer The Plant Kingdom • Nearly all are multicelled • Vast majority are photoautotrophs – Energy from sun – Carbon dioxide from air – Minerals dissolved in water Fig. 23-2, p.372 Charophytes Fig. 23-3, p.372 Nonvascular Plants • Bryophytes • Fewer than 19,000 species • Three groups Liverworts Hornworts Mosses Vascular Plants • Majority of plants • Have internal tissues that carry water and solutes • Two groups – Seedless vascular plants – Seed-bearing vascular plants Seedless Vascular Plants • Arose during the Devonian • Produce spores but no seeds • Four main groups Whisk ferns Lycophytes Horsetails Ferns Seedless Vascular Plants Fig. 23-4a, p.372 Seedless Vascular Plants Fig. 23-4b, p.372 Seedless Vascular Plants Fig. 23-4c, p.373 Seed-Bearing Vascular Plants • Gymnosperms arose first – Cycads – Ginkgos – Gnetophytes – Conifers • Angiosperms arose later – Monocots – Dicots Seed- Bearing Vascular Plants Archaeanthus linnenbergeri Fig. 23-4d, p.373 Plant Evolution Gondwana 420 mya 360 mya Bryophytes Origin of Bryophytes diversify. Vast swamp forests; (liverworts) earliest Lycophytes, horsetails, bryophytes, tree-size appear by seedless ferns undergo early lycophytes, horsetails, 475 mya. vascular adaptive radiations. By 360 ferns dominate. origin plants, in mya, seed plants evolve. of conifers late in the Silurian. Carboniferous. Ordovican Silurian Devonian Carboniferous 505 440 410 360 286 Fig.
    [Show full text]