The Origin of Alternation of Generations in Land Plants
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Topic: Apomixis - Definition and Types
Course Teacher: Dr. Rupendra Kumar Jhade, JNKVV, College of Horticulture,Chhindwara(M.P.) B.Sc.(Hons) Horticulture- 1st Year, II Semester 2019-20 Course: Plant Propagation and Nursery Management Lecture No. 12 Topic: Apomixis - Definition and types Apomixis, derived from two Greek word “APO” (away from) and “MIXIS” (act of mixing or mingling). The first discovery of this phenomenon is credited to Leuwen hock as early as 1719 in Citrus seeds. In apomixes, seeds are formed but the embryos develop without fertilization. The genotype of the embryo and resulting plant will be the same as the seed parent. Definition: “The process of development of diploid embryos without fertilization.” Or “Apomixis is a form of asexual reproduction that occurs via seeds, in which embryos develop without fertilization.” Or “Apomixis is a type of reproduction in which sexual organs of related structures take part but seeds are formed without union of gametes.” In some species of plants, an embryo develops from the diploid cells of the seed and not as a result of fertilization between ovule and pollen. This type of reproduction is known as apomixis and the seedlings produced in this manner are known as apomicts. Apomictic seedlings are identical to mother plant and similar to plants raised by other vegetative means, because such plants have the same genetic make-up as that of the mother plant. Such seedlings are completely free from viruses. In apomictic species, sexual reproduction is either suppressed or absent. When sexual reproduction also occurs, the apomixes is termed as facultative apomixis. But when sexual reproduction is absent, it is referred to as obligate apomixis. -
Anders Langangen Charophytes (Charales) from Crete (Greece) Collected in 2010
Fl. Medit. 22: 25-32 doi: 10.7320/FlMedit22.025 Version of Record published online on 28 December 2012 Anders Langangen Charophytes (Charales) from Crete (Greece) collected in 2010 Abstract Langangen, A.: Charophytes (Charales) from Crete (Greece) collected in 2010. — Fl. Medit. 22: 25-32. 2012. — ISSN: 1120-4052 printed, 2240-4538 online. In this article charophytes are reported from the island of Crete, the largest island in Greece. On 9 visited localities, charophytes have been found in six. All localities, except one (loc. 6) are freshwater. Totally six different species were found: Chara aspera, C. connivens, C. corfuen- sis, C. vulgaris, Nitella hyalina and N. tenuissima. The most interesting locality is Lake Kournas which is an eutrophic Chara-lake with rich vegetation of four species: Chara cor- fuensis, C. aspera and the two species of Nitella. Key words: Crete, Greece, Chara aspera, C. connivens, C. corfuensis, C. vulgaris, Nitella hyali- na, N. tenuissima. Introduction The island of Crete is the largest island in Greece and is situated in the southernmost part of the country. I visited several water bodies, lakes, reservoirs and seasonally wet meadows. The localities are listed in Table 1, and of nine, charophytes were found in six. Charophytes have earlier been reported from Crete in several works e.g. Corillion (1957), Koumpli-Sovantzi (1997), Bergmeister & Abrahamczyk (2008). Materials and methods This work is based on material collected in Crete (Greece) in the given localities in 2010 (Fig. 1). The specific conductivity of the water was measured with a Milwaukee, SM 301 EC meter, range 0-1990 µm/cm. -
Biology and Systematics of Heterokont and Haptophyte Algae1
American Journal of Botany 91(10): 1508±1522. 2004. BIOLOGY AND SYSTEMATICS OF HETEROKONT AND HAPTOPHYTE ALGAE1 ROBERT A. ANDERSEN Bigelow Laboratory for Ocean Sciences, P.O. Box 475, West Boothbay Harbor, Maine 04575 USA In this paper, I review what is currently known of phylogenetic relationships of heterokont and haptophyte algae. Heterokont algae are a monophyletic group that is classi®ed into 17 classes and represents a diverse group of marine, freshwater, and terrestrial algae. Classes are distinguished by morphology, chloroplast pigments, ultrastructural features, and gene sequence data. Electron microscopy and molecular biology have contributed signi®cantly to our understanding of their evolutionary relationships, but even today class relationships are poorly understood. Haptophyte algae are a second monophyletic group that consists of two classes of predominately marine phytoplankton. The closest relatives of the haptophytes are currently unknown, but recent evidence indicates they may be part of a large assemblage (chromalveolates) that includes heterokont algae and other stramenopiles, alveolates, and cryptophytes. Heter- okont and haptophyte algae are important primary producers in aquatic habitats, and they are probably the primary carbon source for petroleum products (crude oil, natural gas). Key words: chromalveolate; chromist; chromophyte; ¯agella; phylogeny; stramenopile; tree of life. Heterokont algae are a monophyletic group that includes all (Phaeophyceae) by Linnaeus (1753), and shortly thereafter, photosynthetic organisms with tripartite tubular hairs on the microscopic chrysophytes (currently 5 Oikomonas, Anthophy- mature ¯agellum (discussed later; also see Wetherbee et al., sa) were described by MuÈller (1773, 1786). The history of 1988, for de®nitions of mature and immature ¯agella), as well heterokont algae was recently discussed in detail (Andersen, as some nonphotosynthetic relatives and some that have sec- 2004), and four distinct periods were identi®ed. -
The Analysis of Pinus Pinaster Snrks Reveals Clues of the Evolution of This Family and a New Set of Abiotic Stress Resistance Biomarkers
agronomy Article The Analysis of Pinus pinaster SnRKs Reveals Clues of the Evolution of This Family and a New Set of Abiotic Stress Resistance Biomarkers Francisco Javier Colina * , María Carbó , Ana Álvarez , Luis Valledor * and María Jesús Cañal Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology (IUBA), University of Oviedo, 33006 Oviedo, Spain; [email protected] (M.C.); [email protected] (A.Á.); [email protected] (M.J.C.) * Correspondence: [email protected] (F.J.C.); [email protected] (L.V.) Received: 15 January 2020; Accepted: 17 February 2020; Published: 19 February 2020 Abstract: Climate change is increasing the intensity and incidence of environmental stressors, reducing the biomass yields of forestry species as Pinus pinaster. Selection of new stress-tolerant varieties is thus required. Many genes related to plant stress signaling pathways have proven useful for this purpose with sucrose non-fermenting related kinases (SnRK), conserved across plant evolution and connected to different phosphorylation cascades within ABA- and Ca2+-mediated signaling pathways, as a good example. The modulation of SnRKs and/or the selection of specific SnRK alleles have proven successful strategies to increase plant stress resistance. Despite this, SnRKs have been barely studied in gymnosperms. In this work P. pinaster SnRK sequences (PpiSnRK) were identified through a homology- and domain-based sequence analysis using Arabidopsis SnRK sequences as query. Moreover, PpiSnRKs links to the gymnosperm stress response were modeled out of the known interactions of PpiSnRKs orthologs from other species with different signaling complexity. This approach successfully identified the pine SnRK family and predicted their central role into the gymnosperm stress response, linking them to ABA, Ca2+, sugar/energy and possibly ethylene signaling. -
Do Leaves Need Chlorophyll for Growth?
Do Leaves Need Chlorophyll for Growth? by Kranti Patil, Gurinder Singh and Karen Haydock Homi Bhabha Centre for Science Education VN Purav Marg, Mankhurd Mumbai 400088 India [email protected] Students may read or hear the following sorts of statements in their classrooms: Plants make their food by photosynthesis. Leaves are green because they contain green pigment (chlorophyll). Without chlorophyll photosynthesis cannot occur. If we assume these statements are true, then what do we think if we see a white leaf? We may assume that a white leaf does not contain chlorophyll, and that therefore it cannot make food. So then ... How does a white leaf survive? Students may raise this question when they see a plant such as this variegated variety of bhendi (Talipariti tiliaceum), an ornamental shrub which has some green leaves, some leaves with asymmetric green and white areas, and some leaves which are completely white. A variegated bhendi (Talipariti tiliaceum) shrub - about 2.5 metres high. 1 An activity which is sometimes done in school in order “to prove that chlorophyll is required for photosynthesis” is to take a variegated leaf, remove its green pigment by dissolving it in alcohol, and then show that only the areas which were formerly green test positive for starch. However, this is a rather tedious procedure, and it actually does not prove that chlorophyll is required for photosynthesis, or even that photosynthesis is occurring. It merely indicates that only the green areas contain starch. It may even lead students to ask a question like, “Then why does a potato - which is not green - also contain starch?” Is the potato also doing photosynthesis? We can question whether starch is an indicator of photosynthesis. -
(7) Chrysophyta Golden-Brown Algae
PLANT GROUPS xanthophyta PLANT GROUPS (7) Chrysophyta Golden-brown Algae General characteristic of the Chrysophyta Habitat Aquatic mainly fresh water Pigments Chlorophyll (a & c), β-carotene & Fucoxanthin Food reserve Fat (Leucosin) Cell wall Cellulose, Hemicellulose often with siliceous scales Growth form Flagellate, Coccoid, Colonial rarely filamentous Flagella Two unequal in length & one of them has tripartite hairs Reproduction Asexual, Sexual Chrysophyta, or golden-brown algae, are common microscopic in fresh water. Some species are colorless, but the vast majority is photosynthetic. As such, they are particularly important in lakes, where they may be the primary source of food for zooplankton. They are not considered truly autotrophic by some biologists because nearly all chrysophyta become facultatively heterotrophic in the absence of adequate light, or in the presence of plentiful dissolved food. When this occurs, the chrysoplast atrophies and the alga may turn predator, feeding on bacteria or diatoms. 1 PLANT GROUPS xanthophyta Division Chrysophyta Class Chrysophyceae Order Ochromonadales Family Ochromonadaceae Genus Ochromonas Ochromonas single-celled naked with two unequal flagella cells spherical cylindrical to pyriform. Cells with 1-2 (rarely more) chloroplasts, with or without an eyespot and/or Pyrenoid chloroplasts sometimes much reduced and pale or completely lost after abnormal division. 2 PLANT GROUPS xanthophyta Division Chrysophyta Class Chrysophyceae Family Synuraceae Genus Mallomonas Mallomonas Single-cell, flagellates, -
Ferns of the National Forests in Alaska
Ferns of the National Forests in Alaska United States Forest Service R10-RG-182 Department of Alaska Region June 2010 Agriculture Ferns abound in Alaska’s two national forests, the Chugach and the Tongass, which are situated on the southcentral and southeastern coast respectively. These forests contain myriad habitats where ferns thrive. Most showy are the ferns occupying the forest floor of temperate rainforest habitats. However, ferns grow in nearly all non-forested habitats such as beach meadows, wet meadows, alpine meadows, high alpine, and talus slopes. The cool, wet climate highly influenced by the Pacific Ocean creates ideal growing conditions for ferns. In the past, ferns had been loosely grouped with other spore-bearing vascular plants, often called “fern allies.” Recent genetic studies reveal surprises about the relationships among ferns and fern allies. First, ferns appear to be closely related to horsetails; in fact these plants are now grouped as ferns. Second, plants commonly called fern allies (club-mosses, spike-mosses and quillworts) are not at all related to the ferns. General relationships among members of the plant kingdom are shown in the diagram below. Ferns & Horsetails Flowering Plants Conifers Club-mosses, Spike-mosses & Quillworts Mosses & Liverworts Thirty of the fifty-four ferns and horsetails known to grow in Alaska’s national forests are described and pictured in this brochure. They are arranged in the same order as listed in the fern checklist presented on pages 26 and 27. 2 Midrib Blade Pinnule(s) Frond (leaf) Pinna Petiole (leaf stalk) Parts of a fern frond, northern wood fern (p. -
Prescribed Fire Decreases Lichen and Bryophyte Biomass and Alters Functional Group Composition in Pacific Northwest Prairies Author(S): Lalita M
Prescribed Fire Decreases Lichen and Bryophyte Biomass and Alters Functional Group Composition in Pacific Northwest Prairies Author(s): Lalita M. Calabria, Kate Petersen, Sarah T. Hamman and Robert J. Smith Source: Northwest Science, 90(4):470-483. Published By: Northwest Scientific Association DOI: http://dx.doi.org/10.3955/046.090.0407 URL: http://www.bioone.org/doi/full/10.3955/046.090.0407 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Lalita M. Calabria1, Kate Petersen,The Evergreen State College, 2700 Evergreen Parkway NW, Olympia, Washington 98505 Sarah T. Hamman, The Center for Natural Lands Management, 120 Union Ave SE #215, Olympia, Washington 98501 and Robert J. Smith, Department of Botany and Plant Pathology, 2082 Cordley Hall, Oregon State University, Corvallis, Oregon 97331 Prescribed Fire Decreases Lichen and Bryophyte Biomass and Alters Functional Group Composition in Pacific Northwest Prairies Abstract The reintroduction of fire to Pacific Northwest prairies has been useful for removing non-native shrubs and supporting habitat for fire-adapted plant and animal species. -
Cell Wall Chemistry Roger M
3 Cell Wall Chemistry Roger M. Rowell1,3, Roger Pettersen1, James S. Han1, Jeffrey S. Rowell2, and Mandla A. Tshabalala 1USDA, Forest Service, Forest Products Laboratory, Madison, WI 2Department of Forest Ecology and Management, University of Wisconsin, Madison, WI 3Department of Biological Systems Engineering, University of Wisconsin, Madison, WI CONTENTS 3.1 Carbohydrate Polymers ..........................................................................................................37 3.1.1 Holocellulose ..............................................................................................................37 3.1.2 Cellulose .....................................................................................................................37 3.1.3 Hemicelluloses............................................................................................................39 3.1.3.1 Hardwood Hemicelluloses ..........................................................................41 3.1.3.2 Softwood Hemicelluloses............................................................................42 3.1.4 Other Minor Polysaccharides .....................................................................................43 3.2 Lignin......................................................................................................................................43 3.3 Extractives ..............................................................................................................................45 3.4 Bark.........................................................................................................................................46 -
Bryophyte Life Cycle
MARCH 2016LEARNING | VELD & FLORA ABOUT BIODIVERSITY Veld & Flora MARCHFACTSHEET: 2016 | VELD MOSS & FLORA 24 25 3. BRYOPHYTE LIFE CYCLE Gametophyte (n) UNDERSTANDING THE GERMINATION MALE ALTERNATION OF GENERATIONS The way that almost all land plants reproduce is by means of two distinct, alternating life forms, a sexual phase that produces and releases gametes or sex cells and allows fertilisation, and a dispersal phase – both of which are adaptations to an essentially waterless environment. The sexual phase is known as the GAMETOPHYTE or haploid spores (n) generation and the dispersal phase is the SPOROPHYTE or diploid (2n) generation. Mature gametophyte plants produce haploid sex cells (egg and sperm) in sex organs (the male antheridia and female archegonia). These sex cells (also called gametes) fuse during fertilisation to form a diploid (2n) zygote which COPING OUT OF WATER grows, by means of mitosis (that results in two daughter cells each having Sperm (n) the same number and kind of chromosomes as the parent cell), into a new released Bryophytes, which include moss, are primitive plants that give us some idea sporophyte plant. The diploid sporophyte produces haploid (n) spores (i.e. from male of how the first plants that ventured onto land coped with their new waterless FEMALE each spore has a single set of chromosomes) by means of the process environment. They share many features with other plants, but differ in some of cell division called meiosis. Meiosis results in four daughter cells each ways – such as the lack of an effective vascular system (specialised tissue for with half the number of chromosomes of the parent cell. -
Botany Botany
bottany_dan 2/16/06 2:54 PM Page 13 The NYC Department of Parks & Recreation presents ™ urban park rangers • education program BBOOTTAANNYY Plant Power nce standards accept academic performa ed s meet ogram City Department of Education, including: pr w York ese e Ne A th th Map Reading and Making • Critical Thinking • Plant Identification ct in by ivit ns d Researching and Writing a Field Guide • Graphing • Site Evaluation ies and lesso use and Creating a Timeline • Data Gathering • Natural Science • Measuring Calculating • Social Science • History • Art City of New York City of New York The New York City Parks & Recreation Parks & Recreation Department of Education Urban Park Rangers bottany_dan 2/16/06 2:54 PM Page 2 11 WWhhaatt iiss tthhee NNaattuurraall CCllaassssrroooomm?? The Natural Classroom is a series of educational programs developed by the Urban Park Rangers to immerse students in the living laboratory of the natural world. These programs combine standards-based education with hands-on field lessons taught by Urban Park Rangers. Based on natural and cultural topics that are visibly brought to life in our parks, The Natural Classroom is designed to stimulate, motivate and inspire your students to apply their developing skills in English, Math, Science and History to real-life critical thinking challenges. The activities in Botany: Plant Power! focus on the following skills: • Creating and Reading Graphs, Measuring, and Making Calculations • Exploring Living Science Concepts by creating Field Guides, and Gathering Data in the field Writing and Drawing How to Use This Natural Classroom Program Guide Find Your Level: Level One = Grades K-2 Prepare for Adventure: Review the park visit descrip- Level Two = Grades 2-6 tion a few days before the trip so you will be aware of the Level Three = Grades 6-8 day’s anticipated activities. -
Cell Wall Ribosomes Nucleus Chloroplast Cytoplasm
Cell Wall Ribosomes Nucleus Nickname: Protector Nickname: Protein Maker Nickname: Brain The cell wall is the outer covering of a Plant cell. It is Ribosomes read the recipe from the The nucleus is the largest organelle in a cell. The a strong and stiff and made of DNA and use this recipe to make nucleus directs all activity in the cell. It also controls cellulose. It supports and protects the plant cell by proteins. The nucleus tells the the growth and reproduction of the cell. holding it upright. It ribosomes which proteins to make. In humans, the nucleus contains 46 chromosomes allows water, oxygen and carbon dioxide to pass in out They are found in both plant and which are the instructions for all the activities in your of plant cell. animal cells. In a cell they can be found cell and body. floating around in the cytoplasm or attached to the endoplasmic reticulum. Chloroplast Cytoplasm Endoplasmic Reticulum Nickname: Oven Nickname: Gel Nickname: Highway Chloroplasts are oval structures that that contain a green Cytoplasm is the gel like fluid inside a The endoplasmic reticulum (ER) is the transportation pigment called chlorophyll. This allows plants to make cell. The organelles are floating around in center for the cell. The ER is like the conveyor belt, you their own food through the process of photosynthesis. this fluid. would see at a supermarket, except instead of moving your groceries it moves proteins from one part of the cell Chloroplasts are necessary for photosynthesis, the food to another. The Endoplasmic Reticulum looks like a making process, to occur.