DOCSLIB.ORG

What Human Reproductive Organ Is Functionally Similar to This Seed?

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
What Human Reproductive Organ Is Functionally Similar to This Seed? Fig. 30-1 What human reproductive organ is functionally similar to this seed? Overview: Transforming the World • Seeds changed the course of plant evolution, enabling their bearers to become the dominant producers in most terrestrial ecosystems • A seed consists of an embryo and nutrients surrounded by a protective coat Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-1 What human reproductive organ is functionally similar to this seed? Seeds and pollen grains are key adaptations for life on land • In addition to seeds, the following are common to all seed plants – Reduced gametophytes – Heterospory – Ovules – Pollen Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Advantages of Reduced Gametophytes • The gametophytes of seed plants develop within the walls of spores that are retained within tissues of the parent sporophyte • Protect female gametophyte from UV and desiccation (good for the land life!) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-2 PLANT GROUP Mosses and other Ferns and other seedless Seed plants (gymnosperms and angiosperms) nonvascular plants vascular plants Reduced, independent Reduced (usually microscopic), dependent on surrounding (photosynthetic and Gametophyte Dominant sporophyte tissue for nutrition free-living) Sporophyte Reduced, dependent on Dominant Dominant gametophyte for nutrition Gymnosperm Angiosperm Sporophyte Microscopic female (2n) gametophytes (n) inside ovulate cone Microscopic Sporophyte female (2n) gametophytes (n) inside Gametophyte these parts (n) of flowers Example Microscopic male gametophytes Microscopic male (n) inside gametophytes (n) these parts inside pollen cone of flowers Sporophyte (2n) Sporophyte (2n) Gametophyte (n) Fig. 30-2c Seed plants (gymnosperms and angiosperms) Reduced (usually microscopic), dependent on surrounding Gametophyte sporophyte tissue for nutrition Sporophyte Dominant Gymnosperm Angiosperm Microscopic female gametophytes (n) inside ovulate cone Microscopic female gametophytes Microscopic (n) inside male these parts gametophytes of flowers Example (n) inside these parts of flowers Microscopic male gametophytes (n) inside pollen cone Sporophyte (2n) Sporophyte (2n) Heterospory: The Rule Among Seed Plants • The ancestors of seed plants were likely homosporous (one type of spore [like ferns]), while seed plants are heterosporous • Megasporangia produce megaspores that give rise to female gametophytes • Microsporangia produce microspores that give rise to male gametophytes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ovules and Production of Eggs • An ovule consists of a megasporangium, megaspore, and one or more protective integuments • Gymnosperm megaspores have one integument • Angiosperm megaspores usually have two integuments Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-3-1 Integument Spore wall Immature female cone Megasporangium (2n) Megaspore (n) (a) Unfertilized ovule Pollen and Production of Sperm • Microspores develop into pollen grains, which contain the male gametophytes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Pollen and Production of Sperm • Microspores develop into pollen grains, which contain the male gametophytes • Pollination is the transfer of pollen to the part of a seed plant containing the ovules Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Pollen and Production of Sperm • Microspores develop into pollen grains, which contain the male gametophytes • Pollination is the transfer of pollen to the part of a seed plant containing the ovules • Pollen eliminates the need for a film of water and can be dispersed great distances by air or animals Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Pollen and Production of Sperm • Microspores develop into pollen grains, which contain the male gametophytes • Pollination is the transfer of pollen to the part of a seed plant containing the ovules • Pollen eliminates the need for a film of water and can be dispersed great distances by air or animals • If a pollen grain germinates, it gives rise to a pollen tube that discharges two sperm into the female gametophyte within the ovule Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-3-2 Female gametophyte (n) Spore wall Egg nucleus (n) Male gametophyte (within a germinated Discharged pollen grain) (n) sperm nucleus (n) Micropyle Pollen grain (n) (b) Fertilized ovule The Evolutionary Advantage of Seeds • A seed develops from the whole ovule Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Evolutionary Advantage of Seeds • A seed develops from the whole ovule • A seed is a sporophyte embryo, along with its food supply, packaged in a protective coat Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Evolutionary Advantage of Seeds • A seed develops from the whole ovule • A seed is a sporophyte embryo, along with its food supply, packaged in a protective coat • Seeds provide some evolutionary advantages over spores: – They may remain dormant for days to years, until conditions are favorable for germination Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Evolutionary Advantage of Seeds • A seed develops from the whole ovule • A seed is a sporophyte embryo, along with its food supply, packaged in a protective coat • Seeds provide some evolutionary advantages over spores: – They may remain dormant for days to years, until conditions are favorable for germination – They may be transported long distances by wind or animals Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-3-3 (c) Gymnosperm seed Fig. 30-3-3 Seed coat (derived from integument) Food supply (female gametophyte tissue) (n) Embryo (2n) (new sporophyte) (c) Gymnosperm seed Fig. 30-3-4 Seed coat Integument Female (derived from gametophyte (n) integument) Spore wall Egg nucleus (n) Immature Food supply female cone (female gametophyte Male gametophyte tissue) (n) Megasporangium (within a germinated Discharged pollen grain) (n) (2n) sperm nucleus (n) Embryo (2n) Megaspore (n) Micropyle Pollen grain (n) (new sporophyte) (a) Unfertilized ovule (b) Fertilized ovule (c) Gymnosperm seed Concept 30.2: Gymnosperms bear “naked” seeds, typically on cones • The gymnosperms have “naked” seeds not enclosed by ovaries and consist of four phyla: – Cycadophyta (cycads) – Gingkophyta (one living species: Ginkgo biloba) – Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia) – Coniferophyta (conifers, such as pine, fir, and redwood) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-UN1 Nonvascular plants (bryophytes) Seedless vascular plants Gymnosperms Angiosperms Gymnosperm Evolution (fun fact) • Fossil evidence reveals that by the late Devonian period some plants, called progymnosperms, had begun to acquire some adaptations that characterize seed plants Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-4 Archaeopteris, a progymnosperm • Living seed plants can be divided into two clades: gymnosperms and angiosperms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Living seed plants can be divided into two clades: gymnosperms and angiosperms • Gymnosperms appear early in the fossil record and dominated the Mesozoic terrestrial ecosystems Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Living seed plants can be divided into two clades: gymnosperms and angiosperms • Gymnosperms appear early in the fossil record and dominated the Mesozoic terrestrial ecosystems • Gymnosperms were better suited than nonvascular plants to drier conditions Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings • Living seed plants can be divided into two clades: gymnosperms and angiosperms • Gymnosperms appear early in the fossil record and dominated the Mesozoic terrestrial ecosystems • Gymnosperms were better suited than nonvascular plants to drier conditions • Today, cone-bearing gymnosperms called conifers dominate in the northern latitudes Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Phylum Cycadophyta • Individuals have large cones and palmlike leaves • These thrived during the Mesozoic, but relatively few species exist today Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-5a Cycas revoluta Very successful during Mesozoic (age of cycads) Phylum Ginkgophyta • This phylum consists of a single living species, Ginkgo biloba • It has a high tolerance to air pollution and is a popular ornamental tree Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-5b Ginkgo biloba pollen-producing (male) tree Fig. 30-5c Ginkgo biloba leaves and fleshy seeds Phylum Gnetophyta • This phylum comprises three genera • Species vary in appearance, and some are tropical whereas others live in deserts Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fig. 30-5d Gnetum Fig. 30-5e Ephedra “Morman Tea” caffeine + ephedrine! Fig. 30-5f Welwitschia SW Africa some of the biggest leaves Fig. 30-5g Ovulate cones Welwitschia Phylum Coniferophyta • This phylum
Load more

Recommended publications
  • HUNTIA a Journal of Botanical History
    HUNTIA A Journal of Botanical History VOLUME 15 NUMBER 2 2015 Hunt Institute for Botanical Documentation Carnegie Mellon University Pittsburgh The Hunt Institute for Botanical Documentation, a research division of Carnegie Mellon University, specializes in the history of botany and all aspects of plant science and serves the international scientific community through research and documentation. To this end, the Institute acquires and maintains authoritative collections of books, plant images, manuscripts, portraits and data files, and provides publications and other modes of information service. The Institute meets the reference needs of botanists, biologists, historians, conservationists, librarians, bibliographers and the public at large, especially those concerned with any aspect of the North American flora. Huntia publishes articles on all aspects of the history of botany, including exploration, art, literature, biography, iconography and bibliography. The journal is published irregularly in one or more numbers per volume of approximately 200 pages by the Hunt Institute for Botanical Documentation. External contributions to Huntia are welcomed. Page charges have been eliminated. All manuscripts are subject to external peer review. Before submitting manuscripts for consideration, please review the “Guidelines for Contributors” on our Web site. Direct editorial correspondence to the Editor. Send books for announcement or review to the Book Reviews and Announcements Editor. Subscription rates per volume for 2015 (includes shipping): U.S. $65.00; international $75.00. Send orders for subscriptions and back issues to the Institute. All issues are available as PDFs on our Web site, with the current issue added when that volume is completed. Hunt Institute Associates may elect to receive Huntia as a benefit of membership; contact the Institute for more information.
    [Show full text]
  • Flower Power
    FLOWER POWER IDAHO BOTANICAL GARDEN WHAT IS A FLOWER? INSTRUCTIONAL OBJECTIVE: When students finish this project, they will have gained respect for the beauty of flowers and appreciate their ecological and practical importance. INTRODUCTION Dear Teacher, The Idaho Botanical Garden is an outdoor learning environment. We want to make your visit comfortable and enjoyable, and ask that your students are dressed appropriately for the weather and have water, especially in the warm weather months. TERMS Angiosperms: Flowering plants that produce seeds enclosed in a fruit. Anthers: The boxlike structures at the top of stamens, where pollen is produced. Botanical garden: A place where plants are collected and displayed for scientific, educational and artistic purposes. Fertilization: The union of male sperm cells and female egg cells. Filament: The stalk of the stamen. Flower: The reproductive structure of an angiosperm. Fruit: A ripened ovary conaining seeds. Nectar: The sweet liquid produced by flowers to attract pollinators. Ovary: The hollow compartment at the base of the pistil which contains ovules. It develops into a fruit containing seeds. Ovules: The structures in a flower ovary that can develop into seeds. Pistil: The female part of a flower; stigma, style, and ovary. Pollen: A yellow, powder-like material containing sperm cells. Pollen tubes: Tubes that carry sperm cells from the stigma into the ovary. Pollination: The process of pollen coming together with the stigma of a flower. Pollinators: Animals which carry pollen from one flower to another. Seed: A structure containing a baby plant and its food supply, which is surrounded by a protective seed coat.
    [Show full text]
  • "Role of the Gynoecium in Cytokinin-Induced Carnation Petal
    J. AMER. Soc. HORT. SCI. 116(4):676-679. 1991. Role of the Gynoecium in Cytokinin-induced Carnation Petal Senescence William R. Woodson and Amanda S. Brandt Department of Horticulture, Purdue University, West Lafayette, IN 47907 Additional index words. benzyladenine, Dianthus caryophyllus, ethylene Abstract. Treatment of cut carnation (Dianthus caryophyllus L. ‘White Sim’) flowers with the synthetic cytokinin benzyladenine (BA) at concentrations >1.0 µM induced premature petal senescence. Flowers treated with 100 µM BA exhibited elevated ethylene production in styles and petals before untreated flowers. The gynoecia of BA-treated flowers accumulated 1-aminocyclopropane-l-carboxyllc acid (ACC) and enlarged before untreated flowers. Removal of the gynoecium (ovary and styles) or styles prevented BA-induced petal senescence and resulted in a substantial delay in petal senescence. In contrast, removal of the gynoecium had no effect on timing of petal senescence in flowers held in water. These results indicate BA stimulates petal senescence by inducing premature ACC accumulation and ethylene production in the gynoecium. The senescence of carnation flowers is associated with a sub- cytokinins have been shown to stimulate petal senescence (Ei- stantial increase in ethylene production (Nichols, 1966, 1968). singer, 1977; Van Staden and Joughin, 1988). We now report This increase in ethylene plays an important role in regulating results that indicate the gynoecium plays a critical role in de- the processes of petal senescence, including changes in gene termining the response of carnations to exogenously supplied expression (Borochov and Woodson, 1989; Lawton et al., 1990; cytokinin. Woodson and Lawton, 1988). While the petals account for a large amount of the ethylene produced by carnation flowers, Materials and Methods other floral tissues, including the gynoecium, produce a signif- Plant material.
    [Show full text]
  • Pollen Tube Guidance by Pistils Ensures Successful Double Fertilization Ravishankar Palanivelu∗ and Tatsuya Tsukamoto
    Advanced Review Pathfinding in angiosperm reproduction: pollen tube guidance by pistils ensures successful double fertilization Ravishankar Palanivelu∗ and Tatsuya Tsukamoto Sexual reproduction in flowering plants is unique in multiple ways. Distinct multicellular gametophytes contain either a pair of immotile, haploid male gametes (sperm cells) or a pair of female gametes (haploid egg cell and homodiploid central cell). After pollination, the pollen tube, a cellular extension of the male gametophyte, transports both male gametes at its growing tip and delivers them to the female gametes to affect double fertilization. The pollen tube travels a long path and sustains its growth over a considerable amount of time in the female reproductive organ (pistil) before it reaches the ovule, which houses the female gametophyte. The pistil facilitates the pollen tube’s journey by providing multiple, stage-specific, nutritional, and guidance cues along its path. The pollen tube interacts with seven different pistil cell types prior to completing its journey. Consequently, the pollen tube has a dynamic gene expression program allowing it to continuously reset and be receptive to multiple pistil signals as it migrates through the pistil. Here, we review the studies, including several significant recent advances, that led to a better understanding of the multitude of cues generated by the pistil tissues to assist the pollen tube in delivering the sperm cells to the female gametophyte. We also highlight the outstanding questions, draw attention to opportunities created by recent advances and point to approaches that could be undertaken to unravel the molecular mechanisms underlying pollen tube–pistil interactions. 2011 Wiley Periodicals, Inc.
    [Show full text]
  • Ap09 Biology Form B Q2
    AP® BIOLOGY 2009 SCORING GUIDELINES (Form B) Question 2 Discuss the patterns of sexual reproduction in plants. Compare and contrast reproduction in nonvascular plants with that in flowering plants. Include the following topics in your discussion: (a) alternation of generations (b) mechanisms that bring female and male gametes together (c) mechanisms that disperse offspring to new locations Four points per part. Student must write about all three parts for full credit. Within each part it is possible to get points for comparing and contrasting. Also, specific points are available from details provided about nonvascular and flowering plants. Discuss the patterns of sexual reproduction in plants (4 points maximum): (a) Alternation of generations (4 points maximum): Topic Description (1 point each) Alternating generations Haploid stage and diploid stage. Gametophyte Haploid-producing gametes. Dominant in nonvascular plants. Double fertilization in flowering plants. Gametangia; archegonia and antheridia in nonvascular plants. Sporophyte Diploid-producing spores. Heterosporous in flowering plants. Flowering plants produce seeds; nonvascular plants do not. Flowering plants produce flower structures. Sporangia (megasporangia and microsporangia). Dominant in flowering plants. (b) Mechanisms that bring female and male gametes together (4 points maximum): Nonvascular Plants (1 point each) Flowering Plants (1 point each) Aquatic—requires water for motile sperm Terrestrial—pollination by wind, water, or animal Micropyle in ovule for pollen tube to enter Pollen tube to carry sperm nuclei Self- or cross-pollination Antheridia produce sperm Gametophytes; no antheridia or archegonia Archegonia produce egg Ovules produce female gametophytes/gametes Pollen: male gametophyte that produces gametes © 2009 The College Board. All rights reserved. Visit the College Board on the Web: www.collegeboard.com.
    [Show full text]
  • Botanical Origin, Pollen Profile, and Physicochemical Properties of Algerian Honey from Different Bioclimatic Areas
    foods Article Botanical Origin, Pollen Profile, and Physicochemical Properties of Algerian Honey from Different Bioclimatic Areas Mounia Homrani 1 , Olga Escuredo 2 , María Shantal Rodríguez-Flores 2 , Dalache Fatiha 1, Bouzouina Mohammed 3, Abdelkader Homrani 1 and M. Carmen Seijo 2,* 1 Laboratory of Sciences and Technics of Animal Production (LSTPA), Abdelhamid Ibn Badis University (UMAB), 27000 Mostaganem, Algeria; [email protected] (M.H.); [email protected] (D.F.); [email protected] (A.H.) 2 Department of Vegetal Biology and Soil Sciences, Faculty of Sciences, University of Vigo, As Lagoas, 32004 Ourense, Spain; [email protected] (O.E.); [email protected] (M.S.R.-F.) 3 Laboratory of Vegatal Protection, Abdelhamid Ibn Badis University (UMAB), 27000 Mostaganem, Algeria; [email protected] * Correspondence: [email protected] Received: 27 May 2020; Accepted: 9 July 2020; Published: 16 July 2020 Abstract: The palynological and physicochemical analysis of 62 honey samples produced in different biogeographical areas of Algeria was conducted. Results showed high variety in the botanical origin of samples and their physicochemical profile. Twenty-six samples were polyfloral honey, 30 were unifloral honey from different botanical sources such as Eucalyptus, Citrus, Apiaceae, Punica, Erica, Rosmarinus, Eriobotrya, or Hedysarum, and 6 were characterized as honeydew honey. Pollen analysis allowed the identification of 104 pollen types belonging to 51 botanical families, whereas the physicochemical profile showed important variations between samples. Multivariate techniques were used to compare the characteristics of samples from different biogeographical areas, showing significant differences between humid-area samples, located in the northeast of the country, and samples taken in semiarid, subhumid, and arid zones.
    [Show full text]
  • Heterospory: the Most Iterative Key Innovation in the Evolutionary History of the Plant Kingdom
    Biol. Rej\ (1994). 69, l>p. 345-417 345 Printeii in GrenI Britain HETEROSPORY: THE MOST ITERATIVE KEY INNOVATION IN THE EVOLUTIONARY HISTORY OF THE PLANT KINGDOM BY RICHARD M. BATEMAN' AND WILLIAM A. DiMlCHELE' ' Departments of Earth and Plant Sciences, Oxford University, Parks Road, Oxford OXi 3P/?, U.K. {Present addresses: Royal Botanic Garden Edinburiih, Inverleith Rojv, Edinburgh, EIIT, SLR ; Department of Geology, Royal Museum of Scotland, Chambers Street, Edinburgh EHi ijfF) '" Department of Paleohiology, National Museum of Natural History, Smithsonian Institution, Washington, DC^zo^bo, U.S.A. CONTENTS I. Introduction: the nature of hf^terospon' ......... 345 U. Generalized life history of a homosporous polysporangiophyle: the basis for evolutionary excursions into hetcrospory ............ 348 III, Detection of hcterospory in fossils. .......... 352 (1) The need to extrapolate from sporophyte to gametophyte ..... 352 (2) Spatial criteria and the physiological control of heterospory ..... 351; IV. Iterative evolution of heterospory ........... ^dj V. Inter-cladc comparison of levels of heterospory 374 (1) Zosterophyllopsida 374 (2) Lycopsida 374 (3) Sphenopsida . 377 (4) PtiTopsida 378 (5) f^rogymnospermopsida ............ 380 (6) Gymnospermopsida (including Angiospermales) . 384 (7) Summary: patterns of character acquisition ....... 386 VI. Physiological control of hetcrosporic phenomena ........ 390 VII. How the sporophyte progressively gained control over the gametophyte: a 'just-so' story 391 (1) Introduction: evolutionary antagonism between sporophyte and gametophyte 391 (2) Homosporous systems ............ 394 (3) Heterosporous systems ............ 39(1 (4) Total sporophytic control: seed habit 401 VIII. Summary .... ... 404 IX. .•Acknowledgements 407 X. References 407 I. I.NIRODUCTION: THE NATURE OF HETEROSPORY 'Heterospory' sensu lato has long been one of the most popular re\ie\v topics in organismal botany.
    [Show full text]
  • Fruits: Kinds and Terms
    FRUITS: KINDS AND TERMS THE IMPORTANT PART OF THE LIFE CYCLE OFTEN IGNORED Technically, fruits are the mature ovaries of plants that contain ripe seeds ready for dispersal • Of the many kinds of fruits, there are three basic categories: • Dehiscent fruits that split open to shed their seeds, • Indehiscent dry fruits that retain their seeds and are often dispersed as though they were the seed, and • Indehiscent fleshy fruits that turn color and entice animals to eat them, meanwhile allowing the undigested seeds to pass from the animal’s gut We’ll start with dehiscent fruits. The most basic kind, the follicle, contains a single chamber and opens by one lengthwise slit. The columbine seed pods, three per flower, are follicles A mature columbine follicle Milkweed seed pods are also large follicles. Here the follicle hasn’t yet opened. Here is the milkweed follicle opened The legume is a similar seed pod except it opens by two longitudinal slits, one on either side of the fruit. Here you see seeds displayed from a typical legume. Legumes are only found in the pea family Fabaceae. On this fairy duster legume, you can see the two borders that will later split open. Redbud legumes are colorful before they dry and open Lupine legumes twist as they open, projecting the seeds away from the parent The bur clover modifies its legumes by coiling them and providing them with hooked barbs, only opening later as they dry out. The rattlepods or astragaluses modify their legumes by inflating them for wind dispersal, later opening to shed their seeds.
    [Show full text]
  • Lesson 6: Plant Reproduction
    LESSON 6: PLANT REPRODUCTION LEVEL ONE Like every living thing on earth, plants need to make more of themselves. Biological structures wear out over time and need to be replaced with new ones. We’ve already looked at how non-vascular plants reproduce (mosses and liverworts) so now it’s time to look at vascular plants. If you look back at the chart on page 17, you will see that vascular plants are divided into two main categories: plants that produce seeds and plants that don’t produce seeds. The vascular plants that do not make seeds are basically the ferns. There are a few other smaller categories such as “horse tails” and club mosses, but if you just remember the ferns, that’s fine. So let’s take a look at how ferns make more ferns. The leaves of ferns are called fronds, and brand new leaves that have not yet totally uncoiled are called fiddleheads because they look like the scroll-shaped end of a violin. Technically, the entire frond is a leaf. What looks like a stem is actually the fern’s equivalent of a petiole. (Botanists call it a stipe.) The stem of a fern plant runs under the ground and is called a rhizome. Ferns also have roots, like all other vascular plants. The roots grow out from the bottom of the rhizome. Ferns produce spores, just like mosses do. At certain times of the year, the backside of some fern fronds will be covered with little dots called sori. Sori is the plural form, meaning more than one of them.
    [Show full text]
  • Chapter 1 Definitions and Classifications for Fruit and Vegetables
    Chapter 1 Definitions and classifications for fruit and vegetables In the broadest sense, the botani- Botanical and culinary cal term vegetable refers to any plant, definitions edible or not, including trees, bushes, vines and vascular plants, and Botanical definitions distinguishes plant material from ani- Broadly, the botanical term fruit refers mal material and from inorganic to the mature ovary of a plant, matter. There are two slightly different including its seeds, covering and botanical definitions for the term any closely connected tissue, without vegetable as it relates to food. any consideration of whether these According to one, a vegetable is a are edible. As related to food, the plant cultivated for its edible part(s); IT botanical term fruit refers to the edible M according to the other, a vegetable is part of a plant that consists of the the edible part(s) of a plant, such as seeds and surrounding tissues. This the stems and stalk (celery), root includes fleshy fruits (such as blue- (carrot), tuber (potato), bulb (onion), berries, cantaloupe, poach, pumpkin, leaves (spinach, lettuce), flower (globe tomato) and dry fruits, where the artichoke), fruit (apple, cucumber, ripened ovary wall becomes papery, pumpkin, strawberries, tomato) or leathery, or woody as with cereal seeds (beans, peas). The latter grains, pulses (mature beans and definition includes fruits as a subset of peas) and nuts. vegetables. Definition of fruit and vegetables applicable in epidemiological studies, Fruit and vegetables Edible plant foods excluding
    [Show full text]
  • Ovary Signals for Directional Pollen Tube Growth
    Sex Plant Reprod (2001) 14:3–7 © Springer-Verlag 2001 REVIEW M. Herrero Ovary signals for directional pollen tube growth Received: 15 December 2000 / Accepted: 13 June 2001 Abstract In angiosperms, the female gametophyte has a work has focussed on pollen tube growth along the stig- secluded life; it is protected by several concentric layers ma and style, the ovary has been neglected; it has often that envelop each other. The embryo sac is surrounded been assumed that once the pollen tubes arrive at the by the nucellus, which in turn is wrapped by the integu- base of the style fertilisation occurs. However, informa- ments forming the ovule, which is nested in the ovary. tion is converging toward the concept (Herrero 2000) These wrappings are not hermetic, but contain little that the process is far from straightforward, and that in “gates” the pollen tube must traverse on its way towards the ovary, also, an interesting male-female interaction the embryo sac. Information is emerging that shows that occurs. the ovary and ovule provide signals orienting and direct- A close look at the ovary shows that the female game- imng the pollen tube on the right course. There are three tophyte has a secluded life, protected by a number of main bodies of evidence supporting this hypothesis. One concentric layers that consecutively envelop each other. relates to developmental changes in the female tissues Thus, the embryo sac is surrounded by the nucellus, and how they affect pollen tube growth. The second re- which in turn is wrapped by the integuments forming the fers to defective ovule mutants, which induce defective ovule, which is nested in the ovary.
    [Show full text]
  • Genetic and Biochemical Mechanisms of Pollen Wall Development
    Review Genetic and Biochemical Mechanisms of Pollen Wall Development 1 1 1 1,2 Jianxin Shi, Meihua Cui, Li Yang, Yu-Jin Kim, and 1,3, Dabing Zhang * The pollen wall is a specialized extracellular cell wall matrix that surrounds male Trends gametophytes and plays an essential role in plant reproduction. Uncovering the Pollen wall development exhibits con- fi mechanisms that control the synthesis and polymerization of the precursors of served and diversi ed features. pollen wall components has been a major research focus in plant biology. We Genes associated with pollen wall devel- review current knowledge on the genetic and biochemical mechanisms under- opment are coordinately regulated. lying pollen wall development in eudicot model Arabidopsis thaliana and mono- The synthesis of exine and anther cutin cot model rice (Oryza sativa), focusing on the genes involved in the biosynthesis, may share common pathways in rice. transport, and assembly of various precursors of pollen wall components. The conserved and divergent aspects of the genes involved as well as their regula- tion are addressed. Current challenges and future perspectives are also highlighted. Pollen Wall Development The pollen wall is the complex multiple-layer outer surface of pollen. It is essential for plant reproduction because of its role in rendering male gametophytes resistant to various biotic and abiotic stresses, as well as its function in male–female interaction, fertilization, and seed production [1]. The underlying genetic, molecular, and biochemical mechanisms of pollen wall development have long defied unraveling, but this is changing fast. Several excellent reviews have summarized the genes and enzymes associated with the biosynthesis and transport of the lipidic and phenolic precursors necessary for the formation of the outer pollen wall named exine 1 Joint International Research – [1 4] (see Glossary).
    [Show full text]