DOCSLIB.ORG

Tamilnadu Board Class 9 Science Chapter 6 Term I

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Tamilnadu Board Class 9 Science Chapter 6 Term I UNIT Living World of Plants - 6 Plant Physiology Learning Objectives At the end of this unit the students will be able to understand, that Plants too have certain autonomic movements how do plants produce their food through the process of photosynthesis? that Plants are the primary producers that feed the rest of the living organisms Introduction (sunflower) follows the path of the sun from dawn to dusk, (from east to west) and Animals move in search of food, shelter and during night it moves from west to east. for reproduction, even microorganisms The dance of Desmodium gyrans (Indian show movement. telegraph plant) leaf is mesmerizing. Do plants show such movement We see a branch of a tree shaking in heavy thunder storm; and leaves dancing in gentle wind. These movements are caused by an external agency. Do they Move on their 6.1 own Accord In short, do plants have spontaneous movements without external agency? Do they breathe? In this chapter we will study some of the biological functions of plants. 6.2 Do Plants Move The leaves of Mimosa pudica (touch-me- not plant) closes on touching, and in like manner, the stalk of Helianthus annuus Mimosa pudica 6 . L i v i ng Wo l d o P a nt P a nt P y s i o og 133 IX_Science Unit-6.indd 133 27-03-2018 12:31:36 Activity 1 Roots grow down and shoots grow up You can do this experiment with some of your friends. Step -1 It is easy and fun. Take four or ve earthen cups or small pots and ll them with soil from a eld. Add a little cow Helianthus annuus dung to the soil. Make sure the cups have a hole at the bottom. Label them as A, B, and C. Put some seeds of green gram in all the cups, water them daily. As soon as the seeds sprout, select a shoot of same height from each of the cups. Remove all the other shoots from the cups. Step-2 Desmodium gyrans You will need a rectangular box with These movements are triggered by an a small window in one of its sides. A external stimuli. Unlike animals, plants shoe box would be ideal. Cut a 1 × 1 cm may not move on their own from one window in one side. When the shoots location to another, but can move their are 10 cm long, cover the plants in all the body parts for getting sunlight, water and cups except cup A with the rectangular nutrients and are sensitive to external box. When covering the cups, place the factors like light, gravity, temperature etc. box such that opening in each of them face different directions. Keep all the More to Know cups including ‘A’ in open sun light. In Desmodium gyrans (Indian telegraph Step-3 plant), the compound leaf shows three leaets, one terminal large leaet and two Wait for three to four days. Remove very small lateral opposite leaets. e the box and look at the plants again. two lateral leaets move up, move back Are the plants tilted? To which side are and then move down and nally back to the plants tilted? With opening facing the original position showing rhythmic different direction, did all the plants tilt movement. Desmodium gyrans is also the same direction? called the dancing plant. is plant was used by Indian scientist Jagadish Chandra Compile the results and discuss Bose for his experiment. with your friends. Mimosa pudica is called Perhaps you have done such as Thotta surungi and experiments in earlier classes and have Desmodium gyrans is called as ozhu kanni in Tamil. found that plants do grow towards the sunlight. 6 . L i v i ng Wo l d o P a nt P a nt P y s i o og 134 IX_Science Unit-6.indd 134 27-03-2018 12:31:37 Do Plants Actually developed Darwin’s experiments. He found 6.3 Sense Light that if he removed the coleoptiles, plant growth stopped. en he inserted a piece of agar and then placed the coleptile on top of it You would have studied in earlier classes about the plant again was able to curve towards the seed germination. In monocot plants like grass, light. Hence this chemical was predicted to there is only one rst leaf (called cotyledon). be water soluble. He reasoned that chemicals Once germinated, the embryo sends a primary that controlled the light sensitive movement root downward into the soil and pushes the (phototropism) moved through agar. primary shoot to the soil surface. e tip of the embryonic shoot (plumule) is covered by a protective sheath called coleoptile. It is the coleoptile covered embryonic shoot that grows above the ground. In one of the experiments initially Darwin noticed that germinated seeds also grow towards light. If, in a dark room light is placed in one end, the growing seedlings bend towards the light. In the next experiment, he carefully removed the tip from growing seedlings. e shoot did not bend towards the light. When he covered the tip (Coleoptile) with foil, preventing light from entering, the shoot did not bend. In the next step, he covered the elongating part of the shoot, but le the tip open. Now the bending could be In his next experiment he replaced the noticed. Covering the elongating part of the agar block with butter. e above mentioned shoot did not a ect the response to light at water soluble chemical did not dissolve in all! Darwin concluded “some ‘in uence’ is butter, as expected the chemical did not pass transmitted from the tip to the more basal through butter. is water soluble “in uence” regions of the shoot thereby regulating growth was later identi ed as the plant hormone and inducing curvature”. is demonstrated Auxin. In response to light, auxin elongates clearly that something within the tip of the the cells on the dark side of a stem so that the coleoptile controlled growth of the plant. plant literally bends towards the light source. C a r l e a r w n Pete Bo s en J en en What is this in uence? In 1913 Peter Boysen-Jensen, a Danish Botanist further Bend ng o t e te tow r d i g t 6 . L i v i ng Wo l d o P a nt P a nt P y s i o og 135 IX_Science Unit-6.indd 135 27-03-2018 12:31:38 Types of Tropisms in Tropism is generally termed 6.4 Plants “positive” if growth is towards the signal and “negative”, if it is away from the signal. While the shoot in a plant moves Tropism is a growth movement, the direction towards the light, the roots move away in of which is determined by the direction of the the opposite direction. us the shoots are stimuli. Unidirectional movement of plant said to have positive phototropism, while part to light stimulus is called Phototropism. the roots have negative phototropism. Heliotropism or motion of plant parts like Can you think of an example of a negative owers or leaves in response to the direction hydrotropism? of the sun is a kind of phototropism. e plant may also respond to gravity and it is termed Geotropism or Gravitropism. e response to water is called Hydrotropism. Climbing vines have to nd a suitable support shortly a er germination. Once the shoot touches a suitable support, it grows towards the surface it is touching. is is called igmotropism. Po i t v e h otot o i s m Growth or movement of a plant in response to chemical stimuli is called ( neg t v e y geot o i c Chemotropism. During fertilization, pollen tube grows down the style in response to the sugars in the style is an example of chemotropism. Neg t v e h otot o i s m ( p o i t v e y geot o i c Activity 2 P otot o i s m Experiment to demonstrate phototropism Info bits i) Take pea seeds soaked in water Tropism allows plant to get the best overnight. conditions for its survival. ii) Wait for the pea seeds to germinate. Tropic movements are slow, iii) Once the seedling has grown put it directional movements towards in a box with an opening for light or away from the stimulus and it on one side. depends on growth. iv) After sometime, you can clearly Nastic movement is an immediate see how the stem has bent and action. grown towards the light. 6 . L i v i ng Wo l d o P a nt P a nt P y s i o og 136 IX_Science Unit-6.indd 136 27-03-2018 12:31:38 Info bits Some halophytes produce negatively geotropic roots (E.g. Rhizophora). ese roots turn 180° upright for respiration. Activity 3 Water or gravity When a seed germinates the primary shoot, Experiment to demonstrate (plumule) goes up while the primary Geotropism root, (radicle) goes down. What stimulus i) Two Clinostats are taken and a is making the primary root to go down? potted plant on each is fixed on a Is it gravity or water that is principally horizontal position. responsible for the direction of the growth ii) One Clinostat is rotated and the of a primary root? We can do an interesting other is kept stationary. experiment to find out for ourselves. Observations made after sometime will What do you need? Glass trough, show that the shoot of the plant fixed on sand, flower pot, plugged at the bottom, the stationary clinostat bends upwards pea or bean seeds and water.
Load more

Recommended publications
  • Stenospermocarpy Biological Mechanism That Produces Seedlessness in Some Fruits (Many Table Grapes, Watermelon)
    Phytohormones The growth and development of a plant are influenced by: •Gene:c factors •External environmental factors •Chemical hormones inside the plant Secondary messengers 1. Involve in the transfer informaon from sources to targets 2. Amplify the signal produced by the phytohormone Phytohormones Plant hormones are organic compounds that are effec:ve at very low concentraon (1g 20,000 tons-1) They interact with specific target :ssues to cause physiological responses •Growth •Fruit ripening Phytohormones •Hormones s:mulate or inhibit plant growth Major groups of hormones: 1. Auxins 2. Gibberellins 3. Ethylene 4. Cytokinins 5. Abscisic acid 6. Brassinostereoids 7. Salicylic acid 8. Polyaminas 9. Jasmonates 10. Systemin 11. Nitric oxide Arabidopsis thaliana Phytohormones EARLY EXPERIMENTS ON PHOTROPISM SHOWED THAT A STIMULUS (LIGHT) RELEASED CHEMICALS THAT INFLUENCED GROWTH Auxins Auxin causes several responses in plants: * Phototropism * Geotropism * Promo:on of apical dominance * Flower formaon * Fruit set and growth * Formaon of adven::ous roots * Differen:aon of vascular :ssues (de novo or repairing existent vascular :ssue) Auxins Addi:on of auxins produce parthenocarpic fruit. Stenospermocarpy Biological mechanism that produces seedlessness in some fruits (many table grapes, watermelon) diploid + tetraploid parent = triploid seeds vegetave parthenocarpy Plants that do not require pollinaon or other s:mulaon to produce parthenocarpic fruit (cucumber) Auxins Synthe:c auxins Widely used in agriculture and hor:culture • prevent leaf abscission • prevent fruit drop • promote flowering and frui:ng • control weeds Agent Orange - 1:1 rao of 2,4-D and 2,4,5-T Dioxin usually contaminates 2,4,5-T, which is linked to miscarriages, birth defects, leukemia, and other types of cancer.
    [Show full text]
  • A Framework for Plant Behavior Author(S): Jonathan Silvertown and Deborah M
    A Framework for Plant Behavior Author(s): Jonathan Silvertown and Deborah M. Gordon Reviewed work(s): Source: Annual Review of Ecology and Systematics, Vol. 20 (1989), pp. 349-366 Published by: Annual Reviews Stable URL: http://www.jstor.org/stable/2097096 . Accessed: 10/02/2012 12:56 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]. Annual Reviews is collaborating with JSTOR to digitize, preserve and extend access to Annual Review of Ecology and Systematics. http://www.jstor.org Annu. Rev. Ecol. Syst. 1989. 20:349-66 Copyright ? 1989 by Annual Reviews Inc. All rights reserved A FRAMEWORKFOR PLANT BEHAVIOR Jonathan Silvertown' and Deborah M. Gordon2 'BiologyDepartment, Open University, Milton Keynes MK7 6AA, UnitedKingdom 2Departmentof Zoology,University of Oxford,South Parks Rd, Oxford,OXI 3PS, UnitedKingdom INTRODUCTION The language of animalbehavior is being used increasinglyto describecertain plant activities such as foraging (28, 31, 56), mate choice (67), habitatchoice (51), and sex change (9, 10). Furthermore,analytical tools such as game theory, employed to model animal behavior, have also been applied to plants (e.g. 42, 54). There is some question whetherwords used to describe animal behavior, such as the word behavior itself, or foraging, can be properly applied to the activities of plants.
    [Show full text]
  • Plant Physiology
    PLANT PHYSIOLOGY Vince Ördög Created by XMLmind XSL-FO Converter. PLANT PHYSIOLOGY Vince Ördög Publication date 2011 Created by XMLmind XSL-FO Converter. Table of Contents Cover .................................................................................................................................................. v 1. Preface ............................................................................................................................................ 1 2. Water and nutrients in plant ............................................................................................................ 2 1. Water balance of plant .......................................................................................................... 2 1.1. Water potential ......................................................................................................... 3 1.2. Absorption by roots .................................................................................................. 6 1.3. Transport through the xylem .................................................................................... 8 1.4. Transpiration ............................................................................................................. 9 1.5. Plant water status .................................................................................................... 11 1.6. Influence of extreme water supply .......................................................................... 12 2. Nutrient supply of plant .....................................................................................................
    [Show full text]
  • History and Epistemology of Plant Behaviour: a Pluralistic View?
    Synthese (2021) 198:3625–3650 https://doi.org/10.1007/s11229-019-02303-9 BIOBEHAVIOUR History and epistemology of plant behaviour: a pluralistic view? Quentin Hiernaux1 Received: 8 June 2018 / Accepted: 24 June 2019 / Published online: 2 July 2019 © Springer Nature B.V. 2019 Abstract Some biologists now argue in favour of a pluralistic approach to plant activities, under- standable both from the classical perspective of physiological mechanisms and that of the biology of behaviour involving choices and decisions in relation to the environ- ment. However, some do not hesitate to go further, such as plant “neurobiologists” or philosophers who today defend an intelligence, a mind or even a plant consciousness in a renewed perspective of these terms. To what extent can we then adhere to pluralism in the study of plant behaviour? How does this pluralism in the study and explanation of plant behaviour fit into, or even build itself up, in a broader history of science? Is it a revolutionary way of rethinking plant behaviour in the twenty-first century or is it an epistemological extension of an older attitude? By proposing a synthesis of the question of plant behaviour by selected elements of the history of botany, the objective is to show that the current plant biology is not unified on the question of behaviour, but that its different tendencies are in fact part of a long botanical tradition with contrasting postures. Two axes that are in fact historically linked will serve as a common thread. 1. Are there several ways of understanding or conceiving plant behaviour within plant sciences and their epistemology? 2.
    [Show full text]
  • Plant Classification and Seeds
    Ashley Pearson – Plant Classification and Seeds ● Green and Gorgeous Oxfordshire ● Cut flowers ● Small amounts of veg still grown and sold locally Different Classification Systems Classification by Life Cycle : Ephemeral (6-8 wks) Annual Biennial Perennial Classification by Ecology: Mesophyte, Xerophyte, Hydrophyte, Halophyte, Cryophyte Raunkiaers Life Form System: based on the resting stage Raunkiaers Life Form System Classification contd. Classification by Plant Growth Patterns Monocots vs. Dicots (NB. only applies to flowering plants - angiosperms) Binomial nomenclature e.g., Beetroot = Beta vulgaris Plantae, Angiosperms, Eudicots, Caryophyllales, Amaranthaceae, Betoideae, Beta, Beta vulgaris After morphological characters, scientists used enzymes and proteins to classify plants and hence to determine how related they were via evolution (phylogeny) Present day we use genetic data (DNA, RNA, mDNA, even chloroplast DNA) to produce phylogenetic trees Plant part modifications ● Brassica genus ● ● Roots (swede, turnips) ● Stems (kohl rabi) ● Leaves (cabbages, Brussels Sprouts-buds) ● Flowers (cauliflower, broccoli) ● Seeds (mustards, oil seed rape) Plant hormones / PGR's / phytohormones ● Chemicals present in very low concentrations that promote and influence the growth, development, and differentiation of cells and tissues. ● NB. differences to animal hormones! (no glands, no nervous system, no circulatory system, no specific mode of action) ● Not all plant cells respond to hormones, but those that do are programmed to respond at specific points in their growth cycle ● Five main classes of PGR's ● Abscisic acid (ABA) ● Role in abscission, winter bud dormancy (dormin) ● ABA-mediated signalling also plays an important part in plant responses to environmental stress and plant pathogens ● ABA is also produced in the roots in response to decreased water potential.
    [Show full text]
  • Motion in Plants and Animals SMPK Penabur Jakarta Motion
    Motion in Plants and Animals SMPK Penabur Jakarta Motion What is that? Which part? Have you ever see the flying bird? Why they can do stable flying? What affects them? Let’s learn! Plant’s motion Animal’s motion in water, on air, and on land Why so important?? To know and explain motion in living things Important Terms Motion Stimulation Inertia Elasticity Surface Tension Mimosa pudica Have you ever see? Mimosa pudica Response to stimulation If the leaves got stimulation, the water flow will keep away from stimulated area Stimulated area water less, turgor tension less leaves will closed Turgor tension= tension affected by cell contents to wall cell in plant Movement Movement in living system they can change chemical energy to mechanical energy Human and animal active movement Plants have different movement Motion in Plant Growth Reaction to respond stimuli (irritability) Endonom Hygroscopic Etionom PHOTOTROPISM HYDROTROPISM TROPISM GEOTROPISM THIGMOTROPISM ENDONOM RHEOTROPISM PLANT MOTION HYGROSCOPIC ETIONOM PHOTOTAXIS TAXIS CHEMOTAXIS NICTINASTY THIGMONASTY/ NASTIC SEISMONASTY PHOTONASTY COMPLEX A. Endogenous Movement Spontaneusly Not known yet its cause certainly Predicted it caused by stimulus from plant itself Ex: ◦ Movement of cytoplasm in cell ◦ Bending movement of leaf bid because of different growth velocity ◦ Movement of chloroplast Chloroplast movement B. Hygroscopic Movement Caused by the influence of the change of water level from its cell non-homogenous wrinkling Ex: ◦ The breaking of dried fruit of leguminous fruit, such as kacang buncis (Phaseolus vulgaris), kembang merak (Caesalpinia pulcherrima), and Impatiens balsamina (pacar air) and other fruits ◦ The opening of sporangium in fern ◦ Rolled of peristomal gear in moss’ sporangium C.
    [Show full text]
  • Plant-Environment Interactions: from Sensory Plant Biology to Active
    Signaling and Communication in Plants Series Editors František Baluška Department of Plant Cell Biology, IZMB, University of Bonn, Kirschallee 1, D-53115 Bonn, Germany Jorge Vivanco Center for Rhizosphere Biology, Colorado State University, 217 Shepardson Building, Fort Collins, CO 80523-1173, USA František Baluška Editor Plant-Environment Interactions From Sensory Plant Biology to Active Plant Behavior Editor František Baluška Department of Plant Cell Biology IZMB University of Bonn Kirschallee 1 D-53115 Bonn Germany email: [email protected] ISSN 1867-9048 ISBN 978-3-540-89229-8 e-ISBN 978-3-540-89230-4 DOI: 10.1007/978-3-540-89230-4 Library of Congress Control Number: 2008938968 © 2009 Springer-Verlag Berlin Heidelberg This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other way, and storage in data banks. Duplication of this publication or parts thereof is permitted only under the provisions of the German Copyright Law of September 9, 1965, in its current version, and permission for use must always be obtained from Springer-Verlag. Violations are liable for prosecution under the German Copyright Law. The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. Cover design: WMXDesign GmbH, Heidelberg, Germany Printed on acid-free paper 9 8 7 6 5 4 3 2 1 springer.com František Baluška dedicates this book to Prof.
    [Show full text]
  • Circadian Regulation of Sunflower Heliotropism, Floral Orientation, and Pollinator Visits
    Title: Circadian regulation of sunflower heliotropism, floral orientation, and pollinator visits Authors: Hagop S. Atamian1, Nicky M. Creux1, Evan A. Brown2, Austin G. Garner2, Benjamin K. Blackman2,3, and Stacey L. Harmer1* Affiliations: 1Department of Plant Biology, University of California, One Shields Avenue, Davis, CA 95616, USA. 2Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA 22904, USA. 3Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA 94720, USA. *Correspondence to: [email protected]. Abstract: Young sunflower plants track the sun from east to west during the day and then reorient during the night to face east in anticipation of dawn. In contrast, mature plants cease movement with their flower heads facing east. We show that circadian regulation of directional growth pathways accounts for both phenomena and leads to increased vegetative biomass and enhanced pollinator visits to flowers. Solar tracking movements are driven by antiphasic patterns of elongation on the east and west sides of the stem. Genes implicated in control of phototropic growth, but not clock genes, are differentially expressed on the opposite sides of solar tracking stems. Thus interactions between environmental response pathways and the internal circadian oscillator coordinate physiological processes with predictable changes in the environment to influence growth and reproduction. One Sentence Summary: Sun-tracking when young, east-facing when mature, warmer sunflowers attract more pollinators. Text+References+Legends Cover Main Text: Most plant species display daily rhythms in organ expansion that are regulated by complex interactions between light and temperature sensing pathways and the circadian clock (1). These rhythms arise in part because the abundance of growth-related factors such as light signaling components and hormones such as gibberellins and auxins are regulated both by the circadian clock and light (2-4).
    [Show full text]
  • Venus Flytrap Conservation
    HerbalGram 114 • May – July 2017 114 • May HerbalGram Modern TCM in Hong Kong • Remembering Fredi Kronenberg • Curcumin Medicinal Chemistry Rose Aroma & Pain Reduction • Garlic & Blood Pressure • Psilocybin & Patients with Cancer Nigella Profile • Venus Flytrap Conservation • Psilocybin & Patients with Cancer • Curcumin Medicinal Chemistry • Modern TCM in Hong Kong • Remembering Fredi Kronenberg in Hong Kong • Remembering Fredi MedicinalTCM Chemistry • Curcumin • Modern with Cancer Conservation & Patients • Psilocybin Flytrap Venus • Nigella Profile The Journal of the American Botanical Council Number 114 | May — July 2017 www.herbalgram.org Venus Flytrap Conservation Nigella Profile US/CAN $6.95 Join more than 190 responsible companies, laboratories, nonprofits, trade associations, media outlets, and others in the international herb and natural products/natural medicine community. Become a valued underwriter of the ABC-AHP-NCNPR Botanical Adulterants Program, a multi-year, supply chain integrity program providing education about accidental and intentional adulteration of botanical materials and extracts on an international scale. For more details on joining the program, and access to the free publications produced to date, please see www.botanical adulterants.org or contact Denise Meikel at [email protected]. Underwriters, Endorsers, and Supporters of the ABC-AHP-NCNPR Botanical Adulterants Program* As of May 9, 2017 Financial Underwriters Products, Inc. Australian Self Medication Southwest College of 21st Century Healthcare /Bioclinic Naturals Industry (Australia) Naturopathic Medicine The forces that shaped the southern Oregon landscape endowed it with lofty mountains, AdvoCare International L.P. Natural Grocers by Vitamin Australian Tea Tree Industry University of Bridgeport College Agilent Technologies, Inc. Cottage Association (Australia) of Naturopathic Medicine sheltered valleys and crystal clear rivers.
    [Show full text]
  • University of Groningen the Thermal Ecology of Flowers Van Der Kooi
    University of Groningen The thermal ecology of flowers van der Kooi, Casper J.; Kevan, Peter G.; Koski, Matthew H. Published in: Annals of Botany DOI: 10.1093/aob/mcz073 IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2019 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): van der Kooi, C. J., Kevan, P. G., & Koski, M. H. (2019). The thermal ecology of flowers. Annals of Botany, 124(3), 343-353. https://doi.org/10.1093/aob/mcz073 Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.
    [Show full text]
  • Tendril Coiling in Grapevine: Jasmonates and a New Role for GABA?
    Journal of Plant Growth Regulation https://doi.org/10.1007/s00344-018-9807-x Tendril Coiling in Grapevine: Jasmonates and a New Role for GABA? Jaiana Malabarba1,2 · Michael Reichelt3 · Giancarlo Pasquali1 · Axel Mithöfer2 Received: 31 January 2018 / Accepted: 9 April 2018 © The Author(s) 2018 Abstract Grapevine (Vitis vinifera L., Vitaceae) belongs to the genus Vitis, and is characterized as a vine due to the presence of ten- drils, which are located opposite to leaves. Tendrils are thigmo-responsive organs, able to carry out delicate mechanosensory responses upon touch and related stimuli. These organs are an adaptation of the plant to climb with the help of support to higher places and finally remain at a position with favorable light quality. In previous studies on Bryonia dioica (Cucur- bitaceae), phytohormones of the jasmonate class were identified as the endogenous hormone signals to initiate coiling of the tendrils. Strikingly, this is still the only example for jasmonate-induced tendril coiling. In grapevine, three compounds (12-oxo-phytodienoic acid, jasmonic acid (JA), and JA isoleucine conjugate) of the jasmonate class were found at higher concentrations in non-coiled tendrils when compared with coiled ones. Upon treatment with phytohormones, we could con- firm the activity of jasmonates on tendril coiling in grapevine. However, not jasmonates but a non-proteinogenic amino acid, γ-aminobutyric acid (GABA), was detected to accumulate in grapevine tendrils at significantly higher levels than in all other tissues, independent of their coiling status. For GABA we detected a significant, transient positive effect on tendril coiling. Use of a GABA synthesis blocker, 3-mercaptopropionic acid, caused reduced GABA- but not JA-induced coiling scores.
    [Show full text]
  • Plant Defenses
    Plant Defenses Naturalist Outreach Speakers Bureau Presented by Ellie Taylor Plants have evolved to oppose pests. One thing that greatly differentiates plants from animals is their lack of motility. This leads plants Odd Defenses to adapt different ways of defending themselves from the same pressures animals face. One odd plant and relatively rare plant Plant Defenses against Herbivory defense is thigmonasty. If you were a plant, how would you defend yourself Thigmonasty is the non- against predation by animals, otherwise known as directional response of herbivory? Plants have many ways to cope with this a plant to touch. The pressure. Many plants develop prickly structures, Mimosa pudica (known especially on their stems. If these structures are as the sensitive plant) has the ability to rapidly close its leaflets upon touch, possibly because herbivores won’t want to eat a quickly moving plant, or to look more twig-like. Thorns Spines Prickles modified from a branch, then they are thorns. If they’re modified from a leaf, it’s a spine, or if it’s an extension of the epidermis, it’s a prickle. You can tell which is which by its placement on the stem of the plant. No matter which it is, they usually prevent herbivores and especially large animals from eating the plant or fruit of Some plants, like the plant. Lithops even utilize Plants also often have hairs on their stems, leaves, and camoflouge. These petioles called trichomes that generally don’t bother us particular plants look handling them, but irritate the mouths of bugs and like rocks, so they are animals trying to eat them.
    [Show full text]