DOCSLIB.ORG

Xylem Sap Flow As a Major Pathway for Oxygen Supply to the Sapwood Of

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Xylem Sap Flow As a Major Pathway for Oxygen Supply to the Sapwood Of Blackwell Science, LtdOxford, UKPCEPlant, Cell and Environment0016-8025Blackwell Science Ltd 2003? 2003 261118031814 Original Article Oxygen transport in the sapwood D. Gansert Plant, Cell and Environment (2003) 26, 1803–1814 Xylem sap flow as a major pathway for oxygen supply to the sapwood of birch (Betula pubescens Ehr.) D. GANSERT Institut für Ökologische Pflanzenphysiologie und Geobotanik, Universität Düsseldorf, Universitätsstraße 1, D-40225 Düsseldorf, Germany ABSTRACT Graham’s law of diffusion (Armstrong 1979; Grosse, Frye & Lattermann 1992; Grosse 1997). However, long-distance The role of xylem sap flow as an aqueous pathway for gaseous oxygen transport primarily takes places in the oxygen supply to the wood parenchyma of Betula pubes- intercellular gas-space continuum of the outer cortex sur- cens saplings was investigated. Using micro-optode sensors rounded by the phellogen (Hook et al. 1972), which has the oxygen status of the sapwood was quantified in relation been identified as a thermo-osmotically active partition in to mass flow of xylem sap. Sap flow was gradually reduced several tree species (Eschrich 1995; Grosse 1997). by an increasing oxygen depletion in the root space. The Radial gaseous diffusion of atmospheric oxygen across effect of sap flow on radial O transport between stem and 2 the cambial sheath towards the wood parenchyma can only atmosphere was assessed by a stoichiometrical approach be effective if continuity through cambium pores is main- between respiratory CO production and O consumption. 2 2 tained. In trees of Betula pendula Roth radial influx of Restriction of sap flow set in 36.5 h after the onset of O 2 oxygen into the sapwood has been suggested as a gaseous depletion, and was complete after 71 h. Interruption of sap pathway mainly effective at night, by which xylem sap will flow drastically increased the O deficit in the sapwood to 2 be enriched with dissolved oxygen (Gansert, Burgdorf & 70%. Sap flow contributed about 60% to the total oxygen Lösch 2001). With respect to species-specific wood anat- supply to the sapwood. Diurnal O flow rates varied 2 omy, oxygen supply to the various types of wood paren- between 3 and 6.3 nmol O m-2 leaf area (LA) s-1 during 2 chyma (Braun 1970; Grosser 1977; Schweingruber 1978; night- and daytime, respectively. Maximum O flow rates of 2 Eschrich 1995) principally depends on both the abundance 20 nmol O m-2 LA s-1 were reached at highest sap flow 2 of intercellular spaces and their effectiveness for gaseous rates of 5.7 mmol H O m-2 LA s-1. Sap flow not only 2 diffusion (i.e. the gaseous path), and xylem sap flow – the affected the oxygen status of the sapwood but also had an aqueous path – that primarily supports those parenchyma effect on radial O transport between stem and atmosphere. 2 strands that shield water transport from embolism and reg- ulate secretion of osmotica and hormones into the xylem Key-words: aquaporins; hypoxia; respiration; roots; sap sap. Oxygen concentrations measured in sapwood of differ- flow; stem heat balance. ent anatomical structure and metabolic activity vary over a broad range from pronounced hypoxia to near saturation INTRODUCTION (Eklund 1990, 1993, 2000; Gansert et al. 2001; Del Hierro et al. 2002; Mancuso & Marras 2003). It has long been recognized that the transpiration stream New types of miniaturized, high-sensitive oxygen sensors plays a vital role in aeration of living tissues surrounded by allow improved quantitative analyses of the oxygen status the cambium of woody plants (Bailey 1913; Haberlandt and oxygen flow rates in different compartments of the 1914). The importance of xylem sap flow for oxygen supply woody cormus on a high-resolution time scale. Previous to and removal of carbon dioxide from parenchymatous efforts on the measurement of oxygen concentrations in tissues of the sapwood was clearly recognized by Bailey the sapwood by use of these sensors focused on the preclu- (1913) when he stated that the xylem of arborescent plants sion from interference with atmospheric oxygen, and main- has an important function for transport of gases dissolved tenance of xylem sap flow by avoidance of embolism. Thus, in water from the roots to the cambium and leaves. Axial underwater access to the sapwood was used as a methodi- oxygen transport in flood-tolerant plant species from aerial cal approach for in situ measurements of diurnal and sea- parts to the roots has been a subject of broad interest sonal variations of endogenous oxygen concentrations in (Hook, Brown & Wetmore 1972) with special reference to woody plants (Gansert et al. 2001). This approach may con- physical processes involved in gaseous diffusion of oxygen tribute to identifying circumstances and metabolic depen- through intercellullar gas-spaces such as thermo-osmosis or dencies that are responsible for the different oxygen status of plant shoots under varying ontogenetic, environmental, Correspondence: D. Gansert. Fax: +49 211 81 13335; e-mail, and seasonal conditions. Using the new type of micro- [email protected] optode oxygen sensors, the purpose of this study was: (1) © 2003 Blackwell Publishing Ltd 1803 1804 D. Gansert to investigate the role of xylem sap flow as an aqueous interference in CO2 and O2 gas exchange due to bark pho- pathway for oxygen supply to the sapwood parenchyma tosynthesis, all internodes and the cuvettes were shielded of young mountain birch (Betula pubescens Ehr.); (2) to from light by strips of black silk cloth wrapped around the quantify its effect on the oxygen status of the sapwood; and woody plant parts. The data of all microclimatic variables (3) to evaluate the potential effect of xylem sap flow on were synchronously recorded at 10 s intervals and averaged oxygen transport between stem and atmosphere during over 5 min intervals by data loggers (Squirrel 1250 series; stem respiration. Grant Instruments Ltd, Barrington Cambridge, UK). MATERIALS AND METHODS Cuvettes for measuring stem gas exchange The experimental set-up Cuvettes for the measurement of O2 and CO2 gas exchange between ambient air and the stem were made out of In early June 2002, two potted plants of 5-year-old field- Plexiglass as shown schematically (Fig. 2). Each cuvette grown B. pubescens saplings about 1.7 m tall were brought consisted of two semi-cylinders (wall thickness =5 mm, into a climate chamber and preconditioned to the experi- thickness of top and bottom =6 mm) which enclosed a stem mental light and temperature regime for 10 d. The soil sub- internode of up to 8 mm in diameter and 20 mm in length. strate was natural loess (volume = 8.3 ¥ 10-3 m3) in which A rubber seal fixed in a groove (2 mm wide, 1.5 mm deep) the roots grew undisturbed for 1 year. In order to sim- along the plane side of one semi-cylinder ensured a leak- ulate a near-daylight spectrum, HRI-T 400 W/D lamps proof seal when both semi-cylinders were pressed onto (Radium; Osram, München, Germany) were used as the each other by two steel strings. Silicon rubber (Loctite no. light source during a 13 h day period (0700 to 2000 h). 5910; Loctite GmbH, München, Germany) was used to Prevention of upper crown parts from excessive warming seal the remaining gap between the stem and the cuvette. was achieved by insertion of a glass pane (4 mm thick) 8 cm Each cuvette was equipped with four Plexiglass tubes beneath the light unit. Horizontal air ventilation between (dout = 10 mm, l = 62 mm) with different inner diameters to the lamps and the glass pane efficiently reduced the effect be connected to different gas analysing instruments. The of excessive heat production on leaf gas exchange. Thus, air cuvette being used for O2 measurements was sealed from temperature measured at 27 cm beneath the lamps fluctu- ambient air by insertion of a silicon septum (3 mm thick) ated between 21 and 23 ∞C during night-time and between into each Plexiglass tube. The one being used for CO2 mea- 23 and 27 ∞C during daytime. Because air ventilation surements was run in a permanent open airflow modus (see started about 30 min prior to the onset of light a drop in air below). temperature of 2–3 ∞C always marked the end of the night. Each pot was packed in a polyethylene bag leaving the top open, and immersed in the water bath of a cryostat O2 cuvette (Type MC5S0; Colora Messtechnik GmbH, Lorch, Ger- The concentrations of molecular oxygen were simulta- many). In each pot three copper–constantan thermocouples neously measured both, in the cuvette atmosphere 3 were inserted at different soil depths (7, 13 and 17 cm from (Vair = 5.28 cm ), and in the aqueous phase of the sapwood the surface) 8 cm radially off the stem base. A mean soil at a depth of 2.9 mm from the stem surface. Measurements temperature of 17 ± 0.3 ∞C at a depth of 13 cm was main- of molecular oxygen were performed by fibre-optical tained by permanent temperature control of the water baths. micro-optode sensors (see below). Two opposite tubes were Figure 1 presents the experimental set-up for both trees used as mechanical guides for the plastic syringes and the schematically. Air temperature and relative humidity were attached cannulae that penetrated through the silicon simultaneously measured at 27 and 95 cm beneath the lamps septa. The third tube was filled with soda lime as the CO2 by use of two Vaisala sensors (HMP 35 A; Vaisala, Helsinki, absorbent (Fig. 2). Thereby, during the experiments total Finland). Photosynthetic photon flux density (PPFD) was pressure in the O2 cuvette remained near constant at atmo- measured at half crown length, 55 cm beneath the lamps by spheric pressure because an increase of CO2 partial pres- use of three sensors (SKP 215; Skye Instruments Ltd, Llan- sure due to continuous CO2 efflux from the stem, was drindod Wells, Powys, UK) which were evenly positioned compensated by an equivalent chemical binding of CO2.
Load more

Recommended publications
  • Transport in Flowering Plants
    Transport in flowering plants Transport systems in plants Plants may not have blood vessels and a heart, but they nevertheless have transport systems of cells which form tubular vessels to transport molecules and ions in solution from one place to another. The xylem tissue carries water and dissolved ions from the roots to the aerial parts of the plant. In the tallest trees this can be over 100 metres. Phloem carries water and dissolved food molecules from the leaves to all parts of the plant. For more about the solvent properties of water see Soil water. Turgor and plasmolysis The shape of plant cells is defined by their cell wall. This is normally slightly stretched and rigid, due to the uptake of water by osmosis. Water will move from a less concentrated solution into a more concentrated solution through a partially permeable membrane, as there will be a diffusion gradient from where there is more water to where there is less water. The ability of water to move from one place to another is called water potential. Water will move from higher to lower water potential. The water potential of a cell,, is given by: = s + p Where s is the solute potential, due to particles dissolved in the water in the cytoplasm (which lowers water potential), and p is the pressure potential due to the stretching of the cell wall (which in increases water potential). The water potential of pure water at one atmosphere pressure is zero, so adding solutes has a negative effect on water potential, tending to make water enter a system.
    [Show full text]
  • The Transpiration Stream and Upward Translocation of Mineral Ions1' 2
    No. 6 MULTIPLE TILLS NEAR SHENANDOAH 357 THE TRANSPIRATION STREAM AND UPWARD TRANSLOCATION OF MINERAL IONS1' 2 JAMES W. O'LEARY Department of Botany, University of Arizona, Tucson ABSTRACT Ca46 and P32 were supplied simultaneously to young Phaseolus vulgaris L. seedlings grown in solution. After short periods of uptake, the Ca45/P32 ratios in opposite leaves and opposite leaflets were very similar. This relationship also held when Ca45 and Cs137 were paired. Ca45/P32 ratios in lateral halves of the same leaf were in good agreement, also. However, the basal halves of leaves always had higher Ca4B/P32 ratios than terminal halves. There was a negative acropetal gradient of Ca45/P32 ratio in the stem, but the ratio in the trifoliate leaves was higher than in the primary leaves. When roots were removed prior to supplying the radioisotopes, the Ca45/P32 ratios in the foliage and stems were lower than in plants with roots intact. The data obtained support the en masse flow concept of ion movement through the stem. The usual mechanism proposed for the upward translocation of mineral ions in plants is visualized as a bulk transport of these ions in the transpiration stream. This concept has led to considerable investigation attempting to ascertain the precise dependency of salt uptake and distribution on the movement of water through the plant. Several investigators have shown that an increase in transpira- tion rate is accompanied by an increase in salt uptake and movement to the shoots (Hylmo, 1953, 1955, 1958; Brouwer, 1954, 1956; Kylin and Hylmo, 1957; Smith, 1957). However, the mechanism whereby transpiration influences the overall p No.
    [Show full text]
  • Measurement of Root Hydraulic Conductance
    Measurement of Root Hydraulic Conductance Albert H. Markhart, III Department of Horticulture Science and Landscape Architecture, University of Minnesota, St. Paul, MN 55108 Barbara Smit Center for Urban Horticulture, University of Washington, Seattle, WA 98195 Plant root systems provide water, nutrients, and growth regulators transpiration at the shoot and osmotic potential. The latter is gen- to the shoot. Growth and production of a plant are often limited by erated by the combination of active solute accumulation, passive the ability of the root to extract water and nutrients from the soil solute leakage, and rate of water movement from the soil to the and transport them to the shoot. The transport of most nutrients and xylem. This is difficult, if not impossible, to determine. Conduc- growth regulators occurs via the transpiration stream. The velocity tivity of the radial pathway is determined by structures through and quantity of water moving from the root to the shoot determines which the water flows. Water flows along the path of least resis- the quantity and concentration of substances that arrive at the shoot. tance. Resistance of the interstices in the cell wall is considered Understanding the forces and resistances that control the movement lower than across plasmalemma and cytoplasm. For these reasons, of water through the soil-plant-air continuum and the flux of po- it is thought that water moves apoplasticly across the root until a tential chemical signals is essential to understanding the impact of significant barrier is encountered, at which point the water is forced the soil environment on root function and on root integration with through the plasmalemma.
    [Show full text]
  • The Dynamics of Transpiration to Evapotranspiration Ratio Under Wet and Dry Canopy Conditions in a Humid Boreal Forest
    Article The Dynamics of Transpiration to Evapotranspiration Ratio under Wet and Dry Canopy Conditions in a Humid Boreal Forest Bram Hadiwijaya 1 , Steeve Pepin 2, Pierre-Erik Isabelle 1,3 and and Daniel F. Nadeau 1,* 1 CentrEau—Water Research Center, Department of Water and Civil Engineering, Université Laval, 1065 avenue de la Médecine, Québec, QC G1V 0A6, Canada; [email protected] (B.H.); [email protected] (P.-E.I.) 2 Centre de Recherche et d’Innovation sur les Végétaux, Department of Soil and Agri-Food Engineering, Université Laval, 2480 boulevard Hochelaga, Québec, QC G1V 0A6, Canada; [email protected] 3 Premier Tech, 1 avenue Premier, Rivière-du-Loup, QC G5R 6C1, Canada * Correspondence: [email protected] Received: 31 January 2020; Accepted: 19 February 2020; Published: 21 February 2020 Abstract: Humid boreal forests are unique environments characterized by a cold climate, abundant precipitation, and high evapotranspiration. Transpiration (ET), as a component of evapotranspiration (E), behaves differently under wet and dry canopy conditions, yet very few studies have focused on the dynamics of transpiration to evapotranspiration ratio (ET/E) under transient canopy wetness states. This study presents field measurements of ET/E at the Montmorency Forest, Québec, Canada: a balsam fir boreal forest that receives ∼ 1600 mm of precipitation annually (continental subarctic climate; Köppen classification subtype Dfc). Half-hourly observations of E and ET were obtained over two growing seasons using eddy-covariance and sap flow (Granier’s constant thermal dissipation) methods, respectively, under wet and dry canopy conditions. A series of calibration experiments were performed for sap flow, resulting in species-specific calibration coefficients that increased estimates of sap flux density by 34% ± 8%, compared to Granier’s original coefficients.
    [Show full text]
  • Grandidentata in the Field at Ambient and Twice Ambient CO2 in Open
    grandidentata in the field at ambient and twice ambient CO2 in open productivity(1-4) This observation has led to the suggestion that, by bottom root boxes filled with organic matter poor native soil. Nitrogen taking up CO2, the terrestrial biosphere might mitigate the potential was added to all root boxes at a rate equivalent to net N mineralization greenhouse warming associated with anthropogenic CO2 emissions(5). in local dry oak forests. Nitrogen added during August was enriched Whiting and Chanton(6) have found, however, that for wetlands of with N-25 to trace the flux of N within the plant-soil system. Above- and varying productivity around the world, higher net primary production is belowground growth, CO2 assimilation, and leaf N content were associated with higher emissions of methane-another important measured non- destructively over 142 d. After final destructive harvest, greenhouse gas. Here we present measurements of methane emissions roots, stems, and leaves were analyzed for total N and N-15. There was from a marsh that has been exposed to twice the present ambient no CO2 treatment effect on leaf area, root length, or net assimilation concentration of atmospheric CO2. We find that over a one-week period, prior to the completion of N addition. Following the N addition, leaf N the CO2-enriched sites had significantly higher emissions of methane content increased in both CO2 treatments, but net assimilation showed than the control sites. Our results suggest that future increases in a sustained increase only in elevated CO2 grown plants. Root relative atmospheric CO2 concentration may lead to significant increases in extension rate was greater at elevated CO2, both before and after the N methane emissions from wetlands.
    [Show full text]
  • The Role Op Transpiration in the Absorption And
    THE ROLE OP TRANSPIRATION IN THE ABSORPTION AND TRANSLOCATION OP MINERAL IONS IN PLANTS, AS MEASURED WITH RADIOACTIVE CALCIUM AND PHOSPHORUS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By RAFIQ AHMAD, B.Sc. (Alig), M.Sc. (Punjab) The Ohio State University 1959 Approved hy Adviser Department of Botany and Plant Pathology ACKNOWLEDGMENT The ■writer wishes to express his gratitude to the faculty and graduate students of the Department of Botany and Plant Patho­ logy, The Ohio State University, for their great help during his stay in the U. S. A. Special thanks are due to Dr. C. A. Swanson for his guidance and encouragement during this investigation and other graduate studies. The writer is also thankful to Dr. R. S. Platt, Jr. for his help in preparing this manuscript and a critical reading of the draft. Thanks are also extended to Dr. C. G. Weis- haupt for critical reading of the manuscript. The writer also wishes to express his appreciation to The University of Karachi, Pakistan, for the grant of study leave, and to the Institute of International Education for the award of a travel grant to pursue these studies. ii TABLE OP CONTENTS Page INTRODUCTION ......................................... 1 LITERATURE R E V I E W ................................... 4 MATERIALS AND M E T H O D S ............................... 8 EXPERIMENTS AND R E S U L T S ............................. 14 Section 1 ....................................... 14 Experiments to investigate whether a low transpiration rate can he growth-limiting Section 2 ....................... .. 2 6 Experiments to determine the rate at which metabolically-absorbed phosphorus^ and c a l c i u m ^ become available for upward trans­ location into shoot Section 3...
    [Show full text]
  • Atmospheric Continuum Model to Study Hydrodynamic Soil‐
    PUBLICATIONS Water Resources Research RESEARCH ARTICLE A vegetation-focused soil-plant-atmospheric continuum model 10.1002/2017WR020467 to study hydrodynamic soil-plant water relations Key Points: Zijuan Deng1,2,3 , Huade Guan1,2, John Hutson1, Michael A. Forster4,5, Yunquan Wang6, and A new SPAC model is developed to Craig T. Simmons1,2 simulate soil/plant water flux and water status at subdaily resolution 1School of the Environment, Flinders University, Adelaide, South Australia, Australia, 2National Centre for Groundwater The model uses a dynamic plant 3 resistance system which is described Research and Training, Bedford Park, South Australia, Australia, Now at Centre for Carbon, Water and Food, Faculty of 4 by a plant physiological vulnerability Agriculture and Environment, University of Sydney, Sydney, New South Wales, Australia, School of Agriculture and Food curve Science, University of Queensland, Brisbane, Queensland, Australia, 5Edaphic Scientific Pty Ltd., Port Macquarie, New The model can be easily South Wales, Australia, 6School of Environmental Studies, China University of Geosciences, Beijing, China parameterized under field conditions and particularly useful to assimilate leaf/stem water potential data Abstract A novel simple soil-plant-atmospheric continuum model that emphasizes the vegetation’s role in controlling water transfer (v-SPAC) has been developed in this study. The v-SPAC model aims to incorpo- Supporting Information: Supporting Information S1 rate both plant and soil hydrological measurements into plant water transfer modeling. The model is differ- ent from previous SPAC models in which v-SPAC uses (1) a dynamic plant resistance system in the form of a Correspondence to: vulnerability curve that can be easily obtained from sap flow and stem xylem water potential time series Z.
    [Show full text]
  • Water Movement in Plants
    Chapter 3 - Water movement in plants Chapter editors: Brendan Choat and Rana Munns Contributing Authors: B Choat1, R Munns2,3,4, M McCully2, JB Passioura2, SD Tyerman4,5, H Bramley6 and M Canny* 1Hawkesbury Institute of the Environment, University of Western Sydney; 2CSIRO Agriculture, Canberra; 3School of Plant Biology, University of Western Australia; 4ARC Centre of Excellence in Plant Energy Biology; 5School of Agriculture, Food and Wine, University of Adelaide; 6Facutly of Agriculture and Environment, University of Sydney; *Martin Canny passed away in 2013 Contents 3.1 - Plant water relations 3.2 - Long distance xylem transport 3.3 - Leaf vein architecture and anatomy 3.4 - Water movement from soil to roots 3.5 - Water and nutrient transport through roots 3.6 - Membrane transport of water and ions 3.7 - References Evolutionary changes were necessary for plants to inhabit land. Aquatic plants obtain all their resources from the surrounding water, whereas terrestrial plants are nourished from the soil and the atmosphere. Roots growing into soil absorb water and nutrients, while leaves, supported by a stem superstructure in the aerial environment, intercept sunlight and CO2 for photosynthesis. This division of labour results in assimilatory organs of land plants being nutritionally inter-dependent; roots depend on a supply of photoassimilates from leaves, while shoots (leaves, stems, flowers and fruits) depend on roots to supply water and mineral nutrients. Long-distance transport is therefore a special property of land plants. In extreme cases, sap must move up to 100 m vertically and overcome gravity to rise to tree tops. Karri (Eucalyptus diversicolor) forest in Pemberton, Western Australia.
    [Show full text]
  • Environmental Factors Influence Plant Vascular System and Water
    plants Review Environmental Factors Influence Plant Vascular System and Water Regulation Mirwais M. Qaderi 1,2,* , Ashley B. Martel 2 and Sage L. Dixon 1 1 Department of Biology, Mount Saint Vincent University, 166 Bedford Highway, Halifax, NS B3M 2J6, Canada; [email protected] 2 Department of Biology, Saint Mary’s University, 923 Robie Street, Halifax, NS B3H 3C3, Canada; [email protected] * Correspondence: [email protected] Received: 9 January 2019; Accepted: 11 March 2019; Published: 15 March 2019 Abstract: Developmental initiation of plant vascular tissue, including xylem and phloem, from the vascular cambium depends on environmental factors, such as temperature and precipitation. Proper formation of vascular tissue is critical for the transpiration stream, along with photosynthesis as a whole. While effects of individual environmental factors on the transpiration stream are well studied, interactive effects of multiple stress factors are underrepresented. As expected, climate change will result in plants experiencing multiple co-occurring environmental stress factors, which require further studies. Also, the effects of the main climate change components (carbon dioxide, temperature, and drought) on vascular cambium are not well understood. This review aims at synthesizing current knowledge regarding the effects of the main climate change components on the initiation and differentiation of vascular cambium, the transpiration stream, and photosynthesis. We predict that combined environmental factors will result in increased diameter and density of xylem vessels or tracheids in the absence of water stress. However, drought may decrease the density of xylem vessels or tracheids. All interactive combinations are expected to increase vascular cell wall thickness, and therefore increase carbon allocation to these tissues.
    [Show full text]
  • Root Uptake of Organic Contaminants Into Plants: Species Differences
    Utah State University DigitalCommons@USU All Graduate Theses and Dissertations Graduate Studies 8-2012 Root Uptake of Organic Contaminants into Plants: Species Differences Naho Orita Utah State University Follow this and additional works at: https://digitalcommons.usu.edu/etd Part of the Civil and Environmental Engineering Commons Recommended Citation Orita, Naho, "Root Uptake of Organic Contaminants into Plants: Species Differences" (2012). All Graduate Theses and Dissertations. 1287. https://digitalcommons.usu.edu/etd/1287 This Thesis is brought to you for free and open access by the Graduate Studies at DigitalCommons@USU. It has been accepted for inclusion in All Graduate Theses and Dissertations by an authorized administrator of DigitalCommons@USU. For more information, please contact [email protected]. ROOT UPTAKE OF ORGANIC CONTAMINANTS INTO PLANTS: SPECIES DIFFERENCES by Naho Orita A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Civil and Environmental Engineering Approved: _____________________ _____________________ William J. Doucette Bruce Bugbee Environmental Chemist Plant Physiologist Major Professor Committee Member _____________________ _____________________ David K. Stevens Mark R. McLellan Environmental Engineer Vice President for Research and Committee Member Dean of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2012 ii Copyright © Naho Orita 2012 All Rights Reserved iii ABSTRACT Root Uptake of Organic Contaminants into Plants: Species Differences by Naho Orita, Master of Science Utah State University, 2012 Major Professor: Dr. William J. Doucette Department: Civil and Environmental Engineering Trace amounts of xenobiotic organic contaminants have been frequently identified in the environment, including surface water and wastewater streams, and some are even in drinking water.
    [Show full text]
  • Water Is a Very Important Substance Obtained and Transported Throughout Plants
    Water is a very important substance obtained and transported throughout plants Transpiration stream is the movement of water through a plant. Transpiration stream is maintained by: 1. Osmosis 2. Root pressure 3. Transpiration Osmosis is the movement of water from high water concentration to low water concentration across a semi-permeable membrane. Root pressure is the force exerted by water within the xylem tissue of the roots. Transpiration is the loss of water from the aerial parts of a plant. Water and mineral uptake: Water enters the root hairs by osmosis, moving from high water concentration to low water concentration. Minerals dissolve easily in water and move into the root by diffusion - either by passive transport or by active transport (requires ATP). Water moves across the ground tissue and into xylem tissue. Water is then transported up the plant. Cohesion-tension model of water transport John Joly and Henry Dixon were two Irish scientists who first proposed the cohesion-tension model of water transport. Water moving into the xylem tissue of the root causes a pressure build up - this is called root pressure. Root pressure contributes to the upward movement of water molecules. Water molecules have hydrogen bonds between them maintaining them in the liquid form - this is cohesion of the water molecules. Water molecules also tend to stick easily to the sides of the xylem vessels - this is called adhesion of the water molecules. Transpiration of the water molecules occurs mainly from the leaves - this pulls the column of water molecules upwards through the xylem, creating a tension in the water molecules.
    [Show full text]
  • Evaporation and Transpiration
    VOL. 17, N0. 6 REVIEWS OF GEOPHYSICS AND SPACE PHYSICS SEPTEMBER 1979 EVAPORATION AND TRANSPIRATION Robert R. Ziemer Pacific Southwest Forest and Range Experiment Station, Forest Service, U.S. Department of Agriculture, Berkeley, California, stationed at Arcata, California 95521 For years, the principal objective of evapo- evapotranspiration equation to include a term for transpiration research has been to calculate the canopy resistance signaled a shift in emphasis in loss of water under varying conditions of climate, evapotranspiration research from a physically soil, and vegetation. The early simple empirical controlled process to one which can be physio- methods have generally been replaced by more de- logically controlled. This change in direction tailed models which more closely represent the was acknowledged by Federer [1975] in his earlier physical and biological processes involved. review and has continued for the past four years. Monteith's modification of the original Penman The scope of this review, as were the reviews of Ekern [1971] and Federer [1975], is, for the most This paper is not subject to U.S copyright. Pub- part, limited to evaporation from terrestrial lished in 1979 by the American Geophysical Union. surfaces rather than from lake or ocean surfaces. Paper number 9R0474 1175 1176 A review of the literature since 1974 shows Stomata that substantial interest has been maintained in The role of stomata in the regulation of trans- understanding the influence of advection and piration has been widely studied. The environ- interception on evapotranspiration. As the com- mental factors that have a major influence on plexity of the models increases, the data require- stomatal resistance are irradiance [Hall et al., ments to drive the equations often make the model 1976], leaf water status [Jarvis, 1976; Shirazi useless for field applications.
    [Show full text]