LS3121           Plant Physiology 2001

T. Y. Lin

Week of                   Topic                                                                Reading assignment

Sept 17, 19              Introduction to plant physiology                                 Chap 1, 2

Sept 24, 26              Water and plant cells                                                 Chap 3

Oct 3, 8                   Water balance of the plant                                         Chap 4

Oct 15, 17               Mineral and solute transport                                      Chap 5, 6

Oct 22, 24               Photosynthesis                                                          Chap 7, 8

Oct 29                     First examination                                                   Chap 1-7

Oct 31                     Photosynthesis                                                          Chap 9

Nov 5, 7                  Translocation    and respiration                                  Chap 10, 11

Nov 12, 14              Respiration and lipid metabolism                               Chap 11

Nov 19, 21              Assimilation of mineral nutrients                                 Chap 12

Nov 26, 28              Plant defenses and cell walls                                      Chap 13, 15

Dec 3                      Second examination                                               Chap 7-12

Dec 5                       Plant Growth and development                                 Chap 16

Dec 10, 12               Phytochrome and blue light receptors                        Chap 17, 18

Dec 17,19                Auxins and Gibberellins                                             Chap 19, 20

Dec 24,26                Cytokinins, ethylene, Abscisic acid                            Chap 21, 22, 23

Dec 31                     Flowering and stress physiology                                Chap 24, 25

Jan 7                       Final examination                                                   Chap 16-23

 

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1.         
There will be some quizzes in class on Monday.

2.          The final grade is calculated as follows.  Each examination is 25%, homework is 15% and quizzes are 10%.

3.          Textbook: Taiz, L. and Zeiger, E.  1998.  Plant Physiology. 2nd ed.  Sinauer Associates, Inc., Sunderland, Massachusetts.

4.          Reference: Hopkins, W. G.  1995.  Introduction to Plant Physiology.  John Wiley and Sons, Inc., Belmont, California.

5.          Reference:Buchanan, B. B., Gruissem, W. and Jones, R. L. 2000. Biochemistry and Molecular Biology of Plants. American Society of Plant Physiologists, Rockville, Maryland.

6.          Office hour (Room: Life Science I-527): Monday 2-4 pm. Tel: 2758 or 3486

7.     TA: Hsiao-Ching Lee, Life Science Building I, Rm 529, Tel:3486

 

Interesting Websites

Orchids

   Phalaenopsis Species A to Z      http://phalaenopsis.net/speciesAZ/

   Royal Botanic Gardens, Kew: Home page         http://www.rbgkew.org.uk/

PlantCell

   ASPP Home Page     http://aspp.org/

   Bean Genes Homepage     http://beangenes.cws.ndsu.nodak.edu/

   Plant Genome Data and Information Center        http://www.nalusda.gov/pgdic/

   Rice-Research           http://www.rice-research.org/

   TAIR (The Arabidopsis Information Resource)   http://www.arabidopsis.org/

   Tissue Cutlture   http://www.xarma.com.au/Culture.html     

Kimball's Biology Pages              http://www.ultranet.com/~jkimball/BiologyPages/

Gene

   European Molecular Biology Laboratory (EMBL) http://www.embl-heidelberg.de/

   Genome Sequence DataBase     http://www.ncgr.org/research/sequence/

   GenomeNet WWW server http://www.tokyo-center.genome.ad.jp/

   Harvard Biological Laboratories - Genome Research         http://golgi.harvard.edu/

   LEHLE SEEDS Home Page      http://www.arabidopsis.com/

   MAFF DNA Bank(Japan)         http://bank.dna.affrc.go.jp/

   Maize Genome Database World Wide Web Server http://www.agron.missouri.edu/

   NCSA BIOLOGY WORKBENCH http://biology.ncsa.uiuc.edu/

   New EBI Home Page        http://www.ebi.ac.uk/

RICE GENOME RESEARCH PROGRAM (RGP) HOME PAGE http://rgp.dna.affrc.go.jp/

   The Institute for Genomic Research    http://www.tigr.org/

   The National Center for Biotechnology Information http://www.ncbi.nlm.nih.gov/

The Sanger Centre     http://www.sanger.ac.uk/

The TIGR Arabidopsis thaliana Database http://www.tigr.org/tdb/ath1/htmls/index.html

   The TIGR Rice Genome Project        http://www.tigr.org/tdb/rice/

   PDB WWW Home Page   http://www.rcsb.org/pdb/

   PSORT WWW Server              http://psort.nibb.ac.jp/

   http://saturn.nchc.gov.tw:8001/

World-Wide Web Virtual Library: Botany (Biosciences) http://www.ou.edu/cas/botany-micro/www-vl/

Foldermus

   Missouri Botanical Garden Information Desk  http://www.mobot.org/MOBOT/

 

LS3121 Plant Physiology

Lec 1    2001

I.    Introduction to plant physiology

1.    Changing technologies with a constant goal.

2.    What is plant physiology?

II.   The plant kingdom: Plantae

1.    Red algae

2.    Green algae (Chlorella)

3.    Plants

(1). Bryophytes

(2). Vascular plants (ferns)

(3). Seed plants

 a.  Gymnosperms

 b. Angiosperms: monocotyledons and dicotyledons

III.  The plant cell

IV.  The Extracellular Matrix

1.    The function of the cell wall-provides rigidity and protection.

2.    The primary cell wall

3.    Secondary walls

4.    The synthesis of wall matrix and cellulose

5.    Plasmodesmata are membrane-lined channels.

6.    Cell wall proteins

V.   Plant Tissues

1.     Dermal tissue-epidermis, ground tissue-parenchyma, vascular tissue-xylem and phloem.

2.         Supporting tissues-collenchyma and sclerenchyma (sclerids and fibers).

 

 

 

 

 

Lecture 2    Water and Plant Cells

I.             Introduction

1.    The importance of water molecules in plant cells

2.          The importance of turgor pressure in plant cells.

II.          Water Transport

1.           The thermal, cohesive and adhesive properties of water

2.           Diffusion

3.         Long-distance water transport in the plant (Poiseuille equation)

Volume flow rate = (pr4/8h) (DYp/Dx)

4.    Osmosis

5.    Osmosis and chemical potential

(1).  Water potential is defined as the chemical potential of water divided by the partial volume of water.

(2). Chemical potential of water

          m = m* + RTlnC + VP

(3). Ys, osmotic potential (p: osmotic pressure)

Ys = -p = iRTlnaw / Vw = -iRTCs (Vant' Hoff equation)

i: a constant that accounts for deviation from perfect solutions

III.  Water Potential and Its Components

1.    The chemical potential of water

             Yw = (m - m*)/ Vw = P - p

             Yw = P - p = Yp + Yp

 

2.    The major factors of water potential

Yw = Ys + Yp + Yg

(1). Yp, turgor pressure

(2). Yg, gravity

Yg = rwgh = 0.01 Mpa m-1h

3.    Water movement in cells and tissues: incipient plasmolysis and plasmolysis

4.           The cell wall is rigid.

(1).  The change in cell volume with any given change in pressure is determined by the rigidity of the wall: volumetric elasticity modulus (e).

                             DYp

                   e =   

DV / V

IV.  The Rate of Water Transport

            Flow rate = driving force ´ 1/resistance

       Flow rate = driving force ´ hydraulic conductivity

       Transport (flow) rate = Lp (DYp)

L: hydraulic conductance

V.   Measuring Water Potential

1.    Measuring Yw: Chardakov developed this method at 1948.

2.    Measuring Ys: thermalcouple psychrometer (Boyer and Knipling, 1965)

3.    Measuring Ys: cryoscopic osmometer

4.    Pressure chamber (Dixon and Scholander, 1965; Tyree and Hammel, 1972)

5.     Pressure probe (Green and Stanton, 1967; Steudle, Hüsken and Zimmerman, 1978)

 

Lecture 3          Water Balance of the Plant

I.    Water in the Soil

1.    Factors that affect water content

(1). Evaporation and transpiration

(2). Field capacity of soils and the permanent wilting point

2.    Soil water potential constitutes two components:

(1). The osmotic pressure (p) of soil water

(2). The hydrostatic pressure (P).

Yp = -2T/r

T: the surface tension of water (7.28 x 10-8 MPa m)

II.   Water Conduction

1.         Water movement

2.         Water absorption by the root

(1). Water moves in the root (Casparian strip)

(2). Root pressure

3.    Water is transported through tracheids and vessels

4.     Water movement through the xylem requires less pressure than movement through living cells.

(1). Pressure gradient required for water moves through an ideal vessel at a rate of 4 x 10 -3 m s-1 (Jv) is

                 DP/Dx = 2 ´ 104 Pa m-1 = 0.02 MPa m-1

(2). Velocity of water moves across a membrane of a living cell

          Lp (membrane hydraulic conductivity) = 4 ´ 10-7 m s-1MPa-1

          DYw = 2 ´ 104 MPa/10-4 m = 2 ´ 108 Mpa m-1

III.  The Ascent of Xylem Water

1.    How does nature lift water to the top of a 100-meter tree?

(1).  Pressure gradient needed is 2 ´ 104 Pa m-1 ´ 100 m = 2 MPa.

(2).  Weight creates a pressure of 0.01 Mpa m-1 ´ 100 m = 1 MPa.

(3).  The cohesion-tension theory

2.     Water evaporation in the leaf generates a negative pressure in the xylem.

IV.  Transpiration

1.    The transpiration process (lysimeter)

2.    Transpiration rate

(1).  Driving force of transpiration: the difference in water vapor pressure between the internal air spaces of the leaf and the surrounding air.

             Diffusion of water vapor in air is fast

                                (distance)2                (10 ´ 10-3 m)2

tC=1/2      =                              =                             =    0.042 s

                           Ds                     2.4 ´ 10-5 m2 s-1

(2). Factors influence transpiration rate

a.    Effect of humidity

b.   Effect of temperature

c.    Effect of wind: boundary layer resistance

(a). The boundary layer is a thin film of still air hugging the surface of the leaf.

(b).  The boundary layer resistance to water vapor diffusion is proportional to its thickness (da).

d.   Stomatal resistance

(a). Regulating water loss: to minimize transpiration

(b). Controlling CO2 uptake: to maximize stomatal control

3.    The transpiration ratio = 1 / water use efficiency     

moles of H2O transpired

Transpiration ratio =                                           »  500

moles of CO2 fixed

 

 

Lecture 4  Mineral and Solute Transport (I)

I.    The Plant Root System and Its Interaction with the Soil

1.    The form of the root system

2.     Mucigel: protects the root apex from desiccation, promotes nutrient transfer, and affects root interaction with soil microorganisms.

II.   Soil and Minerals

1.    Soil particles have negative charges on surfaces (cations and anions)

2.    Soil pH affects nutrient availability, soil microbes and root growth.

3.    The hydroponic system: nutrient film techniques and aeroponic systems.

III.  Essential Nutrient Elements

1.    Criteria for essential element to a plant

2.    Hoagland's solution

IV.  Roles of Essential Elements and Nutrient Disorders

1.    The function of essential elements

2.    Estimating the Nutrient Supply

(1).  Soil analysis

(2). Plant tissue analysis

3.    Elements C, H, O: H2O and CO2

4.    N, P, K, S, Ca, Mg, Fe, B, Cu, Zn, Mn, Mo, Cl, Ni, Na, Si

V.   Sequestration of Heavy Metals (Cd, Pb, Cu, Hg, Zn, Ni) by Phytochelatin

1.    Metallothioneins: low MW proteins with a high cystein content.

2.     Phytochelatin: a family of peptides with one to ten repetitive γ-glutamyl cysteinyl units (Phytochelatin synthetase).

         (γ-Glu-Cys-SH)n-Gly  (n=2-11)

 

 

Lecture 5   Mineral and Solute Transport (II)

I.    A Nutrient Reservoir: the soil

1.    The colloidal nature of soil

(1).  Tyndall effect: the suspended clay particles will scatter the light, causing the path traversed by the light being visible.

(2).  A colloidal suspension is a two-phase system (micelle in a liquid phase).

a.     The large specific surface area of colloids (a hydration shell).

b.    Numerous negative charges on the colloid surface

c.     Humus

(3). Colloids are highly hydrated (a hydration shell).

2.    Ion exchange in the soil

(1). Ion exchange and lyotropic series:

       Al+3 > H+ > Ca2+ > Mg2+ > K+ = NH4+ > Na+

(3). Influence of acid rain

II.   Root-Microbe Interaction

1.    Bacteria

(1).  Root secretions (polysaccharides) and mucigel

(2).  Nitrogen-fixing bacteria to enhance nutrient uptake

2.    Mycorrhiza

(1). The ectotrophic mycorrhizae

a.    Short, highly branched and a tightly interwoven mantle of fungal mycelium

c.     Some penetrates between cortical cells (Hartig net).

(2). Endomycorrhizae

a.          Vesicular-arbuscular mycorrhizae (VAM).

b.    Hyphae penetrate the individual cells of the cortex.

c.     Within the cells, the hyphae can form ovoid structures (vesicles) and highly branched structures (arbuscules) to increase contact surface.

(3). Association of mycorrhizae with plant roots facilitates phosphate uptake.

III.  Membrane Transport

1.    Passive and active transport

2.    Diffusion (passive transport): simple diffusion and facilitate diffusion

III.  Ion Uptake by Roots

1.    Electrochemical gradients and ion movement

(1). Transport of ions across a membrane barrier

a.    The Nernst equation (DEnj = Ei - Eo)

mj* + RT lnCjo + zj FEo = mj* + RT lnCji + zj FEi

                           RT            Cjo              2.3 RT                  Cjo

DEnj =               ln                 =                       log

              zjF             Cji                zjF                        Cji

Cjo

zDEnj = 59 log

Cji

The Nernst equation can be used to determine whether the ion is distributed actively or passively across a membrane.

b.    The Goldman equation

 

RT           PkCko + PNaCNao + PClCCli

DEm =               ln

F             PkCki + PNaCNai + PClCClo

3.    Ionic concentrations in the cytosol and the vacuole

(1). Electrogenic proton transport is mediated by an electrogenic pump

a.    H+-ATPase in plant cells

Dp = proton driving force (Mitchell and chemiosmosis)

DmH                        2.3 RT               [H]i

Dp  =                 =  DEm +                 log

F                                 F                 [H]o

 

2.3RT

Dp = DEm -            DpH = DEm - 59 DpH

F

b.   Electrogenic calcium transport by an ATPase

c.    K+/H+-ATPase of bacteria-electroneutral transport

(2).  Cotransport: Dp generated by electrogenic H+ transport is used to drive transport of other substances against electrochemical gradients.

       Symport and antiport

(3). Solute accumulation in the vacuole is driven by the tonoplast H+-ATPase

The tonoplast H+-ATPase is insensitive to vanadate and inhibited by nitrate.

4.    The radial path

(1). The apoplast and the symplast pathways

(2). Uptake of ions into xylem

5.         Pumps

(1).  F-type H+-pumping ATPases (mitochondria and thylokoid).

(2).  Plasma membrane H+-pumping ATPases is a P-type ATPases.

(3).  F-type H+-pumping ATPases synthesize ATP at the expense of the pmf, wherease P-type ATPases hydrolyze ATP and generate a pmf.

(4).  Ca2+-ATPases are P-type ion-motive ATPases.

(5).  Vacuolar H+-ATPases (V-type) are inhibited by bafilomycin A1.

(6).  Plant membrane possesses a unique H+-PPase.

(7).  Amphipathic compounds are moved across the vacuolar membrane by ATP-binding cassette (ABC) transporters.

6.         Ion channels

(1).  Ionic fluxes through channels are driven solely by electrochemical potential differences.

(2).  Plant inward rectifier K+ channel ATK1 is a member of the Shaker family.

(3).  The outward rectifier KCO1 is a member of the “two-pore” K+ channel family and is sensitive to the cytosolic [Ca2+].

(4).  Voltage-insensitive cation channels may be a major pathway for Na+ uptake across the plasma membrane and for salt release to the xylem.

(5).  Monovalent cation channels at the vacuolar membrane are Ca2+–sensitive and mediate vacuolar K+ mobilization.

(6).   Calcium-permeable channels in the plasma membrane (depolarization) provide potential routes for entry to the cytosol during signal transduction.

(7).   Plasma membrane anion channels facilitate salt release during turgor adjustment and elicit membrane depolarization after stimulus perception.

(8).   Vacuolar malate channels participate in malate sequestration.

7.         Water transport through aquaporins

(1). Directionality of water flow

Jv = Lp (DP -sDp )

(2). Membrane permeability to water

            Pf = Lp RT/Vw

(3).  Aquaporins are members of major intrinsic protein family, which can form water channels when expressed in heterologous systems.