C3C4, First Edition

 

Contents

 

 

 

         Preface

         Abbreviation

 

                                             PART A

Chapter 1

 

1       Introduction

1.1    What is it?

l. 2    Breaking bonds

l. 3    Oxidation and reduction

l. 4    Photosynthesis as an oxidation/reduction

l. 5    Winding the biological mainspring

l. 6    Photosynthesis as the source of organic carbon

l. 7    Analogy and epitaph

 

Chapter 2 Energy and Laws

        

2. l    The laws of thermodynamics

2. 2   The system

2. 3   Entropy(s)

2. 4   Free energy

2. 5   Free energy and equilibria

2. 6   Energy units

2. 7   The energy required for the formation of carbohydrate

2. 8   Bond energies

2. 9   Splitting water

2. l0 Resonance

2. 11 The free energy of hydrolysis of adenosine triphosphate (ATP)

2. 12 ATP as a component of ‘assimilatory power’

2. 13 Redox potentials

 

Chapter 3 Energy and Light

 

3 .l    Where it all starts

3. 2   Light as a waveform

3. 3   Light as a stream of particles

3. 4   Quanta

3. 5   The energy of light

3. 6  Light intensity

3. 7   Sunlight and candles

3. 8   The green man

3. 9   Quantum efficiency

3. l0 Photosynthetic efficiency at the molecular level

3. 11 Maximum photosynthetic efficiency of crops

3. l2 Maximum yield

 

Chapter 4 The Photochemical Apparatus and its Function

 

4. 1 Chloroplast structure

4. 2 The thylakoid compartment

4. 3 The stromal compartment

4. 4 Membrane structure

4. 5 Chlorophylls

4. 6 Chlorophyll synthesis

4. 7 The accessory pigments

4. 8 Chicken and egg

4. 9 Components of the electron transport chain

4. 10 The photosynthetic unit

4. 11 The pigment systems

4. 12 Reaction centres

4. 13 The photosystems (PSI and PSII)

4.14 Atomic absorption

4.15 Molecular absorption

4.16 Excitation of chlorophyll

4.17 De-excitation

4.18 Photochemistry and O2 evolution

4.19 Energy transfer within the pigment systems

4.20 Action spectra

4.21 The red drop

4.22 Enhancement

4.23 The Z-scheme

4.24 P/e ratios

4.25 Energy conservation in the Z-scheme

4. 26 Quantum requirement of the Z-scheme

 

Chapter 5  The Formation of ATP; the Generation of Assimilatory  Power

 

5.1 Oxidative phosphorylation

5.2 The need for assimilatory power

5.3 Cyclic photophosphorylation

5.4 Cyclic photophosphorylation catalysed by ferredoxin

5.5 Cyclic photophosphorylation in vivo

5.6 Pseudocyclic photophosphorylation

5.7 Non-cyclic photophosphorylation

5.8 The Mehler reaction

5.9 Chemiosmosis and the establishment of an electrochemical  potential difference or protonmotive force

5.10 The mechanism of ATP formation

5.11 Coupling, uncoupling and photosynthetic control

5.12 Coupling factor

5.13 Thermodynamics of ATP formation

5.14 Relationship between proton transport, electron transport and energy

5.15 The reduction of nicotinamide adenine dinucleotide phosphate (NADP)

 

 

 

         PART B

 

Chapter  6 The Reductive Pentose Phosphate Pathway and Associated Reactions

 

6.1 Photosynthetic Carbon fixation

6.2 Regeneration

6.3 Autocatalysis

6.4 Energetics

6.5 Affinity for CO2

6.6 Carboxylation characteristics summarized

6.7 Formulation of the reductive pentose phosphate pathway

6.8 Kinetic studies

6.9 Transients

6.10 Intra-molecular labelling

6.11 The enzymes

6.12 Free energies

6.13 The operation of the RPP pathway

6.14 Utilization of assimilatory power

6.15 Feedback

6.16 Integration of the RPP pathway and the photorespiratory carbon oxidation cycle

6.17 Carbon traffic through the RPP pathway and the photorespiratory pathway

6.18 Starch synthesis

6.19 Starch degredation

6.20 Regulation of starch synthesis and degradation

6.21 Sucrose synthesis

6.22 Up the carbon path

SUMMARY

 

 

Chapter 7  Induction

7.1 Induction in whole plants and leaves

7.2 Historical aspects

7.3 The role of stomata

7.4 Lack of induction in photochemistry

7.5 Induction in vitro

7.6 The molecular basis of induction

7.7 The contribution of autocatalysis

7.8 Light activation of catalysts

7.9 Effects of light intensity and temperature

7.10 Induction and orthophosphate

7.11 Reversal of orthophosphate inhibition by cycle intermediates

7.12 The nature of orthophosphate inhibition

7.13 Induction in O2 evolution and the role of PGA

7.14 Induction in CO2-fixation

7.15 Induction in the reconstituted chloroplast system

7.16 Sequence of events in induction

7.17 Restoration of induction

SUMMARY

 

 

Chapter 8  Plastids and Intracellular Transport

8.1 The chloroplast as a transporting organelle

8.2 The experimental basis of transport studies: fractionation of whole tissue

8.3 The experimental basis of transport studies in vitro

8.4 Chromatographic analysis

8.5 Centrifugal filtration

8.6 Indirect methods of following metabolite movement

8.7 Shortening of induction, reversal of orthophosphate inhibition

8.8 Addition of inhibitors

8.9 Catalysis by intact and ruptured chloroplasts

8.10 Osmotic volume changes

8.11 The movement of metabolites

8.12 Carbon dioxide

8.13 Triose phosphates and 3-phosphoglycerate

8.14 Orthophosphate and inorganic pyrophosphate

8.15 Pentose and hexose monophosphates

8.16 Sugar bisphosphates

8.17 Free sugars

8.18 Carboxylic acids

8.19 Amino acids

8.20 ATP and NADP

8.21 Ion fluxes

8.22 Specific permeability of the inner envelope

8.23 The phosphate translocator

8.24 The dicarboxylate translocator

8.25 The adenylate translocator

8.26 Shuttles

SUMMARY

 

 

Chapter 9 The Regulation of Photosynthetic Carbon Assimilation

 

9.1 General principles

9.2 Regulation of catalysis

9.3 Activation of catalysts

9.4 Regulation of catalysis and activation of catalysts - distinction

9.5 Dark deactivation

9.6 Mass action

9.7 Regulation by transport

9.8 Consequences of regulation

9.9 Addendum

SUMMARY

 

 

 

Chapter 10 Discovery of the C4 pathway

 

10.1 C4 dicarboxylic acids as early products of photosynthesis

10.2 Contributions by Hatch and Slack

10.3 Metabolism of C4 dicarboxylic acids

10.4 Anatomy of photosynthetic tissue of C4 plants

10.5 Isolation of chloroplasts, protoplasts and cells from C4 plants

10.6 Current simplified scheme of C4 photosynthesis

10.7 When can a species be considered C4?

l0.8 C4 photosynthesis and development

SUMMARY

 

 

 

Chapter 11 Three C4 subgroups: Biochemistry, Photochemistry and Taxonomy

 

11.1 The carboxylation phase of the C4 pathway

11.2 The decarboxylation phase of the C4 pathway

11.3 Summary of proposed major sequences of carbon flow through three decarboxylating mechanisms

11.4 Charge balance in intercellular transport through the C4 cycle

11.5 Intercellular localization of the RPP pathway in C4 plants

11.6 Photochemical requirements in C4 photosynthesis

11.7 Photochemical differences in chloroplast types

11.8 Taxonomy

SUMMARY

 

 

Chapter 12 Integration of Functions in C4 Photosynthesis.

l2.1 Intracellular localization of enzymes of the C4 cycle in mesophyll cells.

12.2 Enzyme localization and intracellular metabolite transport in the C4 cycle in bundle sheath cells

12.3 Evidence for photosynthetic functions of mesophyll cells

12.4 Evidence for photosynthetic functions of bundle sheath cells

12.5 Mechanism of intracellular metabolite transport

12.6 Mechanism of intercellular metabolite transport

12.7 C4 metabolism linked to cyclic.pseudocyclic and non-cyclic

photophosphorylation

12.8 Regulation of enzymes of the C4 cycle

12.9 Nitrogen assimilation - C4 versus C3 plants

12.10 Starch and sucrose synthesis in C4 plants.

SUMMARY

 

 

Chapter 13 Photorespiration

13.1 Introduction

13.2 Recognition

13.3 Origin of glycolate

13.4 The glycolate pathway in C3 plants

13.5 Simplified scheme of carbon flow in the glycolate pathway

13.6 Reactions of the glycolate pathway and energy requirements

13.7 Intracellular localization of enzymes of the glycolate pathway

13.8 Metabolism of isolated organelles in relation to the glycolate pathway

13.9 The glycolate pathway in C4 plants

13.10 O2 inhibition of photosynthesis and its components

13.11 Percentage inhibition of photosynthesis by O2

13.12 O2 effect on quantum yield

l3.l2a Damping of O2 inhibition through feedback inhibition

13.13 Suggested roles for photorespiration

13.14 Improved growth of C3 plants under low O2 or enriched CO2 environments

SUMMARY

 

 

Chapter 14 Primary Carboxylases and Environmental Regulation of Photosynthesis and Transpiration

14.1 Introduction

14.2 Composition of atmosphere and solubility of gases

14.3 C3 plants - RBP carboxylase

14.4 C4 plants - PEP and RBP carboxylase

14.5 Influence of temperature, light, and water stress on carboxylation

14.6 Water use efficiency

l4.6a Nitrogen use efficiency

14.7 C3, C4, and crop yield

SUMMARY

 

 

Chapter 15 Crassulacean Acid Metabolism

15.1 Introduction

15.2 Discovery

15.3 The Wood and Werkman reaction

15.4 The path of carbon in CAM

15.5 Carbon dioxide as a metabolite in the dark

15.6 The inverse relationship between substrate and product

15.7 The enzymes concerned in acidification and deacidification

15.8 The double carboxylation hypothesis

15.9 Light acidification

15.10 Energy requirements in CAM

15.11 CAM mode versus C3 mode

l5.lla CAM cycling

l5.llb CAM idling

15.12 Isotope fractionation in CAM relative to C3, C4

15.13 The relationship between CAM and C4

15.14 Ecological significance of CAM

SUMMARY

 

 

Chapter 16 Comparative Studies of C3, C4 Metabolism in Other Plant Tissue

16.1 Stomata

16.2 C3, C4 photosynthesis in reproductive tissue

16.3 Greening leaves

16.4 Roots

16.5 Ionic balance and pH-stat

16.6 Malate metabolism in the glyoxylate cycle of germinating seedlings

SUMMARY

 

 

         APPENDICES

 

Appendix A  Chloroplast Isolation and Criteria of Intactness

A.1 Introduction

A.2 Methods

A.3 Growth of plants

A.4 Mechanical procedures

A.5 Chloroplasts from protoplasts

A.5a Criteria for determining intactness of protoplasts

A.6 Advantages and disadvantages of mechanical versus enzymatic procedures

A.7 Criteria for determining intactness of chloroplasts

A.8 Purification

A.9 Chloroplast envelopes

 

Appendix B. Enzyme nomenclature

B.1. Reductive pentose phosphate pathway

B.2. The glycolate pathway

B.3. Metabolism of triose phosphate to sucrose

B.4. Starch synthesis from triose phosphate

B.5. C4 pathway

B.6. Crassulacean acid metabolism

B.7. Nitrate metabolism