Advances in Photosynthesis and Respiration	8
	The Chloroplast: Basics and Applications	4
	Contents	16
	Preface	26
	Contributors	38
	Chapter 1: Investigation of Possible Relationships Between the Chlorophyll Biosynthetic Pathway, the Assembly of Chlorophyll–	42
	I Introduction	44
	II Agricultural Productivity and Photosynthetic Efficiency	44
	A The Primary Photochemical Act of Photosystem I (PS I) I and II	44
	B Conversion of Carbon Dioxide into Carbohydrates	45
	C Theoretical Maximal Energy Conversion Efficiency of the Photosynthetic Electron Transport System of Green Plants	45
	D Actual Energy Conversion Efficiency of the PETS of Green Plants Under Field Conditions	46
	III Molecular Basis of the Discrepancy Between the Theoretical Maximal Efficiency of the Photosynthetic Electron Transport Cha	46
	A Contribution of Extrinsic Photosynthetic Electron Transport System Parameters to the Discrepancy between the Theoretical Phot	46
	B Contribution of Intrinsic Photosynthetic Electron Transport Chain Parameters to the Discrepancy Between the Theoretical Pho	46
	IV Correction of the Antenna/Photosystem Chlorophyll Mismatch	47
	A State of the Art in Our Understanding of Chlorophyll Biosynthesis	47
	1 The Single-Branched Chl Biosynthetic Pathway Does Not Account for the Formation of All the Chlorophyll in Green Plants	47
	2 The Chlorophyll of Green Plants Is Formed Via a Multibranched Biosynthetic Pathway	48
	B Thylakoid Apoprotein Biosynthesis	49
	C Assembly of Chlorophyll–Protein Complexes	50
	1 Assembly of Chlorophyll–Protein Complexes: The Single-Branched Chlorophyll Biosynthetic Pathway (SBP)-Single Location Model	50
	2 Assembly of Chlorophyll–Protein Complexes: The Single- Branched Chlorophyll Biosynthetic Pathway-Multilocation Model	51
	3 Assembly of Chlorophyll–Protein Complexes: The Multi-Branched Chlorophyll Biosynthetic Pathway (MBP)-Sublocation Model	51
	D Which Chl–Thylakoid Apoprotein Assembly Model Is Validated by Experimental Evidence	52
	1 Can Resonance Excitation Energy Transfer Between Anabolic Tetrapyrroles and ­Chlorophyll–Protein Complexes be ­Demonstrated?	53
	(a) Induction of Tetrapyrrole Accumulation	53
	(b) Selection of Appropriate Chlorophyll .a. Acceptors	54
	(c) Acquisition of In Situ Emission and Excitation Spectra at 77 K	54
	(d) Generation of Reference In Situ tetrapyrrole Excitation Spectra	54
	(e) Processing of Acquired Excitation Spectra	54
	(f) Demonstration of Resonance Excitation Energy Transfer Between Anabolic Tetrapyrroles and Chlorophyll–Protein Complexes	54
	2 Development of Analytical Tools for Measuring Distances Separating Various Chlorophyll–Protein Complexes from Anabolic Tetr	55
	(a) Determination of the Molar Extinction Coefficients of Total Chl .a. In Situ at 77 K	55
	(b) Estimation of the Molar Extinction Coefficients of Chl a ~F685, ~F695 and ~F735 at 77 K	55
	(c). Calculation of Distances R Separating Anabolic Tetrapyrroles from Various Chl a–protein Complexes	55
	(d) Calculation of R.0	57
	(e) Calculation of k, the Orientation Dipole	57
	(f) Calculation of the Overlap Integral .Ju at 77K	57
	(g) Calculation of n0., the Mean Wavenumber of Absorption and Fluorescence Peaks of the Donor at 77 .K	57
	(h) Calculation of t0., the Inherent Fluorescence Lifetime of Donors at 77 K	58
	(i) Calculation of Fy.Da. the Relative Fluorescence Yield of Tetrapyrrole Donors in the Presence of Chl Acceptors In Situ at 77	58
	(j) Calculation of tD., the Actual Mean Fluorescence Lifetime of the Excited Donor in the Presence of Acceptor at 77 K	59
	(k) Calculation of R.0. for Proto, Mp(e) and Pchlide .a. donors-Chl .a. Acceptors Pairs at 77 K	59
	(l) Calculation of E, the Efficiency of Energy Transfer In Situ at 77 K	59
	(m) Calculation of the Distances That Separate Proto, Mp(e), DV Pchlide .a., and MV Pchlide .a. from Various Chl .a. Acceptors	60
	3 Testing the Functionalities of the Various Chl–Thylakoid Biogenesis Models	60
	(a) The Single-Branched Pathway-Single Location Model Is Not Compatible with Resonance Excitation Energy Transfer Between An	61
	(b) The SBP-Multilocation Model Is Not Compatible with the Realities of Chl Biosynthesis in Green Plants	61
	(c) The MBP-Sublocation Model Is Compatible with the Realities of Chl Biosynthesis in Green Plants, and with Resonance Excitati	61
	E Guidelines and Suggestions to Bioengineer Plants with Smaller Photosynthetic Unit Size	62
	1 Selection of Mutants	62
	(a) Mutants of Higher Plants Other Than Arabidopsis	62
	(b) Arabidopsis Mutants	62
	(c) Lower Plant Mutants	62
	2 Preparation of Photosynthetic Particles	62
	3 Determination of Biosynthetic Routes Functional in a Specific Mutant or Photosynthetic Particle	62
	References	63
	Chapter 2: Evidence for Various 4-Vinyl Reductase Activities in Higher Plants	66
	I Introduction	67
	II Materials and Methods	70
	A Plant Material	70
	B Light Pretreatment	70
	C Chemicals	70
	D Preparation of Divinyl Protochlorophyllide .a	70
	E Preparation of Divinyl Chlorophyllide .a	70
	F Preparation of Divinyl Mg-Protoporphyrin Mono Methyl Ester	70
	G Isolation of Crude and Purified Plastids	70
	H Preparation of Plastid Membranes and Stroma	71
	I Preparation of Envelope Membranes	71
	J Solubilization of [4-Vinyl] Reductase(s) by 3-[(3-Cholamidopropyl)dimethylammonio]-1-Propanesulfonate	71
	K Assay of [4-Vinyl] Reductase Activities	71
	L Protein Determination	71
	M Extraction and Determination of the Amounts of Divinyl and Monovinyl Tetrapyrroles	71
	III Results	71
	A Experimental Strategy	71
	B Detection of [4-Vinyl]Protochlorophyllide .a. Reductase, [4-Vinyl]Mg-Protoporphyrin Monoester Reductase and [4-Vinyl]Mg-Prot	72
	C Solubilization of [4-Vinyl]Protochlorophyllide .a. Reductase, [4-Vinyl]Mg-Protoporphyrin Monoester Reductase and [4-Vinyl]Mg-	72
	D 4-Vinyl Side Chain Reduction Occurs Before Isocycle Ring Formation in Photoperiodically-Grown Barley	72
	E [4-Vinyl] Chlorophyllide .a. Reductase and [4-Vinyl]Protochlorophyllide .a. Reductase Activities do not Occur in Barley Et	73
	F [4-Vinyl] Protochlorophyllide .a. Reductase Activity Is Detectable in Greening Barley	73
	G NADPH, but Not NADH is a Cofactor for [4-Vinyl]Chlorophyllide Reductase and [4-Vinyl]Protochlorophyllide Reductase Solubilize	73
	H The Presence of NADP or Vitamin B.3. in the Incubation Buffer Has No Effect on the Activities of [4-Vinyl]Chlorophyllide .a.	74
	I Demonstration of [4-Vinyl] Protochlorophyllide a Reductase and [4-Vinyl] Chlorophyllide .a. Reductase Activities in Barley Ch	74
	J Effects of Various Light Treatments on [4-Vinyl] Clorophyllide .a. Reductase Activity	75
	IV Discussion	75
	References	78
	Chapter 3: Control of the Metabolic Flow in Tetrapyrrole Biosynthesis: Regulation of Expression and Activity of Enzymes in th	80
	I Introduction	81
	II Mg Protoporphyrin IX Chelatase	81
	A Structure and Catalytic Activity	81
	B Control of Expression, Activity and Localisation	83
	C Analysis of Mutants and Transgenic Plants	84
	III S-Adenosyl-L-Methionine:Mg Protoporphyrin IX Methyltransferase	85
	IV Mg Protoporphyrin IX Monomethylester Cyclase	86
	V Divinyl Reductase	87
	VI Regulatory Aspects of Mg Porphyrin Synthesis	87
	References	90
	Chapter 4: Regulation and Functions of the Chlorophyll Cycle	95
	I Introduction	96
	A Distribution of Chlorophyll .b	96
	B Establishment of the Chl Cycle	98
	1 Chl .b. Synthesis	98
	2 Chl .b. to Chl .a. Conversion	99
	3 Why Is the Interconversion of Chl .a. and Chl .b. Called the Chl Cycle?	100
	II Pathway and Enzymes of the Chlorophyll (Chl) CycleA Pathway of the Chl Cycle	100
	B Enzymes of the Chl Cycle	102
	1 Chlorophyllide .a. Oxygenase	102
	2 Chl .b. Reductase	103
	3 HM-Chl .a. Reductase	103
	III Diversity and Evolutionary Aspects of Chlorophyllide .a. Oxygenase	103
	A Diversity of CAO Sequences	103
	B Domain Structure of CAO	106
	C Distribution of Chl .b. Reductase	106
	IV Regulation of the Chl Cycle	107
	A Regulation of the Chl .a. to .b. Conversion	107
	1 Transcriptional Control	107
	2 The Signal Transduction Pathway	107
	3 Post-transcriptional Control	108
	B Regulation of the Chl .b. to .a. Conversion	108
	V Roles of the Chl Cycle in the Construction of the Photosynthetic Apparatus	109
	A Coordination of the Chl cycle and the Construction of the Photosynthetic Apparatus	109
	B Construction and Deconstruction of the Photosynthetic Apparatus and Its Coordination with the Chl .b. to .a. Conversion Syste	112
	References	113
	Chapter 5: Magnesium Chelatase	118
	I Introduction	119
	II The 40 kDa Subunit	119
	III Comparision of 40 kDa Subunit with the Golgi Membrane Protein NSF-D2, Heat Shock Locus Protein HslU and the .d¢. Subun	120
	IV The 70 kDa Subunit and Its Complex Formation with the 40 kDa Subunit	122
	V The 140 kDa Subunit	124
	VI The Gun4 Protein	125
	References	126
	Chapter 6: The Enigmatic Chlorophyll .a. Molecule in the Cytochrome .b6f. Complex	128
	I Introduction: On the Presence of Two Pigment Molecules in the Cytochrome .b6f. Complex	129
	II Crystal Structures of the Cyt .b6f. Complex: The Environment of the Bound Chlorophyll	129
	III Additional Function(s) of the Bound Chlorophyll	130
	IV Additional Function of the .b.-Carotene	131
	References	131
	Chapter 7: The Non-mevalonate DOXP/MEP (Deoxyxylulose 5-Phosphate/Methylerythritol 4-Phosphate) Pathway of Chloroplast Isopre	133
	I Introduction	134
	II The Cytosolic Acetate/Mevalonate (MVA) Pathway of Isopentenyl Pyro phosphate (IPP) Biosynthesis and Its Inhibition	135
	III The Plastidic DOXP/MEP Pathway of IPP and Its Inhibition	137
	IV Labeling Experiments of Chloroplast Prenyllipids	138
	V Compartmentation of Isoprenoid Biosynthesis in Plants	139
	VI Branching Point of DOXP/MEP Pathway with Other Chloroplast Pathways	140
	VII Cross-Talk Between Both Cellular Isoprenoid Pathways	142
	VIII Earlier Observations on Cooperation of Both Isoprenoid Pathways	143
	IX Distribution of the DOXP/MEP and the MVA Pathways in Photosynthetic Algae and Higher Plants	144
	X Evolutionary Aspects of the DOXP/MEP Pathway	147
	XI Biosynthesis of Isoprene and Methylbutenol	147
	XII Level of Chlorophylls, Carotenoids and Prenylquinones in Sun and Shade Leaves	149
	XIII Inhibition of Chlorophyll and Carotenoid Biosynthesis by 5-Ketoclomazone	150
	XIV Conclusion	151
	References	152
	Chapter 8: The Methylerythritol 4-Phosphate Pathway: Regulatory Role in Plastid Isoprenoid Biosynthesis	157
	I Introduction	158
	II Regulatory Role of the MEP Pathway in Plastid Isoprenoid Biosynthesis	159
	III Crosstalk Between the MVA and the MEP Pathways	161
	IV Perspectives for Metabolic Engineering of Plastid Isoprenoids	162
	References	162
	Chapter 9: The Role of Plastids in Protein Geranylgeranylation in Tobacco BY-2 Cells	165
	I Introduction	166
	II Protein Isoprenylation in Plants	167
	A The Chemical Modification of a C-Terminal Cysteine	167
	B Functions of Protein Prenylation in Plants	167
	C Isoprenylation of Proteins in Tobacco BY-2 Cells	167
	D Origin of the Prenyl Residue Used for Protein Modification	167
	1 A Double Origin of Prenyl Diphosphates	167
	2 Construction of a Tool to Test the Origin of Geranylgeranyl Residues in Prenylated Proteins	168
	(a) State of the Art	168
	(b) Tobacco BY-2 Cell Suspensions as a Suitable Tool	168
	(c) Description of the System and Results	169
	III Conclusion and Perspectives	172
	References	172
	Chapter 10: The Role of the Methyl-Erythritol-Phosphate (MEP)Pathway in Rhythmic Emission of Volatiles	176
	I Introduction	177
	II The MEP Pathway and Rhythmic Emission of Floral Volatiles	178
	III The MEP Pathway and Rhythmic Emission of Leaf Volatiles	184
	IV The MEP Pathway and Rhythmic Emission of Herbivore-Induced Plant Volatiles	185
	V The MEP Pathway and Rhythmic Emission of Isoprene	185
	VI Conclusions	187
	References	187
	Chapter 11: Tocochromanols: Biological Function and Recent Advances to Engineer Plastidial Biochemistry for Enhanced Oil Seed	191
	I Introduction	192
	II Tocochromanol Biosynthesis and Regulation	195
	III Tocochromanol Pathway Engineering for Enhancement of Vitamin E	197
	IV Optimized Tocochromanol Composition	197
	V Enhancement of Total Tocochromanol Content	198
	VI Enhancement of Tocotrienol Biosynthesis	200
	VII Conclusions and Outlook	200
	References	202
	Chapter 12: The Anionic Chloroplast Membrane Lipids: Phosphatidylglycerol and Sulfoquinovosyldiacylglycerol	206
	I Introduction	207
	II Biosynthesis of Plastidic Phosphatidylglycerol	209
	III Biosynthesis of Sulfoquinovosyldiacylglycerol	210
	IV Functions of Plastid Phosphatidylglycerol	211
	V Functions of Sulfoquinovosyldiacylglycerol	212
	VI The Importance of Anionic Lipids in Chloroplasts	213
	VII Future Perspectives	214
	References	215
	Chapter 13: Biosynthesis and Function of Monogalactosyldiacylglycerol (MGDG), the Signature Lipid of Chloroplasts	219
	I Introduction	220
	II Identification of MGDG Synthase in Seed Plants	220
	III Biochemical Properties of MGDG Synthase	221
	A Enzymatic Features of MGDG Synthase	221
	B Subcellular Localization of MGDG Synthase	221
	C Three-Dimensional Structure of MGDG Synthase	222
	D Two Types of MGDG Synthase in Arabidopsis	222
	E MGDG Synthesis in Non-photosynthetic Organs	223
	IV Function and Regulation of MGDG Synthase	223
	A Regulation of Type A MGDG Synthase	223
	B Regulation of Type B MGDG Synthase	224
	C In Vivo Function of MGDG Synthase by Mutant Analyses	225
	V Substrate Supply Systems for MGDG Synthesis	226
	A DAG Supply to the Outer Envelope	227
	B DAG Supply to the Inner Envelope	229
	VI MGDG Synthesis in Photoautotrophic Prokaryotes	230
	VII Future Perspectives	231
	References	232
	Chapter 14: Synthesis and Function of the Galactolipid Digalactosyldiacylglycerol	237
	I Introduction	238
	II Structure and Occurrence of Digalactosyldiacylglycerol	238
	III Synthesis of Digalactosyldiacylglycerol and Oligogalactolipids	239
	IV Function of Digalactosyldiacylglycerol in Photosynthesis	240
	V Digalactosyldiacylglycerol as Surrogate for Phospholipids	241
	VI Changes in Galactolipid Content During Stress and Senescence	242
	VII Conclusions	243
	References	243
	Chapter 15: The Chemistry and Biology of Light-Harvesting Complex II and Thylakoid Biogenesis: .raison d’etre. of Chlorophyll	246
	I Introduction	247
	A Chlorophyll .a	248
	B Chlorophyll .b	249
	C Chlorophyll .c	249
	D Chlorophyll .d	249
	II Coordination Chemistry of Chlorophyll and Ligands	250
	III Binding of Chlorophyll to Proteins	251
	IV Chlorophyll Assignments in Light Harvesting Complex II (LHCII)	253
	V Cellular Location of Chlorophyll .b. Synthesis and LHCII Assembly	255
	VI Chlorophyllide .a. Oxygenase	257
	VII Conclusions	258
	References	259
	Chapter 16: Folding and Pigment Binding of Light-Harvesting Chlorophyll .a/b. Protein (LHCIIb)	263
	I Introduction	264
	II Time-Resolved Measurements of LHCIIb Assembly In Vitro	265
	A Fluorescence as a Monitor for LHCIIb Assembly	265
	B A Two-step Model of Pigment Binding	267
	C Protein Folding During LHCIIb Assembly	270
	III Concluding Remarks	273
	References	273
	Chapter 17: The Plastid Genome as a Platform for the Expression of Microbial Resistance Genes	277
	I Introduction	278
	II Yield and Resistance	279
	III .Aspergillus flavus.: Managing a Food and Feed Safety Threat	280
	A Economic and Health Impacts	280
	B Approaches to Intervention	280
	IV The Case for Transgenic Interventions	282
	A Modifying the Nuclear Genome for Resistance	282
	V Plastid Transformation	283
	B Features of the Plastid Expression System	283
	1 The Plastome	284
	(a) Integration of Foreign Sequences	284
	(b) Maternal Inheritance	284
	C Moving Beyond the Model System	284
	VI Identifying Candidate Genes for Aflatoxin Resistance	284
	A Chloroperoxidase	285
	1 Antimicrobial Potential	285
	2 Expression of CPO-P in Transgenic Plants	285
	VII An Environmentally Benign Approach	285
	A Plastid Transformation Vector	285
	B Determinants of Foreign Gene Expression in Plastids	286
	1 The .psbA. 5.¢. UTR	286
	(a) The Potential of .psbA. 5.¢. UTR Stems From Its Endogenous Role in Plastids	286
	(b) Translational Control Is Highly Regulated and Dependent on Imported Trans-acting Protein Factors	286
	(c) Light Regulation of Translation Via the .psbA. 5.¢. UTR	287
	C The CPO-P Transplastomic Lines	287
	1 Evaluating CPO-P Expression	287
	(a) Protein Expression	287
	(b) Analysis of Foreign Transcripts	287
	(c) Continued Analysis	287
	VIII Future Challenges: Control of Aflatoxin Contamination in Cottonseed	288
	A Taking a Direct Approach	288
	B Taking an Indirect Approach	288
	1 Drought Tolerance	289
	2 Resistance to Herbivory	289
	C Generation of Transplastomic Cotton	289
	IX Conclusion	289
	References	289
	Chapter 18: Chloroplast Genetic Engineering: A Novel Technology for Agricultural Biotechnology and Bio-pharmaceutical Industr	295
	I Introduction	296
	II Genome and Organization	297
	III Concept of Chloroplast Transformation	298
	IV Advantages of Plastid Transformation	299
	V Chloroplast Transformation Vectors and Mode of Transgene Integration into Chloroplast Genome	301
	VI Methods of Plastid Transformation and Recovery of Transplastomic Plants	302
	VII Current Status of Plastid Transformation	304
	VIII Application of Chloroplast Technology for Agronomic Traits	305
	IX Chloroplast-Derived Vaccine Antigens	307
	X Chloroplast-Derived Biopharmaceutical Proteins	309
	XI Chloroplast-Derived Industrially Valuable Biomaterials	310
	References	312
	Chapter 19: Engineering the Sunflower Rubisco Subunits into Tobacco Chloroplasts: New Considerations	317
	I Introduction	319
	II Transforming the Tobacco Plastome with Sunflower Rubisco Genes	320
	A Replacing the Tobacco .rbc.L with Sunflower .rbc.L.S	320
	B Co-transplanting .rbc.L.S. and a Codon-Modified Sunflower .cmrbc.S Gene	320
	1 A Need to Co-engineer Cognate L- and S-Subunits	320
	2 Altering the Codon Bias of a Sunflower .Rbc.S.s. Gene	321
	3 Using the T7g10 5.¢.UTR to Regulate Sunflower S-Subunit Translation	322
	C Transformation, Selection and Growth of the Transplastomic Lines	322
	III Inadvertent Gene Excision by Recombination of Duplicated .psb.A 3.¢.UTR Sequence	322
	A Preferential Loss of Plastome Copies Containing .cmrbc.S.S	322
	B Why Were the .cmrbc.S.S. Containing Plastome Copies Lost?	323
	IV Simple Removal of .aad.A in T.0. t.Rst.SLA by Transient CRE Recombinase Expression	323
	A Bacteriophage P1 CRE-.lox. Site-specific Recombination	323
	B Removing .aad.A by Bombarding with Plasmid pKO27	324
	1 Selection and Screening for .Daad.A Lines	324
	2 Screening the T.1. Progeny for .aad.A Loss and No Incorporation of the pKO27 T-DNA	325
	V Growth Phenotypes of the tob.Rst., t.Rst.LA and t.Rst.L Lines	325
	A Elevated CO.2. Partial Pressures Augment the Growth of the Juvenile Transformants	325
	B The Comparable Phenotype and Growth Rates of the Transgenic Lines	325
	1 Differences in Leaf and Apical Meristem Development	325
	2 Shoot Development	327
	C Leaf and Floral Development	327
	VI Expression of the Hybrid L.s.S.t. Rubisco in Mature Leaves	328
	A Steady-State .rbc.L.S. mRNA Levels	328
	B Rubisco and Protein Content	328
	C Translational Efficiency and/or Folding and Assembly Limit L.s.S.t. Production	330
	VII Whole Leaf Gas Exchange Measurements of the L.s.S.t. Kinetics	330
	A Measuring Gamma Star (.G.*)	330
	B Measuring the L.s.S.t. Michaelis Constants for CO.2. and O.2	331
	VIII Future Considerations for Transplanting Foreign Rubiscos into Tobacco Plastids	331
	A Improving L.s.S.t. Synthesis	331
	1 Limitations to Translational Processing of .rbc.L.S	331
	2 Subunit Assembly Limitations	333
	B The Assembly and Kinetic Capacity of Other Hybrid Rubiscos	333
	C Constraints on S-Subunit Engineering in Tobacco	334
	D Rubisco Activase Compatibility	334
	IX Quicker Screening of the Assembly and Kinetics of Genetically Modified L.8.S.8. Enzymes in Tobacco Chloroplasts	334
	References	335
	Chapter 20: Engineering Photosynthetic Enzymes Involved in CO.2.–Assimilation by Gene Shuffling	339
	I Introduction	340
	II Potential Targets for Improving Plant Photosynthesis	340
	III Directed Molecular Evolution Provides a Useful Tool to Engineer Selected Enzymes	342
	IV Improving Rubisco CatalyticEfficiency by Gene Shuffling	344
	A Attempts to Express .Arabidopsis thaliana. Rubisco in .Chlamydomonas reinhardtii	344
	B Shuffling the .Chlamydomonas reinhardtii. Rubisco Large Subunit	346
	V Improving Rubisco Activase Thermostability by Gene Shuffling	348
	VI Future Prospects	350
	References	352
	Chapter 21: Elevated CO.2. and Ozone: Their Effects on Photosynthesis	355
	I Introduction	356
	II Regulation of the Photosynthetic Apparatus: Metabolic and Environmental Signals	357
	III Possible Scenarios Explaining Effects of Elevated [CO.2.] and [O.3.] on Plant Behavior in the Altered Earth Atmosphere	359
	A Plant Responses to Elevated [CO.2]	360
	B Plant Responses to Tropospheric [O.3.]	361
	C Combined Effects of [CO.2] and [O.3]	362
	IV Benefits from Model Species:.Arabidopsis thaliana. and .Thellungiella halophila	363
	V Discussion	368
	A The Importance of Model Species	368
	B Gene Networks Explaining Transcript Behavior	368
	VI Conclusions	372
	Chapter 22: Regulation of Photosynthetic Electron Transport	379
	I Introduction	380
	II Chlorophyll Fluorescence: A Non-disruptive Tool for Electron Transport Analysis	381
	III Thermal Dissipation of Absorbed Excessive Light Energy from PSII	382
	IV Balancing Excitation Energy Between Photosystems by State Transition	382
	V Photorespiration and the Water–Water Cycle: Alternative Electron Sinks?	383
	VI The Discovery of PGR5-Dependent PSI Cyclic Electron Transport	384
	VII PSI Cyclic Electron Transport Mediated by Chloroplast NAD(P)H Dehydrogenase	386
	VIII PSI Cyclic Electron Transport and Thermal Dissipation	387
	IX PSI Cyclic Electron Transport and State Transition	388
	X The Water–Water Cycle and PSI Cyclic Electron Transport	388
	XI Concluding Remarks	388
	References	389
	Chapter 23: Mechanisms of Drought and High Light Stress Tolerance Studied in a Xerophyte, .Citrullus lanatus. (Wild Watermelon)	394
	I Introduction	395
	II Experimental Procedures	396
	III Physiological Response of Wild Watermelon	397
	IV Enzymes for Scavenging Reactive Oxygen Species	399
	V Cytochrome .b561. and Ascorbate Oxidase	400
	VI Global Changes in the Proteomes	402
	VII Citrulline Metabolism and Function	402
	VIII Concluding Remarks	404
	References	405
	Chapter 24: Antioxidants and Photo-oxidative Stress Responses in Plants and Algae	409
	I Types of Reactive Oxygen Species	410
	II Sources of Reactive Oxygen Species in Algae and Plants	411
	III Functions of Reactive Oxygen Species	411
	IV Oxidative Damage in Chloroplasts	412
	V Avoidance of Reactive Oxygen Species Production	413
	VI Non-enzymatic Mechanisms for Scavenging Reactive Oxygen Species	413
	A Hydrophilic Antioxidants	414
	1 Ascorbate	414
	2 Glutathione	415
	B Lipophilic Antioxidants	415
	1 Tocopherol	415
	2 Carotenoids	416
	C Antioxidant Interactions	417
	VII Enzymatic Mechanisms for Scavenging Reactive Oxygen Species	418
	A Superoxide Dismutase	418
	B Catalase	419
	C Ascorbate Peroxidase	419
	D Glutathione Peroxidase	419
	E Thioredoxin	420
	F Glutaredoxin	421
	G Peroxiredoxin	421
	References	422
	Chapter 25: Singlet Oxygen-Induced Oxidative Stress in Plants	427
	I Introduction	428
	II Formation of Singlet Oxygen in Plants	428
	III Generation of Singlet Oxygen from Chlorophyll Biosynthesis Intermediates	430
	IV Porphyrin-Generating Compounds	430
	A 5-Aminolevulinic Acid	430
	B Diphenyl Ethers	431
	V Type I and Type II Photosensitization Reactions of Tetrapyrroles	431
	VI Intracellular Destruction of Singlet Oxygen	432
	VII Singlet Oxygen-Mediated Oxidative Damage to the Photosynthetic Apparatus	432
	A Generation of Tetrapyrrole-Induced Singlet Oxygen in Chloroplasts	433
	B Singlet Oxygen-Induced Impairment of the Electron Transport Chain	433
	C Role of Singlet Oxygen Scavengers	434
	D Impact of .1.O.2. on Chlorophyll a Fluorescence	434
	E Effect of Singlet Oxygen on Thermoluminiscence	436
	VIII Singlet Oxygen-induced Oxidative Damage in Mutants	436
	A Chlorophyll Anabolic Mutants	436
	B Chlorophyll Catabolic Mutants	438
	IX Future Prospects	438
	References	439