Chapter 1: Plants and Cell Structure
Plant Life: Unifying Principles 2
Plant Classification and Life History 2
The plant life cycle alternates between diploid and haploid generations2
Box 1.1 Evolutionary Relationships of Plants3
Overview of Plant Structure 6
Plant cells are surrounded by a strong cell wall6
The primary and secondary cell walls have different compositions8
Cellulose microfibrils and matrix polysaccharides are synthesized through different mechanisms9
Plasma junctions allow free movement of molecules between cells9
New cells originate from dividing tissue called meristems10
Type 12 of Plant Cells
The epidermis covers the surface of the plant12
Basic tissues make up the plant body12
Box 1.2 2nd stage plant 14
Vascular tissue forms a transport network between different parts of the plant15
Plant cell organelles 15
A biofilm is a bilayer containing proteins15
Nuclear 19
Gene expression involves both transcription and translation21
Posttranslational regulation determines the lifespan of a protein21
Endometrial system 23
The endoplasmic reticulum is a network of inner membranes23
Vacuoles have various functions in plant cells24
The basophil is a lipid storage organelle25
Microsomes play a special metabolic role in leaves and seeds25
Semiautonomous organelles that divide independently25
Prochromatoplasts mature into specialized chromatoplasts in different plant tissues28
The division of chloroplasts and mitochondria is not related to the division of the nucleus29
Plant cytoskeleton 30
The plant cytoskeleton is composed of microtubules and microfilaments30
Actin, tubulin, and their polymers are constantly fluctuating in living cells30
Microtubule protofilaments initially assemble into a flat plate shape before winding into a cylindrical shape31
Cytoskeletal motor proteins mediate cytoplasmic flow and organelle trafficking33
Cell cycle regulation34
Each phase of the cell cycle has a unique set of biochemical and cellular activities34
The cell cycle is regulated by cyclins and cyclin-dependent kinases35
Mitosis and cytokinesis involve both microtubules and the endomembrane system 36

Chapter 2 Water and Plant Cells 41
Water in Plant Life 42
Structure and Properties of Water 42
Water molecules are polar molecules that form hydrogen bonds42
Water is a great solvent43
Water has relatively distinct thermal properties for its size43
Water molecules have strong cohesion43
Water has high tensile strength45
Diffusion and Osmosis 45
Diffusion is the net movement of molecules due to random thermal motion46
Diffusion is most effective for short-distance movement47
Osmosis describes the movement of water through a selective permeability barrier47
Moisture potential 48
The chemical potential of water represents the free energy state of water.48
Three major factors contribute to the water potential of cells48
Water potential can be measured49
Water potential of plant cells 49
Water enters cells along the water potential gradient49
Water may leave the cell depending on the water potential gradient50
Water potential and its components vary depending on growing conditions and location within the plant body.52
Properties of Cell Walls and Membranes 52
Small volume changes in plant cells cause large turgor pressure changes52
The rate at which a cell gains or loses water is influenced by the water conductivity of its membrane53
Aquaporins facilitate the movement of water across cell membranes54
Water Status of Plants 54
Physiological processes are influenced by the water status of plants54
Solute accumulation helps maintain cell turgor and volume55

Chapter 3: Water Balance in Plants 57
Water in the soil58
Negative hydrostatic pressure of soil water reduces the soil water potential58
Water moves through the soil as bulk flow59
Water absorption by roots60
Water moves through the apoplast pathway, the symplast pathway, and the transmembrane pathway in the root60
Solute accumulation in the xylem causes 'root pressure'62
Water transport through the xylem 62
The xylem is composed of two types of transport cells62
Water moves through the tube as a pressure-driven bulk flow64
Water movement through the xylem requires a smaller pressure gradient than movement through living cells65
How much pressure difference is needed to raise water to the top of a 100 m high tree?65
Explaining water transport in xylem using the cohesion-tension theory65
Water transport in xylem in trees presents physical challenges67
Plants minimize damage from vascular cavitation68
Water movement from leaves to the atmosphere68
Leaves have great resistance to water movement69
The driving force behind the increase is the difference in water vapor concentration.69
Water loss is also regulated by path resistance70
Boundary layers contribute to diffusion resistance71
Porosity is another major component of diffusion resistance71
The cell walls of guard cells have unique features73
Increased turgor pressure in the guard cells causes stomata to open73
Coupling of leaf transpiration and photosynthesis: Light-induced stomatal opening74
Pore ​​opening is regulated by light74
Pore ​​opening is particularly regulated by blue light75
Water use efficiency 75
Overview: The Soil-Plant-Atmosphere Continuum76

Chapter 4: Weapon Nutrition 79
Essential Nutrients, Deficiencies, and Plant Disorders80
Special techniques are used in nutritional research83
Nutrient solution enables rapid plant growth83
Mineral deficiencies disrupt plant metabolism and function85
Plant tissue analysis can detect mineral deficiencies89
Treatment of Nutrient Deficiencies90
Crop yields can be improved by adding fertilizers 90
Some nutrients can be absorbed by the leaves91
Soil, Roots, and Microorganisms91
Negatively charged soil particles affect the adsorption of inorganic nutrients91
Soil pH affects nutrient availability, soil microorganisms, and root growth93
Excessive mineral ions in the soil restrict plant growth93
Plants develop extensive root systems93
Although the roots are different in shape, they share a common structure94
Different parts of the root absorb different inorganic ions96
Nutrient availability affects root growth97
Mycorrhizal symbiosis promotes nutrient uptake by roots98
Nutrients move from mycorrhizal fungi to root cells 101

Chapter 5: Assimilation of Mineral Nutrients 103
Nitrogen 104 in nature
In the biogeochemical cycle, nitrogen takes several forms104
The dangers of unassimilated ammonium or nitrates105
Nitrate assimilation 106
Many factors regulate nitrate reductase106
Nitrite reductase 107, which converts nitrite to ammonium
Nitrate assimilation in roots and stems108
Ammonium assimilation 108
Two enzymes needed to convert ammonium into amino acids108
Ammonium can be assimilated through alternative pathways110
Amination reactions transfer nitrogen110
Asparagine and glutamine link carbon and nitrogen metabolism110
Amino acid biosynthesis 110
Biological nitrogen fixation111
Free-living and symbiotic bacteria fix nitrogen112
Nitrogen fixation requires microaerobic or anaerobic conditions112
Occurrence of symbiotic nitrogen fixation in specialized structures114
Signal exchange process required for symbiosis114
Nod factors produced by bacteria act as signals for symbiosis115
Phytohormones that affect root nodule formation115
The nitrogenase complex fixes N2116
Amides and ureides are transport forms of nitrogen118
Hwang Donghwa 119
Sulfate is the form in which sulfur is transported into plants119
Sulfate assimilation occurs primarily in leaves 119
Methionine is synthesized from cysteine119
Phosphate assimilation 120
Iron Dongwha 120
Modify the root zone to obtain iron120
Iron cations form compounds with carbon and phosphate121
Energetics of Nutrient Assimilation 121

Chapter 6 Solute Transport 125
Passive and active transport126
Ion transport across membrane barriers127
Diffusion rates of different cations and anions that generate diffusion potentials128
Relationship between membrane potential and ion distribution128
Nernst equation 129 distinguishes between active and passive transport.
Proton transport, a major determinant of membrane potential130
Membrane transport process 131
Channels enhance diffusion through membranes132
Carriers bind to and transport specific substances133
Primary active transport requires energy134
Secondary active transport uses stored energy135
Kinetic analysis can elucidate transport mechanisms136
membrane transport protein 137
Genes of many transporters have been identified139
Transporters exist for various nitrogen-containing compounds 139
Cation transporters are diverse140
Anion transporters have been identified142
Metal and metalloid ion transporters transport essential trace nutrients142
Aquaporins have various functions143
The plasma membrane H+-ATPase is a highly regulated P-type ATPase143
Tonoplast H+-ATPase induces solute accumulation in the vacuole144
H+-pyrophosphatase pumps protons across the vacuolar membrane145
Ion transport in pore opening146
Light stimulates ATPase activity and creates a stronger electrochemical gradient across the guard cell plasma membrane146
Hyperpolarization of the guard cell plasma membrane leads to the uptake of ions and water146
Ion transport in roots147
Solutes move through both the apoplast and the symplast147
The ion crosses both the symplast and the apoplast149
Xylem parenchyma cells participate in xylem loading150

Chapter 7 Photosynthesis: Light Reactions 153
Photosynthesis in higher plants 154
General Concepts154
Light has both particle and wave properties154
When molecules absorb or emit light, their electronic states change155
Photosynthetic pigments absorb light, which powers photosynthesis156
Key Experiments for Understanding Photosynthesis158
Action spectra show the relationship between light absorption and photosynthetic activity158
Photosynthesis occurs in complexes containing light-harvesting antennae and photochemical reaction centers158
The chemical reactions of photosynthesis are driven by light160
Light drives NADP+ reduction and ATP formation161
Oxygen-producing organisms have two photosystems that function in series161
Photosynthetic apparatus system 162
Chloroplasts are where photosynthesis occurs162
Thylakoids have integral membrane proteins163
Photosystems I and II are spatially separated within the thylakoid membrane165
System of optical absorption antenna system 165
The antenna system contains chlorophyll and is bound to the membrane165
The antenna focuses energy toward the reaction center166
Many antenna pigment-protein complexes share common structural motifs 166
Electron Transfer Mechanism 167
Electrons leaving the chloroplast are transported through carriers organized in the 'Z diagram'167
Energy is captured when excited chlorophyll reduces an electron acceptor molecule168
The chlorophylls in the reaction centers of the two photosystems absorb different wavelengths170
The photosystem II reaction center is a multisubunit pigment-protein complex170
Water is oxidized to oxygen by photosystem II170
Pheophytin and two quinones accept electrons from photosystem II 172
The flow of electrons through the cytochrome b6f complex also transports protons172
Plastoquinone and plastocyanin transport electrons between photosystem II and photosystem I174
The reaction center of photosystem I reduces NADP+174
Cyclic electron flow produces ATP but not NADPH175
Some herbicides block photosynthetic electron transport176
Proton transport and ATP synthesis in chloroplasts176

Chapter 8 Photosynthesis: Carbon Reactions 181
Calvin-Benson Circuit 182
The Calvin-Benson cycle has three steps: carboxylation, reduction, and regeneration182
CO2 fixation through carboxylation of ribulose 1,5-bisphosphate and reduction of 3-phosphoglycerate synthesizes triphosphate183
Ribulose 1,5-bisphosphate is regenerated for continued CO2 assimilation183
The lag phase precedes the steady state of photosynthetic CO2 assimilation186
Many mechanisms regulate the Calvin-Benson cycle187
Rubisco activator regulates the catalytic activity of Rubisco 187
Light regulates the Calvin-Benson cycle via the ferredoxin-thioredoxin system187
Light-dependent ion transport regulates enzymes of the Calvin-Benson cycle 188
Photorespiration: C2 oxidative photosynthetic carbon cycle188
Oxygenation of ribulose 1,5-bisphosphate activates the C2 oxidative photosynthetic carbon cycle189
Photorespiration is linked to the photosynthetic electron transport chain192
Concentration mechanism of inorganic carbon 193
Concentration Mechanism of Inorganic Carbon: The C4 Carbon Cycle194
Malic acid and aspartic acid are carboxylation products of the C4 cycle194
The C4 cycle assimilates CO2 through the cooperative action of two different types of cells196
Vascular sheath cells and mesophyll cells exhibit other anatomical and biochemical differences196
The C4 cycle concentrates CO2 even within a single cell197
Light regulates the activity of key C4 enzymes197
CO2 photosynthetic assimilation in C4 plants requires more transport processes than in C3 plants197
In hot, dry climates, the C4 cycle reduces photorespiration and water loss197
Mechanism of Concentration of Inorganic Carbon: Crasulic Acid Metabolism 199
Different mechanisms regulate C4 PEPCase and CAM PEPCase200
CAM is a versatile mechanism sensitive to environmental stimuli201
Accumulation and distribution of photosynthetic products (starch and sucrose)202

Chapter 9 Photosynthesis: Physiological and Ecological Considerations205
Photosynthesis is influenced by leaf characteristics206
Leaf anatomy and crown structure maximize light absorption207
Leaf angle and leaf movement regulate light absorption209
Plants are acclimated and adapted to both sunny and shady environments.210
The Effect of Light on Photosynthesis in Intact Leaves210
Light-response curves show the characteristics of photosynthesis210
Leaves must dissipate excess light energy212
Absorbing too much light can cause photoinhibition215
The Effect of Temperature on Photosynthesis215
Leaves must dissipate vast amounts of heat216
There is an optimal temperature for photosynthesis216
Photosynthesis is sensitive to high and low temperatures217
Photosynthetic efficiency is sensitive to temperature217
The Effect of Carbon Dioxide on Photosynthesis218
Atmospheric CO2 concentrations are on the rise 218
Diffusion of CO2 into chloroplasts is essential for photosynthesis219
CO2 limits photosynthesis220
How will respiration and photosynthesis change in the future under elevated CO2 conditions?222

Chapter 10: Transport of the Body 227
Transport Form: From Source to Receiving Unit228
Transport route 229
Sugars are transported within the sieve elements230
Mature body elements are living cells specialized for transport230
Large pores in the cell wall are a prominent feature of sieve elements230
Damaged body elements are sealed231
Companion cells assist highly specialized body elements233
Substances transported in the vascular system233
The sap from the sap tubes can be collected and analyzed234
Sugars are transported in a non-reduced form234
Other solutes are transported in the vascular system236
Movement speed 236
The Seizure Model as a Passive Mechanism of Vessel Transport 236
Osmotically generated pressure gradients drive transport in the sequestration model237
The predictions of the seizure model have been confirmed, but others require further experimentation.237
In a single-celled system, bidirectional transport does not occur, and water and solutes move at the same rate238
The energy requirements for transport through the vascular pathway are low in herbaceous plants 238
Chepankong is an open channel239
The pressure gradients of the elements may not be large; pressures in herbaceous plants and trees appear similar239
240 tons of body weight
Vessel loading can occur via the apoplast or symplast241
The presence of apoplast loading in some plant species is supported by abundant data241
Sucrose uptake in the apoplast pathway requires metabolic energy241
The phloem loading of the apoplast pathway involves sucrose-H+ cotransporters242
Some plant species have simplex phloem loading242
A polymer capture model explains symplasm loading in plants with intermediate cells242
In some trees, vascular loading is passive244
244. Loading of the sieve and the transition from the receiving area to the supply area
Short-distance transport and vascular loading can occur via the symplast or apoplast pathways244
Transport to the receiving tissue requires metabolic energy245
The process by which leaves transition from receptacle to source is gradual245
Distribution of Photosynthetic Products: Allocation and Distribution247
Allocation includes storage, utilization, and transportation247
Various receiving units distribute transport sugar247
The supply leaf regulates the allocation248
Receptor tissues compete for transported photosynthetic products249
Receptor strength is a function of receptor size and receptor activity250
Supply adapts to changes in the supply-to-receiving ratio over long periods of time250
Transport of signaling molecules250
Turgor and chemical signals modulate the activity of source and receptor sites250
Proteins and RNA function as signaling molecules in the phloem to regulate growth and development251
Function of plasmoplasmic contacts in vascular signaling251

Chapter 11: Respiration and Lipid Metabolism 255
Overview of Plant Respiration 255
Course 257
This process metabolizes carbohydrates from various sources258
In the energy conservation step of the process, usable energy is extracted261
Plants have alternative glycolytic reactions261
Fermentation regenerates NAD+, which is needed for glycolysis in the absence of oxygen262
Oxidative pentose phosphate pathway 262
The oxidative pentose phosphate pathway produces NADPH and biosynthetic intermediates263
The oxidative pentose phosphate pathway is regulated by redox263
Tricarboxylic acid cycle 265
Mitochondria are semi-autonomous organelles265
Pyruvate enters the mitochondria and is oxidized through the TCA cycle266
The TCA cycle in plants has unique characteristics268
Mitochondrial electron transport and ATP synthesis269
The electron transport chain catalyzes the flow of electrons from NADH to O2269
The electron transport chain has auxiliary branch pathways270
ATP synthesis in mitochondria is coupled to electron transport271
Transporters exchange substrates and products272
Aerobic respiration produces approximately 60 molecules of ATP per sucrose molecule274
Plants have several mechanisms to reduce the amount of ATP274
Short-term regulation of mitochondrial respiration occurs at different levels276
Breathing is closely connected with other pathways277
Respiration of Complete Plants and Tissues277
Plants expend about half of their daily photosynthetic production through respiration277
Respiration occurs while photosynthesis occurs279
Different tissues and organs breathe at different rates279
Environmental factors alter respiratory rate279
Lipid metabolism 281
Fats and oils can store large amounts of energy281
Triacylglycerols are stored in lipids281
Polar glycerolipids are the major structural lipids of membranes282
Membrane lipids are precursors of important signaling compounds284
In germinated seeds, storage lipids are converted to carbohydrates284

Chapter 12: Signals and Signal Transmission 289
Temporal and spatial aspects of signal transmission290
Signal Detection and Amplification291
Signals must be amplified inside the cell to regulate their target molecules292
Ca2+ is the most common second messenger in plants and other eukaryotes292
Changes in the cytosol and cell wall pH can act as secondary messengers of hormone and stress responses294
Reactive oxygen species are second messengers that mediate both environmental and developmental signals294
Hormones and Plant Development295
Auxin was discovered in early studies on the bending response of cotyledons related to phototropism295
Gibberellins promote stem growth and have been found in rice's 'foolish seedling disease'296
Cytokinins have been discovered as cell division-stimulating factors in tissue culture experiments297
Ethylene is a gaseous hormone that promotes fruit ripening and other developmental processes. 298
Abscisic acid regulates seed maturation and stomatal closure in response to water shortage299
Brassinosteroids regulate flower sex determination, photomorphogenesis, and germination299
Salicylic acid and jasmonate are involved in the defense response300
Strigolactones inhibit stem pruning and promote root-zone interactions 300
Plant Hormone Metabolism and Homeostasis 300
Indole-3-pyruvic acid is a key intermediate in auxin biosynthesis 301
Gibberellins are synthesized by the oxidation of ent-kaurene, a diterpene.301
Cytokinins are adenine derivatives with an isoprene side chain 302
Ethylene is synthesized from methionine via the intermediate ACC302
Abscisic acid is synthesized from carotenoid intermediates303
Brassinosteroids are made from the sterol campesterol304
Strigolactone is synthesized from β-carotene304
Signal Transmission and Intercellular Communication 304
Hormone signaling pathways 305
Cytokinin and ethylene signaling pathways originate from a two-component bacterial regulatory system305
A receptor-like kinase mediates brassinosteroid signaling306
Key elements of ABA signaling are phosphatases and kinases308
Plant hormone signaling pathways generally utilize negative regulation308
Protein degradation via ubiquitin plays a crucial role in hormone signaling308
Plants have mechanisms to turn off or attenuate signal responses308
Cellular responses to signals are often tissue-specific310
Cross-regulation integrates signaling pathways310

Chapter 13: Signals from Sunlight 313
Plant photoreceptor 315
Plant responses to light are driven by the quality or spectral characteristics of the light absorbed316
Plant responses to light can be differentiated by the amount of light required318
Phytochrome 318
Phytochrome is the primary photoreceptor for red and far-red light319
Phytochrome can be interconverted between Pr and Pfr forms319
Phytochrome reaction 320
Phytochrome reactions have varying delay and escape times320
Phytochrome reactions are divided into three main categories depending on the amount of light required321
Phytochrome A mediates the response to continuous far-red light322
Phytochrome regulates gene expression322
Blue light response and photoreceptors322
Blue light responses have characteristic dynamics and latency323
Cryptochrome323
Blue light irradiation of the cryptochrome FAD chromophore induces structural changes in the protein323
The nucleus is the main site of cryptochrome action324
Cryptochrome interacts with phytochrome324
Phototropin 324
Phototropism requires a change in the fluidity of auxin 325
Phototropin regulates chloroplast movement326
Stomatal opening is regulated by blue light, which activates plasma membrane H+-ATPase326
Interactions of Phytochrome, Cryptochrome, and Phototropin328
Reaction to UV rays328

Chapter 14 Embryogenesis 331
Overview of Embryogenesis 332
Comparison of Embryogenesis in Dicotyledons and Monocotyledons333
Morphological similarities and differences between dicotyledonous and monocotyledonous embryos reveal their respective developmental patterns333
Apical-basal polarity is maintained in the embryo during organogenesis 336
Embryonic development requires coordinated communication between cells337
Auxin signaling is essential for embryonic development338
Polar auxin transport is mediated by local auxin efflux transporters339
Auxin synthesis and polar transport regulate embryonic development342
Radial pattern formation leads to the formation of tissue layers343
The original epidermis differentiates into the epidermis343
Vascular centrioles are elaborated by progressive cell division regulated by cytokinins344
Formation and maintenance of apical meristems344
Auxin and cytokinin contribute to RAM formation and maintenance344
SAM formation is influenced by factors related to auxin movement and response345
Cell proliferation in SAM is regulated by cytokinins and gibberellins346

Chapter 15: Seed Dormancy, Germination, and Seedling Establishment 349
Seed Structure 351
The anatomical structure of seeds varies greatly among plant groups351
Seed dormancy 351
There are two basic types of seed dormancy mechanisms: extrinsic and intrinsic353
Non-dormant seeds can exhibit spike germination and premature germination353
The ABA:GA ratio is a key determinant of seed dormancy355
Release from hibernation 356
Light is an important signal for breaking dormancy in small seeds356
Some seeds require chilling or post-ripening to break dormancy356
Seed dormancy can be broken by various compounds357
Seed Germination 357
The germination and post-germination stages can be divided into three stages according to moisture absorption357
Movement of stored nutrients358
The aleurone layer of grains is a specialized digestive tissue that surrounds the starchy endosperm359
Establishment of a plant species 360
The development of newly emerging plants is strongly influenced by light.361
Gibberellins and brassinosteroids inhibit photomorphogenesis in cancer361
Apical hook opening is regulated by phytochrome, auxin, and ethylene362
Vascular differentiation begins during the emergence of seedlings362
Growing roots have distinct areas363
Ethylene and various hormones regulate root hair development364
Lateral roots are derived internally from the pericycle 364
Cell Expansion: Mechanisms and Hormonal Regulation365
Before cell expansion can occur, the rigid primary cell wall must be weakened365
The directionality of microfibrils influences the growth direction of cells undergoing diffusive growth 366
Acid-induced growth and cell wall flexibility in response to pressure are regulated by expansins367
Auxin promotes the growth of stems and cotyledons but inhibits root growth 367
The outer tissues of the stem of dicotyledons are targets of auxin action367
The minimum waiting time for auxin-induced elongation is 10 minutes368
Auxin-induced proton transport relaxes the cell wall369
Ethylene affects microtubule orientation and induces horizontal cell expansion 369
Gravitation: Growth in response to directional stimuli370
Auxin transport is polar and gravity-independent370
Auxin transport and response during gravid growth supports the Cholodny-Went hypothesis372
Gravitational perception is induced by the deposition of starch bodies373
Gravity sensing may involve pH and calcium ions (Ca2+) as secondary signal transmitters 374
Phototropins are photoreceptors involved in phototropism374
Phototropism is mediated by lateral redistribution of auxin375
The phototropism of a suit occurs in several stages375

Chapter 16 Nutrition, Growth, and Aging 379
Suit terminal division tissue 379
The shoot apical meristem has distinct zones and cell layers380
Leaf Structure and Postcard 381
Auxin-induced patterning of shoot tips begins during embryogenesis381
Differentiation of epidermal cell types 383
A specialized epidermal cell lineage gives rise to guard cells384
Leaf vein pattern 385
The primary leaf vein originates from the leaf primordia385
Auxin transport initiates leaf vascular bundle development 386
Chute Pruning and Structure System 387
Auxin, cytokinin, and strigolactone regulate axillary bud growth387
The signal for the initiation of axillary bud growth is probably increased sucrose availability to the bud389
Avoiding the shade 390
Reducing shade avoidance can increase grain yields391
Root system structure 391
Plants can modify their root systems to absorb water and nutrients391
The root systems of monocotyledons and dicots differ in structure.392
Root system structure changes in response to phosphorus deficiency393
Plant Aging394
During leaf senescence, nutrients are recycled from the leaf source to the vegetative or reproductive receptor site394
The developmental age of a leaf may differ from its chronological age394
Leaf senescence can be sequential, seasonal, or stress-induced395
The earliest cellular changes during leaf senescence occur in the chloroplasts395
Reactive oxygen species act as an internal signal in leaf senescence396
Plant hormones interact to regulate leaf senescence396
Leaf thalli399
Leaf abscission is regulated by the interaction of ethylene and auxin399
Whole Plant Aging 400
The life cycle of angiosperms is one, two, or many years.400
Nutrient or hormone redistribution can induce senescence in one-fruiting plants402

Chapter 17: Flowering Regulation and Fruit Development 405
Inducing Flowering: Integration of Environmental Signals406
Suit stop and step change 406
There are three phases in plant development406
Juvenile tissue is produced first and is located at the base of the suit 407
Stage changes can be influenced by nutrients, gibberellins, and epigenetic regulation407
Photoperiodism: Day-Length Monitoring 408
Plants can be classified according to their photoperiodical response408
Photoperiodism is one of the many plant processes regulated by circadian rhythms410
Circadian rhythms have characteristics411
Circadian rhythms adapt to different day-night cycles413
Leaves are the site that detects photoperiod signals413
Plants monitor day length by measuring night length413
Light interruption can nullify the effects of darkness414
Photoperiod time measurement during the night relies on the circadian clock414
The coincidence model links oscillatory light sensitivity to photoperiodism415
Phytochrome is the primary photoreceptor of photoperiodical responses416
Vernalization: Promoting flowering by low temperatures418
Long-distance signaling associated with flowering419
Gibberellin and ethylene can induce flowering421
Development of floral meristems and floral organs421
The SAM of Arabidopsis thaliana changes with development421
The four types of floral organs are separated into a ring421
Two major types of genes control flower development422
The ABC model partially explains how floral organ identity is determined423
Pollen development 424
Development of female gametophytes from ovules424
Functional megaspores divide into several cells through a series of free nuclear mitoses425
Pollination and double fertilization in flowering plants426
Two sperm cells are transferred to the female gametophyte via the pollen tube426
Pollination begins with the attachment and hydration of pollen in compatible flowers426
Pollen tubes grow by apical growth427
The zygote and primary endosperm cells are formed through double fertilization427
Fruit development and ripening427
Arabidopsis and tomato are models for studying fruit development429
The meat undergoes a maturation process429
Ripening involves a change in the color of the fruit430
Fruit softening involves the coordinated action of many cell wall-degrading enzymes431
Taste and aroma reflect changes in acids, sugars, and aroma compounds431
A causal relationship between ethylene and ripening has been demonstrated in transgenic and mutant tomatoes431
432 Turning and non-turning fruits have different ethylene responses.

Chapter 18: Biological Interactions 435
Beneficial Interactions Between Plants and Microbes436
Different types of rhizobacteria can increase nutrient availability, promote root branching, and defend against pathogens437
Harmful interactions between plants, pathogens, and herbivores438
Physical barriers provide a first line of defense against pests and pathogens438
Specialized plant metabolites can protect against herbivorous insects and pathogen infections440
Plants store endogenous toxic compounds in specialized structures441
Plants store defensive chemicals as nontoxic, water-soluble sugar complexes in specialized vacuoles444
Induced defense response to herbivorous insects445
Plants can recognize specific components of insect saliva445
Tube feeders activate defense signaling pathways similar to those activated by pathogen infection446
Jasmonic acid activates defense responses against herbivorous insects446
Hormonal interactions contribute to plant-herbivorous insect interactions 447
JA initiates the production of defensive proteins that inhibit digestion by herbivores447
Damage by herbivores induces systemic defenses447
Long-distance electrical signaling occurs in response to herbivorous insects 449
Volatiles induced by herbivores repel herbivores and attract natural enemies449
Herbivore-induced volatiles can be used as long-distance signals between plants450
Insects have evolved mechanisms to counter plant defenses451
Plant Defenses Against Pathogens451
Microbial pathogens have evolved a variety of strategies to invade their host plants451
Pathogens produce triggers that help them colonize plant host cells452
Pathogen infections can trigger molecular 'danger signals' that are recognized by pattern recognition receptors on the cell surface453
R proteins recognize strain-specific triggers and provide resistance to individual pathogens453
Hypersensitivity reactions are a common defense against pathogens453
A single contact with a pathogen can increase resistance to future attacks455
Plant Defenses Against Other Organisms456
Some plant-parasitic nematodes form specialized relationships through the formation of unique feeding structures456
Plants compete with other plants by secreting allelopathic secondary metabolites into the soil457
Some plants are bioparasitic pathogens of other plants457

Chapter 19: Abiotic Stresses 461
Definition of Plant Stress462
Physiological regulation of abiotic stress involves a balance between nutritional and reproductive development462
Acclimatization and Adaptation 463
Environmental Stressors464
Water deficiency reduces turgor pressure, increases ion toxicity, and inhibits photosynthesis464
Salt stress has two effects: osmotic stress and cytotoxicity.465
Temperature stress affects a wide range of physiological processes466
Flooding causes anaerobic stress in roots466
Light stress occurs when shade-adapted or shade-acclimated plants are exposed to strong sunlight.467
Heavy metal ions mimic essential mineral nutrients and generate ROS467
Combinations of abiotic stresses can induce unique signaling and metabolic pathways467
Sequential exposure to different abiotic stresses sometimes exhibits cross-protection468
Plants perceive abiotic stress through various mechanisms468
Physiological mechanisms that protect plants from abiotic stress469
Plants can change their morphology in response to abiotic stresses469
Plants adapt to various abiotic stresses by switching their metabolism470
Heat shock proteins maintain protein integrity under abiotic stress conditions470
Membrane lipid composition can adapt to changes in temperature and other abiotic stresses471
Chloroplast genes respond to high-intensity light by transmitting stress signals to the nucleus472
Autophagic ROS flux mediates systemic acclimation472
Abscisic acid and cytokinin are stress-responsive hormones that regulate drought stress responses.472
Plants osmoregulate by accumulating solutes in dry soil474
Epigenetic mechanisms and small RNAs provide additional protection against stress476
Submerged organs develop ventilation tissue in response to hypoxia476
Antioxidants and ROS-scavenging pathways protect plants from oxidative stress478
Plants respond to toxic metal and nonmetal ions through exclusion and internal tolerance mechanisms479
Plants produce cryoprotective molecules and antifreeze proteins to prevent ice crystal formation480
Glossary 483
Search 499