Structure-Function Relations of Warm Desert Plants

1 Plant Life Forms of Warm Desert Climates.- 1.1 Distribution and Climates of Warm Deserts.- 1.2 Physiological Problems for Plants.- 1.2.1 Water and Heat Stress.- 1.2.2 Soil Characters.- 1.2.3 Wind and Flash-Flood Damage.- 1.3 Conceptual Models for Desert Plant Adaptations.- 1.3.1 Xerophyte and Similar Terms.- 1.3.2 Stress Resistance.- 1.3.3 Carbon Gain Models.- 1.4 Plants of Warm Deserts.- 1.4.1 Floras and Endemism.- 1.4.2 Primary Vegetation Types.- 1.4.3 Life Forms.- 1.4.3.1 Shrubs and Subshrubs with Drought-Deciduous Leaves.- 1.4.3.2 Evergreen Shrubs.- 1.4.3.3 Phreatophytes.- 1.4.3.4 Perennial Grasses.- 1.4.3.5 Ephemerals.- 1.4.3.6 Nonsucculent Aphyllous Shrubs and Trees.- 1.4.3.7 Stem and Leaf Succulents.- 1.4.3.8 Poikilohydric Cryptogams.- 1.4.3.9 Epiphytes and Mat-Forming Air Plants.- 1.4.3.10 Stem Mistletoes.- 2 Functional Morphology of Nonsucculent Leaves.- 2.1 Energy Balance of a Leaf.- 2.1.1 Absorptance as Influenced by Organ Orientation and Reflectance.- 2.1.2 Effects of Leaf Size and Form.- 2.1.3 Energy Storageand Metabolic Heat Production.- 2.2 Leaf Size.- 2.2.1 Microphylly.- 2.2.2 Broad Desert Leaves.- 2.2.3 Seasonal Heteroblasty.- 2.3 Encelia as a Model System.- 2.4 Structural Nature of Surface Reflectance.- 2.5 Leaf Orientation and Display.- 2.6 Leaf Rolling and Revolute Margins.- 3 Functional Morphology of Nonsucculent Leaves.- 3.1 Gas Diffusion Pathway.- 3.1.1 Water Vapor.- 3.1.2 Carbon Dioxide.- 3.1.3 Flux Density of Gases.- 3.1.4 Characteristics of Leaf Conductances.- 3.1.4.1 Leaf Boundary Layer Characteristics.- 3.1.4.2 Cuticle and Groundmass Epidermis.- 3.1.4.3 Stomata.- 3.1.4.4 Intercelluar Air Spaces.- 3.1.4.5 Liquid-Phase Conduction of C02.- 3.1.5 Factors Limiting Photosynthetic Rates at Saturated Photon Flux Density.- 3.1.5.1 Relative Effects of Parameters.- 3.1.5.2 C4 Physiology and Elimination of Photorespiration.- 3.1.6 Water-Use Efficiency.- 3.2 Physiological Anatomy of Nonsucculent Leaves of Desert Plants.- 3.2.1 Deciduous and Evergreen Shrubs.- 3.2.1.1 Groundmass Epidermis and Trichomes.- 3.2.1.2 Stomata.- 3.2.1.3 Mesophylla.- 3.2.2 Phyllodineous Acacias.- 3.2.3 Woody Dicotyledons with C4 Photosynthesis.- 3.3 Phreatophytes.- 3.3.1 Desert Palms.- 3.3.2 Tropical Dicotyledonous Trees.- 3.3.3 Welwitschia mirabilis.- 3.3.4 Temperate Trees and Shrubs.- 3.3.5 Saltcedars and Casuarina.- 3.4 Herbaceous Species.- 3.4.1 Perennial and Annual Grasses.- 3.4.2 Herbaceous Dicotyledons.- 3.4.3 Geophytes.- 3.4.4 Desert Springs.- 3.5 Fruit Photosynthesis.- 4 Photosynthetic Stems of Nonsucculent Plants.- 4.1 Functional Morphology.- 4.1.1 Energy Budget Considerations.- 4.1.2 Canopy Architecture and Phenology.- 4.2 Anatomy of Woody Plants.- 4.2.1 Epidermis.- 4.2.1.1 Delay in Periderm Formation.- 4.2.1.2 Composition.- 4.2.1.3 Surface Coverings.- 4.2.1.4 Stomata.- 4.2.2 Hypodermis.- 4.2.3 Chlorenchyma and Associated Sclerenchyma.- 4.2.4 Leaf Anatomy.- 4.3 Special Cases.- 4.3.1 Bark Photosynthesis of Cercidium.- 4.3.2 C4 Chenopodiaceae and Calligonum.- 4.3.3 Herbaceous Species.- 4.3.3.1 Solid Stems and Grass Culms.- 4.3.3.2 Inflated Stems.- 5 Succulent Photosynthetic Organs.- 5.1 General Properties of Succulent Photosynthetic Organs.- 5.1.1 Water Content.- 5.1.2 High Volume-to-Surface Ratio.- 5.1.3 Crassulacean Acid Metabolism.- 5.1.4 Epidermal Water Vapor Conductances.- 5.1.5 Stomatal Patterns.- 5.1.6 Chlorenchyma.- 5.1.7 Succulent Hydrostats.- 5.2 Taxon-Specific Adaptations.- 5.2.1 Aloe.- 5.2.2 Agave and Yucca.- 5.2.3 Windowed Leaves.- 5.2.4 Epidermis of Aizoaceae.- 5.2.5 Areoles and Spines of Cacti.- 5.2.6 Euphorbiaceaewith CAM Stem Photosynthesis.- 5.2.7 Stapelieae.- 5.2.8 Leaves of Crassulaceae.- 5.2.9 Fouquieriaceae.- 5.2.10 Elephant Trees, Pachycauls, and Caudiciforms.- 5.2.11 Asteraceae.- 5.3 Fleshy Leaves.- 6 Special Topics in Water Relations.- 6.1 Xerohalophytes.- 6.1.1 Vesiculated Trichomes of Atriplex.- 6.1.2 Excreting Salt Glands.- 6.1.3 Halophytic Succulence.- 6.1.4 Nolana mollis and Other Atacaman Shrubs.- 6.1.5 Crystal Deposition in Shoots.- 6.2 Water Uptake.- 6.2.1 Vesiculated Trichomes of Atriplex.- 6.2.1.1 Morphology and Depth.- 6.2.1.2 Structural Responses to Drought and Rewetting.- 6.2.2 Leaves and Stems.- 6.2.2.1 Bromeliaceae.- 6.2.2.2 Selaginella lepidophylla and Other Poikilohydric Plants.- 6.2.2.3 Water-Absorbing Stem Epidermis.- 6.2.3 Parasitic Vascular Plants.- 6.2.3.1 Mistletoes.- 6.2.3.2 Root Parasites.- 6.3 Vascular Tissues.- 6.3.1 Veins in Leaves.- 6.3.2 Secondary Xylem.- 6.3.2.1 Shrubs and Subshrubs with Drought-Deciduous Leaves.- 6.3.2.2 Evergreen Shrubs.- 6.3.2.3 Phreatophytes.- 6.3.2.4 Nonsucculent Aphyllous Shrubs and Trees.- 6.3.2.5 Succulents.- 6.3.2.6 Herbaceous Angiosperms.- 6.3.3 Split Axis.- 6.3.4 Anomalous Secondary Thickening.- 6.3.5 Ground Tissues.- 7 Origins of Desert Structural Adaptations.- 7.1 Where Desert Adaptations Evolved.- 7.2 Warm Desert Versus Semiarid Habitats.- 7.2.1 Leaves.- 7.2.2 Wood.- 7.2.3 Ontogeny of Desert Shoots.- 7.3 Future Directions of Structure-Function Research.- References.- Taxonomic Index.