Survival Strategies of Annual Desert Plants

1 The Desert Biome, Survival Adaptations and Strategies of Annual Plant Species.- 1.1 Introduction.- 1.1.1 The Environment in Deserts and Arid Zones.- 1.1.2 Deserts with Winter or Summer Rain.- 1.1.3 Classification of Semi-Arid and Arid Zones According to the Amounts of Rain and Vegetation Zones.- 1.1.4 Annuals in Deserts and Survival Adaptations Throughout the Stages of Their Life Cycles.- 1.2 Plant Adaptation and Survival Strategies.- 1.3 The Negev Desert.- 1.3.1 Rain Amounts and Distribution.- 1.3.2 Amounts of Runoff Water After an Intense Rainfall Affected by Soil Crust, Stones and Slope Gradient.- 1.3.3 Biotic Activity, Diggings, Distribution of Runoff Water and Plant Succession.- 1.3.4 Temperatures in Winter or Summer.- 1.3.5 Temperatures, Relative Humidity and Rain Efficiency for Seed Germination.- 1.3.6 Day Length, Date of Seed Germination, Plant Development, Flowering and Plant Life Span.- 1.3.7 Dew During Winter or Summer Affecting Plant Adaptation.- 1.3.8 The Annual Environmental Factors and Life Cycle of Annual Plants.- 1.3.9 Seed Collectors.- 1.4 Conclusion.- 2 Flowering Strategies.- 2.1 Introduction.- 2.2 Flowering Adaptations and Strategies of Perennial Plants.- 2.3 Flowering Adaptations and Strategies of Selected Annual Plants.- 2.3.1 One-Seasonal Winter Annuals.- 2.3.1.1 Facultative Long-Day Response for Flowering (FLD).- 2.3.1.2 The Day Length Independent Response for Flowering (DIF).- 2.3.1.3 Intermediates.- 2.3.1.4 Single-Season Summer Annuals.- 2.3.2 Bi-seasonal Plants.- 2.3.2.1 Long-day (LD) Response for Flowering.- 2.3.2.2 Flowering Under Short Days and High Temperatures.- 2.4 Conclusion.- 3 Strategies of Phenotypic Plasticity of Germination During Seed Development and Maturation.- 3.1 Introduction.- 3.2 Environmental Factors Affecting Phenotypic Germination Plasticity.- 3.2.1 Seed Maturation Dates in a Natural Environment Affecting Germination.- 3.2.2 Day Length During Plant Development and Seed Maturation.- 3.2.2.1 Long or Short Days Affecting Seed Coat Permeability to Water.- 3.2.2.2 Day Length and Plant Age Affect Seed Plasticity of Germination.- 3.2.2.3 Short-Term and Long-Term Seed Banks.- 3.2.2.4 Quantitative Short-Day Effect.- 3.2.2.5 Quantitative Long-Day Effect.- 3.2.2.6 Day Length Effect on Short-Term and Long-Term Seed Banks.- 3.2.2.7 Day Length Affects Seed Germination of Plant Species with Soft Fruit.- 3.2.2.8 The Ecological Importance of the Critical Time During Seed Maturation at Which Day Length Affects Seed Germination.- 3.2.3 Influences of Light Quality During Seed Maturation on Seed Germination.- 3.2.4 Water Stress During Seed Maturation Affecting Seed Germination.- 3.2.5 Water and Temperature Stresses.- 3.2.6 Temperatures During Maturation Affecting Seed Germination.- 3.2.7 Plant Age, Seed Size and Germination Plasticity.- 3.3 Seed Position on the Mother Plant During Seed Development and Maturation Affecting Seed Germination.- 3.3.1 Seed Position in the Capsules, Pods and Fruit.- 3.3.2 The Effect of Position of Capsules or Pods in the Plant Canopy on Seed Germination.- 3.3.2.1 Central or Peripheral Capsules.- 3.3.3 Position of Pods in the Upper and Lower Part of the Inflorescence.- 3.3.4 Position of the Fruits, Dimorphism and Germinability.- 3.3.5 Position, Heteromorphism and Germination.- 3.3.6 Seed Position in Inflorescences That Are Also Dispersal Units.- 3.3.6.1 Position and Heteroblasty in Pteranthus dichotomus.- 3.3.6.2 The Heteroblasty of the Caryopses of Synaptospermic, Lignified Dispersal Units.- 3.3.6.3 The Influences of the Order of the Caryopses on Germination Percentage, Plant Development, Flowering and the Number of Tillers and Spikelets.- 3.3.6.4 The Influence of the Order of the Caryopses on the Size and Germination of the Caryopses of the Following Generation.- 3.3.7 Position in Burr — a Synaptospermic Dispersal Unit.- 3.3.8 Position of Achenes in the Capitulum Whorls Affecting the Time Distribution of Dispersal and Germination (serotinas).- 3.3.9 Position Effect on Seed Germinability and Seedling Survival of Female and Hermaphrodite Flowers in Inflorescences.- 3.3.10 Position of Achenes in Umbels Affecting Germinability.- 3.3.11 Position of Aerial and Subterranean Inflorescences Affecting Dispersability and Germinability.- 3.4 Desiccation Tolerance of Maturing Seeds.- 3.5 Conclusion.- 4 Strategies of Phenotypic Plasticity of Germination: Dormancy After Seed Maturation.- 4.1 Introduction.- 4.2 Post Maturation Environmental Influences on Dry Seed Primary Dormancy (After-Ripening).- 4.2.1 Hordeum spontaneum.- 4.2.2 Schismus arabicus.- 4.2.3 Stipa capensis.- 4.2.4 Ammochloa palaestina.- 4.2.5 Plantago coronopus.- 4.2.6 Spergularia diandra.- 4.3 Periods of Storage of Dry Seeds at High Temperatures Affecting Primary Dormancy in Seeds of Different Plant Species.- 4.3.1 Short Periods of Dry Seed Storage at High Temperatures Increases Germination.- 4.3.2 Long Periods of Dry Seed Storage at High Temperatures.- 4.3.2.1 Portulaca oleracea.- 4.3.2.2 Hirschfeldia incana.- 4.3.3 “Bet Hedging” Germination.- 4.3.3.1 Asteriscus hierochunticus.- 4.3.3.2 Mesembryanthemum nodiflorum.- 4.4 Post Maturation Phenotypic Germination Plasticity of Hard Seeds.- 4.4.1 Day Length During Seed Maturation Affecting Hard Seeds.- 4.4.2 Temperature Amplitude During Summer Affecting Hard Seeds.- 4.4.3 Gradual or Sudden Increase of Relative Humidity Affecting Hard Seeds.- 4.4.4 Low Relative Humidity Affecting Seed Germination.- 4.5 Post-Maturation Supra-optimal Temperatures Affecting Germination of Wet Seeds, and Thermodormancy.- 4.5.1 Lactuca serriola.- 4.5.2 Lactuca sativa.- 4.5.3 Cheiridopsis.- 4.6 Conclusion.- 5 Seed Dispersal Adaptations and Strategies.- 5.1 Seed Consumption, Plant Adaptations and Strategies of Seed Dispersal.- 5.2 One-Season Winter Annuals and Seed Dispersal Seasons.- 5.2.1 Dispersal of Lignified, Synaptospermic, Multi-Seeded Dispersal Units at the End of the Season with Rains.- 5.2.2 Entangled Lignified Dispersal Units.- 5.2.3 Dry Unopened, Lignified Pod as a Dispersal Unit.- 5.2.3.1 Multi-Seeded Dispersal Unit.- 5.2.3.2 Single-Seeded Lignified Sections of a Pod.- 5.2.4 Lignified Aerial Seed Banks with Delayed Seed Dispersal by Rain (Serotinous and Hygriescence).- 5.2.4.1 Dispersal by Rain of Aerial Protected Non-mucilaginous Seeds that ‘Escape’ into the Soil Seed Bank.- 5.2.4.2 Aerial Lignified Seed Banks with Mucilaginous Seeds, Seed Dispersal by Rain During the Season or Seasons Following Maturation.- 5.2.4.3 Shooting of Seeds to a Distance from the Mother Plant Triggered by Rain or Flood Water.- 5.2.4.4 Seeds Released by Rain and Dispersed by Wind.- 5.2.5 Subterranean Lignified, Protected Seed Banks, Germination in Situ.- 5.2.6 Escape Dispersal Adaptations and Strategies of Tiny Seeds.- 5.2.6.1 Tiny, Dust-Like Seeds.- 5.2.6.2 Dispersal by Wind of Small Seeds with Pappus or Corolla.- 5.2.6.3 Dispersal by Wind and Boring Hydrochastic Mechanisms.- 5.2.6.4 Dispersal by Wind of Mucilaginous Seeds During the Dry Season.- 5.2.6.5 Dispersal by Wind of Polymorphic Mucilaginous and Non-mucilaginous Achenes.- 5.2.6.6 Delayed Seed Dispersal and Ballistic Dispersal by Wind.- 5.2.6.7 Seed Dispersal from Exploding Hygrochastic Pods Under Dry Conditions.- 5.2.6.8 Delayed Achene Maturation to the Season with Rain and Dispersal by Wind.- 5.3 Bi-seasonal Annuals and Seed Dispersal by Wind.- 5.3.1 Winged Diaspores Matured Shortly Before the Season with Rains 207.- 5.3.2 Achenes Matured and Dispersed Daily in Small Portions During the Summer.- 5.4 Conclusion.- 6 Germination Adaptations, Strategies and Influences on Germination During Seed Wetting.- 6.1 Introduction.- 6.1.1 “Bet Hedging” Germination Strategies.- 6.1.2 Germination Strategies in Deserts with Winter and Summer Rains.- 6.1.3 Germination Strategies of Seasonal Genotypes.- 6.2 Fitness to Habitats and Range of Temperatures for Germination of some Plants Occurring in the Negev.- 6.2.1 Geophytes: Temperature for Germination and Habitat Location.- 6.2.2 Adaptation to Temperatures and Salinity in Germination of Two Plants Occurring on Opposite-Facing Slopes of One Hill, in the Negev Desert Highlands.- 6.2.2.1 Medicago laciniata var. laciniata and M.laciniata var. brachycantha.- 6.2.2.2 Helianthemum vesicarium and H. ventosum.- 6.2.3 Germination Adaptations of Local Genotypes at Different Elevations.- 6.2.4 Local Genotypes According to Environmental Factors.- 6.2.5 Exposure of Wet Seeds to Supra-optimal Temperatures and the Imposition of Secondary Dormancy According to Location in the Soil or in Depressions.- 6.2.6 Repair Mechanisms by Short Periods of Wetting, and Seed Germination.- 6.2.7 Environmental Factors Affecting the Phenotypic Plasticity of Germination.- 6.2.8 Germination and the Minimum Amount of Precipitation required.- 6.3 Environmental Factors During Seed Wetting and Germination During the Season with Rain.- 6.3.1 Amounts of Rain, Cautious or Opportunistic Germination Strategies of Low or High Risk, Slow or Fast Germinating Seeds.- 6.3.1.1 Plants with Cautious Strategies of Seed Germination.- 6.3.1.2 Plants with Opportunistic Strategies of Seed Germination.- 6.3.2 Speed of Germination.- 6.3.2.1 Strategies of Rapidly Germinating Seeds.- 6.3.2.2 Strategies of Slowly Germinating Seeds.- 6.3.2.3 The Presence of Germination Inhibitors as“Rain Gauges”.- 6.3.3 Species with Mucilaginous Seeds (Myxospermy) as an Adaptation and Part of the Complementary Sets of Survival Strategies.- 6.3.3.1 Mucilaginous Seeds That Are Dispersed by Rain.- 6.3.3.2 Mucilaginous Seeds That Are Dispersed During the Dry Summer.- 6.3.3.3 Mucilaginous and Light-Sensitive Seeds.- 6.3.3.4 Mucilaginous Seeds on the Soil Surface and Water Conditions Required for Germination.- 6.3.3.5 Mucilaginous Seeds Dispersed by Adhering to Mammals and Birds.- 6.3.3.6 Dispersal of Mucilaginous Seeds in Edible Fruit (Endozoochory).- 6.3.4 Germination Under Mild Winter Temperatures and High Daytime Relative Humidity Compared with High Summer Temperatures and Low Daytime Relative Humidity.- 6.3.4.1 The Amount of Rain in Mild Winter Temperatures and High Relative Humidity Affecting Seed Germination in a Natural Desert Area near Avdat.- 6.3.4.2 Amounts of Water in Summer Required for Germination at High Temperatures and Low Relative Humidity.- 6.3.5 Range of Temperatures for Germination in Light or Dark.- 6.3.5.1 Schismus arabicus.- 6.3.5.2 Spergularia diandra.- 6.3.5.3 Plantago coronopus.- 6.3.6 Seed Location on the Soil or in the Soil Seed Bank Affecting Seed Germination, and Soil Turnover Influences.- 6.3.6.1 Seeds on the Soil Surface.- 6.3.6.2 Seeds Buried in the Soil.- 6.3.7 Thermodormancy of Winter Germinating Plant Species.- 6.3.8 Light During Seed Wetting and Germination.- 6.3.8.1 Seed Location in Soil and Germination Regulation by Light.- 6.3.8.2 Influences of the Visible Light Spectrum on Seed Germination.- 6.3.9 Germination Regulation by Soil Inhibitors.- 6.4 Conclusion.- 7 Embryo and Seedling Survival and Plant Development.- 7.1 Introduction.- 7.1.1 Embryo Drought Resistance.- 7.1.2 Seedling Drought Resistance.- 7.2 Seedling Drought Tolerance and Survival.- 7.2.1 Hordeum spontaneum Effects of Seedling Developmental Stages and Local Genotypes.- 7.2.2 Schismus arabicus.- 7.2.2.1 Effects of Seedling Developmental Stages and Caryopsis Size.- 7.2.2.2 Duration of Dry Storage Affecting Seedling Survival and Genotypic Differences.- 7.2.2.3 Size Groups of Caryopses and Re-growth of Seedlings After Rehydration.- 7.2.2.4 Seedling Regrowth After 48 h Affected by Caryopsis Size.- 7.3 Amounts of Water Affecting Seedling Survival.- 7.3.1 Irrigation Affecting Seedling Density and Survival.- 7.3.1.1 Different Amounts of Water Affects Seedling Emergence and Survival.- 7.3.1.2 Water Distribution Affects Seedling Emergence and Survival.- 7.3.1.3 Seedling Emergence and Survival After Single Irrigations with Different Amounts of Water.- 7.3.1.4 Seedling Survival After Irrigation with 10 mm of Water on 9 to 20 days.- 7.3.1.5 Survival of Three Main Species According to Different Apportioning of the 200 mm of Water.- 7.3.1.6 The Number of Seeds (Schizocarps) Produced by Malva aegyptia as Influenced by Irrigation in Summer.- 7.3.2 The Amount of Precipitation in Winter Affecting Seedling Emergence and Survival.- 7.3.2.1 Schismus arabicus.- 7.3.2.2 Gymnarrhena micrantha.- 7.3.3 Inter-Specific and Intra-Specific Competition and Survival.- 7.4 Conclusion.- 8 Summary of the Complementary Sets of Survival Strategies of Some Common Species of the Negev Desert That Have Been Studied in Detail.- 8.1 Introduction.- 8.2 The Complementary Sets of Adaptation and Survival Strategies.- 8.2.1 Schismus arabicus.- 8.2.1.1 Flowering Facultative Long-Day Response.- 8.2.1.2 Influences During and After Maturation on Phenotypic Plasticity of Germination.- 8.2.1.3 Escape Seed Dispersal Strategies.- 8.2.1.4 Opportunistic Germination Strategies in Mild Winters and Cautious Germination Strategies in Hot Summers.- 8.2.1.5 Seedling Drought Tolerance.- 8.2.2 Spergularia diandra.- 8.2.2.1 Flowering.- 8.2.2.2 Phenotypic Plasticity of Germination by Day Length, and Seed Position Effect, During Seed Development and Maturation.- 8.2.2.3 Genotypes and Seed Dispersability.- 8.2.2.4 The Opportunistic Strategy of Seed Germination.- 8.2.2.5 Light, Temperatures and Germination.- 8.2.2.6 Dry Storage Duration and Seed Germinability.- 8.2.2.7 Germination in Summer.- 8.2.2.8 Soil Turnover.- 8.2.2.9 Time of Rainfall.- 8.2.3 Blepharis spp.- 8.2.3.1 Flowering-Day Length Independent.- 8.2.3.2 Seed Dispersal by Rain or Floods from the Protected Aerial Seed Bank and Cautious Germination Strategy.- 8.2.3.3 Regulation of Germination by the Mucilaginous Layer Surrounding the Seeds.- 8.2.3.4 Connection of the Seeds to the Soil by the Mucilage.- 8.2.3.5 Fast Germination of the Dispersed Seeds.- 8.2.4 Plantago coronopus.- 8.2.4.1 Flowering.- 8.2.4.2 Influence of Day Length During Seed Maturation on Seed Numbers, Biomass and Germinability.- 8.2.4.3 Post-Maturation Temperatures and Primary Dormancy (After-Ripening) of the Protected Aerial Seed Bank.- 8.2.4.4 Dispersal of Mucilaginous Seeds by Rain (Myxospermy).- 8.2.4.5 Phenotypic Plasticity of Germination.- 8.2.5 Hordeum spontaneum.- 8.2.5.1 Biodiversity Among Local Genotypes.- 8.2.5.2 Biodiversity of Primary Dormancy.- 8.2.5.3 Biodiversity of Seedling Drought Tolerance.- 8.3 Conclusion.- References.- Index of Latin Names.