In the spring of 1969 a small meeting was convened at the CSIRO Riverina Laboratory, Deniliquin, New South Wales, to discuss the biology of the genus Atriplex, a group of plants considered by those who attended to be of profound importance both in relation to range management in the region and as a tool in physiological research. The brief report of this meeting (Jones, 1970) now serves as a marker for the subsequent remarkable increase in research on this genus, and served then to interest the editors of the Ecological Studies Series in the present volume. This was an exciting time in plant physiology, particularly in the areas of ion absorption and photosynthesis, and unknowingly several laboratories were engaged in parallel studies of these processes using the genus Atriplex. It was also a time at which it seemed that numerical methods in plant ecology could be used to delineate significant processes in arid shrubland ecosystems. Nevertheless, to presume to illustrate and integrate plant physiology and ecology using examples from a single genus was to presume much. The deficiencies which became increasingly apparent during the preparation of the present book were responsible for much new research described in these pages.

Inhalt

1. Physiological Processes in Plant Ecology: the Structure for a Synthesis.- 1.1 The Space-Time Scale.- 1.2 Utility of the Space-Time Scale.- 1.3 The Quest for Adaptive Significance Among Physiological Processes.- 1.4 Structure for a Synthesis.- 2. Systematic and Geographical State of Atriplex.- 2.1 The Habit and Morphology of Atriplex.- 2.2 A Species List for Atriplex.- 2.3 Geographical Distribution of Species.- 2.4 Perspectives from the Systematic and Geographical States.- 3. Genecological Differentiation.- 3.1 Intra-Specific Variation and Ecotypic Differentiation.- 3.2 Morphological Aspects of Genecological Differentiation.- 3.3 Genetic Coherence Between Functional and Morphological Characteristics.- 3.4 Physiological Aspects of Genecological Differentiation.- 3.5 Concluding Remarks.- 4. Genetic and Evolutionary Relationships in Atriplex.- 4.1 Chromosome Numbers in Atriplex.- 4.2 Genetic Structures and Evolutionary Trends in the Atriplex triangularis Group.- 4.3 Interspecific Relationships and Distribution of C4 Photosynthesis in Atriplex.- 4.4 Inheritance of C4 Photosynthesis in Atriplex.- 5. Atriplex Communities: Regional Environments and Their Ecological Analysis.- 5.1 Communities of Arid Continental Interiors.- 5.2 Coastal Communities.- 5.3 Weed and Ruderal Communities.- 5.4 The Major Atriplex Habitats a Resumé.- 5.5 Regional Variation in Atriplex Shrublands.- 5.6 Local Variation and Pattern in Atriplex Shrublands.- 5.7 Regularity in Arid Vegetation.- 5.8 Patterns of Biomass and Nutrient Distribution.- 5.9 Ecological States in Perspective.- 6. Germination and Seedling Establishment.- 6.1 Germination Processes.- 6.2 Establishment Processes.- 6.3 Physiological Processes of Germination and Establishment in the Context of Ecological Processes.- 6.4 Conclusions.-7. Absorption of Ions and Nutrients.- 7.1 Ionic Concentration, Distribution, and Pathways in the Soil-Plant System.- 7.2 Ion Absorption Processes in Plants.- 7.3 Absorption of Nutrient Anions and Interactions with Cell Metabolism.- 7.4 Salinity Responses in Atriplex.- 7.5 Ion and Nutrient Absorption Processes in the Context of Ecological Processes.- 7.2 Conclusions.- 8. Water Movement and Plant Response to Water Stress.- 8.1 Water Transport.- 8.2 Response and Adaptation to Water Stress.- 9. Photosynthesis.- 9.1 The Photosynthetic Process.- 9.2 Photosynthetic Responses to Light.- 9.3 Photosynthetic Responses to Temperature.- 9.4 Photosynthesis in Relation to Water Use and Water Stress.- 9.5 Photosynthesis in Relation to Salinity and Mineral Nutrition.- 9.3 Conclusions.- 10. Productivity and Environment.- 10.1 Photosynthesis and Photosynthate Partitioning in Relation to Primary Productivity.- 10.2 Productivity in Relation to Light.- 10.3 Productivity in Relation to Temperature.- 10.4 Productivity in Relation to Mineral Nutrition and Salinity.- 10.5 Productivity in Relation to Water.- 10.6 Productivity in Plant Communities.- 10.7 Effect of Future Increase in CO2 Level on Water Use and Productivity.- Epilog.- References.- Taxonomic Index.