1 Background for Designing Laboratory Bioassays
1.1 Introduction
1.2 Allelopathic Interactions
1.3 Nature of Allelopathic Compounds
1.4 Sources of Allelopathic Compounds and Modifiers in Soils
1.5 Holism and Reductionism
1.6 Benefits and Limits of Laboratory Bioassays
1.7 False Assumptions and Misconceptions for Laboratory Bioassays
1.8 References
2 Introduction to the Fundamentals of Laboratory Bioassays
2.1 Factors of Bioassay Systems
2.2 Basic Information Required for All Bioassay Systems
2.3 References
3 Some Issues and Challenges When Designing Laboratory Bioassays
3.1 Introduction
3.2 Treatment Concentrations
3.3 Field Inputs and Laboratory Treatments of Water-Soluble Compounds
3.4 Mobility and Proximity of Compounds in Soil Media
3.5 Seed and Seedling Densities
3.6 Symbiotic Relationships
3.7 Soil Microorganisms (Microflora and Fauna)
3.8 Herbivory and Disease
3.9 Physicochemical Environments
3.10 References or Controls
3.11 Measurements
3.12 Final Comments
3.13 References
4 Hypothetical Standard Screening Bioassays
4.1 Introduction
4.2 Living Plants
4.3 Plant Litter and Residues
4.4 Field Soils
4.5 Final Comments
4.6 References
5 Effects, Modifiers, and Modes of Action of Allelopathic Compounds Using Phenolic Acids as Model Compounds
5.1 Introduction
5.2 Individual Compounds
5.3 Simple Mixtures
5.4 Complex Mixtures
5.5 Modes of Action
5.6 Final Comments
5.7 References
6 Hypothetical Cause and Effect Bioassays
6.1 Introduction
6.2 Identified Putative Allelopathic (IPA) Organic Compounds
6.3 Complex Solutions
6.4 Using Regression Analyses to Relate Potential Causes with Effects
6.5 Treatment Surface Areas
6.6 Using Omics Methods as Tools
6.7 References
7 Laboratory Model Systems and Field Systems: Some Final Thoughts
7.1 Introduction
7.2 Comparison of Field and Present Laboratory Model Systems
7.3 Is the Present Criticism by Critics Regarding Plant-Plant Allelopathic Interactions in the Field Credible?
7.4 Improving the Value of Laboratory Bioassay Systems
7.5 Future Directions: Questions that Need Answers
7.6 Central Tenets (i.e., Opinions, Doctrines, or Principles) Articulated in this Volume
7.7 Final Comments
7.8 References
Author Index
Subject Index
About the Author: Professor Emeritus at NC State University, Prof. Udo Blum is interested in characterizing and identifying the mechanisms by which allelopathic compounds, specifically phenolic acids (e.g., ferulic acid, p-coumaric acid, vanillic acid, p-hydroxybenzoic acid), released into the soil environment may impact soil chemistry (e.g., soil nutrition, organic pools, sorption and desorption), soil microbiology (e.g., population biology, natural selection, carbon utilization), rhizosphere ecology (e.g., microbial population biology) and population biology (e.g., germination, seedling emergence) and physiology (e.g., mineral nutrition, carbon allocation, water relations, growth) of dicot weeds in no-till agroecosystems.