Plant Plant Allelopathic Interactions Ii

In an effort to implement conservation measures farmers have used a variety of production methods, including the use of reduced or zero tillage and cover crops. One benefit of these production methods has been early season weed control. The literature suggests that a variety of mechanisms may be involved, among them the allelopathic effects of phenolic acids. This retrospective analysis addresses the following: How likely are phenolic acid concentrations and environmental conditions in wheat no-till cropping systems for the inhibition of annual broadleaf weed emergence? and Do phenolic acids have a dominant role or are they just one component of a larger promoter/modifier/inhibitor complex? The book covers allelopathic plant-plant interactions, laboratory and field experiments, and future research. It uses a journal format, provides justifications for procedures used, if-then hypotheses, and cons and pros so that readers can reach their own conclusions.

This volume presents detailed descriptions and analyses of the underlying features, issues and suppositions associated with seed and seedling laboratory bioassays presented in a previous volume. It is, however, broader in scope and substance in that the information provided is relevant to all water-soluble compounds released to soil by putative allelopathic living plants and their litter and residues. It is ultimately an attempt to update and expand the practical guidelines for designing laboratory bioassays that have previously been provided in the literature with the hope that the designs of future seed and seedling laboratory bioassays will become more relevant to field systems. Standard references have been included to provide background and additional details. This volume has been written specifically for researchers and their graduate students who are interested in studying plant-plant allelopathic interactions.

This volume continues the retrospective analyses of Volumes I and II, but goes beyond that in an attempt to understand how phenolic acids are partitioned in seedling-solution and seedling-microbe-soil-sand culture systems and how phenolic acid effects on seedlings may be related to the actual and/or conditional physicochemical properties (e.g., solubility, hydrophobicity, pKa, molecular structure and soil sorption/desorption) of simple phenolic acids. Specifically, it explores the quantitative partitioning (i.e., source-sink relationships) of benzoic and cinnamic acids in cucumber seedling-solution and cucumber seedling-microbe-soil-sand systems and how that partitioning may influence phenolic acid effects on cucumber seedlings. Regressions, correlations and conceptual and hypothetical models are used to achieve these objectives. Cucumber seedlings are used as a surrogate for phenolic acid sensitive herbaceous dicotyledonous weed seedlings. This volume was written specifically for researchers and their students interested in understanding how a range of simple phenolic acids and potentially other putative allelopathic compounds released from living plants and their litter and residues may modify soil chemistry, soil and rhizosphere microbial biology, seedling physiology and seedling growth. In addition, this volume describes the potential relationships, where they may exist, for direct transfer of organic compounds between plants, plant communication and plant-plant allelopathic interactions and addresses the following questions: Can physicochemical properties of phenolic acids be used as tools to help understand the complex behavior of phenolic acids and the ultimate effects of phenolic acids on sensitive seedlings? What insights do laboratory bioassays and the conceptual and hypothetical models of laboratory systems provide us concerning the potential behavior and effects of phenolic acids in field systems? What potential role may phenolic acids play in broadleaf-weed seedling emergence in wheat debris cover crop no-till systems?

This volume presents detailed descriptions and analyses of the underlying features, issues and suppositions associated with seed and seedling laboratory bioassays presented in a previous volume. It is, however, broader in scope and substance in that the information provided is relevant to all water-soluble compounds released to soil by putative allelopathic living plants and their litter and residues. It is ultimately an attempt to update and expand the practical guidelines for designing laboratory bioassays that have previously been provided in the literature with the hope that the designs of future seed and seedling laboratory bioassays will become more relevant to field systems. Standard references have been included to provide background and additional details. This volume has been written specifically for researchers and their graduate students who are interested in studying plant-plant allelopathic interactions.

This volume continues the retrospective analyses of Volumes I and II, but goes beyond that in an attempt to understand how phenolic acids are partitioned in seedling-solution and seedling-microbe-soil-sand culture systems and how phenolic acid effects on seedlings may be related to the actual and/or conditional physicochemical properties (e.g., solubility, hydrophobicity, pKa, molecular structure and soil sorption/desorption) of simple phenolic acids. Specifically, it explores the quantitative partitioning (i.e., source-sink relationships) of benzoic and cinnamic acids in cucumber seedling-solution and cucumber seedling-microbe-soil-sand systems and how that partitioning may influence phenolic acid effects on cucumber seedlings. Regressions, correlations and conceptual and hypothetical models are used to achieve these objectives. Cucumber seedlings are used as a surrogate for phenolic acid sensitive herbaceous dicotyledonous weed seedlings. This volume was written specifically for researchers and their students interested in understanding how a range of simple phenolic acids and potentially other putative allelopathic compounds released from living plants and their litter and residues may modify soil chemistry, soil and rhizosphere microbial biology, seedling physiology and seedling growth. In addition, this volume describes the potential relationships, where they may exist, for direct transfer of organic compounds between plants, plant communication and plant-plant allelopathic interactions and addresses the following questions: Can physicochemical properties of phenolic acids be used as tools to help understand the complex behavior of phenolic acids and the ultimate effects of phenolic acids on sensitive seedlings? What insights do laboratory bioassays and the conceptual and hypothetical models of laboratory systems provide us concerning the potential behavior and effects of phenolic acids in field systems? What potential role may phenolic acids play in broadleaf-weed seedling emergence in wheat debris cover crop no-till systems?

This book provides the reader relevant information about actual knowledge about the process of allelopathy, covering all aspects from the molecular to the ecological level. Special relevance is given to the physiological and ecophysiological aspects of allelopathy. Several ecosystems are studied and methodological considerations are taken into account in several different chapters. The book has been written to be useful both for Ph.D. students and for senior researchers, so the chapters include all necessary information to be read by beginners, but they also include a lot of useful information and discussion for the initiated.

Allelochemicals play a great role in managed and natural ecosystems. Apart from plant growth, allelochemicals also may influence nutrient dynamics, mycorrhizae, soil chemical characteristics, and microbial ecology. Synergistic action of various factors may better explain plant growth and distribution in natural systems. The book emphasizes the role of allelochemicals in shaping the structure of plant communities in a broader ecological perspective. The book addresses the following questions: (1) How do allelochemicals influence different components of the ecosystem in terms of shaping community structure? (2) Why is it difficult to demonstrate interference by allelochemicals (i.e., allelopathy) in a natural system in its entirety? Despite a large amount of existing literature on allelopathy, why are ecologists still skeptical about the existence of allelopathy in nature? (3) Why are there only scarce data on aquatic ecosystems? (4) What role do allelochemicals play in microbial ecology?.....