Ebook: Applications of Continuous and Steady-State Methods to Root Biology

This book provides an excellent illustration of the interrelationship between progress in scientific methodology and conceptual advances, and its publica­ tion should contribute to further advances. It is well known that major advances in understanding often follow the development of new methods. The development of the acetylene reduction assay for nitrogenase activity provides a good example of this interrelationship between theory and methods. Theoretical knowledge led to a search for substrates for nitro­ genase that could be assayed for more easily than ammonium, the normal product of the enzyme. The discovery of the reduction of acetylene to ethylene by nitrogenase provided the ideal answer to the problem by provid­ ing a rapid, specific, nondestructive, and inexpensive assay for nitrogenase activity. This assay is now used by almost every laboratory doing research on nitrogen fixation. However, further use and development of the acetylene reduction assay has shown that it can underestimate nitrogenase activity and can even give incorrect relative values under some circumstances. The major problem is that exposure of legume nodules to acetylene can cause a large increase in the resistance to oxygen diffusion into the nodule. This reduced supply of oxygen decreases the rate of nitrogenase activity within a few minutes.

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Content:
Front Matter....Pages i-xv
A Multichannel System for Steady–State and Continuous Measurements of Gas Exchanges from Legume Roots and Nodules....Pages 1-28
Quantification of Diffusion Characteristics in Spherical Nodules: A Comparison of Methods....Pages 29-53
Simple Apparatus for Growth of Nodulated Plants and for Continuous Nitrogenase Assay Under Defined Gas Phase....Pages 55-66
Continuous Measurements of Nitrogenase Activity in the Study of Environmental Responses of Frankia and Other Bacteria....Pages 67-77
Limitations and Errors in Gas Exchange Measurements with Legume Nodules....Pages 79-95
Principles and Approaches in Modeling Steady-State Gas Diffusion in Legume Nodules....Pages 97-119
Modeling Gas Exchange by Actinorhizal Root Nodules Using Network Simulation Analysis....Pages 121-146
Continuous and Steady-State Nutrient Absorption by Intact Plants....Pages 147-163
Steady-State Control and Investigation of Root System Morphology....Pages 165-182
Measurement of Carbon Cost in Ectomycorrhizae....Pages 183-196
Approaches to Measuring Soil Nitrogen Transformations under Continuous or Steady-State Conditions....Pages 197-216
Methodological Considerations in Measuring Biomass, Production, Respiration and Nutrient Resorption for Tree Roots in Natural Ecosystems....Pages 217-232
Back Matter....Pages 233-245

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Content:
Front Matter....Pages i-xv
A Multichannel System for Steady–State and Continuous Measurements of Gas Exchanges from Legume Roots and Nodules....Pages 1-28
Quantification of Diffusion Characteristics in Spherical Nodules: A Comparison of Methods....Pages 29-53
Simple Apparatus for Growth of Nodulated Plants and for Continuous Nitrogenase Assay Under Defined Gas Phase....Pages 55-66
Continuous Measurements of Nitrogenase Activity in the Study of Environmental Responses of Frankia and Other Bacteria....Pages 67-77
Limitations and Errors in Gas Exchange Measurements with Legume Nodules....Pages 79-95
Principles and Approaches in Modeling Steady-State Gas Diffusion in Legume Nodules....Pages 97-119
Modeling Gas Exchange by Actinorhizal Root Nodules Using Network Simulation Analysis....Pages 121-146
Continuous and Steady-State Nutrient Absorption by Intact Plants....Pages 147-163
Steady-State Control and Investigation of Root System Morphology....Pages 165-182
Measurement of Carbon Cost in Ectomycorrhizae....Pages 183-196
Approaches to Measuring Soil Nitrogen Transformations under Continuous or Steady-State Conditions....Pages 197-216
Methodological Considerations in Measuring Biomass, Production, Respiration and Nutrient Resorption for Tree Roots in Natural Ecosystems....Pages 217-232
Back Matter....Pages 233-245
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