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An Optimized Rhizobox Protocol to Visualize Root Growth and Responsiveness to Localized Nutrients
Published on: October 22, 2018
A simple model for nitrogen-limited plant growth and nitrogen allocation
1Department of Environmental Sciences, Copernicus Institute for Sustainable Development and Innovation, Utrecht University, PO Box 80.115, 3508 TC Utrecht, The Netherlands.
Annals of Botany
|August 16, 2005
Summary
A new model quantifies nitrogen allocation in plants, linking it to plant nitrogen concentration. This supports the nitrogen productivity theory and explains the negative intercept in growth rate relationships.
Area of Science:
- Plant Physiology
- Ecology
- Mathematical Modeling
Background:
- Nitrogen-limited plant growth often shows a linear relationship between relative growth rate and plant nitrogen concentration.
- This relationship, with a negative intercept at zero nitrogen, underpins the nitrogen productivity theory.
- Empirical data suggest a distinct relationship between nitrogen allocation and plant nitrogen concentration.
Purpose of the Study:
- To develop a mathematical model quantifying the relationship between nitrogen allocation and plant nitrogen concentration.
- To use the model to examine the processes underlying the nitrogen productivity theory.
- To focus on nitrogen allocation to simplify the model, avoiding compartment-specific nitrogen concentrations.
Main Methods:
- Focused on the formation and degradation of photosynthetic nitrogen (enzymes in photosynthesis).
- Assumed photosynthetic nitrogen formation is proportional to nitrogen uptake under nitrogen limitation.
- Assumed degradation of photosynthetic nitrogen follows first-order kinetics.
Main Results:
- Model predictions for nitrogen allocation aligned well with empirical data.
- The ratio of leaf nitrogen to plant nitrogen decreased linearly with the inverse of plant nitrogen concentration.
- Nitrogen productivity was found to be proportional to this ratio, consistent with theory.
Conclusions:
- The model's agreement with empirical data suggests its general applicability for nitrogen allocation and concentration relationships.
- The negative intercept in the relative growth rate vs. plant nitrogen concentration is interpreted as the degradation constant of photosynthetic nitrogen.
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