Estimating age-dependent costs and benefits of roots with contrasting life span: comparing apples and oranges
Article first published online: 21 DEC 2001
Volume 150, Issue 3, pages 685–695, June 2001
How to Cite
Bouma, T. J., Yanai, R. D., Elkin, A. D., Hartmond, U., Flores-Alva, D. E. and Eissenstat, D. M. (2001), Estimating age-dependent costs and benefits of roots with contrasting life span: comparing apples and oranges. New Phytologist, 150: 685–695. doi: 10.1046/j.1469-8137.2001.00128.x
- Issue published online: 21 DEC 2001
- Article first published online: 21 DEC 2001
- Received: 10 October 2000 Accepted: 22 January 2001
- phosphorus uptake;
- root life span;
- root turnover;
- root age;
- simulation modelling;
- uptake kinetics
- •The relation between root age and root function is poorly understood, despite its importance to root longevity.
- •The effect of root age on respiration rates and 32P-uptake kinetics was determined for roots excavated from mature apple and citrus trees (median root life spans of 30 vs 300 d). To evaluate whether root longevity maximizes the efficiency of nutrient capture, daily and lifetime efficiencies were calculated by dividing simulated P-uptake benefits (solute transport model) by age-specific respiration costs.
- •We found that: respiration rates and P uptake capacity change with root age in a species-specific way; and soil characteristics that determine the rate of nutrient depletion in the rhizosphere are as important as changes in root physiology in determining the age at which a root reaches its maximum efficiency.
- •Further testing of the efficiency of nutrient capture as a predictor of root life span requires measurement of both soil properties and age-specific physiology of roots including their mycorrhizal fungi.