Journal
PLANT CELL AND ENVIRONMENT
Volume 35, Issue 9, Pages 1558-1566Publisher
WILEY
DOI: 10.1111/j.1365-3040.2012.02509.x
Keywords
Al2O3 nanoparticles; diffusion limitation; diffusive gradients in thin films; Michaelis constant; Michaelis-Menten kinetics
Categories
Funding
- Vienna Science and Technology Fund (WWTF) [MA07-008]
- Fund for Scientific Research - Flanders (FWO)
Ask authors/readers for more resources
Diffusion towards the root surface has recently been shown to control the uptake of metal ions from solutions. The uptake flux of phosphorus (P) from solutions often approaches the maximal diffusion flux at low external concentrations, suggesting diffusion-controlled uptake also for P. Potential diffusion limitation in P uptake from nutrient solutions was investigated by measuring P uptake of Brassica napus from solutions using P-loaded Al2O3 nanoparticles as mobile P buffer. At constant, low free phosphate concentration, plant P uptake increased up to eightfold and that of passive, diffusion-based samplers up to 40-fold. This study represents the first experimental evidence of diffusion-limited P uptake by plant roots from nutrient solution. The Michaelis constant of the free phosphate ion obtained in unbuffered solutions (Km = 10.4 mu mol L-1) was 20-fold larger than in the buffered system (Km0.5 mu mol L-1), indicating that Kms determined in unbuffered solutions do not represent the transporter affinity. Increases in the P uptake efficiency of plants by increasing the carrier affinity are therefore unlikely, while increased root surface area or exudation of P-solubilizing compounds are more likely to enhance P uptake. Furthermore, our results highlight the important role natural nanoparticles may have in plant P nutrition.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available