Cadmium uptake by roots: Contribution of apoplast and of high- and low-affinity membrane transport systems

Redjala, Tanegmart; Sterckeman, Thibault; Morel, Jean-Louis

doi:10.1016/j.envexpbot.2009.05.012

Cited by 107 publications

(65 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is consistent with the findings of Ryan et al (1992). The higher influx of Cd 2+ , Cu 2+ and Pb 2+ observed in the roots is possibly dominated by a stronger cell wall sorption (Redjala et al 2009(Redjala et al , 2010. Thus after immobilization of the roots in the measuring solution and equilibration for 10 min, the steady ions fluxes were then recorded across the root tips of the wetland plants.…”

Section: Measurement Of Ion Flux Of An Ion Gradient Sourcesupporting

confidence: 88%

Determining the fluxes of ions (Pb2+, Cu2+ and Cd2+) at the root surface of wetland plants using the scanning ion-selective electrode technique

Peijnenburg

et al. 2016

Plant Soil

View full text Add to dashboard Cite

Background and aims Measuring specific ion fluxes from different regions of the root under practical physiological conditions is crucial for understanding metal uptake mechanisms by plants. Methods We developed and tested a neutral carrierbased liquid-membrane Pb 2+ and Cu 2+ ion selective microelectrode (ISME) to investigate ion-transport processes along the roots of three common wetland plant species. Results The Pb 2+ and Cu 2+ ISME exhibited a Nernstian response with Pb 2+ and Cu 2+ activities as low as 1.0 nM and 1.0 μM in deionized water and simulated soil solution, respectively. Phragmites australis had a region of Cu 2+ release for approximately the first 200 μm, while it exhibited Pb 2+ and Cd 2+ outward net flux up to the first 500 μm. Although in older sections of the root of Phragmites australis there were areas of influx of Cu 2+ , Pb 2+ and Cd 2+ , the overall influx was much smaller than that of Typha latifolia or Canna indica. Such a reduced uptake and/or an increased efflux of metal ions across the root-cell plasma-membrane might explain the higher resistance of Phragmites australis to metals, at least in part. Conclusions The Pb 2+ and Cu 2+ ISMEs are shown to permit detailed investigation of heavy-metal ion transport in plant roots, especially for plants used for phytoremediation.

show abstract

Section: Measurement Of Ion Flux Of An Ion Gradient Sourcesupporting

confidence: 88%

Determining the fluxes of ions (Pb2+, Cu2+ and Cd2+) at the root surface of wetland plants using the scanning ion-selective electrode technique

Peijnenburg

et al. 2016

Plant Soil

View full text Add to dashboard Cite

show abstract

“…In short term experiments where roots are exposed to Cd for a few hours, and the plant does not acclimatize to possible toxic effects of Cd, the uptake isotherms are a straight line (Perriguey et al 2008) with α value of 10 −5 cms −1 , similar to our values. Other studies (Redjala et al 2009) show a high affinity saturable transport system (HATS) for Cd with a low affinity transport system (LATS). The HATS had a K m of about 0.3 μmolL −1 while LATS was the linear component of the uptake isotherm.…”

Section: Cadmium Uptake Kineticsmentioning

confidence: 95%

Cadmium uptake kinetics and plants factors of shoot Cd concentration

Stritsis

Claassen

2012

Plant Soil

View full text Add to dashboard Cite

Background and aims Accumulation of Cd in the shoots of plants grown on Cd contaminated soils shows considerable variation. A previous preliminary experiment established that one major reason for this variation was the rate of Cd influx into the roots (mol Cd cm −2 root s −1 ). However, this experiment did not distinguish between solubilization of soil Cd on the one hand and difference in Cd uptake kinetics on the other. The main objectives of the present study were thus to characterize Cd uptake kinetics of plants continuously exposed to Cd concentrations similar to those encountered in soils. Furthermore we determined the factors responsible for differences in shoot Cd concentration such as net Cd influx, root areashoot dry weight ratio, shoot growth rate and proportion of Cd translocated to the shoot. Materials and methods Maize, sunflower, flax and spinach were grown in nutrient solution with five constant Cd concentrations varying from 0 to 1.0 μmolL −1 . Root and shoot parameters as well as Cd uptake were determined at two harvest dates and from these data Cd net influx and shoot growth rates were calculated.Results and conclusions Cadmium uptake kinetics, i.e. the net Cd influx vs. Cd solution concentration followed a straight line. Its slope is the root absorbing power, α,The α values of spinach and flax were about double that of maize and sunflower (5×10 −6 cms −1 vs. 2.5× 10 −6 cms −1 ). Spinach and flax had a 3-5 times higher shoot Cd concentration than maize and sunflower. The difference in shoot Cd concentration was partly due to the higher Cd influx but also to a higher translocation of Cd from root to shoot and also to a slower shoot growth rate.

show abstract

“…(3.11): Mechanistic models generally consider only the symplastic influx to be responsible for the root metal sink (Barber 1995). In order to verify the contributions of the apoplast and symplast to the root influx of Cd (Redjala et al 2009) and Ni (Redjala et al 2010), different models were employed using the Kaleidagraph™ software. The combined MichaelisMenten and linear functions were used to model the symplastic influx, while the Freundlich adsorption model was used to describe the apoplastic uptake (Redjala et al 2009).…”

Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

“…In order to verify the contributions of the apoplast and symplast to the root influx of Cd (Redjala et al 2009) and Ni (Redjala et al 2010), different models were employed using the Kaleidagraph™ software. The combined MichaelisMenten and linear functions were used to model the symplastic influx, while the Freundlich adsorption model was used to describe the apoplastic uptake (Redjala et al 2009). This approach showed the importance of metal adsorption on the root apoplast, which can contribute significantly to the amount of metal extracted from the soil, and that using only a Michaelis-Menten function may not be sufficient in terms of root uptake modeling (Redjala et al 2009).…”

Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

Phytoextraction of Metals: Modeling Root Metal Uptake and Associated Processes

et al. 2014

View full text Add to dashboard Cite

IntroductionPhytoextraction is a process which can remove the soluble (bioavailable) metal pool from soil or aqueous solutions using different kinds of terrestrial or aquatic plants. This transport may be divided into three different steps: (1) absorption from the solution (e.g., soil solution), (2) transport to the root xylem, and (3) transport to the shoots (Mench et al. 2009).A modern approach, how to evaluate the extraction potential of selected plants as well as how to plan and design the most effective metal phytoextraction, is the ability to relevantly model this process. There are many studies aimed at the modeling of metal transport. Nevertheless, there is a limited amount of present studies, which are focused on the modeling of the phytoremediation process. In general, developing an applicable model requires sufficient conceptual model description and a fundamental theoretical understanding of the studied system, as well as its experimental equipment and measurement; these are all crucial aspects required to create a relevant simulation of studied problem. This chapter attempts to describe the problems associated with metal phytoextraction modeling. The term "root metal uptake" is crucial for the simulation of phytoremediation of metals, which is a concrete modification of the general term "root uptake." Root uptake is one of the most important processes considered in numerical models because root surfaces represent the first-phase boundaries in nature for nutrients and toxic elements. In order to efficiently model the phytoextraction processes, it is essential to provide information about (1) the spatiotemporal concentration changes of metals in the root-influenced soil and (2) the cumulative uptake of metals per unit length of root over time (Darrah et al. 2006). Root UptakeDetermining water and metal uptake by plant roots and their subsequent translocation into the tissues of the aerial parts is obviously critical for assessing the modeling of phytoremediation options. Because metals are taken up by plants dissolved in water, it is crucial to have information about the transport of water and the hydraulic properties of the roots. Root Water UptakeWater is primarily absorbed by the root hairs and other root zones and then transported to the aerial parts in xylem tissues. Water absorption by the plants is mainly a response to the water potential gradient (from low to high energy) from the rhizosphere to the xylem of the roots. Soil water has a lower total solute concentration than plant water, and hence the osmotic gradient tends to drive water from the soil into the root. The rate of water uptake from the soil depends on rooting density, the hydraulic conductivity of the roots, and the difference between average soil-water suction and root suction. The root hydraulic conductivity is a measure of the amount of water transported by the root in an interval of time at a determinate pressure [mg g et al. 1987). It depends on osmotic potential gradients which result from differences in the composition and t...

show abstract

Cadmium uptake by roots: Contribution of apoplast and of high- and low-affinity membrane transport systems

Cited by 107 publications

References 34 publications

Determining the fluxes of ions (Pb2+, Cu2+ and Cd2+) at the root surface of wetland plants using the scanning ion-selective electrode technique

Determining the fluxes of ions (Pb2+, Cu2+ and Cd2+) at the root surface of wetland plants using the scanning ion-selective electrode technique

Cadmium uptake kinetics and plants factors of shoot Cd concentration

Phytoextraction of Metals: Modeling Root Metal Uptake and Associated Processes

Contact Info

Product

Resources

About