Contribution of apoplast and symplast to short term nickel uptake by maize and Leptoplax emarginata roots

Redjala, Tanegmart; Sterckeman, Thibault; Skiker, Samia; Echevarria, Guillaume

doi:10.1016/j.envexpbot.2009.10.010

Cited by 59 publications

(21 citation statements)

References 37 publications

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“…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). However, more investigations are necessary to determine the path of metal movement from the apoplast to plant shoots (Redjala et al 2009(Redjala et al , 2010. Additionally, the model of Hung and Mackay (1997), originally applied for transport of contaminants from the soil to trees, has been simplified and used to simulate metal transport from the soil to tree seedlings (Baltrënaïtë and Butkus 2007).…”

Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

“…Apoplastic metal uptake is calculated using Eq. ], and β measures the affinity of the metal to the adsorbent (intensity factor) [-] (Redjala et al 2010). Symplastic metal uptake is then calculated using Eq.…”

Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

“…(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%

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Phytoextraction of Metals: Modeling Root Metal Uptake and Associated Processes

et al. 2014

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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...

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Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

Section: Water and Metal Translocation Modelingmentioning

confidence: 99%

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Phytoextraction of Metals: Modeling Root Metal Uptake and Associated Processes

et al. 2014

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“…It has been shown that accelerated maturation of the endodermis in response to local cadmium availability is of functional significance in protecting the shoot from excessive Cd loads (Lux et al 2011). To characterize the complete Ni root sink over the short term (1 h of 63 Ni uptake), the contributions of apoplast and symplast to the metal root uptake were measured by Redjala et al (2010) for both maize and the Nihyperaccumulator Leptoplax emarginata, using a physico-chemical fractionation of root Ni after exposure. These authors reported that the nickel symplastic influx per unit of root area, accounting for only 12.0-18.7% and 4.5-9.4% of the total root uptake of maize and Ni-hyperaccumulator Leptoplax emarginata, was similar for the two species, suggesting that symplastic uptake is not the main factor of hyperaccumulation and confirming that other processes, such as xylem loading and transport, trafficking and storage in tissues might play an important role.…”

Section: Introductionmentioning

confidence: 99%

Impact of active transport and transpiration on nickel and cadmium accumulation in the leaves of the Ni-hyperaccumulator Leptoplax emarginata: a biophysical approach

et al. 2011

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Aims The primary aim of this study was to investigate the impact of active nickel and cadmium transport, transpiration and shoot biomass production on Ni and Cd accumulation in the leaves of the Ni-hyperaccumulator Leptoplax emarginata. A secondary objective was to observe the effects of various concentrations of nickel and cadmium in solutions on the plant growth and ecophysiological characteristics of these plants. Finally, the study sought to identify possible nickel and cadmium concentration gradients in solution as a function of the root distance. Methods The Intact Plant Transpiration Stream Concentration Factor (TSCF=xylem/solution solute concentration ratio) was determined for both Ni and Cd and for the selected intact transpiring Ni-hyperaccumulator Leptoplax emarginata, cultivated on two contrasting fertilized and Ni-Cd-contaminated sandy porous media (rhizotrons with central root compartments, linked to Mariotte tubes operated at −1 kPa). IPTSCF Ni and IPTSCF Cd were calculated as the ratios between the hyperaccumulator plant's nickel or cadmium mass in the leaves and the nickel or cadmium concentration in solution by the volume of water transpired during the period of culture. Plant growth characteristics and gas exchanges were also recorded.Results IPTSCF values were much greater than 1 (IPTSCF Ni =5.2±0.9 and IPTSCF Cd =4.4±0.6) whatever the amount of available Ni and Cd. This characterized a predominantly active plant metal uptake. Moreover, biological regulation was reported: plant growth and transpiration were significantly lower for hyperaccumulator plants cultivated in sand which was rich in available Ni and Cd, than for hyperaccumulator plants cultivated in topsoil, poor in available Ni and Cd. In the soil rhizosphere, capillary flow was related to transpiration and a depletion pattern was developed for Ni and sometimes for Cd. Conclusions Overall, the Intact Plant Transpiration Stream Concentration Factor appeared to be a relevant metal bioconcentration factor taking into account the predominant type of metal transport from roots to leaves, plant growth and transpiration coupling and metal availability. IPTSCF Ni and IPTSCF Cd values were much greater than 1 and similar whatever the amount of available Ni and Cd. This characterized a predominantly active plant combining Ni and Cd uptake and biological Plant Soil (2012) 350:99-115

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“…One of the possibilities of waste water cleaning is a technology based on a phytoremediation which offer also an opportunity to evaluate a contribution of eventual food chain contamination. Phytoremediation of metals and heavy metals or radioactive elements has been theoretically studied and its efficiency and applicability was already proved [6][7][8].…”

Section: Introductionmentioning

confidence: 99%