Home

Proceedings of the International Academy of Ecology and Environmental Sciences, 2014, 4(2): 50-61
[XML] [EndNote] [RefManager] [BibTex] [ Full PDF (166K)][Supplementary Material (8K)] [Comment Article]

Article

Calcium and potassium dynamics and biopurification in two populations of the subalpine evergreen shrub Rhododendron ferrugineum

Charles Marty1,2 , Thierry Lamaze1, Andre Pornon2, Jerome Viers3
1Centre detudes spatiales de la biosphere (UMR CNES-CNRS-UPS-IRD 5126), 18 Av. Ed. Belin bpi 2801, 31401 Toulouse cedex, France
2Laboratoire Evolution et Diversite Biologique (CNRS-UMR 5174), Universite Toulouse III, Bat. 4 R3, 118 route de Narbonne, F-31062 Toulouse cedex 04, France
3Geosciences Environnement Toulouse, Observatoire Midi Pyrenees CNRS - IRD-Universite Paul Sabatier, 14 avenue Edouard Belin, 31400 Toulouse, France

Received 7 March 2014;Accepted 10 April 2014;Published online 1 June 2014
IAEES

Abstract
Calcium (Ca) and potassium (K) are important acidity neutralizers in soils and essential elements for plants. These two elements are known to undergo a biopurification within the plant (i.e., discrimination against strontium (Sr) and barium (Ba) for Ca, and rubidium (Rb) for K). However variations in the magnitude of this process between plant populations have rarely been reported, especially in high altitude, nutrient-depleted habitats. Concentrations of Ca, Sr, Ba, K and Rb were measured in roots, stems and in the different leaf cohorts in two populations of the evergreen shrub R. ferrugineum located at a granitic high elevation site. Calcium and K concentrations in leaves were respectively ~5 and 3 times higher than in roots and stems. Ca concentration increased while K concentration decreased with leaf age. The ratios Ca/Sr, Ca/Ba and K/Rb increased from roots to leaves, revealing a significant biopurification especially between stems and leaves. This phenomenon was higher for Ca than for K, with Ca/Sr and Ca/Ba ratios more than twice and 4 times higher in leaves than in roots, respectively, while K/Rb ratio in leaves was only 50% higher than in roots. Ca/Sr ratio decreased whereas K/Rb increased with leaf age. While the first could result from a "chromatographic effect" of the vascular column, the latter suggests the existence of biopurification mechanisms during influx/efflux of K from the leaf. Surprisingly, the magnitude of Ca biopurification varied between populations on a small geographical scale suggesting that Ca/Sr ratio should be used cautiously for plant Ca source identification.

Keywords calcium;strontium;barium;potassium;rubidium;biopurification;ericaceous heathlands;Rhododendron ferrugineum.


International Academy of Ecology and Environmental Sciences. E-mail: office@iaees.org
Copyright © 2009-2024 International Academy of Ecology and Environmental Sciences. All rights reserved.
Web administrator: office@iaees.org, website@iaees.org; Last modified: 2024/4/26


Translate page to: