Longitudinal variation in cadmium influx in intact first order lateral roots of sunflower ( Helianthus annuus . L)
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Longitudinal variation in cadmium influx in intact first order lateral roots of sunflower (Helianthus annuus. L) Marie A. Laporte & Laurence Denaix & Loïc Pagès & Thibault Sterckeman & Francis Flénet & Sylvie Dauguet & Christophe Nguyen
Received: 1 February 2013 / Accepted: 30 April 2013 # Springer Science+Business Media Dordrecht 2013
Abstract Aims Contamination of sunflower (Helianthus annuus L.) by cadmium (Cd) is a concern for food and feed safety as this species accumulates Cd to a greater extent than other crops. We examined the relationships between root architecture and Cd2+ uptake by roots. Methods We determined and mathematically modelled the longitudinal variation of Cd2+ influx in first order roots of sunflower grown in hydroponics by using shortterm exposure to 109Cd-labelled solutions (0.8 to 500 nM). Thereafter, by taking into account the longitudinal variation of the influx, we simulated the uptake of Cd2+ for 24 h by cohorts of roots characterised by various architectural characteristics.
Results Cd2+ influx at the root tip was on average 2.9 times that of the basal region close to the taproot. The simulations indicated that the total Cd2+ uptake by root cohorts mainly depends on 1/ the root diameter and the number of roots, 2/ the value of the Cd2+ influx at the basal region 3/ the stronger influx at the root tip. Conclusion Considering a higher Cd2+ influx at the root tip may be important to understand the relationship between root architecture and Cd2+ uptake by the root system. Keywords Cadmium . Influx . Longitudinal variation . Root architecture . Sunflower
Responsible Editor: Henk Schat. Electronic supplementary material The online version of this article (doi:10.1007/s11104-013-1756-3) contains supplementary material, which is available to authorized users. M. A. Laporte : L. Denaix : C. Nguyen (*) INRA, UMR1220 TCEM, 71 avenue Edouard Bourlaux CS20032, 33882 Villenave d’Ornon, France e-mail: [email protected] M. A. Laporte : L. Denaix : C. Nguyen Univ. Bordeaux, UMR1220 TCEM, 33882 Villenave d’Ornon, France L. Pagès INRA - UR 1115 PSH, Domaine St Paul, Site Agroparc, CS 40509, 84914 Avignon cedex 9, France
T. Sterckeman Laboratoire Sols et Environnement, Université de Lorraine - INRA, 2 avenue de la Forêt de Haye B.P. 172, 54505 Vandœuvre-lès-Nancy cedex, France F. Flénet CETIOM, 1 avenue Lucien Brétignères B.P. 4, 78850 Thiverval Grignon, France S. Dauguet CETIOM, 11 rue Monge, Parc Industriel, 33600 Pessac, France
Plant Soil
Introduction Cadmium is a trace element naturally occurring in soils but due to anthropogenic inputs, mainly phosphate fertilizers (Adriano 2001), Cd tends to accumulate in agricultural soils (Rasmussen et al. 1998). Soil Cd2+ is absorbed by plant roots and partly transferred aboveground. Crop contamination by Cd is a serious concern for food and feed safety. This is particularly true for sunflower (Helianthus annuus L.), which is known to accumulate relatively high levels of Cd as compared to other crops such as maize (Grant
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