title: Zinc adsorption and desorption characteristics in root cell wall involving zinc hyperaccumulation in Sedum alfredii Hance.
abstract: Radiotracer techniques were employed to characterize (65)Zn adsorption and desorption in root-cell-wall of hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) species of Sedum alfredii Hance. The results indicated that at the end of a 30 min short time radioisotope loading period, comparable amounts of (65)Zn were accumulated in the roots of the two ecotypes Sedum alfredii, whereas 2.1-fold more (65)Zn remains in NHE root after 45-min desorption. At the end of 60 min uptake period, no difference of (65)Zn accumulation was observed in undesorbed root-cell-wall of Sedum alfredii. However, 3.0-fold more (65)Zn accumulated in desorbed root-cell-wall of NHE. Zn(2+) binding in root-cell-wall preparations of NHE was greater than that in HE under high Zn(2+) concentration. All these results suggested that root-cell-wall of the two ecotypes Sedum alfredii had the same ability to adsorb Zn(2+), whereas the desorption characteristics were different, and with most of (65)Zn binding on root of HE being available for loading into the xylem, as a result, more (65)Zn was translocated to the shoot.
authors.affiliation: Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, Zhejiang University, Hangzhou, China. litq76@163.com
authors.forename: Ting-qiang
authors.initials: TQ
authors.lastname: Li
authors.forename: Xiao-e
authors.initials: XE
authors.lastname: Yang
authors.forename: Fan-hua
authors.initials: FH
authors.lastname: Meng
authors.forename: Ling-li
authors.initials: LL
authors.lastname: Lu
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D002478:Cells, Cultured; D007700:Kinetics; D008657:Metabolic Clearance Rate; D018517:Plant Roots / Q000166:cytology / Q000378:metabolism*; D031963:Sedum / Q000166:cytology / Q000378:metabolism*; D015032:Zinc / Q000493:pharmacokinetics*
chemical_list: D015032:Zinc