Zonal responses of sensitive vs. tolerant wheat roots during Al exposure and recovery

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Silva, S (Author) Other; Rodriguez, E (Author) Other; Pinto Carnide, O (Author) Other; Martins Lopes, P (Author) Other; Matos, M (Author) Other; Guedes Pinto, H (Author) Other; Santos, C (Author) FCUP

Journal

Title: Journal of Plant Physiology

Vol. 169

Pages: 760-769

ISSN: 0176-1617

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 13 Citations

Other information

Authenticus ID: P-002-A2T

DOI: 10.1016/j.jplph.2012.01.011

Abstract (EN): Aluminium (Al) irreversibly inhibits root growth in sensitive, but not in some tolerant genotypes. To better understand tolerance mechanisms, seedlings from tolerant ('Barbela 7/72' line) and sensitive ('Anahuac') Triticum aestivum L genotypes were exposed to AlCl3 185 mu M for: (a) 24 h followed by 48 h without Al (recovery); (b) 72 h of continuous exposure. Three root zones were analyzed (meristematic (MZ), elongation (EZ) and hairy (HZ)) for callose deposition, reserves (starch and lipids) accumulation, endodermis differentiation and tissue architecture. Putative Al-induced genotoxic or cytostatic/mytogenic effects were assessed by flow cytometry in root apices. Tolerant plants accumulated less Al, presented less root damage and a less generalized callose distribution than sensitive ones. Starch and lipid reserves remained constant in tolerant roots but drastically decreased in sensitive ones. Al induced different profiles of endodermis differentiation: differentiation was promoted in EZ and HZ, respectively, in sensitive and tolerant genotypes. No ploidy changes or clastogenicity were observed. However, differences in cell cycle blockage profiles were detected, being less severe in tolerant roots. After Al removal, only the 'Barbela 7/72' line reversed Al-induced effects to values closer to the control, mostly with respect to callose deposition and cell cycle progression. We demonstrate for the first time that: (a) cell cycle progression is differently regulated by Al-tolerant and Al-sensitive genotypes; (b) Al induces callose deposition >3 cm above root apex (in HZ); (c) callose deposition is a transient Al-induced effect in tolerant plants; and (d) in HZ, endodermis differentiation is also stimulated only in tolerant plants, probably functioning in tolerant genotypes as a protective mechanism in addition to callose.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10