Characteristics of cadmium tolerance in 'Hermes' flax seedlings: contribution of cell walls.
Most flax (Linum usitatissimum) varieties are described as tolerant to high concentrations of Cd. The aim of the present paper was to better characterize this tolerance, by studying the responses of flax plantlets, cv Hermes, to 18d growth on 0.5mM Cd. In Cd-treated seedlings, the majority of Cd was compartmentalized in the roots. Analysis of other elements showed that only Fe concentration was reduced, while Mn increased. Growth parameters of Cd treated flax were only moderately altered, with similar mass tolerance-indices for roots and shoots. Tissue anatomy was unaffected by treatment. The effect on lipid peroxidation, protein carbonylation and antioxidative activities appeared low but slightly higher in roots. The most important impacts of Cd were, in all organs, cell expansion, cell-wall thickening, pectin cross-linking and increase of cell-wall enzymatic activities (pectin methylesterase and peroxidase). Thus, the role of the cell wall in Cd tolerance might be important at two levels: (i) in the reinforcement of the tissue cohesion and (ii) in the sequestration of Cd.
Douchiche
Olfa
O
Laboratory Glyco-MEV EA 4358, IFRMP 23, University of Rouen, 76821 Mont Saint Aignan Cedex, France.
Soret-Morvan
Odile
O
Chaïbi
Wided
W
Morvan
Claudine
C
Paynel
Florence
F
D000222:Adaptation, Physiological; D002104:Cadmium / Q000378:metabolism / Q000633:toxicity*; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002412:Cations / Q000378:metabolism; D002473:Cell Wall / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D019597:Flax / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D015227:Lipid Peroxidation / Q000187:drug effects; D009195:Peroxidase / Q000378:metabolism; D012989:Soil Pollutants / Q000378:metabolism / Q000633:toxicity*; D014574:Uronic Acids / Q000378:metabolism
D002412:Cations; D012989:Soil Pollutants; D014574:Uronic Acids; D002104:Cadmium; D009195:Peroxidase; D002265:Carboxylic Ester Hydrolases; C022323:pectinesterase