Structural changes of cell wall and lignifying enzymes modulations in bean roots in response to copper stress.
Fourteen-day-old bean seedlings were cultured in nutrient solution containing Cu(2+) ions at various concentrations (50 and 75 microM of CuSO(4)) for 3 days. This excess of copper induced a reduction in the water volume absorbed by the plants. Moreover, this reduction was accompanied by an increase of the amount of copper taken up by the roots. Analysis by native gel electrophoresis of cell wall peroxidase activities in the roots revealed a stimulation of two anionic isoforms (A(2) and A(3)) under cupric stress conditions. Moreover, the activity of phenylalanine ammonia lyase (EC. 4.3.1.5), which plays an important role in plant defense, was enhanced. Copper-treated bean roots showed modifications in the cell walls of various tissues. Label for lignin, callose, and suberin with berberine-aniline blue revealed abnormal cell wall thickenings in the endodermis, the phloem, and the xylem, especially in plants treated with 75 microM CuSO(4).
Bouazizi
Houda
H
Faculté des Sciences de Bizerte, Laboratoire de Bio, Physiologie Cellulaires, Zarzouna, Tunisia.
Jouili
Hager
H
Geitmann
Anja
A
El Ferjani
Ezzeddine
E
D002473:Cell Wall / Q000187:drug effects*; D019327:Copper Sulfate / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D010544:Peroxidases / Q000378:metabolism; D027805:Phaseolus / Q000033:anatomy & histology* / Q000187:drug effects*; D010650:Phenylalanine Ammonia-Lyase / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects* / Q000201:enzymology*; D013312:Stress, Physiological
D010544:Peroxidases; D010650:Phenylalanine Ammonia-Lyase; D019327:Copper Sulfate