Cell wall accumulation of cu ions and modulation of lignifying enzymes in primary leaves of bean seedlings exposed to excess copper
| Autor: | Ezzeddine El Ferjani, Hager Jouili, Anja Geitmann, Houda Bouazizi |
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| Rok vydání: | 2009 |
| Předmět: |
Endocrinology
Diabetes and Metabolism Clinical Biochemistry chemistry.chemical_element Phenylalanine ammonia-lyase Biochemistry Gene Expression Regulation Enzymologic Inorganic Chemistry Cell wall chemistry.chemical_compound Nutrient Cell Wall Plant Proteins chemistry.chemical_classification biology Biochemistry (medical) Xylem Fabaceae General Medicine Copper Plant Leaves Enzyme chemistry Seedlings biology.protein Coniferyl alcohol Peroxidase |
| Zdroj: | Biological trace element research. 139(1) |
| ISSN: | 1559-0720 |
| Popis: | Copper is both a nutrient and an environmental toxin that is taken up by plants. In order to determine the subcellular localization of copper and to assess the resulting metabolic changes, we exposed 14-day-old bean seedlings to nutrient solutions containing varying concentrations of Cu(2+) ions for 3 days. Biochemical analyses revealed that the cell wall was the major site of Cu(2+) accumulation in the leaves of treated plants. Excess copper modified the activity of lignifying peroxidases in both soluble and ionic cell wall-bound fraction. The activity of ionic GPX (guaiacol peroxidase, EC 1.11.1.7) was increased by 50 and 75 µM CuSO₄. The activities of both ionic CAPX (coniferyl alcohol peroxidase, EC 1.11.1.4) and NADH oxidase were increased by both copper concentrations tested. While soluble CAPX activity decreased in leaves treated by all copper concentrations tested, the activity of soluble NADH oxidase remained unchanged at 50 µM and was enhanced at 75 µM. Treatment with CuSO₄ also increased the abundance of total phenol compounds and induced stimulation in the activity of PAL (phenylalanine ammonia lyase, EC. 4.3.1.5). Using histochemistry in combination with fluorescence microscopy we show that bean leaves from copper-exposed plants displayed biochemical and structural modifications reinforcing the cell walls of their xylem tissues. On the other hand, the perivascular fiber sclerenchyma appeared to be less developed in treated leaves. |
| Databáze: | OpenAIRE |
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