Oxidative stress induced in sunflower seedling roots by aqueous dry olive-mill residues.
The contamination of soils with dry olive-mill residue can represent a serious problem as being an environmental stressor in plants. It has been demonstrated that inoculation of aqueous extract of olive oil-mill residue (ADOR) with saprobe fungi removes some phenolic compounds. In this paper we studied the effect of ADOR uninoculated or inoculated with saprobe fungi in sunflower seedling roots. The germination and root growth, O(2)·(-) generation, superoxide dismutase (SOD) and extracellular peroxidases (EC-POXs) activities, and the content of some metabolites involved in the tolerance of stress were tested. The roots germinated in ADOR uninoculated show a decrease in meristem size, resulting in a reduction of the root length and fresh weight, and in the number of layers forming the cortex, but did not alter the dry weight, protein and soluble amino acid content. ADOR caused the decreases in O(2)·(-) generation and EC-POX's activities and protein oxidation, but enhanced SOD activity, lipid peroxidation and proline content. Fluorescence imaging showed that ADOR induced O(2)·(-) and H(2)O(2) accumulation in the roots. The increase in SOD and the decrease in EC-POX's activities might be involved in the enhancement of H(2)O(2) content and lipid peroxidation. Control roots treated with ADOR for 10 min show an oxidative burst. Roots germinated in ADOR inoculated with saprobe fungi partially recovered normal levels of ROS, morphological characteristics and antioxidant activities. These results suggested that treatment with ADOR caused a phytotoxic effect during germination inducing an oxidative stress. The inoculation of ADOR with saprobe fungi limited the stress.
Departamento Biología Vegetal, Ecología y Ciencias de la Tierra, Universidad de Extremadura, Badajoz, Spain. igarridoc@unex.es
Inmaculada
I
Garrido
Mercedes
M
García-Sánchez
Ilda
I
Casimiro
Pedro Joaquin
PJ
Casero
Inmaculada
I
García-Romera
Juan Antonio
JA
Ocampo
Francisco
F
Espinosa
D006368:Helianthus / Q000187:drug effects / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D007220:Industrial Waste / Q000009:adverse effects*; D015227:Lipid Peroxidation / Q000187:drug effects; D031658:Olea / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects*; D018517:Plant Roots / Q000187:drug effects / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
D007220:Industrial Waste; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase