Oxidative Stress Induced in Sunflower Seedling Roots by Aqueous Dry Olive-Mill Residues

Abstract

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, O2·- 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 O2·- generation and EC-POX′s activities and protein oxidation, but enhanced SOD activity, lipid peroxidation and proline content. Fluorescence imaging showed that ADOR induced O2·- and H2O2 accumulation in the roots. The increase in SOD and the decrease in EC-POX′s activities might be involved in the enhancement of H2O2 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.

Effects of antimony on redox activities and antioxidant defence systems in sunflower (Helianthus annuus L.) plants

“…The O 2 .- generating activity was assayed spectrophotometrically by measuring the oxidation of epinephrine to adrenochrome at A 480 (ε = 4.020 mM -1 cm -1 ) [ 52 ], [ 53 ]. The reaction mixture contained 1 mM epinephrine in acetate buffer 25 mM, pH 5.0.…”

Effects of Antimony on Reactive Oxygen and Nitrogen Species (ROS and RNS) and Antioxidant Mechanisms in Tomato Plants

“…The protein content was determined using the Bradford method (Bradford, 1976). The production of O 2 • − was measured from the formation of adrenochrome at A 480 (ε = 4.020 mM −1 cm −1 ) (Misra and Fridovich, 1972;Garrido et al, 2012). Polyphenoloxidase (PPO, EC 1.14.18.1) activity was determined by measuring A 390 at 30 • C in a medium containing the enzyme extract, 100 mM phosphate buffer, Triton X-100, and 30 µM caffeic acid (Thipyapong et al, 1995).…”

Stress-Triggered Long-Distance Communication Leads to Phenotypic Plasticity: The Case of the Early Root Protoxylem Maturation Induced by Leaf Wounding in Arabidopsis

“…However, the correlation among root length, meristem size and protoxylem element position may be disrupted under stress or phytotoxic conditions [7], and both ROS [11,12] and stress signalling hormones, such as the wound signal jasmonic acid (JA) [13,14], may assume a role in root length and meristem size specification independently from or interfering with the cytokinin/auxin pathway. In this regard, root xylem phenotypic plasticity has been shown to occur in response to drought stress [15,16], as well as to various stress-simulating conditions [17].…”