Re-aeration – induced oxidative stress and antioxidative defenses in hypoxically pretreated lupine roots

• Published in: Journal of plant physiology Vol. 161; no. 4; pp. 415 - 422
• Main Authors: Garnczarska, Małgorzata, Bednarski, Waldemar, Morkunas, Iwona
• Format: Journal Article
• Language: English
• Published: Jena Elsevier GmbH 01-04-2004; Elsevier; Elsevier Science Ltd
• Subjects: Adaptation, Physiological - drug effects; Adaptation, Physiological - physiology; aeration; Agronomy. Soil science and plant productions; annual weeds; antioxidants; Antioxidants - metabolism; Biological and medical sciences; catalase; Catalase - metabolism; Cell Hypoxia - physiology; Economic plant physiology; electron paramagnetic resonance; Electron Spin Resonance Spectroscopy; Enzyme Induction - drug effects; free radicals; Free Radicals - metabolism; Fundamental and applied biological sciences. Psychology; hydrogen peroxide; Hydrogen Peroxide - metabolism; hypoxia; Isoenzymes - metabolism; isozymes; lipid peroxidation; lupine; Lupinus - enzymology; Lupinus - physiology; Lupinus luteus; malondialdehyde; oxidative stress; Oxidative Stress - physiology; Oxygen - pharmacology; oxygen consumption; Oxygen Consumption - physiology; peroxidase; Peroxidase - metabolism; physiological response; plant response; Plant Roots - enzymology; Plant Roots - physiology; plant stress; re-aeration; root growth; roots; spectral analysis; superoxide dismutase; Superoxide Dismutase - metabolism; Symbiosis (nodules, symbiotic nitrogen fixation, mycorrhiza...); hypoxia; electron paramagnetic resonance; re-aeration; peroxidase; superoxide dismutase; hydrogen peroxide; lupine; lipid peroxidation; catalase; Oxidative stress; Root; Enzyme; Superoxide dismutase; lipid peroxidatlon lupine; Absorption; Leguminosae; Dicotyledones; Angiospermae; Hypoxia; Spermatophyta; Oxidoreductases; Lupinus luteus; Pretreatment
• ISSN: 0176-1617; 1618-1328
• DOI: 10.1078/0176-1617-01073

The level of free radicals and activities of antioxidative enzymes were examined in roots of lupine seedlings (
Lupinus luteus L.) that were deprived of oxygen by subjecting them to root hypoxia for 48 and 72 h and then re-aerated for up to 24 h.
Using electron paramagnetic resonance (EPR), we found that the exposure of previously hypoxically grown roots to air caused the increase in free radicals level, irrespective of duration of hypoxic pretreatment. Immediately after re-aeration the level of free radicals was two times higher than in aerated control. The EPR signal with the g-values at the maximum absorption of 2.0057 and 2.0040 implied that the paramagnetic radicals are derived from a quinone. Directly after re-aeration of hypoxically pretreated roots, the activity of superoxide dismutase (SOD, EC 1.15.1.1) increased to its highest value, followed by a decline below the initial level, whereas activities of catalase (CAT, EC 1.11.1.6) and peroxidase (POX, EC 1.11.1.7) were diminished or only slightly influenced during re-aeration. The electrophoretic patterns of the soluble extracts show 4 isozymes of SOD, 4 isozymes of POX and 1 isozyme of CAT. The level of H
2O
2 was enhanced or lowered by re-aeration, depending on the previous duration of hypoxia. At the onset of re-aeration products of lipid peroxidation were present at a three-fourth of the levels found in aerobic control. Their levels increased after prolonged exposure to air but remained lower than those in aerobic control even after 24 h of re-aeration.
Re-admission of oxygen resulted in about 20 % rise in oxygen uptake by root axes segments immediately after transfer of roots from hypoxia and the high uptake rates were observed over whole re-aeration period. Oxygen consumption by root tips was significantly reduced just after transfer from hypoxic conditions as compared to aerated control but after 24 h of re-aeration even approached the control level.
The results are discussed in relation to the ability of lupine roots to cope with oxidative stress caused by re-aeration following hypoxic pretreatment.