Flooding effects on membrane permeability, lipid peroxidation and activated oxygen metabolism in corn (Zea mays L.) leaves were investigated to determine if activated oxygens are involved in corn flooding-injury. Potted corn plants were flooded at the 4-leaf stage in a controlled environment. A 7-day flooding treatment resulted in a significant increase in chlorophyll breakdown, lipid peroxidation (malondialdehye content), membrane permeability, and the production of superoxide (02) and hydrogen peroxide (H202) in corn leaves. The effects were much greater in older leaves than in younger ones. Spraying leaves with 8-hydroxyquinoline (an O~-scavenger) and sodium benzoate (an .OH scavenger) reduced the oxidative damage and enhanced superoxide dismutase (SOD) activity. A short duration flooding treatment elevated the activities of SOD, catalase, ascorbate peroxidase (AP), and glutathione reductase (GR), while further flooding significantly reduced the enzyme activities but enhanced the concentrations of ascorbic acid and reduced form glutathione (GSH). It was noted that the decline in SOD activity was greater than that in H202 scavengers (AP and GR). The results suggested that 02 induced lipid peroxidation and membrane damage, and that excessive accumulation of 0 2 is due to the reduced activity of SOD under flooding stress.

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In older adults, the risk of injury with zolpidem exceeded that with alprazolam and lorazepam and was similar to that with diazepam. If the associations are causal, then the high incidence of these fractures implies that these treatment induce a substantial number of fractures and consequential costs. Further study of the association is imperative.