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The growth of four mangrove species seedlings, namely Bruguiera gymnorrhiza, Kandelia obovata, Aegiceras corniculatum and Acanthus ilicifolius in sediments contaminated by spent lubricating oil, even at the lowest oil dose (2.5 L m(-2)), showed different degrees of sub-lethal damages. All the seedlings of K. obovata and A. corniculatum were killed at 10 L m(-2) oil, while the lethal oil dose was 15 L m(-2) for A. ilicifolius seedlings. B. gymnorrhiza was the most tolerant species to oil pollution, which could survive under the highest oil dose treatment (15 L m(-2)). Biochemical responses including superoxide radical (O(2)(-)) release, superoxide dismutase (SOD) activity and malonyldialdehyde (MDA) content in both leaves and roots of the oil-treated seedlings were increased significantly with oil dose, and presented a positive relationship with leaf and root biomass., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Effects of wastewater discharge on radial oxygen loss (ROL), formation of iron (Fe) plaque on root surface, and their correlations in Bruguiera gymnorrhiza (L.) Poir and Excoecaria agallocha L. were investigated. ROL along a lateral root increased more rapidly in control than that in strong wastewater (with pollutant concentrations ten times of that in municipal sewage, 10NW) treatment, but less Fe plaque was formed in control for both plants. For B. gymnorrhiza receiving 10NW, Fe plaque formation was more at basal and mature zones than at root tip, while opposite trend was shown in E. agallocha. At day 0, the correlation between ROL and Fe plaque was insignificant, but negative and positive correlations were found in 10NW and control, respectively, at day 105, suggesting that more ROL was induced leading to more Fe plaque. However, excess Fe plaque also served as a 'barrier' to prevent excessive ROL in 10NW plants., (Copyright (c) 2009 Elsevier Ltd. All rights reserved.)