Gypsum alleviated hydroxyl radical-mediated oxidative damages caused by alkaline bauxite residue in leaves of Atriplex canescens

The present study investigated pH, electrical conductivity (EC), Al level, and exchangeable sodium percentage (ESP) in a range of alkaline bauxite residue (ABR) treatments. Also investigated was the content change of reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonyl (PCO) in leaves of Atriplex canescens [L.] challenged by ABR in the presence/absence of gypsum (Gy). Local cinnamon soil (CS) was used to improve the nutrient status and physical condition of ABR. Analysis revealed that CS/ABR (2:1, w/w) induced much more hydroxyl radical (OH*) accumulation, lipid peroxidation (LPO), and protein oxidation (PO) than CS/ABR/Gy (6:3:1, w/w) did. While superoxide radical (Of) and hydrogen peroxide (H2O2) accumulation showed little difference between CS/ABR and CS/ABR/Gy treatments. Further, exogenous OH center dot aggravated LPO and PO in a way similar to CS/ABR treatment, which was impaired by OH center dot scavengers such as proline and mannitol. Taken together, the data indicate that OH center dot is more connected with severe oxidative damages than O-2(center dot)- and H2O2 in this case. The caustic properties of ABR can be ameliorated by gypsum to support vegetation. (C) 2016 Elsevier B.V. All rights reserved.