Aluminum-Induced Lipid Peroxidation and Lignin Deposition Are Associated with an Increase in H2O2 Generation in Wheat Seedlings

• Published in: Soil science and plant nutrition (Tokyo) Vol. 51; no. 2; pp. 223 - 230
• Main Authors: Hossain, M. Alamgir, Hossain, A. K. M. Zakir, Kihara, Tomonori, Koyama, Hiroyuki, Hara, Tetsuo
• Format: Journal Article
• Language: English
• Published: Oxford, UK Taylor & Francis Group 01.04.2005; Blackwell Publishing Ltd
• Subjects: aluminum; H2O2; lipid peroxidation; oxidative damage; wheat
• ISSN: 0038-0768; 1747-0765
• DOI: 10.1111/j.1747-0765.2005.tb00026.x

Wheat (Triticum aestivum cv. Kalyansona) seedlings were exposed to 0, 10, 50, and 100 μM Al in a 250 μM CaCl 2 solution for 24 h at pH 4.5. Root elongation decreased gradually, while the Al content markedly increased with increasing supply of Al in the solution. The generation of H 2 O 2 during Al stress was investigated biochemically and histochemically, as well as other events related to the decomposition of H 2 O 2 . After 24 h treatment, root elongation inhibition was detected at all the concentrations of Al. The level of lipid peroxidation at 10 μM Al after 24 h treatment was similar to that of the control, while a significant increase in lipid peroxidation was detected at 50 and 100 μM Al. H 2 O 2 generation was higher at 50 and 100 μM Al than that at 10 μM Al. These results suggest that Al-inducible lipid peroxidation may require excessive yield of H 2 O 2 . Time course experiment with 10 μM Al indicated that there is a strongly positive correlation between root elongation inhibition and cellular H 2 O 2 yield. There were no significant changes in the activities of catalase (CAT) and ascorbate peroxidase (APX) in roots at 10 μM Al after 24 h treatment. However, a significant decrease in the activities of CAT and APX and a large increase in the activities of oxalate oxidase (OXO), guaiacol peroxidase (GPX), and coniferyl alcohol peroxidase (CA-POX) as well as lignin deposition were observed at 100 μM Al. These results suggest the possible involvement of OXO in the production of a large amount of H 2 O 2 under severe Al stress, whereas GPX and CA-POX may be involved in the degradation of H 2 O 2 , leading to lignin deposition.