African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6578

Full Length Research Paper

Alteration of biochemical and antioxidant mechanisms in rice plants under salt stress

Letícia Carvalho Benitez1, Márcia Vaz Ribeiro1, Sidnei Deuner1, Luciano Carlos da Maia2, Jose Antonio Peters1 and Eugenia Jacira Bolacel Braga1*
1Departamento de Botânica, Instituto de Biologia, Universidade Federal de Pelotas (UFPel), RS, Brasil. 2Centro de Genômica e Fitomelhoramento, Universidade Federal de Pelotas (UFPel), RS, Brasil.
Email: [email protected]

  •  Accepted: 29 April 2013
  •  Published: 30 November 2013

Abstract

The aim of this study was to examine possible alterations in the metabolism of rice plants (Oryza sativa L.) that were exposed to high salt concentrations. BRS Ligeirinho seeds were sown, and the plants were grown in a greenhouse. At 14 days following sowing, the plants were alternately irrigated with a nutrient solution and water containing 0, 150 and 300 mM NaCl. After 30 days, the leaves and roots were collected, and the levels of proline, photosynthetic pigments, total protein, hydrogen peroxide, lipid peroxidation and the activities of the antioxidant enzymes superoxide dismutase, catalase and ascorbate peroxidase were analysed. There was a gradual increase in the levels of proline, total protein, hydrogen peroxide and lipid peroxidation with increasing salt concentrations in the irrigation water. The synthesis of photosynthetic pigments increased until the NaCl concentration reached 150 mM, after which the activities of the antioxidant enzymes decreased. These results suggest that proline may have protective effects against protein degradation and that carotenoids may aid in the protection of chlorophyll. Moreover, although, antioxidant enzymes were shown to possess low levels of activity, a large proportion of the hydrogen peroxide that is produced is preferentially directed towards lipid peroxidation.
 
Key words: Oryza sativa L., salinity, oxidative stress, reactive oxygen species, lipid peroxidation, chlorophyll.