Adaptation of wheat cells to short-term ozone stress: the impact of alpha-tocopherol and gallic acid on natural and model membranes
Year: 2016
Journal: Acta Physiol. Plant.
Authors: Rudolphi-Skorska, E; Sieprawska, A
The aim of the study was to investigate subsequent effects of short-term (30 min) ozone stress acting on wheat callus cells grown on media containing hydrophobic (tocopherol) and hydrophilic (gallic acid) antioxidant supplemented to the medium separately or in mixture. 7 days after ozone treatment of in vitro culture of winter wheat cells the fresh mass of calli, the activity of antioxidant enzymes, proline concentration and proportions of the major lipid fractions of cell membranes were determined. The physicochemical parameters characterizing the mechanical properties of monolayers formed by phospholipid and monogalactoglyceride fractions (model of hydrophobic/hydrophilic membrane) were established. It has been shown that oxidative stress induced by ozone treatment caused an increase in mass of calli (relative to the control), dependent on the presence of tocopherol and gallic acid. Changes of MDA level, of activity of antioxidative enzymes and of composition of membrane lipids demonstrate cell adaptation to stressful conditions. The physicochemical parameters of lipid layers determined from model experiments performed using Langmuir trough technique pointed to the changes in the structure of phospholipids caused by ozone stress and indicated that the presence of tocopherol and gallic acid effectively reversed these changes. Galactose groups in polar part of galactolipids may be a "trap'' for ROS, reducing their access to the interior of the membranes. The wheat callus cells use this mechanism in the process of adaptation, as ozone treatment resulted in the reconstruction of membranes by increasing the share of monogalactolipids. Cooperation between tocopherol and gallic acid in the reactions taking place in the presence of ozone was also discussed.
