Mitteilungen der Gesellschaft für Pflanzenbauwissenschaften Band 23

Mitt. Ges. Pflanzenbauwiss. 23: 187 (2011)
Interaction of salinity and boron toxicity on ion relations,
antioxidants and protein pattern of wheat leaves
Sajid Masood 1 , Monika Wimmer 2 , Katja Witzel 1 , Christian Zörb 1 , Christoph Plieth 3 ,
Livia Saleh 3 and Karl H. Mühling 1
1 Inst. of Plant Nutrition and Soil Science, Christian-Albrechts-University, Kiel; 2 Inst. of Crop Science
and Resource Conservation, University of Bonn, Bonn; 3 Zentrum für Biochemie und Molekularbiologie
(ZBM), Christian-Albrechts-University, Kiel. E-mail: smasood@plantnutrition.uni-kiel.de
Introduction
Salinity affects the crop growth in two phases. In the first phase, the reduced osmotic
potential of the soil solution reduces the water availability for plants. In the second
phase, the accumulation of elements such as Na + , Cl - or B to excess concentrations
induces ion toxicities [1]. On the other hand, abiotic stress conditions cause the
accumulation of reactive oxygen species (ROS) [2]. Reactive oxygen species are
strong oxidizing species that cause oxidative damage to membrane lipids and
proteins [3]. We therefore investigated the subcellular ion concentrations, low
molecular weight and high molecular weight antioxidants and subcellular distribution
of apoplastic proteins in wheat leaves.
Materials and Methods
Wheat (Triticum aestivum L. cv. Thasos) plants were grown in nutrient solution for 6
weeks. Boron concentrations were measured spectrophotometrically according to a
miniaturized curcumin method. Antioxidant enzymes activities were quantified via
luminescence assays [4], while apoplastic proteins were separated using two
dimensional gel electrophoresis (2D-PAGE).
Results and Discussion
Antioxidant activity of all enzymes, Na + , Cl - and subcellular B concentrations were
increased under salinity compared to control. Contrary, B concentrations in both
subcellular compartments were significantly reduced in NaCl + B compared to B
toxicity alone due to reduced transpiration under salinity [5]. In NaCl + B, superoxide
scavenging activity (SOSA), glutathione reductase (GR) and catalyse (CAT) activities
remained the same compared to NaCl alone [6] which indicates that the oxidative
stress is mainly caused by NaCl rather than B toxicity. Contrary, total antioxidant
capacity of low molecular weight enzymes (TAC) and luminol converting peroxidase
(LUPO) activities were increased in combined stress compared to NaCl alone
because H2O2 production is enhanced under combined stresses which is mainly
catalysed by peroxidase.
References
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damage and antioxidant and nucleolytic responses in shoot tips culture of the apple rootstock EM9
(Malus domestica Borkh). Environ. Exp. Bot. 56:54-62.
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