Silicon-mediated improvement in the salt resistance of wheat (Triticum aestivum) results from increased sodium exclusion and resistance to oxidative stress
Muhammad Saqib A B D E , Christian Zörb A C and Sven Schubert AA Institute of Plant Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.
B Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad-38040, Pakistan.
C Institute of Plant Nutrition and Soil Sciences, Christian-Albrechts-Universität Kiel, Hermann-Rodewald-Str. 2, D-24118 Kiel, Germany.
D Present address: Biotechnology Research Center, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, 113-8657 Tokyo, Japan.
E Corresponding author. Email: drhmsab@yahoo.com
Functional Plant Biology 35(7) 633-639 https://doi.org/10.1071/FP08100
Submitted: 28 March 2008 Accepted: 30 June 2008 Published: 21 August 2008
Abstract
Silicon (Si) is reported to reduce the effect of salinity on wheat (Triticum aestivum L.) and other crops. In the present study, Si decreased plant Na+ uptake and shoot : root Na+ distribution of a salt-resistant as well as a salt-sensitive wheat genotype. Reduced shoot Na+ concentration and increased shoot K+ : Na+ ratio led to improved plant growth. Silicon increased cell-wall Na+ binding from 49% in SARC-1 and 37% in 7-Cerros under salinity to 87% in SARC-1 and 79% in 7-Cerros under salinity + silicon. It may also have resulted in decreased potentially toxic leaf sap Na+ concentration. The concentration of glutathione, an important antioxidant in plants, was increased due to the addition of Si under saline conditions. The salt-resistant wheat genotype SARC-1 was less Si-responsive in terms of shoot fresh weight, having a 39% increase compared with a 49% increase in 7-Cerros, as well as root fresh weight, having a 12% increase compared with a 22% in 7-Cerros. It is concluded that Si may have improved shoot growth of the salt-resistant as well as the salt-sensitive wheat genotype by decreasing plant Na+ uptake and shoot : root Na+ distribution as well as by increasing glutathione concentration. Silicon may have also improved in-plant Na+ detoxification by increasing cell-wall Na+ binding.
Additional keywords: ascorbate, cell wall, glutathione, salinity.
Acknowledgements
M. Saqib gratefully acknowledges the support of DAAD (Deutscher Akademischer Austauschdienst) in the form of a fellowship that enabled him to carry out this work. The excellent technical assistance of Tina Volk, Anne Weber, Roland Pfanschilling and Christina Plachta is gratefully acknowledged.
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