Na+ exclusion and salt resistance of wheat (Triticum aestivum) in saline-waterlogged conditions are improved by the development of adventitious nodal roots and cortical root aerenchyma

The development of cortical root aerenchyma and adventitious nodal roots are characteristics of waterlogging-resistant plants. This study reports the relationship of aerenchyma and nodal root development with the Na+ exclusion and salt resistance of wheat (Triticum aestivum) in saline-waterlogged conditions. Two wheat genotypes, SARC-6 and MH-97 were tested in waterlogged, saline and saline-waterlogged conditions for various growth related parameters. Salinity and waterlogging in combination decreased the photosynthetic rate, stomatal conductance and shoot growth more than salinity or waterlogging alone. SARC-6 showed less leaf Na+ and more leaf K+ concentration and K+:Na+ ratio, photosynthetic rate and stomatal conductance than MH-97 in saline, waterlogged as well as saline-waterlogged treatments. The two genotypes differed in their ability to develop aerenchyma and nodal roots both in waterlogged and saline-waterlogged conditions with SARC-6 developing more than MH-97. It is concluded that the formation of aerenchymatous nodal roots improves Na+ exclusion and salt resistance of wheat in saline-waterlogged conditions. ((c))2005 Elsevier Ireland Ltd. All rights reserved.