Does mycorrhiza improve salinity tolerance in grafted plants?

Grafting has been reported to give some benefits against salinity stress, however rootstock genotype plays a key role in this tolerance. Beneficial organisms can also used to enhance plant growth and increase salinity tolerance. The aim of this research was to test the combined effects of grafting and mycorrhizal inoculation under salinity stress conditions. The experiment was conducted in a PE covered greenhouse during the autumn and spring seasons of 2008 and 2009. 'Maxifort' and 'Beaufort' hybrid tomato rootstocks grafted with commercial cultivar '191 (Gokce) F-1' were compared with self-grafted plants in the case of mycorrhizal inoculation or not. Half of the plants were placed in a suspension containing 2.5 kg ha(-1) of EndoRoots (R) which contains the spores of endomycorrhizal (VAM) fungi (Glomus spp.). This was done for one day before transplanting while the rest were planted as controls without any treatment. Plants were grown in perlite culture and the EC level of the solution was increased up to 6 dS m(-1) using NaCl. The experimental design was randomized blocks with 3 replicates. Parameters related to plant growth, yield and fruit quality were determined. The use of rootstocks, in particular Maxifort, inoculated with mycorrhizal fungi increased the total and marketable yield. Although there were no statistical differences in fresh and dry weights of plant parts, mycorrhizal inoculation increased root fresh and dry weights. Of the quality parameters, vitamin C increased when VAM was used while titratable acidity decreased. Dry matter percentage, rind strength, titratable acidity, EC and pH also changed in the VAM inoculated rootstocks. It was concluded that salinity tolerance would be improved if grafted plants were inoculated with mycorrhizal fungi. (C) 2012 Elsevier B.V. All rights reserved.