Water relationships and agronomic indices of sunflower infection by microbial inoculants under saline condition

Salinity is one of the most important limiting factors for plant growth and crop production. Saline soils with having low activity in nutrient elements and high osmotic pressure in solution phase make so much nutrition problems and physiological drought in plant. In this study, the effects of arbuscular mycorrhiza fungi and plant growth promoting bacteria with ability to produce ACC deaminase enzyme on water relationships and agronomic indices of sunflower cultivars were investigated. The saline soil (EC = 7.6 dS m-1 ) used in this investigation was taken from Karaj region (Eshtehard) of Iran. In a factorial experimental design on the basis of randomized complete block samples, three levels of arbuscular mycorrhizal inoculants (non inoculation, inoculation with Glomus etunicatum and Glomus intradices), four levels of Pseudomonas fluorescens inoculants (non inoculation, inoculation with Pseudomonas fluorescens strains 4, 9 and 12) on two cultivars of sunflower (Euroflor and Master) with four replications per treatment were applied. Results showed that all of the treatments significantly (P < 0.05) increased relative water content (RWC) of two cultivars. Single inoculation of Pseudomonas fluorescens strains 12 and Glomus etunicatum and also co-inoculation of fungi with each one of the bacteria enhanced fresh and dry weight of tray in Euroflor cultivar, compared with the control treatment. In addition, all of the treatments except Pseudomonas fluorescens strains 4 and also Glomus intradices significantly (P < 0.05) increased dry weight of above ground part in Euroflor cultivar