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Soil salinity is a major constraint on plant growth and metabolism. This work was carried out to study the possible responses of wheat (Triticum aestivum L.) plants to 24-epibrassinolide (EBL) and the arbuscular mycorrhizal (AM) fungus, Glomus mosseae, supplied alone or in combination under salt stress. Plants were leaf sprayed with 5 µM EBL, and then were treated with 0 and 150 mM NaCl for 10 days. Then plants were harvested for biochemical and gene expression (Real-time PCR) analyses involved. All data were analyzed by SPSS v.18 and the treatment means were compared by using Duncan's test at P < 0.05 level of significance. The findings showed improved protein biosynthesis, K+ accumulation and K+/Na+ ratio in shoots as well as reduced Na+ levels in shoots and roots when EBL and G. mosseae were applied together under saline conditions. In addition, the expression of the NHX1 gene was up-regulated in EBL and AM fungi treatments and their interactions compared to control plants under salinity, however, no differences were found when compared with single applications. These results point to the possibility that BRs and AM fungi may have potential in alleviating salt stress by maintaining ion homeostasis in cells and modulating Na+/H+ antiporters. [ABSTRACT FROM AUTHOR]

Soil salinity and arbuscular mycorrhizal fungi (AMF) influence the soil hydrophobicity. An experiment was performed to determine the effects of soil salinity and AMF species on soil water repellency (SWR) under wheat (Triticum aestivumL.) crop. Six AMF treatments, including four exotic species (Rhizophagus irregularis, Funneliformis mosseaeandClaroideoglomus claroideum, a mix of three species), one mix native AMF species treatment and an AMF-free soil in combination with four salinity levels (1, 5, 10, and 15 dS m−1) were used. The soil repellency index (RI) increased with salinity increment ranging from 2.4 to 10.5. The mix of three exotic and native AMF treatments enhanced the RI significantly compared to AMF-free soil in all salinity levels with one exception for native treatment at 1 dS m−1. Among individual AMF species, theC. claroideumtreatment at 10 dS m−1increased the RI by 67% compared to AMF-free soil. The native AMF treatment was more efficient in root colonization, glomalin production and SWR development at 10 and 15 dS m−1, compared to exotic species. In addition to the net positive effect of salinity on SWR, the AMF influences on the RI were greatly dependent on salinity levels. [ABSTRACT FROM PUBLISHER]

Abstract: In many arid and semi-arid areas of the world where sustainability of agriculture is limited by salinity, use of biological potential may be a key component of sustainable plant production. A greenhouse experiment was used to test the effectiveness of inoculation with Azospirillum strains isolated from saline or non-saline soil in alleviating the salinity stress in wheat plants grown with irrigation water with different electrical conductivities (ECw) of 0.7, 4, 8 and 12dSm−1. Inoculation with the two isolates increased salinity tolerance of wheat plants; the saline-adapted isolate significantly increased shoot dry weight and grain yield under severe water salinity. The component of grain yield most affected by inoculation was grains per plant. Plants inoculated with saline-adapted Azospirillum strains had higher N concentrations at all water salinity levels. [Copyright &y& Elsevier]

Abstract: Since most experiments regarding the symbiosis between arbuscular mycorrhizal (AM) fungi and their host plants under salinity stress have been performed only under greenhouse conditions, this research work was also conducted under field conditions. The effects of three AM species including Glomus mosseae, G. etunicatum and G. intraradices on the nutrient uptake of different wheat cultivars (including Roshan, Kavir and Tabasi) under field and greenhouse (including Chamran and Line 9) conditions were determined. At field harvest, the concentrations of N, Ca, Mg, Fe, Cu, and Mn, and at greenhouse harvest, plant growth, root colonization and concentrations of different nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl were determined. The effects of wheat cultivars on the concentrations of N, Ca, and Mn, and of all nutrients were significant at field and greenhouse conditions, respectively. In both experiments, AM fungi significantly enhanced the concentrations of all nutrients including N, K, P, Ca, Mg, Mn, Cu, Fe, Zn, Na and Cl. The synergistic and enhancing effects of co-inoculation of AM species on plant growth and the inhibiting effect of AM species on Na+ rather than on Cl− uptake under salinity are also among the important findings of this research work. [Copyright &y& Elsevier]

A greenhouse experiment was conducted in order to evaluate the interactive effects of microbial inoculants on uptake of nutrient elements (N, P, K, Ca, Mg, Na, Cl, Fe, Zn, Cu, Mn) in two cultivars of sunflower. The trials were carried out on saline (EC = 7.6 dS m-1) calcareous soils taken from Eshtehard (Karaj) region of Iran. In a factorial trial and completely randomized design (CRD), three levels of arbuscular mycorrhizal inoculants (non inoculation, inoculation withGlomus etunicatum and Glomus intradices) and four levels of Pseudomonas fluorescensinoculants (non inoculation and inoculation with Pseudomonas fluorescens strains 4, 9, 12) in two cultivars of sunflower with four replications per treatments were applied. Results revealed that all of the treatments increased the N uptake in Euroflor cultivar. Moreover, in Euroflor cultivar, inoculation with Pseudomonas fluorescens strains 9 and co-inoculation of Pseudomonas fluorescens strains 4 and Glomus intradices made a significant different in phosphorous uptake, while did not make any significant change in the Master cultivar. However, bacterial and fungal treatments significantly (P < 0.05) increased uptake of micro nutrients such as Fe, Zn and Mn. [ABSTRACT FROM AUTHOR]