This research was conducted in the format of two separate pot and field experiments. The pot experiment eva‎luated the effects of inoculation with different mycorrhizal species (Funneliformis mosseae, Rhizophagus irregularis, Claroideoglomus. claroideum, Cl. etanicatum, Glomus versiform, G. fasciculatum, G. caledonium and G. geosporum) on two sesame cultivars (Yekta and Naz). In this experiment, the inoculation with most mycorrhizal species increased the concentration of P, K, Fe, Zn, soluble carbohydrates, chlorophyll and carotenoids. However, the increase in plant dry matter was only significant in Yekta inoculated by irregularis and mosseae and in Naz inoculated by fasciculatum and clarodium . Inoculation with other mycorrizal species either had no significant effects or even decreased (inoculation of Ykata by versiform and geosporum and inoculation of Naz by etunicatum and geosporum) plant growth. In the field experiment the effects of inoculation with four mycorrhizal species (irregularis, mosseae, claroideum and claroideum) selected from pot experiment were studied on the two sesame cultivars (Yekta and Naz) under two soil moisture levels (well-watered and water stress conditions). In both years, water deficit decreased mycorrizal infection, relative water content, the concentration of P and Zn, soluble carbohydrates and chlorophyll, shoot and root dry weights, grain yield and its components, harvest index, grain oil content and water use efficiency but increased electrolyte leakage, the concentration of N, K and Fe in shoot, the contents of carotenoid, proline, hydrogen peroxide and malondialdehyde, the activities of ascorbate peroxidase, catalase and guaiacol peroxidase enzymes, the activity of soil acid phosphatase and alkaline phosphatase enzymes, soil glomalin content, phenol and flavonoid contents and total antioxidant capacity. In the first year, the extent of decreases in grain yield were less in the none inoculated plants and in the plants inoculated by fasciculatum in Yekta and in the plants inoculated by mosseae, irregularis and Claroideum in Naz but in the second year lower decreases in grain yield were obtained in the plants inoculated by mosseae and fasciculatum in Yekta and in the none inoculated plants and in the plants inoculated by irregularis and Claroideum in Naz. However, in most cases the decreases in plant biomass were less in Naz. Inoculation with mycorrizae increased all plant growth parameters and in most cases specially under water stress the positive response to mycorrhizae in terms of biomass production and grain yield was greater in Naz. Water stress in most cases increased the contents of oleic, palmitic and stearic acid but decreased the contents of linoleic and linolenic acids. Mycorrhizal inoculation in most cases increased the content of oleic and linoleic acids in both cultivars, but this increases were more obvious for oleic acid in Yekta and linoleic acid in Naz. However, in most cases inoculation decreased the contents of linolenic, palmitic and stearic acids. Six phenolic (chlorogenic, ellagic, gallic, caffeic, p-coumaric and ferulic) and three flavonoid (rutin, quercetin and apigenin) components were identified in sesame grains. Water stress increased chlorogenic and caffeic acids but the water stress response of other phenolic and flavonoid compounds depended on the interaction effect of cultivar and mycorrhizae. Mycorrhizal inoculation in most cases decreased chlorogenic acid but increased gallic, caffeic, p-coumaric and ferulic acids. The results of this experiment therefore showed that in both years the highest grain yield under non-stressed condition was obtained in Yekta inoculated with irregularis but under water stress condition it was achieved in Naz cultivar inoculated with claroideum mycorrhizal species.

مرتضي زاهدي

پرويز احسان زاده , مهدي قيصري , بنفشه خليلي

حسن كريم مجني , عليرضا گوهري , علي اكبر احسان پور