The effect of mycorrhizal fungi on the oxidant enzymes activity in the medicinal herb, hyssop, under water deficit conditions

Some crops have the ability to withstand environmental stresses as they prevent further production of oxygen free radicals or cope with the produced free radicals. Accordingly, in order to investigate the effect of mycorrhizal fungi species on eco-physiological characteristics of Hyssopus officinalis L., a factorial experiment based on randomized complete block design was conducted with three replications at the research farm of west Azarbaijan Agricultural and Natural Resources Research Center in 2012. Treatments were species of mycorrhizal fungi (Glomus mousseae, G. intraradicese, G. fasiculatum, G. claroideum, Acaulospora longula and control without mycorrhiza) and four levels of irrigation (irrigation at 80, 70, 60 and 50% field capacity). Results showed the significant effects of irrigation and mycorrhiza on the ascorbate peroxidase, and significant interaction between irrigation and fungi species on the percentage of mycorrhizal colonization, catalase activity and superoxide dismutase. The order of highest colonization of Hyssop root was G. mosseae, G. intraradices, G. fasiculatum, G. claroideum and A. longula compared to control treatment in all irrigation levels. The highest activity of superoxide dismutase and catalase in plants inoculated with G. mosseae, G. fasiculatum, G. fasiculatum and G. claroideum belonged to irrigation at 50, 60, 50 and 50% of field capacity, respectively. However, the highest ascorbate peroxidase belonged to irrigation at 50% field capacity. In conclusion, the results showed that mycorrhizal species affected the amendment of water deficit stress due to the increased antioxidant enzyme activity in order to neutralize the effects of free radicals and cell membrane stability.