Effect of mycorrhizal inoculation in reducing water stress in sesame (Sesamum indicum L.): The assessment of agrobiochemical traits and enzymatic antioxidant activity

The yield of crops is threatened significantly by drought in various parts of the world. The purpose of this paper was to evaluate the potential of mycorrhiza fungi in reducing water stress effect on sesame (Sesamum indicum L.) by assessing antioxidant activity. The experiment was carried out as a split plot based on a randomized complete block design, in two cropping seasons. The main factor consisted of different levels of irrigation whereas subplot included two different species of mycorrhiza fungi namely, Funneliformis mosseae and Rhizophagus irregularis, applied separately. A non-inoculated subplot served as the control one. Plant biomass, grain yield, amounts of chlorophyll a and b and relative water content decreased with the severity of water stress. At the same time, the amount of proline, malondialdehyde level and enzymatic and non-enzymatic antioxidants increased significantly. Severe water stress reduced the biomass and grain yield by approximately 51% and 65%, respectively. Oxidative damage (hydrogen peroxide and MDA content) induced by water stress was significantly reduced in colonized plants. Compared with the control plot, using two species of mycorrhiza fungi caused an increase in biomass, grain yield, relative water content and all enzymatic and non-enzymatic antioxidant activities; however, the improvement in plant water status led to significantly decreased proline. Obtained results indicated that mycorrhiza fungi can enhance the enzymatic antioxidant activities that resulted in scavenging free radicals and improving resistance to water stress.