Investigating the Effect of Arbuscular Fungus on the Medicinal Plant Lemon Grass (Cymbopogon citratus) under Salt Stress

Introduction  Medicinal plants have reservoirs rich in the active ingredients of many medicines. Medicinal plants have rich reservoirs of essential active ingredients of many drugs. Considering the importance of medicinal plants, especially in the pharmaceutical industry and their scarcity in nature, it is very important to study the various agricultural aspects of these plants, considering the increasing spread of saline soils, to find a solution. It seems necessary to prevent living and non-living environmental stresses or at least reduce them. One of these methods is the use of symbiotic relationships between mycorrhizal fungi and host plants, which reduces the stress caused by salinity. Due to the increasing expansion of saline soils, it seems necessary to find solutions that can prevent or at least reduce the living and non-living environmental stresses. There are different ways to overcome these tensions in different situations. Water salinization is one of the most important environmental limiting factors for crop production, especially in arid and semi-arid regions of the world, since Iran is located in the arid region of the world, given that salinity is one of the environmental factors. Are that have a strong effect on the growth and activity of lemongrass; There are also vast resources of saline and semi-saline groundwater, although not currently used and likely to be used in the future. Solutions to address abiotic stresses include the use of biofertilizers. One of these methods is to use the symbiosis of fungi with host plants, which leads to a reduction in salinity stress. The aim of this study was to investigate the effect of Arbuscular mycorrhizal fungi. On vegetative and biochemical traits of lemongrass under salinity stress. Salinity is one of the most important factors limiting the growth and production of crops. Fungi as a biological fertilizer can be useful in meeting the nutritional needs of plants and reducing the effects of environmental stresses on plants.   Materials and Methods  The experiment was a factorial experiment in a completely randomized design with two factors of four salinity levels (0, 5, 10 and 15 ds.m-1 NaCl) and fungi (no inoculation and fungal inoculation). For inoculation of Arbuscular mycorrhizal fungi with mixed potting soil was applied to the lemongrass. Plant height, root length, fresh and dry weight of leaves, relative water content, catalase, peroxidase and polyphenol oxidase were measured.   Results and Discussion  The results indicate that all studied traits were significantly affected by the interaction of mycorrhiza and salinity stress. The application of mycorrhizal fungi in the presence of salinity stress due to the absorption of nutrients and water led to improved growth of lemongrass. The results showed that under salinity stress of 150 mM plant height, root length, fresh and dry weight of leaves, relative water content, catalase, peroxidase and polyphenol oxidase enzymes in lemongrass inoculated with arbuscular fungus at 23.05, 32.69, 25.31, 48.14, 31.83, 30.33, 52.72 and 33.41% respectively, increased compared to the control (no inoculation). In general, based on the results of this study, it can be concluded that the use of mycorrhizal fungi can increase the salinity tolerance of lemongrass and cultivate it in saline soil.   Conclusion In summary, the results of the present study showed that inoculation of the fungi can protect the lemongrass plant against salinity stress. In addition, the effect of mycorrhizal fungi on lemongrass under salinity stress has been investigated for the first time. According to the results obtained in this study, salinity reduced morphological parameters and lemongrass as a reaction to salinity to maintain its status to increase the amount of enzyme activity through the mechanism of osmotic regulation to stress conditions. Compromise and to some extent deal with salinity. In the study, it was observed that inoculation with Arbuscular had a positive effect on all measured traits. The application of mycorrhizal fungi in the presence of salinity stress due to the absorption of nutrients and water led to improved growth of lemongrass. By examining all the measured traits, it can be concluded that by using mycorrhizal fungi, the salinity resistance of lemongrass can be increased and cultivated in saline soil. Arbuscular species seems to be more suitable for improving the growth of lemongrass in all conditions.