Evaluation of the effect of Glomus fascollaria on some morphological characteristics, photosynthetic pigments and antioxidant activity of Chicory (Cichorium intybus L.) under drought stress

Introduction Drought stress is one of the most important stresses that affects plant growth and yield (Redd et al., 2004). Drought stress results in the formation of reactive oxygen species by the partial regeneration of oxygen in the processes of photosynthesis and respiration by increasing the transfer of electrons to oxygen molecules (Asada, 1999), Plants have different mechanisms to reduce the harmful effects of activated oxygen species. In recent years, due to the changing weather conditions, drought stress has become more severe. Thus, the study of mechanisms that enable plants to adapt to drought stress can ultimately help to produce resistant plants in arid and semi-arid regions (Hassani et al., 2003). In addition to improvement of nutrition, the fungus symbiosis is able to reduce the negative effects of environmental stresses on host plant in various ways, such as increasing the levels of antioxidant enzymes and maintaining chlorophylls (Zarea, 2012). The negative effects of environmental stresses on host plants are reduced. In this study, the effect of mycorrhizal fungus on photosynthetic pigments and the characteristics of antioxidant enzymes of chicory under drought stress were investigated. Materials and Methods In order to study the effect of mycorrhizal fungus on photosynthetic pigments and the antioxidant specification of chicory under drought stress, the factorial experiment was conducted in a completely randomized design with three replications in a Greenhouse of Agricultural Research Center of Zabol University in 2016. Treatments were four levels of drought stress (control), 70, 50 and 30% of crop capacity and inoculation with mycorrhizal fungi at two levels of inoculation and uninoculation. Before planting, 50 g of mycorrhizal fungus was added to the soil of each pot. From the beginning of the fifth week, drought stress was applied to weights In the end, vegetative parameters including fresh and dry weight of root and shoot were measured. Arnon method (Arnon, 1976) was used to measure chlorophyll and carotenoid. The enzyme gyAgol peroxidase (Cam-mada and Nelson Shspra, 1999), the polyphenol oxidase enzyme (Janovitz-Klapp et al., 1990) and the measurement of the catalase enzyme by Beers and Sizer (1952) Made.   Results and Discussion The highest fresh and dry weights of shoot Plant in 90% stress and inoculated with Glomus Fascollaria fungus treatments were obtained and the least amount was obtained in drought stress 30% agronomic capacity and non inoculation with Glomus Fascollaria fungus (Table 2). The highest fresh and dry weights of roots were obtained in stress 90% and inoculation of Glomus Fascollaria fungi and its lowest in drought stress 30% of field capacity and non-inoculation with Glomus Fascollaria fungus (Table 2).The results showed that in the interaction of Glomus Fascollaria fungus treatments and drought stress, the highest levels of chlorophyll a, chlorophyll b, carotenoids and total chlorophyll were obtained in 90% stress (control) and inoculated with Glomus Fascollaria fungi and the lowest levels of chlorophyll a, chlorophyll b, carotenoids and Total chlorophyll was obtained in drought stress 30% of field capacity and uninoculation with Glomus Fascollaria fungus (Table 2). The highest effect of interaction between fungal treatments and drought stress in catalase, polyphenol oxidase and Guayaquil peroxidase enzymes was observed in drought stress 30% of field capacity and inoculation with fungi and its lowest level in 90% stress (control) and uninoculation with fungi Came. In corn plants, inoculation of Glomus Fascollaria fungi increased chlorophyll content, and attributed an increase in chlorophyll content to increased nitrogen uptake by the mycorrhizal system (Tang et al., 2009). It was reported that chlorophyll content in Citrus tangerine seedlings mixed with fungi under full irrigation conditions had a significant difference with chlorophyll content in non-fungal seedlings, and in drought stress conditions, chlorophyll content in plantlets containing fungi was higher than that of plants There was no fungus (Wu and Xia, 2006). In studies on zoo, the highest activity of catalase was found in leaves of plants inoculated with Glomus Fascollaria fungi under drought stress than uninoculated plants (Suleimani and Pirzad, 2016).Based on the results, with increasing drought stress, the amount of photosynthetic pigments, fresh and dry weight of the shoot and fresh weight and root crop decreased. Inoculation with Glomus fascollaria during drought stress reduced drought stress and increased photosynthetic pigmentation, fresh and dry weight gain of the shoot and increased fresh and dry weight of roots. The inoculation of chicory with Glomus fascollaria fungi under drought stress conditions by stimulating the activity of antioxidant enzymes such as catalase, polyphenol oxidase and guaiacol peroxidase prevents the oxidative effects of ROS. Thus, the use of mycorrhiza fungi improves the physiological function and plant tolerance Chicory was drought stressed