Effect of root inoculation of mycorrhiza fungi (Glomus mosseae) on growth and ‎resistance to drought stress in Gleditsia caspica seedlings

Drought is one of the most important environmental factors which limit the growth of woody plant. In order to evaluvate the resistance of Caspian locust seedlings to drought stress through inoculation with arbuscular mycorrhiza fungi a factorial experiment was performed in completely randomized design in 2016-2018. The factors were included mycorrhiza at two levels (inoculation and uninoculated with Glomus moseae) and drought stress at two levels (Well-watered and withholding water). Drought stress significantly reduced growth traits such as relative water content, percentage of aerial and root dry biomass, content of total chlorophyll, total carotenoid content and cell membrane stability index and significantly increased proline content. Root inoculation of seedlings with mycorrhizal fungi improved relative water content (14%), total carotenoid content (25%), aerial dry biomass percentage (4.5%), root dry biomass percentage (6.2%), and total antioxidant capacity (54.8%) than to uninoculated seedlings. Also, cell membrane stability index, total chlorophyll content, total phenol content and total flavonoid content in inoculated seedlings were higher than non-inoculated seedlings under both drought and normal irrigation conditions. Overall, the results showed that mycorrhizal fungi improved growth characteristics and reduced adverse effects of drought stress by increasing antioxidant compounds in Caspian locust seedlings.