Effect of mycorrhiza application on some physiological and biochemical characteristics of Quercus brantii saplings under drought stress conditions

Drought is one of the most important environmental factor limiting the growth of woody and non woody plants. Especially, in arid and semiarid regions, establishment, growth and development of trees, especially young seedlings are severely affected by water scarcity. So, in order to study the effect of mycorrhizal fungi inoculation on drought resistance of Quercus brantii Lindl. saplings, a factorial experiment was performed in completely randomized design with three replications. Treatments were included drought stress at two levels (well-watered and withholding water) and mycorrhiza at two levels (inoculation and/or uninoculated with Funneliformis moseae). Under drought stress, all growth indices including relative water content, photosynthetic pigments content, dry matter percentage and membrane stability index decreased. Inoculation of arbuscular mycorrhizal fungi significantly improved root dry matter percentage (4/1%), chlorophyll b content (37/1%), total phenol content (100%), total flavonoid content (53%) and total antioxidant capacity (4%) compared with the uninoculated seedlings. Mycorrhiza inoculation also increased relative water content, membrane stability index, shoot dry weight percentage, chlorophyll a and total content and carotenoids content and decreased leaf proline content of Iranian oak saplings under both regular irrigation and drought stress conditions. Overall, the results showed that mycorrhiza arbuscular fungi improved growth indices of Iranian oak saplings by improving plant water relations and antioxidant compounds. Therefore, inoculation of Iranian oak saplings before planting and their establishment in the main site is recommended.