Effect of water stress on the growth and antioxidant enzymes activities of pistachio mycorrhiza seedlings (Pistacia vera L.)

Abiotic environmental stress is an important factor in the limitation of plant growth and production. At the same time, environmental stresses such as drought and salinity become more widespread globally. One of the resistance mechanisms against the stress is symbiosis with soil microorganisms, including arbuscular mycorrhizal. In order to evaluate the effect of water stress on the growth and antioxidant enzymes activities of Pistachio mycorrhiza seedlings (Pistacia vera L.) inoculated seedlings with mycorrhizal fungi with Funneliformis mosseae produced. In this study the vases irrigated for two years to complete establishment seedling for (three time in weeks), then drought stress was imposed in during nine days. After measuring growth factors, the effect of the fungus growth factors such as stem length stem diameter, branch length, branch diameter and leaf area index was statistically significant different in mycorrhizal seedlings ( P < 0.01). However, in diameter of branches and ramifications phenomenon any significant difference was not observed. The results showed that mycorrhizal fungi symbiosis resulted to reduce the amount of chlorophyll a and b and total chlorophyll in seedlings during drought stress in compare with reference. The CAT, POD activity and total protein were higher in mycorrhiza seedling than non-mycorrhiza seedling in drought condition, but it was no significant effect in SOD activity. The antioxidan activities have significant impacts on stress tolerance and reducing the damage. It seems that, when plants are close to permanent wilting point, the majority of biochemical systems of plants is affected and reaches to lowest point such as enzyme activity. Drought stress is caused to creation of simulated natural conditions and the actual performance of mycorrhizal fungi on seedlings determined. According to these results, we can say the arbuscular mycorrhizal fungi had useful effect and mycorrhizal seedlings can be used for improving and restoring the degraded areas of Pistachio.