Effect of mycorrhizal fungi symbiosis on some morphological, physiological and biochemical characteristics in trifoliate orange (Poncirus trifoliate L.) under salinity stress

Symbiosis effect of three arbuscular mycorrhizal fungi (AMF) species from the Glomus genus with two and three mixtures were studied on growth characteristics, chlorophyll concentration, gas exchange, chlorophyll florescence and the activity of some antioxidant enzymes in trifoliate orange (Poncirus trifoliate L.) under salinity stress. 40 days old trifoliate orange seedlings were transferred into the pots containing G. intraradices×G. mosseae, G. hoi×G. intraradices×G. mosseae and no fungi (control). After 175 days, seedlings were exposed to 0 (control), 35 and 70 mM sodium chloride for 45 days. Mycorrizal colonization, shoot and root dry weight, leaf number, plant height, transpiration rate and photochemical efficiency (maximum quantum yield through the dark adaptation “Fv/Fm”) were increased in colonized seedlings under salinity stress specially when the three mixture of fungi were used compared with the non-AMF seedlings under salinity stress. Seedling colonization particularly with three fungi mixture caused increase in the activity of antioxidant enzymes (catalase and ascorbate peroxidase) compared with the control. Overall, AMF colonization could help trifoliate orange seedlings against salt stress through increasing growth and oxidative damage reduction.