Abstract

To evaluate the effect of arbuscular mycorrhizal fungi and phosphorus levels on root traits of cucumber plants, a factorial experiment was carried out based on a randomized completely design pot culture. Four phosphorus fertilization treatments, including 2, 5, 10 and 15 mg P kg^-1 soil possessed phosphorus fertilization levels as the first factor. At the second factor arranged Glomus mosseae, Glomus intraradices of mycorrhiza species and non-inoculum as a control with three replications were conducted in the greenhouse of agricultural research center of west Azarbaijan province Urmia, in 2013. Results show that above-ground dry matter of inoculated cucumber at both species with 155.00 and 160.83 mg/plant had the highest values. Both species had more root fresh and dry weight, root length and root volume than control. Colonization of G. mosseae and G. intraradices, with 53.20 and 44.59% had the highest values at the 2 mg P kg^-1 soil. G. mosseae and G. intraradices had the highest leaf phosphorus with 486.06 and 477.60 mg/100 g of leaf dry weight at the 15 mg P kg^-1 soil, respectively. Leaf phosphorus (r = 0.62**), root dry weight (r = 0.79**), root length (r=0.44**), root volume (r = 0.82**) and fresh root weight (r = 0.74**) had positive correlation coefficients with above-ground dry matter. Although application of phosphorus increased above-ground dry matter and root traits, but our study clearly demonstrates that mycorrhizal fungi play an important role in the enhancement of growth of cucumber plants under very low phosphorus conditions.

Key words: Colonization, cucumber, dry matter, insoluble phosphorus, mycorrhiza.