Fig. 1.

Effects of root-specific and constitutive reduction of cytokinin (CK) levels on arbuscular mycorrhizal (AM) fungal colonization. The transgenic tobacco line W6:CKX1 with a root-specific reduction of CK levels, the 35S:CKX1 and 35S:CKX2 transgenic lines with constitutive reduction of CK levels and the corresponding wild-type (WT) were inoculated with the AM fungus Rhizophagus irregularis strain RI, strain FM, or both (RI + FM). Plants were grown in a glasshouse for 8 weeks and sampled to determine the percentage of root length colonization (RLC) by the AM fungal hyphae and arbuscules. Values are means + SE, n = 10. For each AM fungal parameter, bars topped by the same letter are not significantly different (p < 0.05) according to Duncan’s multiple range test