Fig. 4
Effects of different concentrations of NH4+ supply on the mycorrhizal colonization and the expression of AM-marker genes. a and b, mycorrhizal colonization level (a) and arbuscule abundance (b) in mycorrhizal roots of chili pepper plants were determined. c and d, the transcript levels of CaPT4 (c) and RiTub (d) in chili pepper inoculated or non-inoculated with Rhizophagus irregularis. CaPT4 and RiTub from chili pepper and R. irregularis, respectively, were used for evaluating AM colonization. Values are means ± SE of six biological replicates from two pots (n = 6). Different letters indicate significant differences, P < 0.05