Figure 7.

In vitro antimicrobial activities of AMF against Verticillium dahliae. Divided Petri dishes prevent nonvolatile solutes from diffusing between two compartments. The upper compartment of divided Petri dishes contained a complete growth medium (M+) used for the growth of AMF symbionts, and the lower compartment contained the same medium lacking sugar (M−), thus permitting the development of AMF hyphae and spores. Two discs covered with V. dahliae of 5 mm diameter were transferred to the M− compartment and incubated in the dark at 25 °C for 1 week. Before the inoculation of V. dahliae discs, fresh blank M+ and blank M− medium were decanted into divided Petri dishes. The height of M− was equal to the middle baffle while slightly higher than M+. The heights of M+ and M− in each plate were comparable to each other. Treatments were divided as follows: (A) empty M− and empty M+; (B) M− with AMF hyphae and spores (h + s) and empty M+; (C) empty M− and M+ with mycorrhizal roots (myc-roots); (D) M− with AMF h + s and M+ with myc-roots; (E) empty M− and M+ with dead myc-roots heated at 65 °C for 30 min; (F) empty M− and M+ with non-mycorrhizal roots (nm-roots). Experiments were repeated three times with similar results.