Figure 2.

Effect of Trichoderma on H₂O₂ accumulation in Arabidopsis. Representative photographs of leaves (A) and roots (C) from axenicallygrown (control) seedlings or from seedlings co-cultivated with T. atroviride for 6 d (B, D and E). Arabidopsis seedlings were treated with a solution of 3,3′-diaminobenzidine (DAB). In the presence of H₂O₂, DAB polymerizes, forming a dark red-brown coloration in plant tissues. Microscopy was performed using a Leica MZ6 Stereomicroscope. Bar = 1 mm. Arrow shows the spots of accumulated H₂O₂. Photographs show representative individuals of at least 15 seedlings stained with DAB. The experiment was repeated twice with similar results.