Focus 6.5.2 pro

2-Week-old flax seedlings were subjected to 100 μM ABA treatment (sprayed all over the plants) and after 24 h growth they were infected with 1.3 × 10 5 F. oxysporum conidia prepared as described by Di et al. (2017) , and grown for another 4 h. Then the plants were collected and subjected to clearing with 0.15% TCA in ethanol:chloform mixture (4:1, v/v) for 48 h and then submitted to staining with safranin and solophenyl flavine 7GFE (0.1% w/v in 0.1 M Tris/HCl, pH 8.5) as follows. Whole plants were submerged in safranin solution (0.2% w/v safranin in 10% v/v ethanol) for 5 min and then washed three times in water. Subsequently, the plants were stained for 10 min with solophenyl flavine 7GFE (0.1% w/v in 0.1 M Tris/HCl, pH 8.5), and washed again with water (four times) (Knight and Sutherland 2011) . Roots were cutoff and mounted on the slides, observed under the epi-fluorescent microscope Olympus BX50 using UV excitation light (360-370 nm) and documented using the Olympus DP71 camera and Cell^B software (Olympus Optical Co.). Images, taken at different depths, were processed using Helicon Focus 6.5.2 Pro (Helicon Soft Ltd.) and CorelDRAW 2017 (Corel Corporation).