2.4. Scanning electron microscopy
R. stolonifer was grown in Potato Dextrose Broth (PDB) amended with: (i) CaCl2 at 1.5 g/l, (ii) 2 ml/l LO, or (iii) with the two combined treatments. PDB without any addition served as a control. Collected fungal mats were fixed in 2.5% glutaraldehyde at 4 °C for 24 h and post-fixed in 1% osmium tetraoxide for 1 h at room temperature (Harley and Fergusen, 1990). Then they were dehydrated with ascending concentrations of acetone, critical point dried, and finally sputter coated with gold. Examination and photographing was done through scanning electron microscope (JSM-1200 EX, Joel, Peabody, MA, USA) in National Centre for Radiation Research and Technology (Cairo, Egypt).