2.2. Antimicrobial effect assays
A suitable aliquot of fresh spore suspensions of P.expansum was added to a 250 mL conical flask contain-ing 100 mL potato dextrose broth (PDB) to obtain a final concentration of 1.0 × 106spores/mL with the aid of a hemo-cytometer. NaHCO3 was, respectively, added to the medium withfinal concentrations 0, 0.15%, 0.3%, 0.45%, 0.6% (m/v). After shaking culture at 25◦C, at least 100 spores per replicate were observed microscopically to determine germination rate during 6 to 10 hand germ tube length during 11 to 14 h.