The filamentation of Saccharomyces cerevisiae was investigated.S.cerevisiae strains were cultured on agar plates with limited carbon or nitrogen sources or supplemented with fusel alcohols and then cell morphology was observed under an optical microscope.Diploid strains GGFS16,GJ2008 and haploid strains SC2012,SS2012 showed filamentation induced by propanol,butanol and pentanol.With fructose,maltose and lactose as the sole carbon source,GJ2008 and SS2012 showed invasive growth,whereas GGFS16 and SC2012 did not.On synthetic low-ammonia dextrose(SLAD) medium agar plate,all strains tested did not filament.Propanol,butanol and pentanol stimulate filamentous growth in both haploid and diploid S.cerevisiae cells.In carbon limitation medium,invasive growth responses are dependent on strains for both haploid and diploid S.cerevisiae cells.