ThenewspreadingconchosporesotPorphyrayezoensis,P.haitanensisandP.katadaivar.hemiphyllaareinducedbyN-Methy-N'-Nitro-N-Nitrosoguanidine(NG),astrongmutagentoinducethemutantofchromatophore.Itisshowedthat(1)nomutantshavebeeninvestigatedinallcontrolgroup.(2)TheconchosporesofallthethreespeciesofPorphyraareeasytobeinducedbyNGfortheyareinthestageofbreeding,Inthelowestdose(10μg/mL)ofthisexperiment,themutantrateofP.yezoensisisupto57.9%,thatofP.haitanensis30.7%andthatofP.katadaivar.hemiphylla51.7%.(3)Themutantratecannotincreaseobviouslybyincreasingthereagentconcentrationorprolongingtheinductiontime.Withinthescopeofexperiment,theinducementeffectsofthreespeciesofPorphyraaremuchsimilar,andthemutantrateisnear50%.TheoptimuminductionconcentrationofNGis10μg/mL,andtheoptimuminductiontimeis30minutes.
