Zoospore germination in the water mold, Blastocladiella emersonii: II. Influence of cellular and environmental variables on germination☆☆☆

[摘要] Theeffectsofcellularandenvironmentalvariablesinvolvedinthepopulationassayofzoosporegerminationhavebeenexamined.Thefollowingresultswereobtained:1.1.Withinthestandardconditionsemployed,onlygrowthdensityand,toalesserextent,temperature,seriouslyaffecteitherthesynchronyortherateofzoosporeconversiontoroundcells.2.2.SynchronyofroundcellformationvariesasafunctionofgrowthdensityinDM-2,butnotPYG,medium.3.3.Synchrony,andprobablyrate,ofroundcellformationareprofoundlyinfluencedbytemperature;neitheratemperaturethresholdnoratemperatureoptimumwasfoundwithintheviable(growth)range.4.4.Neithersynchronynorrateofroundcellformationisaffectedbyvariousmanipulationsofthezoosporespriortogermination(centrifugation,deflagellation,prechilling,extendedperiodsofswimming)orbyzoosporeconcentration(withinthestandardrange).Athighzoosporeconcentrations,T50isincreased.5.5.Synchronyandrateofroundcellformationareindistinguishableingerminationsolution,aninorganicsaltsmedium,andDM-2,adefinedgrowthmedium.Roundcellformationisconsiderablymoreasynchronousinthepreviouslystandard,undefinedgrowthmedium(PYG).6.6.Oftheconstituentsofgerminationsolution,onlyKClisnecessaryformoderatelysynchronousroundcellformation,andthedegreeofsynchronyismarkedlydependentonKClconcentration.Onthebasisoftheseandother(Solletal.,1969)results,thefollowingconclusionsbearingonthegerminationprocessandonitscontrolhavebeenmade:1.1.Themomentofinitiationofzoosporegerminationispreciselydefined.2.2.KCl(orchloridesaltsofcertainothermonovalentcations)caninitiatethechangesassociatedwithzoosporegermination.3.3.Neitherinitialpresenceofaflagellum,flagellarretractionnorlaterpresenceofaninternalflagellaraxonemearerequiredforthesuccessfulcompletionofgermination.4.4.Atstandardzoosporeconcentrations,cellsdonotinteracttopermitsemisynchronousgermination;athigherconcentrations,cellsdointeracttoinhibitgermination.5.5.Zoosporescansuccessfullycompletegerminationaticetemperature.6.6.Heterogeneityinzoosporepopulationswithrespecttotimeofgerminationcanbepredictablyvariedbycontrollingthedensityofgrowthculturesfromwhichthezoosporesarederived.

[学科分类] 生物科学（综合）