简介：Adoublemutantwithstreakedleafandabnormalfloretwasfoundandtemporarilynamedstreakedleafandfloralorgannumbermutant(st-fon).Forthismutant,besideswhitestreakappearedonculm,leavesandpanicles,thenumberoffloralorgansincreasedandfloretscracked.Theextremephenotypewasthatseveralsmallfloretsgrewfromonefloretorbranchrachisinsmallfloretsextendedanddevelopedintopanicles.Byusingtransmissionelectronmicroscopetoobservetheultrastructureofwhitehistocytesofleavesattheseedlingstage,thewhitetissueswhichshowedabnormalplastids,lamellasandthylakoidscouldnotdevelopintonormalchloroplast,andthedevelopmentofchloroplastwasblockedattheearlygrowthstageofplastid.Scanningelectronmicroscopeandparaffinsectionwerealsousedtoobservethedevelopmentoffloralorgans,andtheresultsindicatedthatthedevelopmentoffloralmeristemwasoutoforderandunlimited,whereasinthetwistyleaves,vascularbundlesheathcellsgrewexcessively,orsomebubblycellsincreased.Geneticanalysescarriedoutbymeansofcrossandbackcrosswithfournormal-leaf-colormaterialsrevealedthatthemutantisofcytoplasminheritance.

简介：Apopulationofricebrownplanthopper(BPH)NilaparvatalugenscollectedfromapaddyfieldinHangzhouwassuccessivelyrearedonsusceptiblericeTaichungNative1(TN1)inalaboratoryfreefrominsecticidesformorethan14generations.Thechangesinsusceptibilitytoinsecticidesandecologicalfitnessondifferentresistantricevarietiesweremonitoredineachgeneration.Theresistanceratiotoimidaclopridsharplydeclinedwiththesuccessionofrearinggenerationswithoutinsecticidesfrom359.94-foldatF1to6.50-foldatF14comparedwiththesusceptiblestrain,andtheresistanceratiotochlorpyrifoswasfrom9.90-foldatF1to5.94-foldatF14.Nymphaldurationandweightsofnewlyhatchedfemaleadultsweresignificantlyaffectedbyricevariety,generationandtheirinteractions,butnymphalsurvivalwassignificantlyaffectedbythegenerationonly.Theratioofbrachypterousadultsinmaleswasaffectedbythegenerationandgeneration×varietyinteraction,whereasnodifferencewasfoundinfemales.Nymphaldurationextendedwithincreasinggenerations,andthefemalenymphaldurationwasshorterinthesusceptiblevarietyTN1thanthoseintheresistantvarietiesIR26andIR36.Inaddition,thefemaleadultweightinTN1washigherthanthoseinIR26andIR36.TheseresultsindicatedthattheresistanceoffieldBPHpopulationtoinsecticideswasreversedafterseveralgenerationsofno-exposuretoinsecticides,andtheecologicalfitnessinTN1washigherthanthoseinIR26andIR36.ThesefindingssuggestedtherationalandreduceduseofinsecticidesincombinationwiththemanipulationofresistantricevarietieswouldbeeffectiveforBPHmanagement.