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.
简介:Inaspectofthescaleofworks,theThreeNorthShelterbeltProgramisuptonowthemostmagnificentprojectofforestryecologicalconstructionintheworld.Attheendof2000,the1st,2nd,and3rdperiodsofconstructioninthe1stphase(1978-2000)hadbeencompleted.Basedonfuzzycomprehensiveevaluationmethod,thepaperisabouttheresearchesonpost-evaluationinthe1stphaseaimsoftheThreeNorthShelterbeltProgram.Theconclusionobtainedisthattheaimsarepartlysuccessful.