遗传改良作物杂草化的风险评估

Riskassessmentsforweediness

ofgeneticallymodifiedcrops

遗传改良作物杂草化的风险评估

1.1.Agriculturalhabitats

2.Non-agriculturalhabitats

1.农业环境

2.非农业环境

AlanRaybould,EcologicalSciences,SyngentaWeedinessinagriculturalhabitats–problemformulation

农业环境中的杂草化–问题定义TypicalmanagementobjectivefromthePlantProtectionAct(USA) “safeguardagricultureandnaturalresourcesfromtherisksassociatedwiththeentry,establishment,orspreadofanimalandplantpestsandnoxiousweedstoensureanabundant,high-quality,andvariedfoodsupply”美国植物保护条例的典型管理目的 “保护农业和天然资源,减少动物,害虫和有害种子传播的风险,确保充分的,高质量的,丰富的食物供应.”Weedinessinagriculturalhabitats–problemformulation

农业环境中的杂草化–问题定义AssessmentendpointsmaybederivedfromtheseobjectivesAbundance–cropyieldHigh-quality–nutritionalvalueofcropsVaried–diversityofcrops评估终点来源于下列目标大量–作物产量高质量–作物营养含量变化性–多样作物种类Weedinessinagriculturalhabitats–conceptualmodel

农业环境中的杂草化–概念模型HowmayaGMcropaffecttheseendpoints?J.Orson1993.

Thepenaltiesofvolunteercrops.AspectsofAppliedBiology35:1-8ReviewofharmassociatedwithvolunteercropsinUKThreecategoriesofharmCompetitionGreenBridges(hostsofdiseasewhennocroppresent)ContaminationGM作物怎样影响这些终点?J.Orson1993.

Thepenaltiesofvolunteercrops.AspectsofAppliedBiology35:1-8英国自生作物危害性回顾三种危害性竞争绿桥(无作物存在时疾病的宿主)污染Competition 竞争Slowgrowingcropfollowsfastgrowingcrop慢速生长作物跟随快速生长作物Onionssownafterpotatoes洋葱在土豆之后播种Yieldnoweedcontrol: 0-13tonnes/hectareYieldhandweeding: 20-62tonnes/hectareBestherbicidecontrol: 53tonnes/hectare无杂草控制的产量: 0-13吨/公顷有杂草控制的产量: 20-62吨/公顷最好的除草剂控制: 53吨/公顷Greenbridges 绿桥Yellowrustinfectionofwheat 小麦的黄锈病感染YarhamDJ,GladdersP.1993.Effectsofvolunteerplantsoncropdiseases.AspectsofAppliedBiology35:75-82中文表请见下页Greenbridges 绿桥Contamination 污染Lossofqualityifseed(orotherparts)ofvolunteerharvestedwithcropDifferentcropse.g.peasafterlinseedLinseedpodssimilarsizetopeas–difficulttoseparateFactoriesrejectedpeassowninrotationwithlinseedSamecropHighglucosinolate/lowglucosinolateoilseedrapeWheatforanimalfeed/wheatformilling如果自生植物种子(或其他部分)和作物一起被收割将影响作物的质量不同作物例如豌豆亚麻子亚麻子的豆荚与豌豆大小相似很难分离厂商一般不接受在亚麻子之后播种得到的豌豆相同作物高芥甙/低芥甙油菜籽磨粉用/饲料用小麦Weedinessinagricultural 农业环境中的杂草化

habitats–conceptualmodel –概念模型CropsharmassessmentendpointsofyieldandnutritionalvalueYield–competitionandgreenbridgesNutrition–contaminationGMcropscanharmtheseendpointsinthesamewayAnyotherwaysinwhichGMcropscanharmtheseendpoints?“作物危害性评估的产量和营养价值终点产量–竞争和绿桥营养–污染GM作物可以以相同的方式来危害这些评估终点GM作物还有其他危害方式么?Weedinessinagricultural

农业环境中的杂草化habitats–conceptualmodel

–概念模型Thetransgenicprocesspresentsnonewcategoriesofriskcomparedtoconventionalmethodsofcropimprovement”NationalResearchCouncil.2002.EnvironmentalEffectsofTransgenicPlants:theScopeandAdequacyofRegulationCompetition,greenbridgesandcontaminationaresufficient“转基因过程和传统的作物改良方式相比并没有引进新的风险”NationalResearchCouncil.2002.EnvironmentalEffectsofTransgenicPlants:theScopeandAdequacyofRegulation竞争,绿桥和污染已经足够了Weedinessinagricultural

农业环境中的杂草化habitats–conceptualmodel

–概念模型CurrentagriculturalpracticeisdeemedtoposeacceptablerisktotheassessmentendpointsRiskofweedinessofGMcropscanthereforebeassessedbyevaluatingwhethertheyshowincreasedweediness:Morecompetitivethanthenon-GMcropGreaterprobabilityofbeingagreenbridgethanthenon-GMcropMorefrequentormoreseriouscontaminationthannon-GMcrop现行的农业实践被认为会引起一些可接受的评估终点风险因此,GM作物的杂草化风险可以用以下几点来评估:比非GM作物更有竞争性比非GM作物更有可能成为绿桥比非GM作物的污染持续性更强或更严重Weedinessinagricultural

农业环境中的杂草化habitats–conceptualmodel

–概念模型ThenullhypothesisisthattheGMcropisnomoreweedythanthenon-GMcrop:thisistheriskhypothesisAsecondaryriskhypothesisisthatGMcropxwildplanthybridsarenomoreweedythannon-GMhybridsinagriculturalhabitats初始假设是GM作物不会比非GM作物引进更多的杂草:这是风险假设次级假设是GM作物与野生种杂交后代在农业环境中不会比非GM作物引进更多的杂草Testingtheriskhypothesis 检验风险假设

-competition –竞争TraitsthatmayindicateincreasedcompetitionAppendixIICanadaandUnitedStates“BilateralonBiotechnology”ReproductionandsurvivalcharactersLifespan,vegetativebiomass,over-winteringcapacity,floweringbehaviour,seedproduction,seeddormancy,germination,seedlingsurvival,outcrossingfrequency,pollenviability,dispersalability一些特征表明竞争增加附录II加拿大和美国“双边生物技术”繁殖和生存特征生存期限,植物数量,越冬能力,开花行为,种子产生,种子休眠,萌发,幼苗存活,异型杂交频率,花粉发育能力,散播能力Testingtheriskhypothesis 检验风险假设

-competition –竞争AdaptationtostressBiotic: pathogens,herbivores,otherplantsAbiotic: atmospheric,pollutants,nutrient,deficiency,temperatureextremes,drought,floodPesticides压力适应生物压力:病原,草食动物,其他植物非生物压力:大气污染,营养不足,温度极限,干旱,洪水杀虫剂Testingtheriskhypothesis 检验风险假设

-competition –竞争ReproductionandsurvivalcharactersaremeasuredinagronomicfieldtrialsComparisonofGMcropandnon-GM,near-isogeniclinesSeveralgeneticbackgroundsMultiplelocations–representrangeofproposedcultivationTwoyearsDataonefficacyandperformancearethemainobjectivesDataaresuitableforsafety遗传和生存特征可以在农业试验田中测得GM和非GM作物比较,相似-相同基因列几个遗传背景不同位置–代表不同耕作区域两年功能和表现上的数据是主要的目标数据对安全性来说是合适的Testingtheriskhypothesis 检验风险假设

-competition –竞争Bioticstress-toleranceparametersarealsomeasuredPestsanddiseaseWeedinfestation生物压力-耐受参数也要测试害虫和疾病杂草丛生Testingtheriskhypothesis 检验风险假设Willtheintendedeffectofthetransgeneincreaseweediness?Arevolunteerweedscontrolledbythepestprotectedagainst?AgriculturalequivalentofecologicalreleaseUsuallynospecialstudiesarecarriedouttoassessthis转基因的作用会增加杂草化么?自生杂草会因为害虫控制而被保护起来么?生态释放的农业平衡通常没有特殊的研究来执行这个评估Testingtheriskhypothesis 检验风险假设FieldtrialsaremonitoredforunusualfrequencyofvolunteersAlsoargumentsfromtimingandeffectsofpestattackIfpestsattackmatureplants,unlikelytoaffectvolunteeringIncreaseinyieldisunlikelytoleadtomorevolunteersifseedshavenodormancyandplantscannotover-winter在试验田监测异常的自生植物生长频率一些害虫攻击的时间和效果的争论如果害虫攻击成熟植株,那么就不会攻击自生植物如果种子没有休眠而且植物没有越冬,增加作物产量并不会导致自生植物的增加Testingtheriskhypothesis 检验风险假设

-competition –竞争IfexposureassessmentindicatescropxweedhybridsarepossibleCouldtestthecompetitiveabilityofGMandnon-GMhybridsAlotofworktogeneratehybridsNeedtoconductaseparatetrialfromtheagronomictrial如果暴露评估显示作物与杂草杂交是可能的那么就能够测定GM作物与非GM作物杂交后代的竞争能力产生杂交后代需要大量工作需要一个与农用田分离地试验田Testingtheriskhypothesis 检验风险假设

-competition –竞争RegardthehybridsasanadditionalgeneticbackgroundUseagronomicdatatotestfortransgenexgenotypeinteractionsIfnointeraction,cropdatapredicthybridbehaviour把杂交后代作为另外的遗传背景利用农业数据测试转入基因和原基因相互作用如果没有相互作用,作物数据可预测杂交行为

Testingtheriskhypothesis 检验风险假设

-competition –竞争MeasurementsofabioticstresstolerancearenotusuallymadeIndirectlyassessedbyperformanceinmultiplelocationsSometimesspecificstudiesarecarriedout并不需要经常监测非生物压力的耐受间接评估不同区域的表现有时候需要特殊的研究Testingtheriskhypothesis 检验风险假设

-competition –竞争E.g.,maizeover-winteringstudyforJapanGMandnon-GMseedsaregerminatedSeedlingsareplacedinagrowthchamberatca.0oCSurvivalismeasuredSimulatesconditionsrequiredforover-wintering例如,在日本的玉米越冬研究GM作物和非GM作物种子萌发幼苗置于0oC培养箱测试存活量模拟越冬条件Testingtheriskhypothesis 检验风险假设

-competition –竞争HerbicidetolerantcropsaretestedforefficacyObviouslyshowhighertolerancethanthenon-GMcropRiskofgreaterweedinessinfollowingcrop测试除草剂耐受作物的功效和非GM作物相比显示出很高的耐受能力在下列作物中杂草化风险较高Testingtheriskhypothesis 检验风险假设

-competition –竞争E.g.,glyphosatetolerantmaizeandsoybeanrotationsUseriskmanagementtoreduceriskCultivationtoremovevolunteersRotateherbicides,usetankmixesThesepracticeswillalsoreduceriskoftheevolutionoftoleranceinweeds(byselectionorgeneflow)例如,草苷膦耐受玉米和大豆风险管理的应用可降低风险适当耕作以清除自生植物轮换除草剂,使用罐子混合这些方法可以降低杂草耐受性进化的风险Testingtheriskhypothesis 检验风险假设

-competition -绿桥NullhypothesisisunchangedprobabilityofbeingagreenbridgeNochangeinpersistenceandabundanceafterharvestNochangeinsusceptibilitytopestsanddisease (otherthananyintendedincreaseinresistanceduetothetransgene)初始假设:形成绿桥的可能性是不变的在收割后在持续性和丰富性上没有变化对害虫和疾病的敏感性上没有变化 (与转基因产生的抗性增加不同)Testingtheriskhypothesis 检验风险假设

-competition -绿桥EstimatesoftheseparametersaremadeintheagronomicstudiesThereforedatarequirementsarethesameasforcompetition对这些参数的评估建立在农业研究的基础上因此必须的数据和竞争性研究是相同的Testingtheriskhypothesis 检验风险假设

-contamination -污染TherearetwosourcesofincreasedcontaminationIncreasedabundanceofthecontaminatingcropIncreasedhazardofthecontaminantIncreasedabundanceisassessedfromtheagronomicdataIncreasedhazardisassessedusingavarietyofstudiesCompositionstudyDevelopmentalstudyToxicitystudiesontheGMproteins有两种途径可能增加污染程度被污染作物的丰富性增加污染的危害性增加农业数据可以评估丰富性的增加多种研究可以评估危害性的增加成分分析发展研究GM蛋白的毒性研究Testingtheriskhypothesis 检验风险假设

-contamination -污染CompositionstudyComparescompositionofGMandnon-GMcropsNumerousparametersarecomparedNutrients,andanti-nutrientsandtoxinswhererelevant成分分析比较GM和非GM作物的成分需要比较许多参数相关的营养,非营养和毒性物质Testingtheriskhypothesis 检验风险假设

-contamination -污染OECDhaspublishedguidanceonwhichparameterstomeasureCropsincludeoilseedrape,soybean,maize,sugarbeet,potatoes,wheat,rice,cotton,barleyandalfalfaIndexofdocumentsisontheOECDwebsite:OECD出版了参数测量指导包括油菜,大豆,玉米,甜菜,土豆,小麦,水稻,棉花,大麦和苜蓿等作物文件索引在OECD的网页上:Testingtheriskhypothesis 检验风险假设

-contamination -污染Compositionalsoassessedindirectlyinlong-termfeedingstudiesAnimalsfedmaterialofGMplantComparedwithanimalsfednon-GMmaterial42-daybroilerchickenstudyGrowthanddevelopment90-dayratratstudyBiochemical,physiologicalandhistologicalmeasuresGrowthanddevelopment成分评估也可以在长期饲养研究中间接进行GM植物作为动物饲料与非GM植物作为饲料的动物相比42天布罗勒鸡研究生长与发育90天大鼠研究生化,生理和组织学方法测试生长与发育Testingtheriskhypothesis 检验风险假设

-contamination -污染DevelopmentalstudyDetermineswhere,whenandatwhatconcentrationtheGMproteinsareexpressedintheGMcropAllowspredictionoftheconcentrationsoftheGMproteinsthatmayoccurunderdifferentcontaminationscenariosEnvironmentalfateassessmentE.g.,ifproteinsareconfinedtograin,contaminationwillnotoccurifvolunteersareremovedbeforeflowering发育研究确定GM蛋白在作物中表达的时间位置和浓度可以预测发生在不同污染模式下的GM蛋白浓度环境归趋评估例如,如果蛋白质局限于谷物,那么如果在开花前清除自生植物的话,污染就不会发生Testingtheriskhypothesis 检验风险假设

-contamination -污染ToxicityoftheGMproteinistestedforhumansafetyassessmentAcuteratormousestudiesatveryhighdoseNoobservableeffectlevel(NOEL)isdeterminedUsuallyhighestdoseinthestudy人类健康评估测试GM蛋白的毒性极高浓度大鼠小鼠急性研究可以测得非可见作用水平(NOEL)在研究中通常使用最高浓度Testingtheriskhypothesis 检验风险假设

-contamination -污染Iftheproteinisdeemedsafeinafoodcrop,itshouldberegardedassafewhenthecropisacontaminantinadifferentcropInanon-foodcrop,comparetheNOELwiththepredictedlevelsinfoodcropsshouldcontaminationoccurAlsoconsiderexposureviahybridswithwildrelativesifrelevantEstimateofrisk=NOEL/predictedlevel如果在食用作物中蛋白被认为是安全的,那么当这种作物污染其他作物时,也是安全的在非食用作物中,比较NOEL与可能发生污染的食用作物预测水平还需考虑通过与野生物种杂交的后代的暴露性评估的风险值=NOEL/预测水平Summaryriskassessmentfor 农业环境中杂草化

weedinessinagriculturalhabitats 风险评估概述SafetyisdemonstratediftheriskhypothesisthattheGMcropisnomoreweedythanthenon-GMcropisnotfalsified:AgronomicfieldtrialscomparingGMandnon-GMcropNosignificantdifferenceinreproductionandsurvivalNotransgenexgenotypeinteraction(ifhybridsarepossible)Nosignificantdifferenceindiseaseandpestsusceptibility (otherthananyintendedincreaseinresistanceduetothetransgene)安全研究证明了GM作物不会比非GM作物产生更多的杂草这一风险假设:农业试验田比较GM作物和非GM作物在繁殖和生存率上没有显著差异没有转基因品种和原基因型品种相互作用(如果有可能出现杂交后代的话)在疾病和害虫敏感性上没有显著差异(由转基因引起的抗性没有明显增强)Summaryriskassessmentfor 农业环境中杂草化

weedinessinagriculturalhabitats 风险评估概述Abioticstress-tolerancestudycomparingGMandnon-GMcropNosignificantdifferenceinsurvival在非生物压力耐受性方面比较GM作物和非GM作物在存活率上没有显著差异Summaryriskassessmentfor 农业环境中杂草化

weedinessinagriculturalhabitats 风险评估概述CompositionstudycomparingGMandnon-GMcropNosignificantdifferenceincompositionFeedingstudiescomparingGMandnon-GMcropNosignificantdifferenceingrowth,survivaletc.在成分分析方面比较GM作物和非GM作物在成分上没有显著差异在饲料研究方面比较GM作物和非GM作物在生长和存活率等方面没有显著差异Summaryriskassessmentfor 农业环境中杂草化

weedinessinagriculturalhabitats 风险评估概述ToxicitystudyandenvironmentalfateassessmentNOEL>predictedworst-caseexposureviacontaminatedcropIftheseresultsareobtained,weedinessriskisminimal毒性研究和环境归趋评估NOEL>预测的通过污染作物暴露的最坏结果如果得到了这些结果,杂草化风险将达到最小化,杂草化风险是最小的Riskmanagementofweediness

杂草化的风险管理Herbicidetolerance:HTcropsmayposeincreasedweedinessriskUseagronomicpracticestominimiseriskRotateherbicides,mechanicallyremovevolunteersetc.除草剂耐受:HT作物可能会引起杂草化风险的增加应用农业实践来降低风险使用不同的除草剂,用机械清除自生植物Riskmanagementof 杂草化的风险管理

WeedinessPharmaceuticalproteins:IfNOEL>predictedexposureviacontaminatedcrop,theremaybeaneconomicrisk,eventhoughnosafetyriskRigorouscontrolofvolunteers药用蛋白:如果NOEL>预期的通过污染作物的暴露量,那么即使没有安全风险,也会有经济风险对自生植物严格控制Weedinessinnon-agricultural 在非农业环境中的

habitats–problemformulation 杂草化—问题表达Assessmentendpointsforweedinessinnon-agriculturalhabitatsPimentel(2001)reviewedharmfrominvasivealienplantsDisplacementofnativeplantsspeciesPhysicalchanges:reducedwatersupply,increasedfrequencyoffiresandchangednutrientcycles在非农业环境中的杂草化评估终点Pimentel(2001)评论外来入侵植物的危害性取代了本地植物物理上的改变:减少了水供给,增加了火灾发生的可能性,改变了营养循环Weedinessinnon-agricultural 在非农业环境中的

habitats–problemformulation 杂草化—问题表达Detrimentaleffectsonrecreation:aparticularproblemwithaquaticplantsthataffectfishing,boating,swimmingetc.Lossofyieldinsemi-naturalpasturesCostsofcontrolUsetheseassessmentendpointstoassessrisksofGMcrops对人们休闲娱乐的影响:特别的水生植物问题会影响人们钓鱼,划船,游泳等娱乐半自然牧场产量减少成本控制应用这些评估终点来评估GM作物的风险性Weedinessinnon-agricultural 在非农业环境中的

habitats–problemformulation 杂草化—概念模型HowmayaGMcropaffecttheseendpoints?BybeinganinvasiveplantitselfByhybridisingwithawildrelative,producinganinvasiveplantGM作物是怎样影响这些终点的?自身作为入侵植物与野生植物杂交,产生入侵物种Weedinessinnon-agricultural 在非农业环境中的

habitats–problemformulation 杂草化—概念模型CurrentagriculturalpracticeisdeemedtoposeacceptablerisktotheassessmentendpointsCropsarerarelyinvasiveofnaturalhabitatsCroptraitsaredisadvantageousinnaturalhabitatsNodormancy,lowdispersal,highlypalatableseedsetc.现在的农业实践被认为会产生适合的风险评估终点作物不会入侵自然环境作物的遗传特征不利于在自然环境中生存没有休眠期,低传播率,种子非常适合食用等特征Invasiveplantsarehorticulturalnotagricultural

入侵植物是园艺中的,并不是农业上的JapaneseknotweedRhododendronHimalayanbalsamGianthogweed日本书草喜马拉雅香胶树北美杜鹃巨豚草Weedinessinnon-agricultural 在非农业环境中的

habitats–problemformulation 杂草化—概念模型CurrentagriculturalpracticeisdeemedtoposeacceptablerisktotheassessmentendpointsThenullhypothesisisthatGMcropsandtheirhybridswithwildrelativesarenomoreinvasivethanthenon-GMequivalentsTesttheriskhypothesisofnogreaterweediness现在的农业实践被认为会产生适合的风险评估终点初始假设GM作物及其与野生亲缘杂交后代并不会比非GM作物有更强的侵略性测试少量杂草的风险假设Testingtheriskhypothesis 检验风险假设Theagronomicstudyisusefulforpredictingweedinessinnon-agriculturalhabitatsGMcropandhybridsareunlikelytobemoreinvasivethanthenon-GMcropifthefollowingappliesNosignificantdifferenceinreproductionandsurvivalNotransgenexgenotypeinteractionNosignificantdifferenceindiseaseandpestsusceptibility农艺研究对于预测在非农业环境中的杂草化是有效的如果出现以下情况表明GM作物及其杂交后代不会比非GM作物表现出更强的入侵性在繁殖和生存率上没有显著差异没有转基因和原基因相互影响在疾病和害虫敏感性上没有显著差异Testingtheriskhypothesis 检验风险假设Tocompletetheriskassessmentneedtoconsiderwhethertheintendedeffectofthetransgenewillleadtoecologicalrelease为了完成风险评估,我们需要考虑是否转基因会导致生态释放Predictingecologicalrelease 预测生态释放Forcropsthatrarelyformferalpopulations,ecologicalreleasecanbeassessedwithoutspecificstudiesLackofinvasivenessislikelytobeduetorestricteddispersal,lackofdormancyandinabilitytoestablishonundisturbedground对于很少产生野化种群的作物来说,不用特殊的研究也可以测得生态释放入侵的减少可能是由于种子传播受到限制,缺乏休眠期,和没有形成无干扰区的原因Predictingecologicalrelease 预测生态释放IncreasesinpestanddiseaseresistancearehighlyunlikelytochangeabilitytodisperseandpersistIfnoincreaseinreproductionorsurvivaltraitsintheagronomictrial,riskofecologicalreleaseisminimal对害虫和疾病抗性的增强很可能会改变种子传播和持续的能力如果在农业试验中繁殖和生存的特征没有增强,生态释放的风险是最小的Predictingecologicalrelease 预测生态释放Forcropsthatfrequentlyformferal 对于经常会产生野化种群的作物来,populations,mayneedtoassess 说需要用特殊的研究方法来评估生ecologicalreleasewithspecificstudies 态释放Couldsimulateeffectoftransgene 可以模拟转基因的效果E.g.,testforecologicalreleaseofinsect 例如,抗虫油菜生态释放测试resistantoilseedrapeSowseedintohabitat将种子播种到种子可以自然散布的环境中whereseedmaydispersenaturally 保护种子不被害虫攻击(如施用杀虫剂)Protectsomereplicatesfrominsectattack比较新补充的植物和未受保护的植物(e.g.,insecticide) 如果没有差异,生态释放风险很低ComparerecruitmentofplantswiththatinunprotectedreplicatesIfnodifference,riskofecologicalreleaseislowPredictingecological 预测杂交后代的

releaseinhybrids 生态释放IdentifyspeciesandlocationswherehybridslikelyExposureassessmentdescribedinprevioustalkCouldcarryoutstudiessimulatingtheeffectofthetransgeneMaynotbepossibleinnaturalpopulationsApplicationofpesticidesmaybeprohibitedMaynotbepossibletoexcludepestsordiseaseeffectively确定杂交后代的种类和可能出现的区域在前面谈到了暴露评估可以模拟转基因的作用来进行研究可能对于自然种群来说不可能杀虫剂的施用是被禁止的不可能排除害虫或疾病的影响Predictingecological 预测杂交后代的

releaseinhybrids 生态释放AlternativeapproachesarepossibleIdentifyphenomenathatmusthappenforecologicalreleaseTestforthesephenomenaundercontrolledconditionsExampleusingturnipmosaicvirusresistanceinoilseedrape有其他可供选择的方法确定生态释放必定发生的现象在一定条件下测定这些现象例如在油菜中使用芜菁花叶病毒抗性基因Speciesstudied 物种研究Brassicanapus–oilseedrapeB.oleracea–wildcabbageB.rapa–wildturnipB.nigra–blackmustard油菜野生甘蓝黑芥子野生芜菁Tieredtestsforhazard 危害性的分级测试For“ecologicalrelease”tooccurTheplantmustbesusceptibletothevirusThevirusmustreduceplantsurvivalorreproductionTheplantmustbecomeinfectedinthefieldPopulationdynamicsmustbedensity-independentCandesignsimpletestsforexistenceofthesephenomena生态释放发生植物必须对病毒敏感病毒必须要减少植物的存活率或繁殖能力植物在田地内必须被感染种群动态必须是密度依赖型可以为了检验这些现象的存在而设计简单的测试Tieredtestsforhazard 危害性的分级测试TierI:inoculateplantwithvirusinthelabIfimmune,nohazard,stoptesting;notimmune,tierII阶段I:在实验室中将病毒输入植物体如果有免疫,没有危害性,停止测试;没有免疫,进入阶段IITieredtestsforhazard 危害性的分级测试TierII:measuresurvivalandreproductionofinfectedplantsIfunchanged,nohazard,stoptesting;iflower,tierIII阶段II:测试被感染植物的存活率和繁殖能力如果没有变化,没有危害性,停止测试;如果降低,进入阶段IIITieredtestsforhazard 危害性的分级测试TierIII:measureinfectioninthefieldIfnoinfection,nohazard,stoptesting;ifinfection,tierIV阶段III:在田间监测感染如果没有感染,没有危害性,停止测试;如果感染,进入阶段IVTieredtestsforhazar