读书报告6_BT棉花对根际土壤酶活性和土壤微生物的影响.ppt

effectofbtcottononenzymesactivityandmicroorganismsinrhizosphere bt棉花对根际土壤酶活性和土壤微生物的影响ushamina anitachaudhary anjukamrajournalofagriculturalscience 2011 outline 1introduction2materialsandmethods2 1fieldpreparationandculturalpractices2 2soilsampling2 3dehydrogenase alkalinephosphatase urease nitratereductaseactivity2 4nematodes 线虫 collembola 弹尾目 andants3resultsanddiscussion 1introduction inindianinemillionhectares mha areawasundercottoncultivationanditisonefourthoftheglobalareaundercottoncultivation bacillusthuringiensis bt cottonwasintroducedinindiain2002 followingitssuccess duringthelast7years 2002 2008 theareaunderbtcottonhasincreasedby7 6mhafrom0 029mha 在印度棉花的种植面积达九百万公顷 占全球棉花种植面积的四分之一 印度在2002年引进苏云金芽孢杆菌 bt 棉 在过去的7年 2002 2008 种植面积从29万公顷增加到760万公顷 james 2008 althoughtherearediversebenefitsofbtcotton publicconcernalsoexistbecausebothinvitroandinvivostudiesonbtcottonshowedthatbttoxinproducedinleaves stemsandrootsofbtcottonplantsisintroducedinsoil 通过对bt棉体外和体内的研究表明 bt棉花在叶片 茎和根部产生bt毒素并释放到土壤中 bt toxinfrombtcottonplantsintroducedintothesoilthroughtwopathways i e biomassincorporationandrootexudates bt毒素通过两条途径从bt棉花植物体释放到土壤 例如 生物量合成和根分泌物 saxenaandstotzky2001minaetal 2008liu2009 bttoxinreleasedinsoilgetadsorbedorboundonclayparticles humiccomponents ororganicmineralcomplexesandthenbeprotectedagainstdegradationbysoilmicroorganisms tappetal 1995 释放到土壤中的bt毒素被粘土颗粒 腐植酸或有机矿物复合体吸附或束缚 防止其被土壤微生物降解 continuousgrowingofbtcropsonsamelocationenhanceitsexistinglevelstoacertainconcentrationthatmightaffectthecompositionandactivityofsoilmicrobialcommunities doneganandseidler1999 stotzky2004 weietal 2006 andthesoilbiochemical 在同一地点连续种植bt作物其浓度就会增加 当达到某一定浓度时就有可能影响土壤微生物群落的组分和活动以及土壤的生物化学特性 somestudiesindicatethatbtcottonhasnonegativeeffectsonsoilfloraandfaunaandmayevenhavebeneficialeffects saxenaandstotzky2001 sarkaretal 2009 whilesomehavereportedadverseeffects cuiandxia2000 tanetal 2002 一些研究表明bt棉花不会对土壤植物和动物造成负面影响 甚至可能产生有益作用 同时也有一些不良影响的报导 therefore wehavestudiedtheeffectsofbtcotton var mech162 onactivityofsoilenzymesandmicroorganismsatindianagricultureresearchinstitutefarms newdelhi india anevaluationoftheecologicalrisksofbtcottonwasmadeonthebasisofchangesinenzymesactivityandnumberofnematodes collembolaandantsascomparedtononbtcottonintherespectiverhizospheres 因此 我们研究印度农业研究所农场 新德里 印度的bt棉花对土壤酶活性和土壤微生物的影响 针对bt棉花和非bt棉花的植物根际酶活性变化量和线虫 弹尾目昆虫和蚂蚁的数量变化进行生态风险评价 2materialsandmethods 2 1fieldpreparationandculturalpracticesfieldexperimentswereconductedattheresearchfarmoftheindianagriculturalresearchinstitute newdelhi india 田间试验布置在印度的农业研究所的农场 新德里 印度 experimentswereconductedforthreeconsecutiveyears 2004 2005and2006 inalargeplot 450m2 wherebtandnonbtcottonhadeverplanted thisplotwassubdividedinto24subplots 3 75mx5m 在常年种植bt和非bt棉花的土壤上进行了三年 04 05 06年 的连续试验 总面积为450m2 分为24个小区 3 75m 5m treated seedsofnonbtcottonandbtcotton distancebetweenrowtorowandplanttoplant 60cmand45cmrespectively bufferzone a6malsoestablishedsurroundingthemainplot recommendeddoseofnpkfertilizer 660gnasurea 250gpasssp 350gkasmopappliedtime phosphorusandpotashwasappliedattimeofsowing whereasnitrogenwasgiveninsplitdose halfatthetimeofthinningandotherhalfatfloweringstage irrigatetime firstirrigationtocottonwasgivenoneweekaftersowingandsubsequentirrigationsatanintervaloftwoweeks harvesttime inthefirstweekofdecemberinallthethreeyears 2 2soilsamplingsoilsamplesfromtherhizosphereofbtcottonandnonbtcottonplantswerecollectedatregularinterval 30daysinterval coincidingwithdifferentgrowthstageofcotton sincethedateofsowingstillharvestinginallthethreeyears bt棉花和非bt棉花根际土壤样品在整个三年内都是自播种之日起有规律间隔采集的 30天间隔 正好与棉花不同生育期相符合 2 3dehydrogenase alkalinephosphatase urease nitratereductaseactivity measuredusinguv visspectrophotometer uv 1201 shimadzucorp japan 紫外可见光谱分光光度计 2 4nematodes 线虫 collembola 弹尾目 andants nematodes 从水里提取后用立体解剖显微镜计数 collembolaandants 用干漏斗提取后用立体解剖显微镜计数 3 resultsanddiscussion onaveragedehydrogenase alkalinephosphatase nitratereductaaseandureaseenzymesactivitywashighinbtcottonrhizosphereascomparedtononbtrhizosphere oncomparingenzymesactivityfortheinteractionofcropvariety btandnonbttrait overamonthlyperiod activityofdehydrogenaseandureaseenzymeswerenonsignificantandactivityofphosphatesandnitratereductaseenzymesweresignificant 总体来讲 与非bt棉花根际土壤相比 bt棉花根际土壤的脱氢酶 碱性磷酸酶 硝酸还原酶和脲酶活性较高 在比较作物品种 bt和非bt特质 相互作用的酶活性超过一个月后 脱氢酶和脲酶活性都没有较大变化 而磷酸酶和硝酸还原酶有显著的变化 figure1 variationsinactivityof a dehydrogenase b alkalinephosphatase c nitratereductaseand d ureaseenzymesatdifferentgrowthstagesinbtandnonbtcottonrhizosphere exceptdehydrogenaseenzyme differencesinactivityofalkalinephosphatase nitratereductaseandureaseenzymesbetweenbtandnonbtplantsrhizospherewerestatisticallynonsignificant overthecropgrowthperiod of150days theactivityofphosphatase nitratereductaaseandureaseenzymesactivitywashighintherhizosphereatearlyvegetativeandfloweringstage whereasactivityofdehydrogenaseenzymewashighatbollformationstage activityofallthefourenzymesdeclinedatcropharvestingstage 除了脱氢酶以外 碱性磷酸酶 硝酸还原酶和脲酶活性在bt和非bt棉花根际之间的差异不显著 作物生长期间 150天 磷酸酶 硝酸还原酶和脲酶活性在早期营养生长和开花阶段较高 脱氢酶活性则在铃形成阶段较高 四种酶在作物收获阶段活性都会降低 studydemonstratedenhancedphosphatase nitratereductaseandureaseactivityintherhizosphereofbtcotton butmostofthetimedifferencesinenzymesactivitybetweenbtandnon btcottonrhizospherewerenonsignificant 有研究证实bt棉花根际土壤的磷酸酶 硝酸还原酶和脲酶活性增强 但大部分时间里 bt棉和非bt棉根际酶活性之间的差异并不显著 inpresentstudyvariationindehydrogenaseenzymeactivitybetweenbtandnon btcottonrhizospherewassignificant p 0 05 andactivityofdehydrogenaseenzymewashighinbtcottonrhizosphere 目前的研究表明 非bt棉和bt棉花之间根际土壤脱氢酶活性变化是显著的 p 0 05 bt棉花根际土壤的脱氢酶酶活性高于非bt棉 theenhancementinactivityofdehydrogenaseinbtcottonrhizospheremaybeduetoalteredcompositionofitsrootexudates rootexudateshaveaprofoundqualitativeandquantitativeeffectontherhizosphericmicroorganisms bt棉花根际土壤的脱氢酶活性增强可能是由于其根际分泌物成分的变化 根际分泌物对于微生物的组成起着重大的定性和定量的作用 schenck 1976 table4 numberofnematodes collembola antsinbtandnonbtcottonrhizosphere significantdifferences p 0 05 wereobservedinthenumberofnematodes collembolaandantsbetweenthebtandnonbtcottonrhizosphere table4 numberofnematodes collembolaandantsweremoreinbtplantsrhizosphereascomparedtononbtplantsrhizospere numberofnematodes collembolaandantswerehighestinbtandnonbtcottonrhizosphereatfloweringstage 研究发现bt棉花和非bt棉花根际的线虫 弹尾目昆虫及蚂蚁数量 表4 有显著差异 p 0 05 与非bt棉花相比 bt棉花根际的线虫 弹尾目昆虫和蚂蚁数量更多 bt和非bt棉花这三者的数量均在开花阶段达到最高 temporalvariationinnumberofnematodes collembolaandantsisacomplicatingfactorinimpactassessmentofbttransgeniccotton becausetheimpactofthegeneticmodificationmaybetransientandminorcomparedtothevariationcausedbysoilconditionandgrowthstageofcrop 线虫 弹尾目昆虫和蚂蚁数量的时间变化在bt转基因棉影响评价中是一个复杂因素 因为与土壤条件和作物的生长阶段带来的变化相比 基因转变的影响可能是短暂的 微小的 howevertheseresultsshouldbeconsideredaspreliminary asnematodes collembolaandantsaremobileandslightchangeintheirnicheenvironmentmayaffecttheirmobility 然而 这些结果应该认为