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1、Universitycode:10223Classifiedcode:S513Graduatenumber:XS1211041Confidentialdegree:PublicHeilongjiangBayiAgriculturalUniversityMasterDissertationScreeningofDrought-tolerantMaizeVarietiesandWaterStressandRehydrationResponsesofTheirSeedlingsPostgraduate:LiuChengSupervisor:ProfessorXuJing-YuMajor:
2、CropCultivationandGeoponicsResearchdirection:PlantStressPhysiologyCollege:CollegeofAgronomyDaqingChinaJune,2015摘要本試驗(yàn)采用聚乙二醇(PEG-6000)通過(guò)滲透脅迫人工模擬干旱條件對(duì)22個(gè)玉米雜交種進(jìn)行了萌芽期抗旱性綜合評(píng)價(jià),獲得抗旱性強(qiáng),抗旱性中等以及抗旱性弱品種。選取抗旱性強(qiáng)的3個(gè)品種和抗旱性弱的3個(gè)品種進(jìn)行苗期反復(fù)干旱存活率鑒定,最終篩選出抗旱性強(qiáng)和抗旱性弱的品種各一種。以篩選出的玉米品種為試驗(yàn)材料,采用聚乙二醇(PEG-6000)模擬水分脅迫方法,研究了水分脅迫及
3、復(fù)水對(duì)不同抗性玉米苗期相關(guān)生理特性的影響。主要的結(jié)果如下:1.相對(duì)發(fā)芽勢(shì)、相對(duì)發(fā)芽率、相對(duì)貯藏物質(zhì)運(yùn)轉(zhuǎn)率、相對(duì)胚根長(zhǎng)、相對(duì)胚根干重和種子萌發(fā)抗旱指數(shù)顯著性相關(guān),這幾個(gè)指標(biāo)可以作為玉米萌芽期抗旱性鑒定指標(biāo)。通過(guò)五級(jí)評(píng)分法綜合評(píng)價(jià)鄭單958、慶單6、海禾558和信玉9綜合評(píng)價(jià)值最大,在22份玉米種質(zhì)材料中抗旱性綜合評(píng)價(jià)最優(yōu),屬于抗旱性最強(qiáng)的品種;宏育319、慶單11、龍單46和吉單522四個(gè)品種為抗旱性較差的種質(zhì)材料;其他品種為抗旱性中等品種。2.相關(guān)分析表明玉米苗期反復(fù)干旱存活率和種子萌發(fā)抗旱指數(shù)密切相關(guān),綜合分析這兩個(gè)不同發(fā)育階段的抗旱指標(biāo),確定鄭單958為抗旱性最強(qiáng)品種,吉單52
4、2為抗旱性最弱品種。3.在水分脅迫及復(fù)水條件下,鄭單958和吉單522的光合參數(shù)、葉綠素含量和相對(duì)含水量(RWC)均呈先下降后上升趨勢(shì),除吉單522的Ci和葉綠素含量分別在脅迫后2d和復(fù)水后1d到達(dá)最低值外,其余各指標(biāo)均在脅迫后3d達(dá)到最低值,且吉單522下降幅度更大,復(fù)水后恢復(fù)緩慢,但是在脅迫過(guò)程中鄭單958和吉單522的RWC品種間各處理差異不顯著。相對(duì)電導(dǎo)率、MDA含量、抗氧化酶活性、滲透調(diào)節(jié)物質(zhì)含量在水分脅迫及復(fù)水條件下呈先升高后下降趨勢(shì),并在脅迫后3d達(dá)到最大值,其中吉單522的相對(duì)電導(dǎo)率和MDA含量上升幅度大于鄭單958,其余各指標(biāo)鄭單958增加幅度高于吉單522。抗旱
5、性強(qiáng)的鄭單958在水分脅迫時(shí)受到的傷害程度要小于抗旱性弱的吉單522,且在復(fù)水過(guò)程中鄭單958具有良好的生理補(bǔ)償效應(yīng)。關(guān)鍵詞:玉米,萌芽期,苗期,抗旱,生理特性IAbstractInthisstudy,polyethyleneglycol(PEG-6000)wasusedtosimulateosmoticstressconditionandcomprehensivedroughtresistanceevaluationwasmadeontheseedlingsof22maizehybrids,thenthetestedmaizevarietieswereclassifiedasst
6、rongdrought-tolerant,moderatedrought-tolerant,anddrought-sensitive.Repeateddehydration/rehydrationsurvivaltestswereconductedontheseedlingsofthreedrought-tolerantvarietiesandthreedrought-sensitivevarieties,andfinalyscreenedouttwomaizevarietiesasthetopdrought-resistanceanddrought-sensitiveones,r
7、espectively.Theselecteddrought-tolerantanddrought-sensitivevarietieswereusedasstudymaterials,andthepolyethyleneglycol(PEG-6000)wasusedtosimulatewaterstressconditiontoinvestigatetheimpactsofwaterstressandsubsequentrehydrationonphysiologi