【作者】 马殿荣；

【导师】 陈温福；

【作者基本信息】 沈阳农业大学 ， 作物栽培学与耕作学， 2009， 博士

【摘要】 杂草稻是指在人工栽培稻田中或稻田周边耕地里，通过种子落粒、休眠和对环境极强的适应能力而自然繁衍，对稻田生态系统产生不利影响的稻属植株或群体。杂草稻目前已成为世界稻作生产中一种严重的杂草类型。本文于2003年～2008年对中国辽宁稻区的杂草稻进行了初步考察、收集和整理，对其植物学特性进行了研究；利用收集到的部分杂草稻、栽培稻和野生稻，采用SSR分子标记方法对杂草稻的遗传多样性、群体分化和起源进行了研究；并研究了杂草稻对稻田生态系统的影响、杂草稻田间自生出苗动力以及杂草稻的耐寒和耐盐特性。主要结果如下：1、杂草稻广泛分布在辽宁水稻主产区，且杂草稻的发生程度与当地的生产水平和栽培管理水平密切相关。杂草稻作为一种特殊类型的稻田杂草在辽宁乃至东北稻区发生越来越普遍，其正从稻田中逐渐向池埂、沟渠及周边地块扩散。杂草稻通过种子调运、种子销售等可进行跨地区间的大范围远距离扩散；通过农户自己留种和串换种子、农事活动等近距离扩散。辽宁省杂草稻多发现于常规稻中，在多年种植杂交稻的地块中较少发现杂草稻分布。杂草稻在常规稻区和杂交稻区发生程度不同的原因很可能与其种子生产有关。同一地块中经常有多种杂草稻类型发生；即使在同一地区同一地块中，不同年季间杂草稻发生的类型及程度也有很大的变化。田间早期自生的杂草稻生长发育动态与栽培稻相似，以不同比例分布在行间或行内；田间自生杂草稻表现为持续萌发的特性，甚至持续到生育后期，发生较晚的杂草稻由于受栽培稻的影响多具较少的分蘖，但多数能正常成熟落粒。2、植物学特性研究表明，辽宁杂草稻变异类型丰富，一般植株较高，分蘖力较强。不同地区杂草稻的株高、分蘖能力、单株穗数及芒长等生物学特性变异较大；杂草稻多具有红色、褐色或白色长芒，多具有红色或褐色的果皮，也有部分杂草稻的果皮为无色；辽宁杂草稻籼粳分化不明显，大部分为介于籼粳之间的中间类型，在亚种分类上大部分属粳型和偏粳型，只有少数为偏籼型。3、SSR分子标记研究结果表明，辽宁杂草稻具有较高的遗传多样性，30对SSR引物有26对在杂草稻中扩增出多态产物，多态性位点所占的比例（P）为86．67％，Shannon多样性指数平均为0．762。辽宁杂草稻等位基因观察值（N_a）平均为3．923，等位基因有效值（N_e）平均为2．110，群体内基因多样性（H_s）平均为0．067，总的基因多样性（H_T）平均为0．425，群体间基因多样性(D_sT)平均为0．358。SSR不同位点的变异来源有较大差别，PM437、RM204的变异全部来自群体内，基因分化系数(G_ST)为0；RM341、RM486、RM169、RM234、RM242的变异全部来自群体间，基因分化系数(G_ST)均为1；其他位点的变异也主要来自于群体间，基因分化系数(G_ST)均在0．5以上，且有很多位点的基因分化系数（GST）在0．8以上，甚至接近于1。杂草稻群体的基因分化系数(G_ST)平均为0．843，这表明杂草稻群体的变异大部分来自群体间，杂草稻群体结构变异较大。不同群体之间的遗传关系非常复杂，各群体遗传距离的远近与地理分布关系不大，地理分布很远的海城与凡河、老河湾、杨威楼、开原稻区的杂草稻，其遗传关系却非常近，遗传距离仅为0．0666、0．0923、0．0519、0．0814。地理分布很近的新民和法库，其杂草稻群体的遗传关系却较远，遗传距离达到了0．3314。在30个不同SSR位点上，绝大多数杂草稻具有与不同粳稻相同的等位基因。在杂草稻起源与演化中，伴随着少量籼稻基因和野生稻基因的渗入。籼稻基因的渗入很可能与长期的籼粳稻杂交育种有关，而野生稻基因的渗入途径及时间还有待于深入研究。中国辽宁杂草稻与当地的粳型栽培稻血缘关系很近，与籼稻和野生稻的遗传关系较远，很可能起源于当地栽培稻品种，杂草稻很可能是栽培稻种个体间自然杂交、回复突变等产生的退化类型，辽宁杂草稻的发生与育种手段和栽培措施的弱化有关。4、在每平方米分别有9株、7株、5株、3株、1株杂草稻时，栽培稻产量分别减少44．65％、36．89％、24．67％、17．58％、1．37％。当每平方米杂草稻密度超过3株时，杂草稻对栽培稻产量产生极显著影响，而且随着杂草稻密度的增大，栽培稻减产加剧；栽培稻单株穗数、每穗粒数、结实率和千粒重随杂草稻密度的增大均有显著或极显著降低的趋势，栽培稻产量降低的原因是由单株穗数、每穗粒数、结实率和千粒重共同降低所致。杂草稻的竞争对栽培稻群体株高、体叶片性状、光合作用及蒸腾速率影响不大，对栽培稻群体中、下部的光照影响显著，明显降低了群体中、下部的光照强度。群体内杂草稻密度较大时（9株／m²、7株／m²），群体日平均气温、白天平均气温、夜间平均气温、日最高气温和日最低气温都与对照（不插杂草稻的处理）有极显著差异。日平均气温、白天平均气温、夜间平均气温、日最高气温和日最低气温均与杂草稻的密度呈负相关，其中日平均气温、白天平均气温和日最高气温与杂草稻密度均达到极显著水平。随着杂草稻密度的增大，栽培稻群体相对湿度有增大的趋势，群体日平均湿度、白天平均湿度和日最高湿度都与杂草稻的密度呈显著正相关。5、在辽宁发现的部分杂草稻具有较强的中胚轴伸长特性和芽鞘节间伸长特性。在播种深度较浅时，杂草稻依赖于中胚轴的伸长顶土发芽；当覆土较深时，杂草稻中胚轴伸长特性更加明显，伸长长度加大，同时杂草稻的芽鞘节间也明显伸长，中胚轴和芽鞘节间的共同伸长为深覆土条件下杂草稻的出苗提供了动力基础。黑暗条件下参试的辽宁省杂草稻材料和栽培稻材料的幼苗中胚轴均有不同程度的伸长，杂草稻的中胚轴平均伸长长度（1．03cm）＞籼稻（0．71cm）＞粳稻（0．43 cm）。以中胚轴长度为指标的聚类分析结果显示，参试的材料可以分为长、中、短中胚轴三种类型。大部分栽培稻（除籼稻IR70）中胚轴伸长能力较差，属于短中胚轴类型。杂草稻中胚轴伸长能力较强，57％的杂草稻材料属于中、长中胚轴类型。根据聚类分析结果，筛选出7个长中胚轴杂草稻材料，分别为WR04-6、WR04-8、WR04-32-2、WR04-7、WR04-24、WR05-6和WR04-46。研究还发现，黑暗条件下培养前三天，杂草稻中胚轴伸长极短，萌发到第4 d到第5 d时伸长最快，到第7 d后中胚轴伸长逐渐停止。杂草稻中胚轴伸长较明显，伸长的速度也较快，栽培稻品种辽粳294中胚轴伸长速度较慢且较短。杂草稻中胚轴伸长过程中，籽粒a-淀粉酶、β-淀粉酶活性逐渐增强，可溶性糖含量逐渐升高，这为中胚轴伸长提供了能量基础；细胞壁离子型结合POD、蛋白含量抑制杂草稻中胚轴的伸长，共价结合型蛋白与中胚轴伸长无明显的联系。内源生长激素对杂草稻中胚轴伸长有较大影响。内源对GA₃、内源IAA、内源CTK对中胚轴的伸长生长起促进作用，而内源ABA则抑制中胚轴的伸长生长。.采用经典数量遗传学方法分析了长中胚轴杂草稻与短中胚轴栽培稻的杂交后代F₁和F₂的表型值，结合双亲表型值。研究初步表明，控制杂草稻WR04-6（P₂）中胚轴伸长的性状为2对加性-显性-上位性主基因+多基因混合遗传，初步认为杂草稻WR04-6中胚轴伸长长度由两对隐性主基因控制，同时受微效多基因的影响。利用长中胚轴杂草稻与短中胚轴栽培稻杂交衍生的F₂群体，采用SSR分子标记的方法对控制杂草稻中胚轴伸长特性的数量性状位点（QTLs）进行了初步检测。由于多种原因未能检测到控制杂草稻中胚轴伸长特性的数量性状位点（QTLs）。6、对辽宁地区的杂草稻幼苗期耐寒性进行鉴定结果表明，大多数杂草稻材料的苗期耐寒性强于对照品种秋光。在苗期低温条件下，供试材料随胁迫强度增强，酶系统活性和渗透调节物质含量先升高后降低，幼苗期耐寒性较强的杂草稻WR03-45，WR04-35比对照栽培稻秋光具有较强的清除自由基的酶系统活性，同时其可溶性糖和游离脯氨酸含量也保持了较高水平，而MDA含量相对较低，表明WRO3-45，WRO4-35具有一定的抵抗低温能力。更多还原

【Abstract】 Weedy rice refers to rice plants or populations of O.sativa f.spontanea growing in paddyor other fields as a weedy type,which have an serious effect on rice ecosystem throughreproducing themselves by seed shattering,dormancy,and strong competition ablity againstnatural conditions.Weedy rice is a serious weed in rice-transplanting areas in LiaoningProvince of north China now.Field surveys conducted to define the distribution region ofweedy rice and weedy rice resources were collected from the main rice-growing regions ofLiaoning Province in the autumns 2003-2005.A research has been done at the Rice ResearchInstitute of Shenyang Agricultural University in 2006-2008 to determine the phenotypicdiversity,genetic dversity and population differentiation,origin,the effect on rice paddy ecosystem,germination dynamics of weedy rice.The main results are summarized as follows:1、Weedy rice is easily found in many rice growing areas in Liaoning province inNorth-east China.The distribution of weedy rice among farms is likely to be accomplished byseveral means,including culture,farming,machinery.Weedy rice spread quickly from paddy toother fields as a weedy type in North-east China now.The present paper indicated that weedyrice diffused widely by seed transportation and spread nearly by farming.The results alsoshowed that weedy rice distribute widely in conventional cultivars and was not found inhybrid rice in main rice growing regions of Liaoning.2、A research has been done at the Rice Research Institute of Shenyang AgriculturalUniversity in 2006 to determine the phenotypic diversity of weedy rice.Data were collectedon various morphological variables of weedy rice.The paper indicated considerablemorphological variation among weedy rice collections from Liaoning.This study revealed thatthere is great phenotypic diversity in weedy rice accessions from different regions based onplant height,tillering capacity,panicles,presence of own and other biological traits.Most ofweedy rice have white or red long awn,red pericarp.The weedy rice appears to bedifferentiated into japonica and indica unconspicuously based on six characteristics ofCheng’s index.Most of weedy rice was classified into japonica andjaponica-cline types,whileminority was classified into indica-cline.3、Samples of weedy rice have been analysed with 30 SSR makers in comparison to arepresentative to collection of cultivated rice varieties and wild O.rufipongon.The percent ofpolymorphic loci was 86.67% and Shannon’ s information index was 0.762,these resultsshowed that the genetic diversity of Liaoning weedy rice was very high.The results alsoshowed that the genetic differentiation of Liaoning weedy rice was very complex based onanalysis with 30 SSR makers.The G发_STvalues was 0.843 suggesting that the main genetic variation of weedy rice resided among populations.Weedy rice populations of Liaoning wereclosely related to japonica cultivated rice varieties but distantly related to wild O.rufipongonand indica cultivated rice varieties.Weedy rice from Liaoning most probably originated fromjaponica cultivated rice varieties planted in Liaoning by natural hybridization and naturalmutation.The weakness of breeding and cultivation methods promoted origin of Liaoningweedy rice.4、Field experiments were conduct to determine effects of season-long interference ofweedy rice densities of 1,3,5,7,and 9 plants/m² on a rice variety Shennong265.Cultivated ricegrain yield were reduced by 44.65%,36.89%,24.67%,17.58%,and 1.37% when weedy ricedensities were 9,7,5,3and 1 plants/m²,respectively.The competition of weedy rice to cultivatedconsiderably reduced rice grain yield when weedy rice densities were 9,7,5 and 3 plants/m²,respectively.This interference reduced panicle number per plant,number of grains per panicle,seed setting rate,and 1000-garins weight.Grain yield reductions were due to decreases inpanicle number per plant,in number of grains per panicle,in seed setting rate,and in1000-garins weight.The competion of weedy rice have no significant effect on plant height,leaf length andwidth,net photosynthesis rate and transpiration rate of cultivated rice.Daily meantemperature,daytime mean temperature,night mean temperature,daily maximum temperatureand daily minimum temperature of treatment of transplanting high density of weedy ricesignificant more than CK.Daily mean humidity,daytime mean humidity,night meanhumidity,daily maximum humidity and daily minimum humidity of treatment oftransplanting high density of weedy rice significant more than CK.5、We conducted pot experiment to study the seedling emergence of weedy rice inNorthern China at different planting depths.It shows that the elongation of mesocotyl andinternode of coleptile plays important roles in the seedling emergence of China weedy rice.Weedy rice elongated the mesocotyl at 3 cm planting depth and elongated the mesocotyl andcoleptile at 5 cm planting depths.The germination dynamics of weedy rice at deep plantingdepth depending on the elongation of mesocotyl and the elongation of coleptile.Weedy rice materials collected in rice field and 16 cultivated rice are used to study themesocotyl elongation characteristics under illumination condition.The results indicate thatweedy rice’s mesocotyl elongation characteristics are better than cultivated rice’s.Amongcultivated rice,indica rice’s mesocotyl elongation characteristics are better than japonicarice’s.Although weedy rice’s mesocotyll elongation characteristics are better,but there isgreat difference between weedy rice materials.The systematical cluster analysis of mesocotylelongation characteristics reveal that the 109 materials in experiment may divide into longmesocotyl type,short mesocotyl type and intermediate type.57% weedy rice materials belongto long mesocotyl type and intermediate type.Long mesocotyl weedy rice germplasmWR04-6, WR04-7,WR04-8,WR04-24-white,WR04-43,WR04-46 and WR05-6 are screened.Study on dynamic analysis of mesocotyl elongation showed that the activity ofα-amylase andβ-amylase in seed increased,the content of soluble sugar added and the solubleprotein decreased,which provided powerful growth dynamics for the elongation of mesocotyl.Study on the cell wall-bound enzyme activity showed,The ionically bound cell wall proteincontent,POD activity,IAA oxidant enzyme were higher than which were covalently boundcell wall.The ionically bound cell wall protein content,POD activity inhibited the elongationof mesocotyl.Call wall-bound IAA oxidant enzyme to the elongation of mesocotyl was notobvious.The changes of covalently bound cell wall protein content,enzyme activity werecomplex and the relations with the elongation of mesocotyl were not obvious.Study ofinternal hormone indicated,IAA did not have evident action on mesocotyl elongation,GApromoted the elongation of mesocotyl,ABA inhibited it.The results of genetic analysis indicate that the mesocotyl elongation is controlled bytwo additive-dominance-epistatic major genes and polygenes.6、The cold tolerance at seedling period for 100 weedy rice and Akihikari wasindentified.The results showed that much weedy rice has stronger cold tolerance thanAkihikari.The results indicated that protective enzyme activities and soluble organicosmoticum were increased at first and then decreased,lipid peroxidation content was lastingincreased under low temperature treatment at seedling stage.WR03-45 and WR04-35 hadhigher soluble sugar content and soluble proline content,stronger protective enzymeactivities,and lower MDA content.That indicated WR03-45 and WR04-35 had strong coldtolerance at seedling stage.更多还原