玉米和狗尾草光周期敏感性的比较研究

光周期是影响植物生长发育的关键因素之一。玉米和狗尾草都是短日照禾本科植物,且都具有光周期敏感性。对玉米和狗尾草的光周期敏感性比较研究,探索易于研究的狗尾草光周期敏感性机理,借以解析玉米光周期敏感性反应的机理。以玉米自交系CML288、黄早四和狗尾草自交系A10为材料,研究在长日照、短日照和在不同生育时期长短日照相互挪移处理下的光周期反应。结果表明,玉米和狗尾草在长日照条件下都表现出营养生长旺盛和生育期延迟,二者在长日照条件下的光周期敏感阶段都比短日照条件下的光周期敏感阶段长;玉米在进入光周期敏感期之前有一段时间的光周期钝感期,而狗尾草从发芽出苗就直接进入光周期敏感期。两个光周期敏感程度不同的玉米自交系比较,光周期敏感自交系CML288比光周期相对不敏感自交系黄早四的光周期敏感阶段长。     

玉米光周期敏感特性研究及长日照光周期诱导差减文库构建

以热带玉米自交系CML288为材料,通过对比研究表明,CML288对光周期非常敏感。通过长、短日照挪移试验发现,CML288短日照处理条件下,6～7叶期是光周期反应最敏感时期,7～9叶期是光周期敏感持续期,但敏感效应明显减弱。以CML288敏感期叶片与茎尖为材料,利用SSH技术构建了对长日照敏感而特异表达的基因文库,3 000多个单克隆被有效富集。对差减文库中分离的64个特异表达EST序列分析表明,16个EST序列与玉米已知功能的蛋白序列具有较高的同源性;41个序列与其它物种编码序列同源性较高;7个EST没有同源的序列,可能代表了新基因。     

对温、热带玉米杂交后代RIL的评价及其光周期敏感性研究

分析了温带玉米自交系黄早四、热带玉米自交系CML288及其衍生的F6重组家系(RIL)在中纬度和低纬度生态环境下的生育性状,对来自于同一亲本材料的F6重组家系和F3家系做了比较分析,研究了热带、亚热带玉米光周期敏感性及其相关性状的遗传特点。结果表明:在郑州长日照和三亚短日照条件下,F6重组家系的抽雄期、散粉期、吐丝期、株高、穗位高和叶片数等光周期敏感指数均表现出数量遗传特点。F6重组家系的平均值接近双亲平均值,有一定数量的双向超亲家系;F3家系通过随机选择连续自交到F6代后,生育期稍有提前,植株和穗位降低,变异范围扩大。因此,F6重组家系群体可以用于进行QTL定位分析。长、短日照两种条件下F6重组家系光周期敏感相关性状与F3家系的相关系数极显著,F6重组家系各性状变异范围与F3家系相比均有明显扩大的趋势。说明随着世代数的增加,杂合基因型家系在群体中的比例逐步减小,显性、隐性纯合基因型的家系所占的比例越来越大。     

160个玉米自交系光周期敏感性鉴定

以国内160个来源于温带、热带与亚热带玉米自交系为材料,于自然条件短日照(低纬度冬季,三亚)与长日照(中纬度夏季,北京、哈尔滨)环境下,鉴定自交系的雌雄开花期、株高与穗位高等性状。雌、雄开花期、株高和穗位高的遗传力分别为0.952、0.973、0.780与0.745,存在极显著水平的基因互作以及基因型与环境互作,表明这些性状受复杂遗传网络调控,并受光周期等环境因素影响。7884、65232宽、8902、B73、CA335与E28等24个自交系对光周期反应最为钝感,是光周期性状改良的优良供体亲本。鉴定的光周期敏感性的基础数据对基于这些自交系的杂交种组配、生态区适应性评估、种质改良与引进等具有重要意义,并为光周期反应特性相关基因的关联性分析奠定了基础。     

生殖生长期干旱对不同耐旱型玉米自交系根系性状及产量的影响

2016～2017年,在大田微区PVC管栽条件下,采用裂区试验设计,主区为玉米自交系,裂区为水分处理,测定根系形态、根冠生长配比和产量等指标。研究结果表明,与耐旱性较弱的玉米自交系CML58相比,耐旱性较强的玉米自交系黄早四在水分胁迫后有效气生根根夹角增大明显,其根数、根长和根表面积等形态指标降幅峰值均早于CML58,40 cm以下土层的根长、根表面积和根体积降幅明显小于CML58,且0～20 cm土层的根系生长冗余在乳熟期后显著少于CML58,其根冠干重比降幅、根冠长度比和根冠面积比均高于CML58,根冠角度比较CML58小39.4%。与CML58相比,黄早四水分胁迫后能较好地调控有效气生根角度,及时调控根冠纵横生长,维持根系主要分布区结构与功能,提高深层根系分布比,减少根系生长冗余,提高物质转化效率。     

光周期对青饲玉米养分吸收及利用的影响

通过3个对光周期不同敏感型的玉米品种进行光周期试验,研究了光周期对玉米的营养生长及其N、P、K养分吸收及利用率的变化。结果表明,光周期对敏感型青饲玉米品种华农1号的地上部营养生长、根系生长和养分吸收有显著的调控作用,而对相对不敏感型的青饲玉米品种粤农9号的调控作用则不显著。华农1号在长日照条件下根干物重较短日照条件下增幅为390.38 %,光周期相对敏感型品种大暑麦的增幅为119.34 %,粤农9号的增幅为45.47 %;华农1号与粤农9号吸收的N总量分别增加了42.42 %和12.38 %,吸收P总量分别增加了171.76 %和12.23 %,吸收的K总量分别增加了319.27 %和62.42 %。试验结果还表明,随着光照时数的延长,光周期敏感型品种在长日照条件下的N养分利用率提高了,而P、K养分利用率却与光周期敏感特性无显著直接关系。     

玉米光敏雄性不育的发现及初步研究

我们于1994年发现了玉米光敏雄性不育材料CA507，经过初步研究，认为该玉米光敏感雄性不育材料在短日照条件下表现雄性不育，在长日照条件下表现雄性可育，育性转换的临界日照长度是14～15h。光敏雄性不育性状表现隐性遗传。     

长日照条件下玉米开花期光反应相关基因差异表达模式分析

以Suwan种质代表性自交系T32(光敏感)和QR273(光钝感)为材料,利用实时qRT-PCR方法研究10个光反应相关基因在长日照条件下(16 h光照/8 h黑暗)的差异表达模式。结果表明,长日照条件下,不同光反应相关基因在不同自交系间表现出震荡表达模式,其中,开花促进基因ZmCOL、ZmELF4、ZmGI、ZmHd1、ZmHd6、ZCN8在光钝感系QR273中的相对表达量显著高于光敏感系T32;开花抑制基因ZmCCT9、ZmCCT10的相对表达量则显著低于T32。此外,ZmTFL1与ZmCCT虽为开花抑制基因,但其在光钝感自交系QR273中显著高表达,而在光敏感自交系T32中则低表达。     

黑龙江省常用玉米杂交种光周期特性的研究

选用黑龙江省的主栽玉米品种作为试验材料,在玉米的生育期间进行遮光处理,对其光周期的敏感性进行了研究.结果表明,不同品种对遮光处理的反应不同,且同一品种的不同性状反应也不同.9叶期至抽雄期的间隔时间长短是光周期的敏感性状。     

光周期对光敏核不育水稻小孢子发生和花粉发育的超微结构的影响

 以光敏核不育水稻农垦58S为材料，在杭州中国水稻研究所人工气候箱(Koitotron S-153W )群中进行光周期处理。自秧苗6叶期开始，先经10 h／d的短日照处理10 d 到幼穗开始分化，然后分别在13.14 h／d的光周期条件下发育。通过透射电镜观察探索光周期在决定花粉育性中的作用。结果发现，在13 h／d光周期条件，花粉发育正常，而在14h／d的光周期条件下，花粉在单核晚期败育，表现在核糖体呈聚合状态，内质网、质体、线粒体等细胞器逐渐解体，缺乏淀粉积累，吞噬泡增多，细胞质稀薄，最终变成不育。另一方面，绒毡层细胞保持完整状态，无解体迹象。     

黑龙江省常用骨干自交系光反应特性研究

以黑龙江省常用玉米自交系为试验材料,对21个玉米自交系的每日阶段遮光处理研究其光反应特性。结果表明：缩短光照直接影响玉米品种的生育阶段,其中9叶至抽雄期遮光处理与正常光照的叶龄值差异显著,可作为衡量光反应特性的指标性状。缩短光照后使大部分自交系的花期提前,其中1134、龙系85、H172、4F1对光敏感;Mo17、合344、434、706、446光反应迟钝。     

玉米光周期敏感基因ZmELF4的克隆及其亚细胞定位

以热带玉米自交系CML288为供试材料,根据拟南芥ELF4基因保守序列设计引物,采用RT-PCR方法克隆了ELF4在玉米上同源基因的全长cDNA序列(GenBank上的登录号为HQ009862)。序列分析表明,该基因cDNA序列全长683 bp,开放阅读框为432 bp,编码了144个氨基酸,与拟南芥、水稻的氨基酸序列同源性分别高达62%和75%,此外它们还共同包含一个高度保守的DUF1313未知功能结构域。利用基因重组技术分别构建了能够高效表达的过量表达载体pBI-ZmELF4和带有GFP标记的融合表达载体pGIT-ZmELF4-GFP,利用融合表达载体进行洋葱表皮瞬时表达实验,结果将ZmELF4定位于细胞核内,说明该基因在细胞核内起作用。     

Large-scale screening for maize drought resistance using multiple selection criteria evaluated under water-stressed and well-watered environments

A total of 550 maize inbred lines collected from global breeding programs were evaluated for drought resistance under both well-watered and water-stressed environments. The evaluation was based on multiple measurements of biomass taken before and after the drought stress was applied using the normalized difference vegetation index (NDVI), along with other selection criteria including anthesis-silking interval, leaf senescence, chlorophyll content, root capacitance, final grain yield, and grain yield components. Kernel weight was the most stable trait under drought stress. Correlations between the primary trait (grain yield) and the secondary traits, except the root capacitance and ASI under water-stressed condition, were all significant. Root capacitance had relatively low heritability and low genetic correlation with other drought resistance criteria, and is not recommended as a drought resistance criterion. Significant reduction of NDVI values measured in the afternoon when the leaves became rolling, compared to those measured in the morning when the leaves were open, provides a reliable index for leaf rolling, which however was not significantly correlated with grain yield. NDVIs measured across different developmental stages were highly correlated with each other and with most of the secondary traits as well as, grain yield, indicating that NDVI can be used as a secondary trait for large-scale drought resistance screening. Regression models built based on non-yield drought criteria and yield components explained about 40% and 95% of the variation for the grain yield, respectively. Some maize lines developed in China for temperate regions showed strong drought resistance comparable to tropical maize lines when tested under tropical condition, indicating that temperate lines with a wide adaptability can be used in drought resistance breeding for both temperate and tropical environments.     

玉米穗轴对穗腐病抗性鉴定体系与优异抗源的研究

穗轴作为拟轮枝镰孢菌侵染果穗引发玉米穗腐病的重要途径之一,能够影响病原菌的侵染和扩散。为了深入开展玉米穗轴对拟轮枝镰孢菌抗性的研究以及了解玉米穗腐病子粒与穗轴抗性的差异,进行抗性鉴定体系的优化,利用164份国内外玉米骨干自交系进行两年两点的接种鉴定筛选优异抗源,对发病边长、发病芯长、发病面积、发病相对面积等4个抗性指标进行研究。结果表明,发病边长能较大程度地区分不同自交系间的抗感差异且又在材料内具有较好的重演性。把发病边长确定为玉米穗腐病穗轴抗性鉴定指标,对参试自交系进行抗性评价,鉴定出CML27、BT-1、CML274等58份穗轴高抗自交系,筛选出BT-1、CML173、CML193等8份子粒与穗轴均抗穗腐病的优异抗源。     

不同耐旱型玉米自交系冠层光合及产量对生殖生长期干旱胁迫的响应

在PVC管栽和大田条件下,采用裂区试验设计,主区为玉米自交系、裂区为水分处理,测定玉米冠层光合和产量等指标。结果表明,与对照(CK)相比,干旱胁迫(WS)处理下冠层叶色值(SPAD)、光合速率(Pn)、蒸腾速率(Tr)和叶面积指数(LAI)均呈下降趋势,耐旱性较强的黄早四(HZS)平均降幅小于耐旱性较弱的CML58,其SPAD和LAI的降幅较高期(R3)出现早于CML58(R5);干旱胁迫后,水分利用效率(WUE)呈升高趋势,HZS平均升幅高于CML58。HZS的SPAD、Pn、Tr、WUE、LAI、单株粒重、收获指数和群体产量均高于CML58。与CK相比,WS处理下HZS群体产量平均降幅低于CML58。综上,耐旱性较强的玉米自交系冠层光合参数对生殖生长期干旱胁迫响应相对滞后,可在干旱胁迫后维持相对较高的光合性能、水分利用效率和叶面积指数,促进植株干物质转化与子粒建成,最终获得较高产量。     

Photoperiod-sensitive development phases in quinoa (Chenopodium quinoa Willd.)

Effects of photoperiod on phasic development, leaf appearance and seed growth in two cultivars of quinoa (Chenopodium quinoa Willd.), and of photoperiod × temperature interactions on seed growth in one cultivar, were examined. The cultivars were Kanckolla (an early-flowering cultivar from the Andean plateau in Southern Peru) and Blanca de Junín (an intermediate flowering cultivar from the tropical valleys of central Peru). The main objectives were to establish which developmental phases are sensitive to photoperiod and whether conditions during a particular phase had delayed effects on subsequent development. Plants were grown in naturally lit growth cabinets and photoperiods were given as 10 h of natural daylight followed by extensions with low intensity artificial light giving either a short (SD, 10.25 h) or long (LD, 14 or 16 h) photoperiod. Treatments were constant (SD or LD) photoperiods or involved transfers between photoperiods at different developmental stages. A quantitative SD response was observed for time to anthesis and total number of leaves, and more than 50% of leaf primordia were formed after floral initiation. With transfers effected during the reproductive phase, the maximum number of leaf primordia, total number of leaves and time to anthesis varied by up to 9%, 33% and 24%, respectively, in relation to controls under constant SD; and by up to 8%, 39% and 12%, respectively, in relation to controls under constant LD. Photoperiods applied after leaf primordia initiation had ceased affected duration of the reproductive phase and total number of leaves through effects on the proportion of primordia that remained unexpanded (range 7–33%). Plants grown in SD until anthesis produced seed, measured 66 days after anthesis, four-fold larger in diameter than seed on plants always grown in LD. Seed diameter was also reduced by 24% by LD applied after anthesis, and by 14% by high temperature (28°C cf. 21°C), but the combination of high temperature with LD gave the greatest inhibition of seed growth (73%). Clearly, photoperiod had strong effects on all stages of plant reproduction and often acted indirectly, as shown by delayed responses expressed in later phases of development.