偃麦草种质资源外部性状变异及其形态类型的初步研究

对41份偃麦草Elytrigia repens种质资源的16个外部性状变异及其分布规律进行研究,并在对16个指标性状进行相关分析及主成分分析的基础上,对34份材料进行聚类分析。结果表明,偃麦草种内形态指标变异较大,变异系数为4.88%～33.30%,其中叶层高度变异系数最大,达33.30%,其次为旗叶长(26.03%),而种子宽度、种子长度、种子厚度、颖长、叶长变异较小,均在10.0%以下;海拔高度与偃麦草生殖枝高呈显著正相关(P0.01),与颖长呈显著负相关(P0.01),而在纬度上的相关性却呈现相反趋势;经度仅与穗下第1节间长呈显著正相关(P0.01);在对外部性状相关分析及主成分分析的基础上,通过聚类分析,在欧氏距离5.0处,34份偃麦草材料可被划分为高大型、偏高大型、特殊型、低矮型4个类型,且特殊型和低矮型均具有开发为草坪草的潜能。     

Control of Elymus repens by rhizome fragmentation and repeated mowing in a newly established white clover sward

Control of perennial weeds, such as Elymus repens, generally requires herbicides or intensive tillage. Alternative methods, such as mowing and competition from subsidiary crops, provide less efficient control. Fragmenting the rhizomes, with minimal soil disturbance and damage to the main crop, could potentially increase the efficacy and consistency of such control methods. This study's aim was to investigate whether fragmenting the rhizomes and mowing enhance the control of E. repens in a white clover sward. Six field experiments were conducted in 2012 and 2013 in Uppsala, Sweden, and Ås, Norway. The effect of cutting slits in the soil using a flat spade in a 10 × 10 cm or 20 × 20 cm grid and the effect of repeated mowing were investigated. Treatments were performed either during summer in a spring‐sown white clover sward (three experiments) or during autumn, post‐cereal harvest, in an under‐sown white clover sward (three experiments). When performed in autumn, rhizome fragmentation and mowing reduced E. repens shoot biomass, but not rhizome biomass or shoot number. In contrast, when performed in early summer, rhizome fragmentation also reduced the E. repens rhizome biomass by up to 60%, and repeated mowing reduced it by up to 95%. The combination of the two factors appeared to be additive. Seasonal differences in treatment effects may be due to rhizomes having fewer stored resources in spring than in early autumn. We conclude that rhizome fragmentation in a growing white clover sward could reduce the amount of E. repens rhizomes and that repeated mowing is an effective control method, but that great seasonal variation exists.     

长穗偃麦草EeHKT1;4基因的克隆与植物表达载体构建

采用RT-PCR方法从长穗偃麦草(Elytrigia elongata)中克隆得到高亲和K+转运蛋白基因,命名为EeHKT1;4,全长cDNA序列为1 977bp,开放阅读框1 722bp,编码573个氨基酸,与一粒小麦(Triticum monococcum)TmHKT1;4-A2的氨基酸同源性为94%。系统进化树分析结果显示,EeHKT1;4与单子叶植物HKT1;4亲缘关系较近。利用In-Fusion技术,成功构建了pBI121-35SEeHKT1;4-Nos植物表达载体,为长穗偃麦草EeHKT1;4的耐盐功能鉴定奠定基础。     

猪屎豆抗氧化活性成分的提取及活性测定体系的优化

[目的]研究猪屎豆（Crotalaria mucronata Desv.）乙醇提取物的抗氧化活性。[方法]采用超声波辅助乙醇提取法提取猪屎豆抗氧化活性成分,用H2O2-鲁米诺化学发光体系测定清除羟自由基（·OH）的效率。并对测定体系进行优化。[结果]在料液比为3.6∶1,乙醇体积分数为70%,提取时间为30min,提取温度为80℃,猪屎豆乙醇提取物对·OH的清除效果最佳。清除率测定体系中,H2O2浓度为0.60%和Luminol浓度为1.00×10-4mol/L时测定结果较准确。[结论]猪屎豆乙醇提取物对·OH有很好的清除作用。     

Cytological Evaluation and Karyotype Analysis in Plant Germplasms of Elytngia Desv.

Elytrigia Desv. is widely distributed throughout the world and is represented with species of various levels of ploidy including diploids, tetraploids, hexaploids, octaploids, and decaploids. The distribution pattern of these ploidy levels, however, is not well-defined. In this study, the levels of ploidy for 64 accessions of Elytrigia from 25 countries were determined with microscopic procedures. The results showed that accessions of E. intermedia and E. repens were grouped into three distinct levels of ploidy including diploids, tetraploids and hexaploids. For E. elongata, E. pontica, and E. caespitosa, it was found that two ploidy levels presented, and only one ploidy level was in those of E. hybrid, E. pycnantha, E. pungens, E. juncea, and E. alatavica. Karyotype analysis indicated that the karyotype formula of diploid, tetraploid and hexaploid of E. intermedia was 2n = 2x = 14 = 6m ＋ 6sm ＋ 2st, 2n = 4x = 28 = 2M ＋ 10m ＋ 16sm and 2n = 6x = 42 = 4M ＋ 18m ＋ 20sin, respectively. Furthermore, the karyotype formula of three germplasms in tetraploid of E. intermedia was 2n=4x=28 =2M＋ 10m＋ 16sm, 2n=4x=28=4M＋22m （sat）＋2sm and 2n=4x=28 =4M＋ 12m＋ 12sm （sat）, which were not completely uniform. Therefore, it could be suggested that the studies about chromosome constitution would be helpful for the detail understanding of the diversity of germplasm resource in Elytrigia and promoting the utilization in the crop molecular breeding.     

4份偃麦草资源对干旱胁迫的生理响应

为了解偃麦草(Elytrigia repens (L.) Nevski)的抗旱生理机制,在盆栽控水条件下,对抗旱性不同的4份偃麦草种质资源进行干旱胁迫生理响应研究。结果表明:干旱后土壤含水量呈下降趋势,且胁迫后0 d,5 d,10 d,15 d间土壤含水量差异显著(P<0.05);干旱胁迫过程中偃麦草叶片水分饱和亏缺(WSD)、电导率、丙二醛(MDA)含量、脯氨酸(Pro)含量呈上升趋势,超氧化物酶(SOD)活性与可溶性蛋白含量呈现先升高后降低趋势,而过氧化物酶(POD)活性则表现降低趋势;与其他材料相比,抗旱性强的材料E01的WSD值上升慢、增加率低,SOD活性峰值出现时间晚且峰值最高,可溶性蛋白含量变化小,脯氨酸积累少,且MDA积累慢、含量低。     

中间偃麦草、长穗偃麦草及其杂种F1代同工酶研究

通过对过氧化物酶(POD)、酯酶(EST)、超氧化物歧化酶(SOD)和多酚氧化酶(PPO)同工酶谱的分析,探讨中间偃麦草(Elytrigia elongata(Host)Nevski)、长穗偃麦草(E.intermedia(Host)Nevski)及其杂种F₁代的酶谱特征和亲缘关系。结果表明:亲本同工酶酶带数目、迁移率、着色程度等差异不大,二者亲缘关系较近。与亲本相比,杂种F₁代存在POD、SOD、PPO酶带丢失现象,但正、反交植株中均产生了一些亲本没有的新生带。杂种F₁代EST酶谱与亲本基本相同,仅着色程度略有差异。杂种F₁代植株的POD、PPO酶谱特征有偏向中间偃麦草的倾向,而SOD酶谱特征倾向于长穗偃麦草。杂种F₁代同工酶具有多态性,可作为遗传标记用于杂种鉴定和后代株系目标性状的选择。     

VE161异代换系雄性不育原因的探讨及其保持

VE1 61小麦包括具有一对长穗偃麦草染色体的雄性不育异代换系、可育附加系和杂育系 ,杂育系由其代换系×附加系产生。对 VE1 61雄性不育异代换系的两种保持途径进行的比较研究表明 ,采用杂育系自交的方法较好 ,并探讨 E染色体对育性的影响     

偃麦草种质资源遗传多样性的RAPD分析

通过对DNA提取方法及RAPD反应体系进行探讨,建立了适应偃麦草基因组DNA提取的方法及优化的RAPD反应体系。在此基础上,依据Jaccard相似系数,采用UPGMA方法进行聚类,判定32份偃麦草种质材料间的亲缘关系及遗传多样性。结果表明:(1)改良常规CTAB法,即对样品先进行洗涤并提高CTAB含量到3%可提高偃麦草DNA的提取质量。(2)对100条随机引物进行筛选,共筛选出18条多态性高、重复性好的随机引物,以此对32份材料进行PCR扩增,共扩增出264条带,多态性条带为93.7%。(3)以遗传相似系数为依据,对32份偃麦草材料进行聚类分析,在相似系数为0.373处可将供试偃麦草种质资源划分为5大类群。     

PEG模拟干旱胁迫下29份偃麦草种质种子萌发期抗旱性评价

以20%聚乙二醇溶液(PEG-6000)为渗透介质模拟干旱胁迫条件,对29份偃麦草种质资源进行了种子萌发期抗旱性评价。结果表明:PEG胁迫降低了偃麦草种质资源的发芽率、发芽势、发芽指数、活力指数,抑制了胚芽和胚根的生长发育。以相对发芽率、相对胚根长、相对胚芽长、萌发抗旱指数、胁迫指数、相对发芽势及相对活力指数为依据,通过隶属函数法综合评价认为,29份偃麦草种质资源的抗旱性顺序依次为:E39E14E11E13E16E03E07E25E34E42E09E29E17E31E21E26E06E10E12E27E38E08E01E04E41E19E37E02E24。