2种三叶草杂种F1代胚性愈伤组织筛选

以高加索三叶草(Trifolium ambiguum Bieb.)与白三叶(Trifolium.repens L.)杂交后胚离体培养产生的F₁无菌苗的茎段为外植体,筛选诱导愈伤组织的最适培养基,将F₁茎段产生的愈伤组织经过继代后转移到分化培养基中,研究不同浓度激素组合对体细胞胚胎产生的影响。结果表明:MS+6-BA+NAA是诱导F₁茎段愈伤组织的适宜培养基;MS+2,4-D+6-BA+NAA+KT+CH为F₁茎段愈伤组织的适宜分化培养基;对分化后的胚性愈伤进行组织学观察,可见其表面形成许多瘤状突起,即胚性细胞团,它们可以继续发育形成体细胞胚,为快速得到数量较多的杂种F₁再生苗奠定基础。     

高加索三叶草×白三叶胚萌发条件的探索

以六倍体高加索三叶草Trifolium ambiguum与四倍体白三叶T.repens为亲本,通过远缘杂交,采用组织培养手段对杂交胚的萌发条件进行探索.结果表明:以高加索三叶草为母本、白三叶为父本,在花期8:00-9:00授粉,授粉后12～13 d取胚,用质量分数10%NaClO灭菌6.5～7 min,在不加任何外源激素的改良MS培养基上,胚萌发率最高,达8%.高频扩繁时,再附加0.25 mg/L 2,4-D+0.50 mg/L 6-BA可获得较高萌发率.     

Diversity of <Emphasis Type="Italic">Trifolium ambiguum</Emphasis>—nodulating rhizobia from the lower Caucasus

Kura clover (Trifolium ambiguum M.B.) is a perennial rhizomatous forage legume whose use is currently limited by difficulties in its establishment in part attributable to nodulation problems and very specific rhizobial requirements. A limited number of Kura clover-nodulating rhizobial strains are currently available and many have a limited effectiveness. In this study, 128 rhizobia were isolated from four sites in the center of origin of Kura clover (i.e., two in Azerbaijan, one in Armenia, and one in Northwest Iran) using the three ploidy levels of Kura clover (diploid, tetraploid, and hexaploid), red clover (Trifolium pratense L.), and white clover (Trifolium repens L.) plants as trap hosts. Rhizobia were fingerprinted using repetitive extragenic palindromic polymerase chain reaction (BOXA1R primer) and their genetic diversity was measured using the Shannon-Weaver diversity index. The nodulation specificity and phenotypic diversity of a subset of 13 isolates was determined. Genetic diversity among the 128 isolates was large and similar for rhizobia grouped according to their geographic origin or original host plant. Phenotypic diversity was significant; percentage of similarity among 13 isolates ranging between 38 and 92%. Nodulation specificity of the Kura clover-nodulating rhizobial isolates studied was less complex and not as clearly delineated as previously reported. Some strains originally isolated from Kura clover could effectively nodulate more than one ploidy level of Kura clover and even one or both of two other Trifolium species (i.e., red clover and white clover). Three strains formed effective nodules on both Kura clover and white clover; however, none promoted plant growth of both species to levels currently obtained with commercial inoculants when evaluated in a growth chamber. Rhizobial isolates that are highly effective with both species have yet to be identified.     

Organic Food Demand: A Focus Group Study Involving Caucasian and African-American Shoppers

A focus group study using four groups of food shoppers provides insights into consumers’ knowledge, beliefs, and behaviors regarding organic foods. Two focus groups consisted of shoppers who regularly bought organic foods and two focus groups of shoppers who predominantly purchased conventional foods. Participants in one of the conventional groups were all Caucasian; in the other they were all African-American. While familiarity with organic foods was much lower in the African-American group, its members were more receptive and positive towards organic foods. Likewise, the African-American shoppers were more accepting of price premiums for organics foods. In comparing the two organic shopper groups with the two conventional shopper groups, it was found that the former were generally more knowledgeable about organic foods. They were also more likely to follow a special diet than conventional Caucasian shoppers. However, the behavior of organic shoppers varied widely. The research supports examining social justice and access as motivations for changing policies to support organic agriculture. Lydia Zepeda is a Professor of Consumer Science at University of Wisconsin and Senior Fellow of the Center for World Affairs and the Global Economy. Her research focuses on agricultural technology adoption, farm household decision making, and consumer perceptions and behavior towards agricultural technology and food. Hui-Shung Chang is a Senior Lecturer in the School of Economics at the University of New England, Armidale, New South Wales, Australia. Her research focuses on demand analysis and agribusiness marketing. Catherine Leviten-Reid is a research assistant and graduate student in the Department of Consumer Science at the University of Wisconsin–Madison. She is interested in household behavior and sustainable community development.     

Habitat selection by East Caucasian tur (Capra cylindricornis)

Habitat selection by East Caucasian tur (Capra cylindricornis), a species of global conservation concern, was examined in relation to terrain, climate and degree of human disturbance using a Geographical Information System and logistic regression. The study area was in the part of the Greater Caucasus of Georgia, where the species protection was not enforced. Two models of tur habitat requirements were obtained: one model at a scale of 20 × 20 m plots, and the other one at a scale of different habitat fragments made up of 20 × 20 m plots identified by the first model at its optimal cut-off value. The second model refined the first one.The first model suggested that the probability of a 20 × 20 m plot being part of tur habitat was positively correlated with slope, distances to roads and livestock summer camps, and negatively correlated with human population density and annual rainfall. The probability had a bell-shaped correlation with elevation, reaching its maximum at 3008.4 m. The second model suggested that a fragment of a land made up of 20 × 20 m plots with optimal characteristics for tur occurrence was more likely to contain tur if the area of the fragment was larger and its distance to the nearest area where tur occurred was shorter.The results show that the occurrence of East Caucasian tur is affected by climate, terrain, human disturbance and habitat fragmentation, and can be predicted regardless of seasonality in the species movements. These models can be applied to the management of the species and its habitat in the areas of the Caucasus that lie at >1000 m asl and have an annual rainfall >600 mm, and where the species protection is not enforced.     

GA3和6-BA对高加索三叶草根蘖芽生长及内源激素含量的影响

为了研究植物生长调节剂赤霉素(GA₃)和6-苄氨基腺嘌呤(6-BA)对高加索三叶草根蘖芽生长发育及内源激素含量的影响,在不同浓度的GA₃(0对照、300、600、900 和1200 mg·L^-1)和6-BA(0对照、25、50、100和200 mg·L^-1),对其根蘖芽生长后的植株高度、叶片数、叶绿素含量和内源激素含量(地上部分和地下部分)进行测定与分析。结果表明:与对照相比,所有GA₃处理均显著增加了株高(P<0.05)。尤其在600 mg·L^-1 GA₃处理下,平均株高为21.33 cm(高于对照处理4.12倍)。GA₃还促进了叶绿素a的合成,最显著效果是在600 mg·L^-1 GA₃处理下,叶绿素a的浓度为0.92 mg·g^-1(高于对照76.92%) (P<0.05)。GA₃对叶绿素b含量无显著影响(P>0.05)。在6-BA所有处理浓度下,株高约为对照处理2.6倍,并且对于叶片数,6-BA处理比GA₃处理更敏感,在200 mg·L^-1时最多,高于对照2.99倍。 6-BA显著促进了叶绿素a和b的积累(P<0.05)。内源激素含量在整个处理浓度下均显示出对外源激素应用的剂量反应。对于地上植物部分,600 mg·L^-1的外源GA₃引起内源玉米素(ZT),GA₃和生长素(IAA)分别增加约23.84%,55.71%和137.99%,而脱落酸(ABA)减少约44.09%。与对照相比,外源200 mg·L^-1 6-BA使内源ZT,GA₃和IAA含量分别提高了约293.23%,49.71%和49.84%,而ABA降低了约52.48%。对于地下植物部分,内源激素变化与地上部分植物的响应大致相似,明显不同在于外源同样浓度GA₃(600 mg·L^-1)和6-BA(200 mg·L^-1)处理引起的ABA降低要少(分别为15.15%和28.26%)。总之,600 mg·L^-1 GA₃和200 mg·L^-1 6-BA是促高加索生长发育的最佳浓度。     

高加索三叶草响应不同降温模式低温胁迫的代谢组学分析

为探究高加索三叶草(Trifolium ambiguum Bieb.)对不同降温模式低温胁迫的代谢响应机制,本试验对其分别进行缓慢降温(Gradual cooling,GC)和骤然降温(Sudden cooling,SC)处理,利用广泛靶向代谢组学技术检测叶片代谢物,并比较2个处理组与常温对照组(CK)间的代谢物差异....     

不同降温模式下高加索三叶草的转录组比较分析

为探讨高加索三叶草(Trifolium ambiguum Bieb.)对不同降温模式低温胁迫的响应机制,本试验以缓慢降温(Gradual cooling,GC)和骤然降温(Sudden cooling,SC)处理对其进行了胁迫处理.通过转录组测序,比较了2个低温处理组与常温对照组(CK)间的转录组差异,并筛选了抗寒相关...     

高加索三叶草ISSR-PCR反应体系的建立与优化

高加索三叶草(Trifolium ambiguum Bieb.)是许多干旱和寒冷地区可以种植并在各方面表现优良的三叶草种,建立适用于高加索三叶草的ISSR反应体系,将为ISSR标记技术在三叶草属品种资源研究中的应用提供参考.本试验通过优化影响高加索三叶草ISSR-PCR的主要参数,建立适于高加索三叶草的ISSR反应体系和扩增程序.在25μL体系中各反应物的最适含量为:20 ng模板DNA,0.2 mmol/L dNTP,0.8μmol/L ISSR引物,1.0 U TaqDNA聚合酶,2.5μL 10×PCR Buffer,2.0mmol/L MgC12.PCR扩增程序为:94℃预变性2 min,94℃变性30s,55℃退火45s,72℃延伸1 min,共30个循环;72℃延伸7min,4℃保温.