毛花猕猴桃原生质体再生植株根尖染色体数目变异与细胞多核现象

对18株毛花猕猴桃(Actinidia eriantha Benth.)原生质体再生植株的体细胞染色体数做了观察,其中12株为整倍体:二倍体(2n=58)和四倍体(2n=116)各6株;另外6株为混倍体,其染色体数目变化在59～203之间。还发现原生质体再生植株有丝分裂间期细胞存在多核现象,有多核细胞的共10株,细胞核数目以双核和三核较常见,最多的有7个核。对照植株为2n=2x=58,未发现多核细胞。     

Elymus与普通小麦属间杂种的细胞遗传学研究

本研究以Elymus pendulinus(Nevski)Tzvelev(2n=4x=28,SSYY)、E.shandongenisis B.Salomon(2n=4x=28,SSYY)与普通小麦(Triticum aestivum L.:2n=6x=42,AABBDD)进行了属间远缘杂交。通过对杂种胚的离体培养,两个组合均产生了杂种F_1植株。杂种F_1为多年生,植株生长旺盛;形态上介于亲本种之间而兼具双亲的某些特征;穗状花序发育正常,但均完全不育。两个组合的根尖和花粉母细胞染色体数目为2n-5x=35。通过对杂种减数分裂染色体配对行为的分析,发现其MI染色体的配对水平很低,二价体均为棒状,每细胞的平均染色体交叉数在0.25-0.31之间。这表明E.pendulinus t E.shandongensis 所含的SY染色体组与普通小麦的ABD染色体之间的同源程度很低。由于在E.shandongeasis 及其它具有SY染色体组的Elymus 单倍体中,SY染色体组之间的部份同源染色体配对数均明显高于该杂种中的配对数,这表明存在于普通小麦中的ph基因及其它具类似作用的基因系统能抑制SY染色体组之间的部份同源染色体配对。     

宜昌橙与伏令夏橙种间体细胞杂种

宜昌橙(Citrus ichangensis SwingIe)试管实生苗叶肉原生质体与伏令夏甜橙(C．Sin-ensis Osbeck)胚性悬浮细胞系原生质体,经聚乙二醇(PEG)诱导融合。再生出的胚状体为畸形,转移到生芽培养基中诱导产生丛芽。丛芽微嫁接在15天龄的枳壳砧上成为完整植株。幼叶染色体检查表明,两亲本均为二倍体2n=2x=18,融合后再生出的植株为四倍体2n=4x=36。过氧化物酶(POX)及谷草酰胺转氨酶(GOT)同工酶分析证明,这些四倍体均为体细胞杂种,它们同时含有双亲的酶带。杂种植株叶片形态更像甜橙。植株移八土壤后生长旺盛。     

新疆猪毛菜属4种植物核型分析及进化研究

采用常规压片法,对钠猪毛菜、准噶尔猪毛菜、小药猪毛菜和薄翅猪毛菜等4种新疆猪毛菜属植物的染色体核型进行了分析,并对已报道的12种新疆猪毛菜属植物核型进行了比较.结果表明:(1)钠猪毛菜体细胞染色体数2n=2x=18=12m+6sm,准噶尔猪毛菜、小药猪毛菜体细胞染色体数为2n=2x=18=18m,该3种均属于1A型;薄翅猪毛菜体细胞染色体数为2n=2x=54=50m+2sm+2st,属2A型;(2)12种新疆猪毛菜属植物核型比较结果证明,猪毛菜属植物的染色体基数为9,钠猪毛菜、准噶尔猪毛菜和小药猪毛菜均为二倍体,薄翅猪毛菜为六倍体,钠猪毛菜和准噶尔猪毛菜具有随体.准噶尔猪毛菜、小药猪毛菜、薄翅猪毛菜属植物的核型均属于首次报道.     

不同萝卜品种游离小孢子的诱导及培养体系优化研究

以19个萝卜品种为试验材料,研究各种因素对萝卜游离小孢子培养的影响.结果表明:(1)13个品种可诱导出胚状体,诱导率达到68.4%,但不同品种间产胚量存在较大差异,其中路路通翠雪产胚量可达每蕾10个,而圆白萝卜的产胚量最小为每蕾0.125个,进一步培养有8个品种得到再生植株;(2)在NLN-13液体培养基中添加活性炭和6-BA对萝卜游离小孢子出胚有较好的促进作用,小孢子分离30d后将胚状体转移至固体MS培养基上,子叶型胚可获得大量的再生植株,而畸形胚状体转移后不能获得正常的再生植株.     

以异源四倍体体细胞杂种为父本杂交培育三倍体柑桔植株的研究

以 3个柑桔原生质体融合而来的四倍体体细胞杂种为父本 ,与二倍体单胚性种柚子 (Citrusgrandis)以及单多胚混合型品种“华农本地早”桔 (C.reticulata)有性杂交 ,授粉后 90 d,发现种子干瘪 ,大部分种子的胚败育。将干瘪种子在 MT附加 1mg/L GA3 或 50 0 mg/L麦芽浸出物的培养基中 ,经培养抢救 ,有 2 5.6%的种子萌发成苗或继续进行胚的生长 ,后者进一步诱导能形成丛芽 ,经试管嫁接或诱导生根形成完整植株。共获得 6个组合 73棵完整植株 ,染色体数检查表明 ,2 0株为三倍体 (2 n=3x=2 7) ,32株为二倍体 (2 n=2 x=18) ,8株为非整倍体 ,其它 13株还有待于进一步检查。     

田埂报春多倍体诱导及其形态学研究

在离体培养条件下,比较不同浓度、不同处理时间的秋水仙素对田埂报春进行染色体加倍的诱导效果。结果表明:0.08%秋水仙素处理48h的诱变效果最佳,诱变率高达56%。经秋水仙素诱导后形成的多倍体植株与原二倍体植株比较,在形态上,四倍体植株表现出多倍体特征,叶片变厚,叶形指数减小,保卫细胞增大,单位面积气孔数减少,叶绿体数明显增多。对变异植株进行细胞学研究发现,体细胞中期染色体数目为2n=4x=36,而原二倍体的染色体数目为2n=2x=18,基数x=9,因此,变异植株(2n=4x=36)为四倍体。前者的核型公式为2n=4x=8L+12M2+4M1+12S,核型属于1A;后者的核型公式为2n=2x=4L+6M2+2M1+6S,核型也属于1A。检测发现少数个体有非整倍体变异。     

4x菜心×2x芥蓝的胚胎发育观察及离体培养获得异源三倍体

对4x菜心×2x芥蓝和4x芥蓝×2x菜心的授粉受精及胚胎发育进行了观察,并对其杂种幼胚进行了离体培养.结果表明,4x菜心×2x芥蓝和4x芥蓝×2x菜心的授粉受精均能完成,但胚胎发育受阻,前者在授粉后11d左右(球形胚时期)胚胎败育,后者在授粉后5d左右(几个细胞的原胚时期)胚囊便干缩坏死. 经子房离体培养,4x菜心×2x芥蓝获得了杂种植株,适宜的培养时期是授粉后6～8d,而4x芥蓝×2x菜心未能培养成功.经形态学观察和核型分析,杂种植株在花色、花大小等方面具双亲特征,染色体数为2n=3x=29,含有菜心的2个染色体组(AA)和芥蓝的1个染色体组(C),为异源三倍体(AAC).     

同源四倍体灯盏花离体再生及其倍性鉴定

以四倍体灯盏花的无菌苗叶柄为外植体进行离体培养,研究其再生体系,并对再生植株进行染色体倍性鉴定。结果表明:叶柄外植体在MS+0.05 mg·L-1NAA+0.5 mg·L-16-BA+0.65%琼脂+3%蔗糖的培养基上不定芽的再生频率可达87.3%;继代培养(MS+0.1 mg·L-1NAA+0.3 mg·L-16-BA+0.65%琼脂+3%蔗糖)增殖系数为7.8,诱导(1/2MS+1.0 mg·L-1NAA+1.0 mg·L-1IBA+0.65%琼脂+3%蔗糖)生根率100%,移栽成活率为90%。细胞学鉴定结果表明,再生植株的染色体数为2n=4x=36,而原二倍体的染色体数目为2n=2x=18,基数x=9,因此,再生植株为四倍体。     

中间锦鸡儿(caranaga intermedia)染色体变异研究

对中间锦鸡儿(caranaga intermedia)种子根尖染色体进行检测,统计分析了染色体数目和结构变异类型.核型分析结果表明中间锦鸡儿正常核型为2n=2x=16=14m+2sm,还发现了核型公式为2n=2x=16+1B=1st+9m+2sm+1m(sAT)+1sm(SAT)+2m(SAT)+1B;核型公式为2n=2x=16+1B=6sm+8m+2m(SAT)+IB;以及核型公式为2n=2x=15=7sm+8m的变异类型.本研究首次发现了中间锦鸡儿存在B染色体和中间随体,此外还发现存在单体植株.随体具有个体差异,有中间随体和端部随体两种,且无论个体间和个体内B染色体均存在数目和结构的多态性.对其中120粒种子根尖染色体结果统计分析.发现具有15条染色体的植株占0.83%;具有16条染色体的植株占89.17%;具有17条染色体的植株占3.3%;具有18条染色体的植株占2,5%,其中有一个体中多于的一条染色体始终呈点状;19条染色体的植株占1.67%,5条多于染色体的占0.83%,而多余染色体条数在1～3之间变动的植株占1.67%.     

大白菜与紫甘蓝种间杂种的获得与鉴定

以不同类型的大白菜与紫甘蓝为材料,运用蕾期授粉结合胚挽救技术获得大白菜与紫甘蓝的种间杂种,并对其进行细胞学鉴定.结果表明,大白菜与紫甘蓝杂交,获得了57株F1代幼苗;对根尖染色体数量进行观察和杂种花粉特性调查发现,其中47株具有预期的染色体数目,2n =19,鉴定为真杂种,其花粉败育;另有6株具有38条染色体,鉴定为种间异源双二倍体,应该是发生了染色体自然加倍,其花粉可育.可育的杂种F1代与大白菜回交,获得了大白菜-紫甘蓝BC1代材料.田间观测结果显示,杂种F1代植株综合性状均介于双亲之间,BC1代植株包球明显,综合性状偏向母本大白菜.     

Cytological and molecular characterization of oat x maize partial hybrids

In cereals, interspecific and intergeneric hybridizations (wide crosses) which yield karyotypically stable hybrid plants have been used as starting points to widen the genetic base of a crop and to construct stocks for genetic analysis. Also, uniparental genome elimination in karyotypically unstable hybrids has been utilized for cereal haploid production. We have crossed hexaploid oat (2n=6x=42, Avena sativa L.) and maize (2n=2x=20, Zea mays L.) and recovered 90 progenies through embryo rescue. Fifty-two plants (58%) produced from oatxmaize hybridization were oat haploids (2n=3x=21) following maize chromosome elimination. Twenty-eight plants (31%) were found to be stable partial hybrids with 1–4 maize chromosomes in addition to a haploid set of 21 oat chromosomes (2n=21+1 to 2n=21+4). Ten of the ninety plants produced were found to be apparent chromosomal chimeras, where some tissues in a given plant contained maize chromosomes while other tissues did not, or else different tissues contained a different number of maize chromosomes. DNA restriction fragment length polymorphisms (RFLPs) were used to identify the maize chromosome(s) present in the various oat-maize progenies. Maize chromosomes 2, 3, 4, 5, 6, 7, 8, and 9 were detected in partial hybrids and chromosomal chimeras. Maize chromosomes 1 and 10 were not detected in the plants analyzed to-date. Furthermore, partial self-fertility, which is common in oat haploids, was also observed in some oat-maize hybrids. Upon selfing, partial hybrids with one or two maize chromosomes showed nearly complete transmission of the maize chromosome to give self-fertile maize-chromosome-addition oat plants. Fertile lines were recovered that contained an added maize chromosome or chromosome pair representing six of the ten maize chromosomes. Four independently derived disomic maize chromosome addition lines contained chromosome 4, one line carried chromosome 7, two lines had chromosome 9, one had chromosome 2, and one had chromosome 3. One maize chromosome-8 monosomic addition line was also identified. We also identified a double disomic addition line containing both maize chromosomes 4 and 7. This constitutes the first report of the production of karyotypically stable partial hybrids involving highly unrelated species from two subfamilies of the Gramineae (Pooideae — oat, and Panicoideae — maize) and the subsequent recovery of fertile oat-maize chromosome addition lines. These represent novel material for gene/ marker mapping, maize chromosome manipulation, the study of maize gene expression in oat, and the transfer of maize DNA, genes, or active transposons to oat.Joint contribution of the Minnesota Agricultural Experiment Station and USDA-ARS. Scientific journal series paper No. 21 859 of the Minnesota Agricultural Experiment Station. Mention of a trademark or proprietary product does not constitute a guarantee or warranty by the USDA-ARS or the University of Minnesota and does not imply approval over other products that also may be suitable     

大麻染色体行为分析

以大麻不同性别的植株为材料,常规压片法观察细胞染色体行为规律。核型分析结果表明:大麻雌雄株的体细胞染色体数目均为2n=20,核型公式分别为雌株2n=2x=20=18m 2sm,雄株2n=2x=20=18m 2sm(1SAT)。雌株体细胞中有2条X染色体,而雄株只有一条X染色体和一条具有大随体的Y染色体。雌雄株核型均为2A型,为较对称核型。这一结果可为进一步研究大麻性别的分化机制提供细胞遗传学理论依据。     

Identification of mitotic chromosomes of tuberous and non-tuberous solanum species (Solanum tuberosum and Solanum brevidens) by GISH in their interspecific hybrids.

GISH (genomic in situ hybridization) was applied for the analysis of mitotic chromosome constitutions of somatic hybrids and their derivatives between dihaploid clones of cultivated potato (Solanum tuberosum L.) (2n = 2x = 24, AA genome) and the diploid, non-tuberous, wild species Solanum brevidens Phil. (2n = 2x = 24, EE genome). Of the primary somatic hybrids, both tetraploid (2n = 4x) and hexaploid (2n = 6x) plants were found with the genomic constitutions of AAEE and AAEEEE, respectively. Androgenic haploids (somatohaploids) derived from the tetraploid somatic hybrids had the genomic constitutions of AE (2n = 2x = 24) and haploids originating from the hexaploid hybrids were triploid AEE (2n = 3x = 33 and 2n = 3x = 36). As a result of subsequent somatic hybridization from a fusion between dihaploid S. tuberosum (2n = 2x = 24, genome AA) and a triploid somatohaploid (2n = 3x = 33, genome AEE), second-generation somatic hybrids were obtained. These somatic hybrids were pentaploids (2n = 5x, genome AAAEE), but had variable chromosome numbers. GISH analysis revealed that both primary and second-generation somatic hybrids had lost more chromosomes of S. brevidens than of S. tuberosum.     

Cytogenetic analysis of Lycopersicon esculentum (+) Solanum etuberosum somatic hybrids and their androgenetic regenerants

The aim of the study was to characterize genomic relationships among cultivated tomato (Lycopersicon esculentum Mill.) (2n=2x=24) and diploid (2n=2x=24) non-tuberous wild Solanum species (S. etuberosum Lindl.). Using genomic in situ hybridization (GISH) of mitotic and meiotic chromosomes, we analyzed intergeneric somatic hybrids between tomato and S. etuberosum. Of the five somatic hybrids, two plants were amphidiploids (2n=4x=48) mostly forming intragenomic bivalents in their microsporocytes, with a very low frequency of multivalents involving the chromosomes of tomato and S. etuberosum (less than 0.2 per meiocyte). Tomato chromosomes showed preferential elimination during subsequent meiotic divisions of the amphidiploids. Transmission of the parental chromosomes into microspores was also evaluated by GISH analysis of androgenic plants produced by direct embryogenesis from the amphidiploid somatic hybrids. Of the four androgenic regenerants, three were diploids (2n=2x=24 or 2n=2x+1=25) derived from reduced male gametes of the somatic hybrids, and one plant was a hypertetraploid (2n=4x+4=52). GISH revealed that each anther-derived plant had a unique chromosome composition. The prospects for introgression of desirable traits from S. etuberosum into the gene pool of cultivated tomato are discussed. Received: 2 August 2000 / Accepted: 4 December 2000     

Somaclonal Variation in Chromosome Number and Nuclei Number of Regenerated Plants from Protoplasts of Actinidia eriantha

By counting the chromosome number of root tip cells in 18 regenerated plants derived from protoplasts of Actinidia eriantha Benth., the authors found 12 euploid plants and 6 mixoploid plants. Of the 12 euploid plants, 6 were diploid (2n = 2x = 58) and the other 6 were tetraploid (2n =4x = 116). The chromosome numbers of the mixoploid plants varied from 59 to 203. Mttltinueleate phenomenon was also observed in the interphase cells of 10 protoplast-derived plants. Cells with binuclei or trinuelei were common and cells having heptanuclei were also seen occassionally. Muhinucleate phenomenon did not occur in the control, i. e., the donor plant, where the chromosome number was 2n = 2x = 58.     

Chromosome markers and alterations in mitotic cells from interspecific Citrus somatic hybrids analysed by fluorochrome staining

Mitotic cells from Rough lemon (Citrus jambhiri Lush.), Ohta ponkan (C. reticulata Blanco) and two somatic hybrid plants obtained from protoplast fusion were analysed by double staining with chromomycin A₃ (CMA) and 4′-6-diamidino-2-phenylindole. Only CMA-positive bands were observed in metaphasic chromosomes. The two parental karyotypes (2n=2x=18) were heteromorphic, yielding some marker chromosomes that could be identified in the somatic hybrids. One of the somatic hybrids had 2n=37 chromosomes, and the possible extra chromosome was distinguishable. The second somatic hybrid was tetraploid (2n=4x=36), with one of the chromosomes bearing a putative structural alteration. Furthermore, aneusomaty and some mitotic abnormalities were also observed in this latter plant. Such irregularities are reported for the first time for citrus somatic hybrids, and their possible causes and implications are discussed. Received: 23 December 1996 / Revision received: 21 May 1997 / Accepted: 16 June 1997     

Introgression mapping of genes for winter hardiness and frost tolerance transferred from Festuca arundinacea into Lolium multiflorum

Genes for winter hardiness and frost tolerance were introgressed from Festuca arundinacea into winter-sensitive Lolium multiflorum. Two partly fertile, pentaploid (2n = 5x = 35) F(1) hybrids F. arundinacea (2n = 6x = 42) x L. multiflorum (2n = 4x = 28) were generated and backcrossed twice onto L. multiflorum (2x). The backcross 1 (BC(1)) and backcross 2 (BC(2)) plants were preselected for high vigor and good fertility, and subsequently, a total of 83 BC(2) plants were selected for winter hardiness after 2 Polish winters and by simulated freezing tests. Genomic in situ hybridization (GISH) was performed on 6 winter-hardy plants selected after the first winter and shown to be significantly (P < 0.05) more frost tolerant than the L. multiflorum control. Among the analyzed BC(2) winter survivors, only diploid (2n = 2x = 14) plants were found. Five plants carried 13 intact L. multiflorum chromosomes and 1 L. multiflorum chromosome with a single introgressed F. arundinacea terminal chromosome segment. The sixth BC(2) winter survivor appeared to be Lolium without any Festuca introgression capable of detection by GISH. A combined GISH and fluorescence in situ hybridization analysis with rDNA probes of the most winter-hardy (after 2 winters) and frost-tolerant BC(2) plant revealed the location of an F. arundinacea introgression on the nonsatellite arm of L. multiflorum chromosome 2, the same chromosome location reported previously as a site for frost tolerance genes in the diploid and winter-hardy species Festuca pratensis.     

中国桔梗多倍体诱导与鉴定

在离体培养条件下,比较了不同浓度、不同处理时间的秋水仙素对中国桔梗（Platycodon grandiflorus A．CD）进行染色体加倍的诱导效果。结果表明：用含0．1％秋水仙素处理40h后诱导频率可达50％,诱导效果最佳。经秋水仙素诱导后形成的多倍体植株与原二倍体植株比较,在形态上,多倍植株叶片变宽变大,叶色变深,茎变粗且节距长,气孔增大而单位叶面积气孔数目减少。对变异植株进行细胞学研究发现,体细胞中期染色体数目为2n=4x=36,而原二倍体的染色体数目为2n=2x=18,基数x=9,因此,变异植株（2n=4x=36）为四倍体。前者的核型公式为2n=4x=14m＋20sm＋2st,核型属于2B;后者的核型公式为2n=2x=7m＋10sm＋1st,核型也属于2B。检测发现有少数个体有非整倍体变异。