青海仲彬草和黑药仲彬草的生物系统学研究

黑药仲彬草Kengyilia melanthera(Keng)J．L. Yang,Yen et Baum和青海仲彬草K．kokonorica(Keng)J.L．Yang,Yen et Baum是分布于我国西部的两种多年生六倍体植物。将其分别与鹅观草Roegneria kamoji Ohwi(2n=42,StStHHYY)、糙毛仲彬草K．hirsuta(Keng)J．L. Yang,Yen et Baum(2n=42,PPStStYY)进行了杂交;对亲本及杂种F_l代花粉母细胞减数分裂中期I染色体配对行为进行了观察。杂种F1减数分裂染色体配对平均构型分别为：R．kamoji×K．melanthera,18.201+11.74Ⅱ 十0.09Ⅲ十0.01V;K．hirsuta×K．melanthera,1.06Ⅰ十20.47Ⅱ;R．kamoji×K．kokonori-ca,19.36Ⅰ十11.26Ⅱ十0.04Ⅲ;K．hirsuta×K．kokonorica,2.46Ⅰ十19.44Ⅱ 十0.14Ⅲ十0.06Ⅳ。根据以上结果,并结合形态特征,将黑药仲彬草和青海仲彬草从鹅观草属拟冰草组Roegneriasect．Paragropyron Keng中组合到仲彬草属Kengyilia Yen et Yang更为恰当,而不应划分到披碱草属E-lymus L．或偃麦草属Elytrigia Desv．中。     

窄颖仲彬草生物系统学研究

窄颖仲彬草Ｋｅｎｇｙｉｌｉａ ｓｔｅｎａｃｈｙｒａ（Ｋｅｎｇ） Ｊ．Ｌ． Ｙａｎｇ ,Ｙｅｎ ｅｔ Ｂａｕｍ 是分布于我国西部的一种多年生六倍体植物。将其与犬草Ｅｌｙｍｕｓ ｃａｎｉｎｕｓ（Ｌ．） Ｌ．, 鹅观草Ｒｏｅｇｎｅｒｉａ ｋａｍｏｊｉ Ｏｈｗｉ, 糙毛仲彬草Ｋ．ｈｉｒｓｕｔａ （Ｋｅｎｇ） Ｊ．Ｌ．Ｙａｎｇ,Ｙｅｎ ｅｔ Ｂａｕｍ ３ 个种进行了杂交。对亲本及杂种Ｆ１ 代花粉母细胞减数分裂中期Ｉ染色体配对行为进行了观察。减数分裂平均构型分别为： Ｅ． ｃａｎｉｎｕｓ×Ｋ． ｓｔｅｎａｃｈｙｒａ２３－７９ Ⅰ＋ ５－２０ Ⅱ＋ ０－２７Ⅲ; Ｒ．ｋａｍｏｊｉ ×Ｋ．ｓｔｅｎａｃｈｙｒａ１８－２３ Ⅰ＋ １１－６８ Ⅱ＋ ０－０６ Ⅲ＋ ０－０６ Ⅳ; Ｋ．ｈｉｒｓｕｔａ ×Ｋ．ｓｔｅｎａｃｈｙｒａ４－８３Ⅰ＋ １７－３１ Ⅱ＋ ０－５５ Ⅲ＋ ０－２０ Ⅳ＋ ０－０２ Ⅴ。根据以上结果, 结合种的形态特征, 窄颖仲彬草应从鹅观草属Ｒｏｅｇｎｅｒｉａ Ｃ． Ｋｏｃｈ 拟冰草组ＰａｒａｇｒｏｐｙｒｏｎＫｅｎｇ 中组合到仲彬草属Ｋｅｎｇｙｉｌｉａ Ｙｅｎ ｅｔ Ｙａｎｇ。     

Somatic hybridization between Solanum ochranthum and Lycopersicon esculentum

Incorporation of genes from wild species has been a major contributor to tomato improvement in recent years. Solanum ochranthum, a woody vine-like tomato relative, is a potential source of resistance against tomato diseases and insect pests but is genetically isolated from tomato. Somatic hybridization methods were developed to facilitate the use of S. ochranthum for tomato germplasm improvement. Leaf mesophyll protoplasts of S. ochranthum and selected Lycopersicon esculentum genotypes were chemically fused with polyethylene glycol. The protoplasts were initially cultured in Shepard's CL, a Murashige and Skoog-based medium, containing 1 mg l^-1 NAA, 0.5 mg l^-1 N⁶-benzyladenine and 0.5 mg l^-1 2,4-dichlorophenony-acetic acid. Tetraploid and hexaploid hybrid regenerants and regenerants of an L. esculentum parent were recovered; S. ochranthum did not regenerate. Hybridity was established by morphological characters, peroxidase isozyme and RAPD markers.Abbreviations MS Murashige and Skoog (1962) medium - CL Shepard (1980) cell layer medium - 2,4-d 2,4-dichlorophenoxyacetic acid - NAA -naphthaleneacetic acid - BAP N⁶-benzyladenine - MES 2-N-morpholinoethanesulfonic acid - PEG polyethylene glycol - RAPD randomly amplified polymorphic DNA - PPM potato propagation medium - TPM tomato propagation medium - OM modified Murashige and Skoog (1962) medium - OM + AC modified Murashige & Skoog (1962) medium + activated charcoal     

Production and cytogenetics of intergeneric hybrids between the three cultivated Brassica diploids and Orychophragmusviolaceus

It has been proposed that both complete and partial separation of the parental genomes during mitosis and meiosis occurs in the intergeneric hybrids between Orychophragmus violaceus (2n=24) and the three cultivated Brassica tetraploids (B. napus, B. carinata and B. juncea). The hypothesis has been that this and the variations in chromosome numbers of these hybrids and their progenies result from the different roles of the A, B and C genomes originating from Brassica. To test this hypothesis, we produced hybrids between O. violaceus and the cultivated Brassica diploids. The hybrids with B. oleracea (2n=18, CC) had an intermediate morphology, but their petals were purple like those of O. violaceus. They were sterile and had the expected chromosome number (2n=21) in their mitotic and meiotic cells. The hybrid with B. campestris (2n=20, AA) was morphologically intermediate, except for its partial fertility and its yellow petals, which were similar to those of B. campestris. It was mixoploid (2n=23–42), and cells with 2n=34 were most frequent. Partial separation of parental genomes during mitosis, leading to the addition of O. violaceus chromosomes to the B. campestris complement, was proposed to explain the findings in the mitotic and meiotic cells of the hybrid and its progeny. In crosses with B. nigra (2n=16, BB), the majority of the F₁ plants were of the maternal type (2n=16), a small fraction had B. nigra morphology but were mixoploids (2n=16–18), predominantly with 2n=16 cells and three plants, each with a specific morphology, were mixoploids consisting of cells with varying ranges of chromosome numbers (2n=17–26, 11–17 and 14–17). The origin of these different types of plants was inferred to be a result of the complete and partial separation of parental genomes and the loss of O. violaceus chromosomes. Our findings in the three crosses suggest that the A genome was more influential than the C genome with respect to complete genome separation during mitosis and meiosis of the hybrids with B. napus. Possible complete and partial genome separation during mitotic divisions of the hybrids with B. carinata was mainly attributed to the role of the B genome. The combined roles of the A and B genomes would thus contribute to the most variable chromosome numbers of mitotic and meiotic cells in the hybrids with B. juncea and their progenies. The possible cytological mechanisms pertaining to these hybrids and the potential of genome separation in the production of Brassica aneuploids and homozygous plants are discussed. Received: 8 February 1998 / Accepted: 12 March 1999     

Production and cytogenetics of the intergeneric hybrids Brassica juncea×Orychophragmus violaceus and B. carinata×O. violaceus

 Intergeneric hybrids between Brassica juncea (2n=36), B. carinata (2n=34) and Orychophragmus violaceus (2n=24) were produced when B. juncea and B. carinata cultivars were used as female parents. The hybrids between B. juncea and O. violaceus had an intermediate morphology except for petal colour and were partially fertile. The hybrids between B. carinata and O. violaceus had a matroclinous morphology and were nearly fertile. Cytological analysis of the hybrids and their progenies gave the following results. (1) In the hybrids between B. juncea and O. violaceus, the somatic tissues of the roots, leaves and styles were mixoploid (2n=12–42), and cells with 24, 30 or 36 chromosomes were the most frequent. Based on the recorded numbers and behaviour of the mitotic and meiotic chromosomes, complete and partial separation of the parental genomes was proposed to have occurred during mitosis. This resulted in the occurrence of cells with possibly complete and incomplete complements of the parental species and cells with parental complements and some additional chromosomes from the other parent. (2)  Pollen mother cells (PMCs) possibly with both parental chromosome complements, only B. juncea chromosomes or a complete B. juncea complement with additional O. violaceus chromosomes were more competitive in entering meiosis. The majority of fertile gametes were deduced to have been produced by PMCs with a B. juncea complement with or without additional O. violaceus chromosomes. (3) The progeny plants from selfed hybrids between B. juncea and O. violaceus were morphologically either of a B. juncea, hybrid or variable type. Cytologically they were grouped into six types according to the frequencies of cells with various chromosome numbers. All of the plants except 2 which constituted two types, were mixoploids, composed of cells with various chromosome numbers, mainly in a certain serial range. (4) The hybrid plants between B. carinata and O. violaceus were mixoploids with chromosome numbers in the range of 12–34, and cells with 2n=34 were the most frequent. The main categories of PMCs with 17 bivalents at metaphase I and 17 : 17 segregations at anaphase I contributed to the high fertility of the hybrids and the fact that their progeny after selfing were mainly plants with 2n=34. Somatic and meiotic separation of the parental genomes was proposed to have occurred in the hybrids between B. carinata and O. violaceus. (5) Mitotic and meiotic elimination of what could be O. violaceus chromosomes might also have contributed to the observed mitotic and meiotic cell types in the two kinds of hybrids studied. Finally, the possible mechanisms behind these cytological observations and their potential in the production of Brassica aneuploids were discussed. Received: 4 February 1997/Accepted: 29 July 1997     

Cytogenetical studies on artificial hybrids amongElymus sibiricus,E. dahuricus andAgropyron tsukushiense in the tribe Triticeae,Gramineae

To explore the cytogenetical relationships ofElymus andAgropyron of the tribe Triticeae, Gramineae, two species of AsiaticElymus, E. sibiricus (2n=28) andE. dahuricus (2n=42), and a JapaneseAgropyron, A. tsukushiense (2n=42) were crossed. Pentaploid and hexaploid F₁ hybrids were vigorous. All pollen grains were aborted and none of the hybrids produced seed. For the crossE. sibiricus × A. tsukushiense, the average chromosome pairing per cell at the MI of the PMCs in the F₁ was 16.38 univalents, 8.93 bivalents, 0.25 trivalents and 0.01 quadrivalents; for the crossE. dahuricus × A. tsukushiense, it was 4.41 univalents, 17.67 bivalents, 0.32 trivalents, 0.28 quadrivalents and 0.04 quinquevalents; and for the crossE. dahuricus × E. sibiricus, it was 17.11 univalents, 8.74 bivalents, 0.04 trivalents and 0.07 quadrivalents. From the present results, it is concluded thatE. sibiricus contains one genome andE. dahuricus contains two genomes, which are homologous to those ofA. tsukushiense, and that the third genome ofE. dahuricus might be partially homologous to the remaining genome ofA. tsukushiense. This conclusion is also supported by the cytogenetical analysis ofE. dahuricus × E. sibiricus. Contribution No. 27 from the Plant Germ-plasm Institute, Faculty of Agriculture, Kyoto University, Kyoto, Japan.     

Wide hybridization experiments in cereals

Summary Wide hybridization is a useful tool in plant breeding, but little is known about its possible range. For the cereals, wheat, barley and rye, this was tested with 15 different species of the Poaceae and Panicoideae. Embryo formation could be obtained with Agropyron repens, Alopecurus agrestis, Dactylis glomerata, Festuca glauca, Hordeum bulbosum, Lolium perenne, Pennisetum americanum, and Zea mays. As well, haploid as diploid embryos occurred. New embryo culture techniques should enable these embryos to grow to plants.     

Cytogenetics of the trigeneric hybrid, (Hordeum vulgare ×Triticum aestivum) ×Secale cereale

Summary Chromosome pairing was studied in hybrids of (Hordeum vulgare ×Triticum aestivum) ×Secale cereale. Chiasma frequency per cell varied from 1.94 to 3.16 between the different hybrids. This variation was attributed to genetic variability in rye parents which affected homoeologous pairing. The pairing of rye chromosomes as revealed by Giemsa C-banding was a combination of nonhomologous association between rye chromosomes and associations with chromosomes of wheat and barley. Contribution No. 634 Ottawa Research Station     

甘蓝型油菜与诸葛菜属间杂种无性系的变异研究

从形态及细胞学两方面对甘蓝型油菜与诸葛菜属间杂种无性系的变异进行了研究。经过长期继代培养后,杂种在形态上越来越偏向母本甘蓝型油菜,而表现出较少的父本诸葛菜性状,但表现出对等双分枝的新性状。经细胞学观察表明,杂种体内杂种细胞比例下降,而甘蓝型油菜细胞比例大幅度上升并远高于核质杂种细胞（具有油菜细胞质与诸葛菜细胞核）的比例,以至较多的甘蓝型油菜染色体组被遗传下去。在该杂种继代培养中还观察到杂种细胞内的染色体消除及体细胞配对现象。     

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。     

青花菜与萝卜属间杂种的表型和分子鉴定

应用形态学、细胞学和分子标记的方法对通过胚挽救获得的青花菜与萝卜属间杂种植株进行了鉴定。结果表明:杂种植株的生长势明显强于父本和母本,大部分形态性状超出了父、母本的范围,部分性状介于父母本之间或偏向于父本或母本一方。表型和细胞学观察显示杂种植株具有类似母本的雄性不育特性。SSR分子标记分析表明,杂种植株包含了双亲的遗传信息。可见,远缘杂种是双亲间的真杂种。远缘杂交种的获得与初步鉴定为促进萝卜属和芸薹属的基因交流提供了桥梁种质,为进一步创制萝卜或芸薹属作物新种质提供了基础材料。     

Analysis of meiosis in triticale (XTriticosecale Wittmack) X rye (Secale cereale L.) F1 hybrids at three ploidy levels

Summary Triticales (XTriticosecale Wittmack) at three ploidy levels (8x, 6x, 4x, x=7) were crossed with diploid rye (Secale cereale L.) to produce a solitary hypopentaploid hybrid (2n=32), and a number of tetraploid (2n=4x=28) and triploid (2n=3x=21) hybrids. The hybrids exhibited a morphology which was intermediate between the parents. The number of bivalents ranged from 1–7 (4.65 per cell) in hypopentaploid, from 2–12 (7.13 per cell) in tetraploid and from 4–9 (6.84 per cell) in triploid hybrids. In 4x and 3x hybrids, trivalents and quadrivalents were also observed at low frequencies (range 0–1; mean 0.01–0.03 per cell). Chiasmata frequency was highest in triploid hybrids (12.44 per cell), lowest in hypopentaploid (5.37 per cell) and intermediate in tetraploids (10.54 per cell). More than 7¹¹ were found in 39.7% pollen mother cells (PMC's) in the 4x hybrids and in 5.0% PMCs in 3x hybrids. It is concluded that an increase in the relative proportion of wheat chromosomes in the hybrids had a slight suppression effect on homologous as well as homoeologous pairing of rye chromosomes. Contrary to this, the relative increase in rye complement promoted homoeologous pairing between wheat chromosomes. In triploid hybrids, the chiasmata frequency as well as the c value were the highest, suggesting that in tetraploid hybrids rye chromosomes had a reduced pairing (low frequency of ring bivalents).     

甘蓝型油菜与诸葛菜属间杂种的减数分裂观察

在甘蓝型油莱与诸葛菜属间杂种细胞减数分裂中,观察到两种类型的染色体分离方式。第一种,细胞内的３１条染色体呈两组分离,其中１９条染色体至细胞一极,１２条染色体至另一极;且在两极的染色体进行分裂,产生４个核,两个具有１９条染色体,另两个具有１２条染色体。故杂种细胞通过这种染色体分离方式,可同时产生具有１９与１２条染色体的两类配子。杂种细胞内发生的这种染色体行为,极有可能与来自两个亲本种的染色体组相关;即在细胞两极的１９与１２条染色体分别来自甘蓝型油菜与诸葛菜。第二种,在后期Ｉ至末期Ｉ,花粉母细胞内以６个二价体形式出现的１２条染色体被落后在赤道板附近,而被排斥在末期核之外。这些落后二价体很有可能来自诸葛菜。因此,在杂种细胞减数分裂中,来自两个亲本种的染色体组被分开。文中还对染色体组分开的遗传意义等进行了讨论。     

Production of trigeneric (barley × wheat) × rye hybrids

Summary Rye (Secale cereale cv. Prolific 2n=14 and 2n =14 + 2B was crossed onto hybrids between barley (Hordeum vulgare 2n = 14) and wheat (Triticum aestivum 2n= 42). Pollinated florets were injected with GA₃ to promote fertilization and hybrid embryo development. At 16 days after pollination the watery caryopses were removed, embryos dissected and cultured on a modified B₅ medium. Approximately 20% of the cultured embryos produced both roots and coleoptile and developed into viable seedlings. Viable seeds were also obtained at a low frequency from the same cross combinations. The hybrids were wheat-like except for the hairy neck characteristic of rye. There were 35 chromosomes in somatic tissue; 21 wheat, 7 barley and 7 rye. The rye chromosomes were distinguishable by their larger size and terminal C-bands. A lower seed set was obtained using pollen from rye plants with 2n=14 + 2B chromosomes than from plants without B chromosomes.Contribution No. 577, Ottawa Research Station     

大麦与小麦属间杂种的形态学和细胞遗传学研究

通过幼胚培养技术分别获得了大麦(Hordeum vulgare L., 2n=2x=14)与普通小麦(Triticum aestivum L., 2n=6x=42)、硬粒小麦(T. durum d. sf., 2n=4x=28)以及栽培二粒小麦(T. dicoccum Schrank 2n=4x=28)之间的属间杂种,平均杂交结实率分别为3.0％、1.2％和0.8％。杂种在形态上偏向小麦,自交不孕,用父本作回交亲本获得了大麦×普通小麦杂种的回交一代。所有杂种均表现细胞学上的不稳定性。杂种减数分裂中期1 PMC染色体平均配对频率和交叉结频率分别为27.31Ⅰ 0.33Ⅱ 0.011Ⅲ,0.45;20.571 0.20Ⅱ 0.008Ⅲ,0.25和20.41Ⅰ 0.28Ⅱ 0.005Ⅲ,0.32,表明双亲染色体组间不存在同源关系。大麦×四倍体小麦杂种小孢子的染色体计数表明,杂种中未减数雄配子的频率在60％以上。     

硬粒小麦、提莫菲维小麦与四倍体长穗偃麦草属间杂种的形态和细胞遗传学研究

首次获得硬粒小麦（Triticum durum Desf),提莫菲维小麦（T.timopheevi Zhuk)与四倍体长穗偃麦草（tetraploid Elytrigia elongata)的属间杂种,杂交当代结实率分别为5．29％和1．41％,杂种均表现为多年生,具很强的生活力,形态上呈双亲中间类型,杂种F1自交不育,用普通小麦,硬粒小麦回交,以硬粒小麦为母本的F1均获得交种子,杂种F1花粉母细胞减数分裂中期I染色体配以构型分别为：13．78I＋6．87II＋0．147III,9．10I＋9．11 II＋0．20III,F1形成的二价体主要是四倍体长穗偃麦草染色体之间配对所致,并推测四倍体长穗偃麦草具促进小麦部分同源染色体配对或抑制小麦ph基因作用的特殊遗传系统。     

植物逆转座子及其在基因功能和基因组分析中的应用

植物逆转座子及其在基因功能和基因组分析中的应用路铁刚孙敬三（中国科学院植物研究所,北京１０００９３）ＰｌａｎｔＲｅｔｒｏｔｒａｎｓｐｏｓｏｎｓａｎｄｔｈｅＰｅｒｓｐｅｃｔｉｖｅｏｆＴｈｅｉｒＡｐｐｌｉｃａｔｉｏｎｉｎＧｅｎｅＦｕｎｃｔｉｏｎａｌａｎｄ...     

Karyotype stabilization in intergeneric hybrids of the subtribe Triticinae

Summary The C-banded data obtained from Triticinae hybrids are studied with reference to the stabilization of their karyotypes. The types of hybrids distinguished according to genome structure are type I with minimally one diploid genome and type II with a haploid set only. Comparative analysis demonstrates that type I differs from II in karyotype stabilization. The chromosomes from various haploid genomes are combined into new genomes in type I; type II is represented only by amphiploids with the complete set of the chromosomes from all the genomes. The meiotic behaviour of the haploid genome chromosomes were found to have a modifying effect on karyotype stabilization: type II becomes I when homoeologous pairing level is high and when it is associated with the reductional division of univalents.The paper is dedicated to the memory of Professor V. V. Khvostova