Mutation breeding of Chrysanthemum morifolium Ram. using in vivo and in vitro adventitious bud techniques

Summary During experiments, which are being carried out to study the factors which control the process of adventitious bud formation in vivo on detached leaves of Chrysanthemum morifolium Ram, adventitious shoots were produced from leaves, irradiated with 500 rad of X-rays. The most important but disadvantageous result was that the majority of the adventitious shoots proved to be of a chimeral nature and obviously developed from more than one cell.An in vitro adventitious bud technique was developed using different types of explants. Pedicel segments regenerated the highest number of adventitious shoots and, moreover, they developed faster as compared to explants of young flower heads or leaves. The mutants produced by irradiating the various explants were almost exclusively of a solid (non-chimeral) nature. In addition, histological observations suggest that single epidermal cells are involved in the initiation of the adventitious shoot apices.The optimum dose for mutant production is approximately 800 rad X-rays. Rather often, more than one phenotypically identical mutant was found, which was always derived from the same explant. They could for instance originate from a multi-apical meristem formed by a single mutated cell.     

彩色马蹄莲离体快繁体系的优化

以彩色马蹄莲球茎为外植体,通过不定芽途径建立彩色马蹄莲离体快繁体系。结果表明：采用“二次消毒法”能够明显降低初代培养过程中的污染率;由外植体直接诱导产生不定芽的彩色马蹄莲快繁体系切实可行,最佳不定芽诱导培养基为MS+6-BA1mg/L+NAA0.1mg/L,不定芽增殖培养基为MS+6-BA2mg/L+NAA1mg/L,最佳生根培养基为1/2MS+6-BA0.1mg/L+NAA0.5mg/L+AC0.5 mg/L;炼苗3d后移栽到土壤:河沙:草炭土=1:1:1的土壤中,并进行遮阳处理,成活率90％以上。     

Stimulation of adventitious bud production in detached sweet potato leaves by high levels of nitrogen supply

Summary Treatment of rooted sweet potato (Ipomoea batatas (L.) Lam.) leaves with high levels of nitrate-nitrogen supply (210 ppm) in sand culture, stimulates the development of adventitious buds and shoots. Up to six adventitious shoots have been produced on a single rooted leaf, grown at 210 ppm NO₃–N. The method may be useful in the production of non-chimeral mutants in mutagenic breeding of sweet potato. It is being used to study physiological factors affecting bud and shoot development as well as tuberisation, as they influence the longevity of the rooted leaf. The method is also being investigated as a technique for the conservation and rapid multiplication of sweet potato genetic resources.     

杨树叶片高效离体再生系统的构建

利用速生杨树（Populus.tomentosa Car）叶片为外植体建立离体培养体系,结果表明,叶脉处和叶柄处,极易发生不定芽;芽大多是从叶片上直接产生;培养基中BA浓度是影响不定芽形成的关键;BA浓度在05~2.0mg/L范围内均有不定芽发生,BA 1.0mg/L与NAA 0.05mg/L搭配有利于不定芽的形成,培养基中添加GA3 0.1~0.2mg/L可以提高不定芽的发生频率,增殖培养基采用MS+BA 0.5mg/L+NAA 0.05mg/L+GA3 0.05mg/L,不仅能够快速增殖,而且芽苗粗壮,玻化率降低。生根过程采用过渡培养效果较好,ABT3生根粉的加入,使试管苗质量大为提高,在此基础上建立起杨树叶片离体再生系统,利用该体系能够获得高的芽苗再生频率,但是不同品种间略有差异。     

皇家夏天葡萄离体叶片再生体系的建立

叶片再生效率的高低直接影响目的基因转化的成功率,为建立稳定、高效的葡萄离体叶片不定芽再生体系,以优良无核葡萄品种皇家夏天为试材,取试管苗顶端1￣3叶位幼嫩叶片,研究了基本培养基成分、生长调节物质的种类和浓度、碳源等因素对叶片不定芽再生的影响。结果表明:供试WPM、1/2MS、B5和NN694种基本培养基,均可诱导其叶片再生不定芽,差异不显著;碳源以添加10￣20g/L的葡萄糖或食用白砂糖较好;培养基中附加3.0mg/L的6-BA与0.05mg/L的IAA配比利于出芽和成苗,应用TDZ虽出芽较多,但芽丛多畸形、出苗困难,不宜使用。     

Diploids and natural autotetraploids in the predominantly vegetatively propagated Brassica oleracea L. var. ramosa DC and their cytology

Summary Perennial kale is a rare vegetable and forage crop in the Dutch province of Limburg where it is disappearing. It may be a relic of a primitive kale form which could have been grown on a large scale in West-Europe. The crop is predominantly vegetatively propagated.Cytological investigations indicated that a number of accessions are autotetraploid with 2n=4x=36. The origin and age of these autotetraploid accessions are not known, but they may stem from adventitious buds on wounded tissue during the vegetative propagation.     

北沙参根茎不定芽诱导及生根的研究

摘要：【研究目的】研究北沙参试管繁殖的诱导、分化、生根、移栽等过程,筛选优良试管苗。【方法】以北沙参根茎为试材,通过筛选激素种类、浓度和光暗条件、 基质等因素找到不定芽诱导、分化、生根及移栽的最佳条件。【结论】根茎不定芽分化诱导适宜的培养基为MS+ NAA0.2mg?L-1 + 6-BA 2.2mg?L-1~2.4mg?L-1+蔗糖30g?L-1＋琼脂8g?L-1,适宜北沙参不定芽生根的培养基为1/2MS+ IBA 0.2 mg?L-1+蔗糖15g?L-1+琼脂6g?L-1,对不定芽带茎段切割可以显著提高转接芽的存活率,添加0.2 g?L-1活性炭有利于提高单株平均生根数,促进根毛发育。采用两步法半封闭炼苗{培养基覆沙法半封闭短期（2d）炼苗结合混合基质移栽长期(10d)半封闭炼苗}效果较好,适宜的移栽基质有两种,分别是：1/3园土+1/3草炭 +1/3细沙和1/3园土+1/3草炭+1/3蛭石。     

向日葵未成熟胚培养中不定芽的发生

研究了向日葵未成熟胚培养中不定芽的发生情况,结果表明,向日葵子叶(?)未成熟胚再生不定芽的能力很强,下胚轴较子叶容易产生不定芽;基因型和培养基是影响不定芽再生频率的重要因子.基因型不同,其不定芽的再生频率差异很大.本实验中大多数基因型都能诱导出不定芽.再生频率在40%以上.最高的达91%.自交系、杂一代和保持系的再生频率高于普通品种.培养基中高含量蔗糖及适宜的6—BA含量有利于不定芽的发生.由不定芽培育出的绿苗在温室条件下,大部分可以正常开花结实.     

Adventitious shoots: Do they develop from one cell?

Summary One of the bottle-necks in mutation breeding of vegetatively propagated crops is the chimera formation after irradiation of multicellular apices in buds of vegetative material. This difficulty can be overcome with in vivo or in vitro adventitious bud techniques which, in combination with radiation, give almost exclusively solid, non-chimeric mutants and unmutated plants. This is usually explained on the basis of the ultimate development of the apex of adventitious shoots from single (epidermal) cells.To investigate whether chimera formation is a matter of chance as a result of which genotypically different cells form the apex of an adventitious shoot, a stochastic model has been developed which describes the process of apex formation and by which the expected relative chimera percentages E(RCP's) are calculated. The discrepancy between these RCP's and the actual figures obtained in various crops, either propagated in vivo or in vitro, leads to the postulate that the apex of the adventitious shoot is formed from only one (epidermal) cell of the meristem or the callus. Another possibility is thatapex formation is not a random process and that the first dividing cell, forming the future meristem or callus, soon occupies the major part of this meristem, on top of which a few cells (most likely genetically identical vegetative daughter cells-mutated or unmutated) form the apex of the adventitious shootlet.     

Isolation of a pure thornless loganberry by meristem tip culture

Summary Thornless Loganberry (TL) is a periclinal chimeral blackberry in which a layer of mutant (thornless) epidermis surrounds a core of wild-type (thorny) tiusse. Due to its chimeral arrangement, TL produces thorny adventitious root cuttings and thorny offspring. To separate the chimera into its components parts, meristems of TL were grow in vitro on modified Murashige and Skoog medium to yield callus and adventitious shoots. One of these shoots has survived, flowered, and produced thornless offspring from seed. The importance of this non-chimeral TL is discussed.List of terms BA 6-benzylaminopurine - GA₃ gibberellic acid - NAA naphthalene acetic acid - hybridberry polyploid bramble interspecific hybrids - MS Murashige & Skoog (1962) high mineral salt medium - TL Thornless Loganberry - TL_tc tissue culture-derived (non-chimeral) Thornless Loganberry     

The inheritance of thornlessness from tissue culture-derived ‘Thornless evergreen’ blackberry

Summary Thornless Evergreen (TE) blackberry (Rubus laciniatus Willd.) is a tetraploid thornless periclinal chimera which produces thorny adventitious root suckers and breeds as if it were genetically thorny. Using tissue culture procedure, several pure thornless (non-chimeral) plants were obtained from TE. These tissue cultured-derived plants (TE_tc) were grown to maturity, flowered, hybridised with various thorny and thornless cultivars, and selfed. When TE and TE_tc were used as female parents, a high degree (ca 94%) of the seedlings were apomictic. However, both thorny and thornless sexual offspring occurred in all crosses. The thornless: thorny segregation ratios suggest that the thornless gene(s) of TE_tc is (are) dominant to the thorny alleles.     

Effects of the shoot-cutting method on field propagation in napiergrass (<Emphasis Type="Italic">Pennisetum purpureum</Emphasis> Schum.)

In this study, the effects of shoot-cutting method on propagation using overwintering napiergrass (Pennisetum purpureum Schum.) buds were examined under soil conditions compared with plant growth regulators (PGRs) that are used as an effective method for increasing adventitious buds of several gramineous crops. To increase adventitious budding, we cut shoots of napiergrass at 2 weeks after planting and treated with the following four types of PGR in comparison with shoot-cutting: 4.44 mM BA as cytokinin, 3.63 mM triazine as anticytokinin, 5.37 mM NAA as auxin, and 2.22 mM TIBA as antiauxin, either by injection or direct spraying onto the buds. A large number of adventitious buds were observed in BA- and TIBA-injected buds at 4 WAT compared to shoot-cut or PGR-sprayed buds. However, an extremely low survival rate for tiller-divided plants (nursery plants) derived from both BA- and TIBA-injected plants was observed compared with non-PGR controls. Similar trends on the survival rate and relative tiller number in main shoot-cut plants derived from intact buds (without PGR treatment) were also observed in a repeat trial. The present study demonstrated that the method of shoot-cutting could contribute to increasing propagation efficiency for nursery plants compared with exogenous PGR application, and would be a practical method for increased nursery propagation of napiergrass under soil conditions.     

鸡冠花离体快繁及多倍体诱导

以鸡冠花顶芽为外植体,研究其离体快繁程序并在无菌体繁殖条件下探索了秋水仙素溶液不同浓度和时间处理对鸡冠花的诱变效应.快繁研究结果显示:最适初代培养基为MS 6-BA 1.0 mg/L NAA 0.2 mg/L;以芽和茎段为培养对象诱导产生不定芽的最适培养基分别是MS 6-BA 1.0 mg/L NAA 0.1 mg/L,MS 6-BA1.0 mg/L NAA 0.02 mg/L,最佳生根培养基是1/2 MS IBA 0.4 mg/L.采用浸泡法将鸡冠花营养芽在0.05%、0.1%、0.15%和0.2%不同秋水仙溶液浓度下分别处理12 h、24 h、36 h和48 h,并对诱导处理后获得的再生植株进行鉴定,得出以0.15%秋水仙素溶液浸泡36 h为诱导多倍体的最佳处理组合,诱导率达23.3%.     

4个优良石榴品种叶片高频再生体系的建立

为提高石榴叶片再生率,增加再生芽数量及缩短再生周期,以‘泰山红’‘、泰山三白甜’‘、皮亚曼’‘、牡丹’4个石榴品种盆栽苗和无菌苗叶片为试材,研究培养基类型、生长调节剂配比、叶片来源和培养步骤对不定芽再生的影响。结果表明：MS是叶片再生最适培养基类型;无菌苗叶片比盆栽苗叶片更易再生不定芽;BA3.0mg/L+KT1.0mg/L+IBA0.3mg/L是叶片愈伤组织诱导、分化和不定芽形成过程中生长调节剂最佳配比;先在液体培养基上培养3~5天,再转至固体培养基比仅在固体培养基上效果更好,叶片再生率最高达98.47%,出芽数达7.51个。叶片不定芽的最佳单芽培养基和增殖培养基分别为B5+BA0.6mg/L+IBA0.5mg/L+椰汁100mL/L+PVP2.0g/L+GA31.0mg/L和B5+BA0.8mg/L+IBA0.5mg/L+椰汁100mL/L+PVP2.0g/L,增殖系数为5.56。适宜的生根培养基为B5+IBA1.0mg/L+椰汁100mL/L,生根率为89.63%。由此建立了石榴叶片高频再生体系。     

黑赤松成熟胚诱导不定芽的研究

以黑赤松成熟胚为外植体进行不定芽诱导分化技术的研究,以此建立黑赤松的再生体系。探讨了基本培养基、激素配比、不同摆放方式、外植体不同取材时间、培养基不同无机盐浓度及不定芽继代增殖等问题。结果表明：成熟胚不定芽诱导以WPM培养基最好,不定芽的平均增值倍数达到3.01;WPM中加入6-BA2~3mg.L-1+NAA0.01~0.05mg.L-1时不定芽的诱导率达76%,平均增值倍数可达3.55;垂直摆放有利于不定芽的分化;外植体预培养21~28d、3/4WPM无机盐浓度诱导效果佳;不定芽继代增值的最佳培养基为：3/4WPM+6-BA 0.5mg.L-1 + NAA 0.02mg.L-1。     

An allotriploid derived from a amphidiploid × diploid

A fully fertile interspecific hybrid (Cucumis hytivus Chen and Kirkbride, 2n =4x =38) between Cucumis hystrix Chakr. (2n= 2x =24) and C. sativus L. (2n = 2x = 14) was previously produced by means of F₁ (2n = 19) embryo rescue and subsequent chromosome doubling. This amphidiploid, a new synthetic species, may serveas a genetic bridge in Cucumis, and thus is a source for broadening the genetic base of C. sativus. The identification and characterization of fertile progeny possessing lower ploidy levels would facilitate bridging among Cucumis species. Putative allotriploids (2n = 26) were recovered from C. hytivus × C. sativus matings by means of embryo culture, and experiments were designed to confirm their genetic constitution, describe their morphology, and establish an efficient protocol for their micropropagation. Apical and axillary buds of these putative allotriploid plants were used as explants to establish a micropropagation system for subsequent verification and characterization of ploidy. Of the array of micropropagation media tested, then ability to be most effective for the induction of adventitious buds (desginated Stage II) was a Murashige and Skoog (MS)growth media containing 13.3μM BA + 1.1μM NAA or containing10 μm BA only. The mean number of adventitious buds per explant in the two media was 6.8 and 6.5, respectively. Shoots resulting from adventitious buds produced roots (Stage III) in relative abundance (39 of 42, 92.8%) on half-strength MS medium containing 1.0 μm IBA. The survivorship of rooted plantlets after acclimatization as assessed by relative production of leaves in plantlets (designated Stage IV) was 91.4% (148 of 162). The chromosome number in putative allotriploid plants as determined in mitotic root tip figures in all plants was 2n = 26, the number expected for allotriploids derived from such a mating. An examination of pollen viability in five samples of each plant by cytochemical staining revealed stainability to be < %.Compared to their parents, the allotriploid genotypes possess a high degree of parthenocarpy (84.8%) as measured by setting fruit in pollen-free conditions. While allotriploid fruit are black-spined and similar to the maternal parent C. hytivus, the dark green leaves typical of allotriploid plants mirrors that of the paternal C. sativus parent. This revised version was published online in July 2006 with corrections to the Cover Date.     

‘北林雄株1号’和‘北林雄株2号’叶片再生体系的建立

为了解决白杨杂种三倍体‘北林雄株1号’和‘北林雄株2号’无性繁殖困难问题,以白杨杂种三倍体‘北林雄株1号’和‘北林雄株2号’的半木质化嫩枝为材料,对外植体消毒方法以及不同激素组合对叶片诱导不定芽的效果进行研究。结果表明：（1） ‘北林雄株1号’和‘北林雄株2号’启动培养最佳的消毒处理方法为20%浓度的84消毒液处理20 min;（2）激素6-BA以及TDZ对‘北林雄株1号’叶片不定芽再生率以及再生系数的影响显著,NAA对叶片不定芽再生率影响不显著,对再生系数的影响极显著,筛选出‘北林雄株1号’叶片再生的适宜培养基为MS+ 0.2 mg/L 6-BA+ 0.1 mg/L NAA+ 0.005 mg/L TDZ;（3）激素6-BA、NAA以及ZT对‘北林雄株2号’叶片再生率和再生系数的影响均达到了显著水平,筛选出‘北林雄株2号’叶片再生的适宜培养基为MS+ 1.0 mg/L 6-BA+ 0.05 mg/L NAA+ 1.2 mg/L ZT。‘北林雄株1号’与‘北林雄株2号’高效叶片再生技术体系建立,为该品种的规模化无性繁殖以及后续的基因工程育种等研究提供了技术基础。     

The use of adventitious buds to prevent chimerism in mutation breeding of potato

Summary Investigations are described to reduce chimerism by means of adventitious buds. Adventitious buds were obtained from tuber slices that had been rooted by auxin. Mutagenic treatments were applied at different stages previous to the development of adventitious buds. Mutations were induced by ethyl methanesulphonate (EMS) and X-rays. The use of the adventitious-bud technique resulted in a considerable reduction of chimerism when X-rays were used, but not so with EMS. A dose of 2 krad of X-rays was optimal for the production high numbers of mutated plants. With higher doses rooting of slices and bud formation were inhibited.     

On the inheritance of the dwarf character in Polyantha × Rosa chinensis minima (Sims) Voss F1-populations

Summary The inheritance of the dwarf character was studied in F1-seedling populations arisen from crosses between diploid Polyantha cultivars and the diploid dwarf species R. chinensis minima (Sims) Voss. Dwarfness is controlled by a single dominant gene D. R. chinensis minima and its dwarf descendants are heterozygous for D, while polyanthas are homozygous for d. The origin of R. chinensis minima and its potential for breeding new pot roses are discussed.     

羊踯躅离体叶片再生体系的建立

为了建立羊踯躅规模化无性繁殖和高效遗传转化体系,以羊踯躅试管苗叶片为外植体,探讨了基本培养基类型、叶片切割方式、叶位、暗培养时间及不同激素组合等因素对叶片再生不定芽的影响。结果表明：WPM培养基为最适基本培养基。垂直于主脉切割一刀并去除叶柄和叶稍的叶片再生不定芽的频率最高。羊踯躅试管苗中、上部叶片的再生能力较强,其中第5和第6位叶的不定芽诱导效果最佳。初始暗培养有利于叶片再生,暗培养10~15天的效果最佳。诱导羊踯躅试管苗叶片再生不定芽的适宜培养基为WPM+TDZ 1.0 mg/L+IAA 1.0 mg/L,其不定芽分化率和平均分化芽数分别达到82.3%和7.2个。