氨磺灵和秋水仙素诱导橡胶草四倍体效果的比较研究

为探讨不同诱变剂对橡胶草四倍体的诱导效果,以橡胶草幼芽为材料,采用浸芽法,比较分析氨磺灵和秋水仙素2种诱变剂不同浓度和处理时间对橡胶草多倍体的诱导效果及多倍体橡胶草的形态特征变化。结果表明：氨磺灵处理橡胶草的成苗率(60%~75%)和最高诱变率(14.08%)均高于秋水仙素处理（0~59%和5.56%）,其嵌合体率(27.27%)低于秋水仙素处理(75.00%),其中0.04 mmol/L氨磺灵处理 30 min,成苗率为71.00%,变异率14.08%,为最佳诱变条件。可见,氨磺灵比秋水仙素更适合用于橡胶草多倍体诱导。诱导后获得的四倍体橡胶草叶片厚度、气孔大小、花和种子大小均显著大于野生型二倍体植株,气孔密度则显著低于野生型植株,这些形态特征可辅助多倍体橡胶草快速筛选和鉴定。本研究初步探明了2种诱变剂对橡胶草染色体加倍的诱导效果,为今后橡胶草多倍体育种提供理论依据和技术支持。     

东方百合Siberia多倍体诱导及其细胞学鉴定

本文以东方百合Siberia的试管苗为试验材料,研究了预培养时间、秋水仙素处理方法及浓度等因素对诱导试管苗多倍体的影响.研究结果表明:秋水仙素溶液直接浸泡较共培养法好,且以0.05%的浓度和浸泡48 h为最佳组合,最终获得了18株四倍体试管苗.通过根尖染色体计数确定其为稳定的同源四倍体.显微观测气孔特征后发现:二倍体与四倍体植株的叶下表皮气孔密度及气孔保卫细胞长、宽差异均达到了极显著水平.     

不同浓度秋水仙素对贡蕉的多倍体诱导

本试验以贡蕉胚性细胞悬浮系、胚性愈伤组织和多芽体为试验材料,利用不同浓度的秋水仙素溶液对不同外植体材料进行不同时间的诱变处理,以期获得染色体加倍的植株。结果表明,试验所用的胚性悬浮细胞系、胚性愈伤组织和多芽体三种不同外植体对秋水仙素处理的敏感性都较高,出现了不同程度的死亡,以0.4%(w/v)浓度的秋水仙素溶液处理多芽体48h诱导效果较好,多芽体的死亡率达到45.83%,接近半致死率,诱变率为18.64%。通过染色体计数和气孔鉴定,获得62株纯合四倍体小苗。诱变获得的植株的染色体数目加倍,叶片气孔数量减少,体积增大。本次试验为香蕉多倍体诱变育种和新种质的创新提供了技术参考和相关依据。     

野生碧玉兰多倍体诱导及鉴定

以云南野生碧玉兰种子无菌萌发的试管苗为材料,采用浸泡法,在无菌条件下用不同浓度的秋水仙素溶液对碧玉兰丛生芽进行多倍体诱导,结果表明：以0.04%的秋水仙素处理72h效果最好,诱导变异率达60%,死亡率为30%,变异试管苗形态上表现为叶片变宽、叶色较深、叶面粗糙、部分叶尖开叉并有双脉、植株矮壮,且生长缓慢;经细胞学检测,二倍体碧玉兰染色体数目为40（2n=2x=40）,变异苗染色体数目大部分为80（2n=4x=80）;四倍体叶表皮气孔变大,单位面积内气孔数明显减少;通过RAPD分析,结果显示二倍体和四倍体在带型上存在差异。     

二甲戊乐灵诱导金线莲多倍体

本研究以二倍体的金线莲无菌苗顶芽为试验材料,选择二甲戊乐灵、处理时间为试验因子进行完全试验设计,研究离体培养条件下二甲戊乐灵对金线莲多倍体诱导的诱变效应。研究结果显示:金线莲对二甲戊乐灵较为敏感,随着二甲戊乐灵处理浓度和时间的增加,植株的死亡率和变异率升高。在二甲戊乐灵处理浓度为200μmol·L-1、处理时间8 d的条件下,对金线莲的诱变效果最佳,诱变率可达到44.17%。对诱导处理后获得的变异植株进行形态和细胞学鉴定,变异植株呈现茎秆粗壮、叶片宽大肥厚、气孔器变大以及保卫细胞叶绿体数增加等多倍体植物的特征,说明二甲戊灵能在离体条件下能有效诱导金线莲产生多倍体,可替代秋水仙素对金线莲细胞染色体的加倍作用,用于多倍体品种选育。     

白魔芋多倍体诱导研究初报

采用种子浸泡法和根状茎顶芽滴液法进行白魔芋多倍体诱导，比较了不同秋水仙素浓度和不同处理时间对出苗率和变异率的影响。结果表明，滴液法对材料的毒害性更小，经同一浓度秋水仙素溶液处理后出苗率和植株形态变异率均高于种子浸泡法，但诱变加倍的效果不如浸泡法。实验中获得一株纯合四倍体植株，由0.20%秋水仙素溶液处理种子48h诱变得到。     

涪陵胭脂萝卜多倍体诱导研究

以不同浓度秋水仙素溶液处理胭脂萝卜幼苗茎尖生长点,通过苗期和成株期对诱变植株和正常二倍体植株进行形态学和细胞学鉴定,探讨四倍体胭脂萝卜的诱导方法与途径.结果表明,5种浓度秋水仙素都能诱变出四倍体胭脂萝卜,其中2 g/L秋水仙素诱变率最大,为33.3％.四倍体胭脂萝卜平均叶片厚度、叶长、株高、叶宽和开展度较二倍体分别增加32.4％、39.6％、39.8％、24％和31.7％,四倍体胭脂萝卜叶片单位视野内的气孔数目少于二倍体72.2％,但气孔的横径和纵径分别较二倍体大40.8％和30.7％.说明叶片厚度、叶长、株高、叶宽、开展度、气孔数目、气孔的横径和纵径等性状可以作为四倍体鉴定的重要特征,特别是气孔数目、气孔的横径和纵径可以作为快速鉴定四倍体与二倍体胭脂萝卜的重要指标.利用秋水仙素诱导是获得四倍体胭脂萝卜的有效途径之一.     

盾叶薯蓣组织培养及四倍体诱导技术的初步研究

以盾叶薯蓣的茎段、叶柄、叶作为外植体进行离体组织培养,其效果以茎段和叶柄最好。诱导愈伤组织的培养基以MS+2,4-D 2.0mg/L+BA 0.5mg/L为佳;在培养过程中,可用MS+BA 3.0mg/L+NAA 0.2mg/L作为分化培养基,后逐步转为MS+BA 1.Omg/L+NAA 0.2mg/L作为继代培养基;生根培养可使用MS+NAA 1.0mg/L的培养基。在组织培养条件下,对盾叶薯蓣进行了多倍体诱导的研究。结果表明,用0.15%的秋水仙素处理24小时后,诱导率可达50%,效果较好。经秋水仙素诱导的变异株,与正常的二倍体植株相比,植株粗壮,叶片变大变厚,叶色浓绿,部分还出现畸形叶。叶片表皮气孔检测发现,多倍体植株叶片表皮气孔变大,且单位面积下的气孔数目减少;进行细胞学研究发现,正常植株的染色体的数目为2n=2x=20,变异植株染色体数目为,变异植株染色体数目为2n=4x=40,为四倍体。     

秋水仙素诱导马铃薯野生种S.acaule多倍体的初步研究

马铃薯野生种需通过人工诱导染色体加倍后才能与栽培种进行杂交。本试验以马铃薯野生种S.acaule无菌苗带腋芽茎段为材料,采用浸泡法和混合培养法研究了秋水仙素诱导马铃薯野生种S.acaule产生多倍体的诱导效果。结果表明:在继代增殖培养基中添加浓度为0.3%的秋水仙素,共同培养时间为14d时获得诱导变异率最大,为31.6%;获得的87株变异株有2株为多倍体植株。     

陆地棉与斯特提棉种间杂交及多倍体诱变

挖掘野生棉资源是棉花育种的一个重要方向,而野生斯特提棉含有栽培棉所缺乏的许多优良基因。本研究以陆地棉品种中12为母本与斯特提棉进行远缘杂交,获得不育杂种F1。结果显示,杂种F1的花粉母细胞减数分裂存在许多异常行为,包括游离染色体、落后染色体、染色体断片、不均等分离等,异常现象出现的频率达41.03%,小孢子母细胞减数分裂异常的可能原因是由染色体后期Ⅱ向多极不均等分离形成的,导致杂种F1高度不育。为使杂种F1的育性恢复,本研究利用不同浓度的秋水仙碱琼脂凝胶对该杂种进行多倍体诱变,结果显示最佳诱变参数为浓度为0.2%,时间1 d,存活率达55%,诱变率5%。和对照株相比,本研究获得的一株变异株形态表现为:节间缩短;子叶变大;真叶出现晚,着生子叶的茎杆处和子叶柄处出现瘤状;变异株具有较强的生长势,叶色浓绿,花瓣变大但较薄,初步形态学特征分析证实获得的一株诱变株可能是多倍体。诱变株17.4%的花粉母细胞减数分裂恢复正常,诱变株正常花粉粒比例较未诱变对照株提高了6.66%,表明诱变株的育性有恢复的趋势。通过探究杂种F1不育的原因,为其育性的恢复提供了一定的理论依据。     

不结球白菜同源四倍体苏州青的诱导鉴定

为获得高产优质的不结球白菜四倍体苏州青,本研究使用浓度分别为0.1%,0.2%及0.3%的秋水仙素溶液,点滴处理二倍体苏州青幼苗植株的子叶生长点,进行5次处理后,通过形态学和细胞学方法筛选鉴定四倍体苏州青植株,并比较二、四倍体苏州青的农艺性状及品质差异。结果表明：秋水仙素浓度为0.2%时加倍效果最好。形态解剖学鉴定结果表明：四倍体在株型、叶片、花、种荚、种子大小都有较明显的变大趋势;四倍体植株叶片气孔较二倍体变大,气孔密度变小;同时四倍体植株花粉粒比二倍体更膨大,更不规则;细胞学鉴定结果表示,四倍体植株染色体数为40条,二倍体植株为20条;通过流式细胞仪鉴定,四倍体植株荧光强度约为二倍体的2倍。通过品质比较分析,结果显示四倍体苏州青的各项生理指标含量较于二倍体均有不同。通过农艺性状比较,单株质量、叶宽、叶厚都有一定程度的增加。本研究利用秋水仙素操作技术,抑制有丝分裂后期纺锤丝的形成,实现染色体加倍,创制不结球白菜新种质,为选育四倍体不结球白菜提供理论基础和种质资源。     

Production of 2n pollen of Asiatic hybrid lilies by nitrous oxide treatment

Tetraploid varieties of lilies have superior agronomic traits such as large flowers and resistance to physiological disorders. In the present study, we attempted to induce 2n pollen of Asiatic hybrid lilies by arresting the meiotic process with nitrous oxide (N₂O) gas. To determine which meiotic stage is optimal for induction of 2n pollen, plants with attached buds at different meiotic stages were treated with N₂O for 24 h in a pressure-tolerant cylinder. A few 2n pollen grains were induced using plants with anthers in prophase I, whereas mixed pollen grains of differing size were produced using plants undergoing meiotic metaphase predominantly in anthers. Although normal lily pollen grains are elliptical, nitrous oxide exposure induced giant pollen grains that appeared spherical. Flow cytometry analysis showed that the giant pollen grains were diploid. When mixed pollen that included normal and giant pollen was crossed to tetraploid cultivars, the resulting seedlings were tetraploid and aneuploid, indicating that the giant pollen grains were diploids that could generate tetraploid seedlings through fusion to diploid eggs supplied from a tetraploid female parent. Thus, treatment with N₂O is useful for the production of 2n lily pollen and may provide a new approach for tetraploid lily breeding.     

Studies on colchicine induced tetraploids of jute

Summary Colchicine induced tetraploid jute plants were shorter than their diploid counterparts. C₂ tetraploid plants became taller than C₁ plants. Leaves were larger in size and with higher breadth/length ratios compared to those of diploids. Stomata were bigger than those in diploid leaves but their frequency was less in tetraploid leaves. Tetraploid flowers were bigger than the diploids and bore a reduced number of stamens. Tetraploid pollen grains were larger but the percentage of sterility in them was more than that of the diploids. Fewer fruits with a reduced number of seeds were formed in tetraploid plants. They usually were shorter but wider than diploid fruits. Tetraploid seeds were larger and heavier. C₂ tetraploid plants bore more fruits with an increased number of seeds than C₁ plants. Breadth of individual fibres increased but length remained unchanged.The paper was read at the Eighth Pakistan Science Conference held at Dacca, 1956.     

Scanning Electron Microscope Observation on Floral Organs and Leaf Epidermis of F. suspensa

[Objective]To observe the morphological characteristics of floral organs and leaf epidermis of F.suspensa,so as to provide basic information for introduction,cultivation and taxonomy study of fine varieties.[Method]The pollen,stigma,style,upper and lower leaf epidermis of F.suspensa respectively adhered to the double faced adhesive tap of sample cup,observed,photographed and measured under scanning electron microscope(SEM).[Result]The pollen,whose extine surface is coated with netlike ornamentations and 3-colporate,is prolate in shape.Stigma is dichotomous branching and dry stigma.The stomatal apparatuses of style epidermis are anomocytic type.The upper and lower leaf epidermises have different cuticle ornamentations,both of which are covered by glands and without trichomes.In addition,the stomatal apparatus are restricted to the lower epidermis.[Conclusion]This method is accurate,reliable.It could provide theoretical basis for introduction,cultivation and taxonomy study of fine varieties of F.suspensa.     

四倍体与二倍体紫薇光合特性研究

为了解四倍体紫薇和二倍体紫薇光合生理特性的差异,培育优质林木,采用英国PP-Systems公司产CIRAS-1型便携式光合系统测定人工诱变培育的四倍体紫薇品种和二倍体紫薇品种的各项光合生理参数及其变化规律。结果表明：四倍体和二倍体紫薇的叶片净光合速率日变化都呈单峰型曲线,但峰值出现的时间不同。两个紫薇品种的净光合速率(Pn)、气孔导度(Gs)和水分利用率(WUE)差异显著,蒸腾速率(Tr)、表观量子效率(AQY)和羧化效率(CE)差异不显著。光饱和点(LSP)为二倍体紫薇[1445μmol/(m2?s)]<四倍体紫薇[1670μmol/(m2?s)],光补偿点(LCP)为二倍体紫薇[12.23μmol/(m2?s)]<四倍体紫薇[42.2μmol/(m2?s)];CO2饱和点(CSP)为二倍体紫薇[1200μmol/mol]<四倍体紫薇[1427.5μmol/mol],CO2补偿点(CCP)为二倍体紫薇[32.24μmol/mol]<四倍体紫薇[35.71μmol/mol]。四倍体紫薇单位叶面积叶绿素含量显著高于二倍体紫薇(P<0.05)。     

Hybridization, Through Culture of Embryos and Immature Seeds, of a Range of Tomato Cultivars with a Tomato Somatic Hybrid [Lycopersicon esculentum (+) L. peruvianum]: Emergence of a Possible New Marker Gene for Tomato Breeding

Two hexaploid somatic hybrids [Sh; L. esculentum (+) L. Peruvianum] accessions 6 and 18 were back-crossed with two diploid L. Esculentum cultivars ‘Moneymaker’ (mm) and ‘pusa Ruby’ (pr). Twenty-two plants of the bc2 generation were produced by backcrossing 7 bcl plants (mm x sh, 6, 18) with five tomato cultivars. Fourteen of the bc2 plants were self-fertile, five produced anther cones with anthocyanin pigmentation not present in the parents. A bc3 generation was developed by crossing the four cultivars as female parent with three bc2 generation plants. The bc3 progeny derived from one pollen parent plant were produced without the need to culture immature seeds. They segregated with respect to pigmented anther cones and were self-fertile. The anther cone pigmentation of the pollen parent plant was associated with increased seed set, greater fruit size and an orange-red fruit colour. These features were transmitted to the fertile bc3 generation. Conversely, bc3 offspring involving the other two parent plants were only recovered by culture of immature seeds. The recovery of diploid plants in BCl and self-fertility in BC2 resulted in almost total recovery of the tomato cultivar characteristics (fruit size, colour and number of seeds) by BC3.     

A tetraploid hybrid plant from 4x × 2x crosses in Vitis and its origin

To study the origin of unreduced (2n) gametes in diploid Vitis cultivars, we surveyed the occurrence of tetraploid hybrid seedlings from 40 interploid crosses with five tetraploid and seven diploid cultivars. A total of 250 seedlings from the interploid crosses were established through embryo culture and by seed sowing. In 20 2x × 4x crosses, no tetraploid hybrid seedlings were derived from 8,902pollinations. In 20 4x × 2x crosses, two tetraploid hybrid seedlings were obtained from 8,057 pollinations. Investigation of isozyme genotypes of the two tetraploid seedlings using three variable enzyme systems indicated that one of the two seedlings resulted from the union of a diploid egg with a 2n male gamete and that failure of second meiotic division resulted in the formation of the 2n male gamete. The percentage of giant pollen grains in `Muscat Bailey A', a pollen parent of the tetraploid seedling, was relatively high(about 5.9%) and 10.9% of the giant pollen grains germinated on agar medium. These results suggested that 2n pollen of diploid cultivars are useful for breeding tetraploid grape. This revised version was published online in August 2006 with corrections to the Cover Date.     

弱光逆境对番茄幼苗形态、生理特征及叶片超微结构的影响

以两个不同生态型的番茄变种为试材,分别在对照(400～450 μmol/(m~2·s))和弱光逆境下(75～100 μmol/(m~2·s))研究番茄形态、生理指标及叶绿体超微结构的变化.结果表明:弱光显著抑制了番茄的生长,普通大果番茄(美粉二号)和樱桃番茄(红圣果)总的干物质含量分别下降了22.43%和28.87%,二者的壮苗指数分别比对照下降33.53%和51.48%,说明弱光条件下的植株发生了徒长.弱光下叶片光合色素含量显著增加,Chla/b则显著下降,有利于叶片捕获有限的光能.弱光逆境下番茄叶片净光合速率(Pn)下降,气孔导度也随Pn降低,但胞间CO_2浓度增高,表明弱光下番茄光合作用的限制因素是非气孔因素.弱光使番茄叶片厚度薄,栅栏组织与海绵组织比值减小.电镜观察结果表明,番茄叶片栅栏细胞内叶绿体数目及淀粉粒数目成比例减少,叶绿体和淀粉粒减小,叶绿体内基粒数和单个基粒中的片层数增加,这是弱光逆境对番茄叶绿体超微结构影响的首次报道.揭示了弱光与番茄生长及其光合系统结构性能之间的关系,为番茄耐弱光品种的选育提供理论参考.     

Induction of <Emphasis Type="Italic">Anthurium andraeanum</Emphasis> “Arizona” tetraploid by colchicine in vitro

Tetraploids plants of Anthurium andraeanum “Arizona” were successfully induced after treating diploid tissue masses with colchicine. Masses originating from diploid aerial roots were treated with colchicine at three different concentrations (i.e., 0.1, 0.2, 0.3%) for about 3, 5 and 7 h, and then were transferred into Murashige and Skoog medium containing 3 mg/l BAP + 0.2 mg/l 2,4-D. After 60 days, the survival rate and numbers of regenerative shoots were scored. The high concentration and longer duration sharply reduced survival rate. In contrast, the regeneration of plantlets was not noticeably affected by colchicine. Tetraploid plants were obtained in all treatments, but the percentage of induced tetraploids ranged from 0.2 to 7.6%. The best induction was obtained with a 5-h, treatment with 0.3% colchicine. The stomatal size of tetraploid plants was larger than in diploid plants; however, the stomatal density was lower than in diploid plants. Tetraploid plants possessed stronger petioles, thicker and deeper green leaves, and thicker and longer lived spathes in comparison with diploid plants. Abnormal spathes, such as double spathes or those lacking pedicels, were observed in tetraploid plants. Tetraploid plantlets could be regenerated via aerial roots; this technique could be applied to tetraploid plant propagation.     

Colchicine-induced chromosome doubling in Platanus acerifolia and its effect on plant morphology

We report the production of tetraploid plants of Platanus acerifolia, with the ultimate aim of improving the ornamental qualities of this important urban landscaping tree. Chromosome doubling was achieved by the application of colchicine to either pre-soaked seed or to the apical meristems of young seedlings. Treatment of the ungerminated seed was the more efficient method in terms of numbers of tetraploid seedlings (up to 40%, as determined by chromosome counting of the root-tip nuclei) but this method produced no mature tetraploid plants due to the deleterious effect of colchicine on subsequent root growth. When colchicine was applied directly to the apical growing tip of cotyledon-stage seedlings, leaf and stem growth was temporarily affected but the plants eventually recovered. We conducted a preliminary screen for putative tetraploids based on the observation in other plant species of a correlation of stomatal size and distribution with ploidy. Plants containing significantly larger stomata and at a lower density across the lower leaf epidermis, were selected for further analysis by flow cytometry and chromosome counting. These techniques confirmed that, of the 12 putative polyploids, four were tetraploid, five were mixoploid and three were, in fact, diploid. Morphological differences of the tetraploids included a more compact growth habit and broader, thicker leaves. These plants are being grown to full maturity in order to test their potential for use in a breeding programme aimed at producing sterile triploid lines.