曲穗草属天然杂种的鉴定及形成研究

本研究通过形态学、细胞学、系统发育分析等方法对小麦族曲穗草属(Campeiostachys)的两株疑似天然杂种进行鉴定,探究其可能的亲本及杂种形成机制.结果显示:两株天然杂种在形态上与短芒曲穗草(Cam-peiostachys breviaristata(Keng)Y.H.Zhou,H.Q.Zhang et C.R.Y...     

RAPD技术在植物遗传育种研究中的应用进展

RAPD技术是一种随机扩增多态性DNA的方法,操作简单、快捷且经济,可从分子水平提供直接的遗传证据。RAPD技术在植物遗传育种中的应用如下：1）遗传图谱的构建;2）分子标记辅助选择育种;3）外源染色体片段的鉴定和标记;4）遗传关系与遗传多样性的研究;5）体细胞杂种的鉴定。     

紫花含笑（♀）与灰岩含笑（♂）及其杂种F1代叶表皮微形态和叶结构的比较观察

通过比较观察紫花含笑（♀）和灰岩含笑（♂）及其杂种F1代叶表皮微形态和叶结构发现,紫花含笑和灰岩含笑在叶表皮微形态及叶解剖结构方面有很大差异。杂种F1代个体间在叶表皮微形态及叶解剖结构方面变异很大,为连续的数量遗传;其中57．7％以上的杂种F1代气孔密度高于父母本。杂种F1代矮化型植株叶片气孔密度较小,推测其抗寒性较强,可以通过进一步杂交改良,获得矮化型的盆栽含笑新品种。观察结果可为深入探讨含笑属种间杂种F1代的遗传变异,并从这些杂种F1代中选育观赏新品种积累科学资料。     

Production and characterization of somatic hybrids between the Japanese radish and cauliflower

Summary Somatic hybrids between the Japanese radish and cauliflower (Brassica oleracea) were produced by protoplast electrofusion in order to introduce clubroot disease resistance in the Japanese radish (Raphanus sativus) into Brassica crops. After electrofusion of iodoacetamide-treated cauliflower protoplasts with untreated radish ones, culture was performed under conditions, that allowed only cauliflower protoplasts to regenerate. Out of 40 regenerated plants, 37 were morphologically of a hybrid type and 3 of a cauliflower type. On the basis of isozyme and RFLP analysis, all of the hybrid-type plants tested proved to be true hybrids. Of the 10 true hybrids tested, 9 were found to contain chloroplasts similar to those found in the Japanese radish, while only 1 contained those of the cauliflower. Using two mitochondrial genes as probes, we were able to show that 3 hybrids contained mitochondria of the Japanese radish, with some modification, while 7 hybrids had either parental or new patterns. All of the hybrid-type plants showed resistance to clubroot disease as high as that found in the Japanese radish. Some hybrids were self-fertile. All of the self-fertile hybrids were found to contain 36 chromosomes, indicating that they were amphidiploids. In addition, a few seeds were obtained from a backcross of the self-fertile hybrids to both parents.     

利用分子标记技术检测玉米杂种纯度研究

以12份玉米自交系及其组配的8个杂交种为材料,利用分子标记技术进行杂种纯度检测研究。有用RAPD标记方法,从300个随机引物中,筛选确定了8个杂交种种子纯度检测引物,制定了检测标准标记图谱。建立了海禾3纯度分析的SCAR标记,该SCAR标记与RAPD标记在种子纯度检测上结果完全一致。     

Progress of chromosome engineering mediated by asymmetric somatic hybridization

Plant somatic hybridization has progressed steadily over the past 35 years. Many hybrid plants have been generated from fusion combinations of different phylogenetic species, some of which have been utilized in crop breeding programs. Among them, asymmetric hybrid, which usually contains a fraction of alien genome, has received more attention because of its importance in crop improvement. However, few studies have dealt with the heredity of the genome of somatic hybrid for a long time, which has limited the progress of this approach. Over recent ten years, along with the development of an effective cytogenetical tool ＂in situ hybridization （ISH）＂, asymmetric fusion of common wheat （Triticum aestivum L.） with different grasses or cereals has been greatly developed. Genetics, genomes, functional genes and agricultt, ral traits of wheat asymmetric hybrids have been subject to systematic investigations using gene cloning, genomic in situ hybridization （GISH） and molecular makers. The future goal is to fully elucidate the functional relationships among improved agronomic traits, the genes and underlying molecular mechanisms, and the genome dynamics of somatic introgression lines. This will accelerate the development of elite germplasms via somatic hybridization and the application of these materials in the molecular improvement of crop plants.     

Isozyme expression in F1 hybrids between carp and goldfish

Interspecific genetic differences in malate dehydrogenase (MDH), lactate dehydrogenase (LDH), superoxide dismutase (SOD), and esterase (EST) isozymes in carp (Cyprinus carpio) and goldfish (Carassius auratus) were used to examine the allelic expressions in the hybrid between these species. A unique liver SOD and muscle LDH phenotype unambiguously identifies all presumed hybrid individuals. There was no evidence of F₂ or backcross phenotypes in hybrid individuals. Liver MDH and EST phenotypes in hybrids show a preferential expression of goldfish isozymes. Variation in the levels of carp liver MDH isozymes may result from the polymorphism of a regulatory mutation affecting isozyme expression, leading to gene silencing after duplication.This work was supported through NSERC (Canada) grants to James P. Bogart and John F. Leatherland.     

甜橙与酸橙体细胞杂种核质组成鉴定

采用流式细胞术(flow cytometry,FCM)、简单重复序列(simple sequence repeat,SSR)和酶切扩增多型性序列(cleaved amplifiedpolymorphic sequence,CAPS)等技术分析酸橙(Citrus aurantium L.)叶肉原生质体和甜橙(C.sinenis Osbeck cv.Shamouti)胚性愈伤组织原生质体电融合再生的体细胞杂种.FCM研究结果表明,所有的体细胞杂种植株荧光强度是二倍体对照的2倍,说明所分析的植株为四倍体.用SSR和CAPS分析了体细胞杂种的核质遗传组成,在试验的4对SSR引物中,有2对能区分开融合亲本.在2对引物中,体细胞杂种植株包含双亲的全部特异带,表明它们为异核杂种.通用引物扩增结合限制性内切酶酶切能鉴别融合亲本,在具有多型性的引物/酶组合中,所有体细胞杂种的线粒体和叶绿体DNA带型与胚性亲本(甜橙)完全一样.结果表明体细胞杂种核基因组来自双亲,而胞质基因组来自悬浮系亲本.讨论了所用技术的特点、柑橘四倍体体细胞杂种核质遗传规律及本组合体细胞杂种的应用.     

紫花含笑（♀）、灰岩含笑（♂）及其杂种F1代花粉萌发试验研究

对紫花含笑(Michelia crassipes)、灰岩含笑(M.calcicola)及其杂种F1代花粉生活力进行了研究,为基于紫花含笑和灰岩含笑杂种F1代的含笑属观赏植物新品种培育与种质创新提供科学数据及研究资料.研究发现,亲本(紫花含笑和灰岩含笑)新鲜花粉萌发率均可达90％以上,杂种F1代花粉萌发率从38％到79％不等,平均为57.7％,低于双亲.亲本及其杂种F1代花粉萌发的最适温度为25℃,温度过高花粉管的伸长受到抑制,并导致花粉管顶端破裂.亲本及多数杂种F1代的新鲜花粉在100 g/L和150 g/L的蔗糖浓度下萌发率都较高;经-20℃贮藏后的花粉对蔗糖浓度的敏感性要高于新鲜花粉.杂种F1代及其亲本的花粉在离体培养中均会出现双萌发管现象.番红染料对液体培养基中的花粉有致死和染色作用,有利于统计杂种F1代及其亲本的花粉萌发率.     

4种杂交杨对土壤水分变化的生态学响应

以田间持水量的100% (T1, 对照)、70% (T2)、50% (T3)和30% (T4)为4个水分处理梯度, 比较研究了4种不同品系的杂交杨(Populus)——15-29 (P. trichocarpa × P. deltoids)、DN-2 (P. deltoids × P. nigra)、DN-14274 (P. deltoids × P. nigra)和R-270 (P. deltoids × P. nigra)在不同水分处理和不同处理阶段对水分亏缺的反应。结果表明, 4种杂交杨品系对水分亏缺较敏感, 都通过关闭气孔、降低叶面积以有效地调节水分的散失, 降低光合速率、蒸腾、水势, 增加水分利用效率, 改变生物量的分配等一系列生理适应机制以及形态策略, 来应对不同程度的水分亏缺, 只是不同品系的适应程度不同。在生物量分配上, R-270主要降低叶干重, 而其它3个品系的叶、茎和根干重全部降低; 随着水分亏缺的加重, 15-29和R-270的根冠比增加, 根部获得更多的同化物分配, 从而有利于水分的吸收, 增加其抗旱性。DN-2的碳同位素组成δ¹³与水分利用效率呈显著正相关(r= 0.631, p<0.01)。而R-270的δ¹³与水分利用效率呈负相关, 但不显著, 只有在处理T4下呈显著负相关(r= -0.732, p<0.01), 表明土壤水分影响了碳同位素的分馏, 不同品系相反的结果表明同位素分馏的遗传变异。与T3和T4相比, T1和T2处理的苗木具有较高的生物量、叶面积、光合速率、蒸腾、水势以及气孔导度, 说明4个杂交杨品系在充足或适当的灌溉条件下具有较高的生产力。在T3和T4处理下, 4个品系表现出不同的生存策略, 但生产力均较低, 因此在干旱胁迫下很难形成高生产力。与DN-2和DN-14274相比, 15-29和R-270对水分胁迫表现出更强的适应性反应, 具有较强的抗旱性, 可用作防护林品种。