Most organs of sugar-beet (<Emphasis Type="Italic">Beta vulgaris</Emphasis> L.) plants at the vegetative and reproductive stages of development are polysomatic

Polysomaty was studied using flow cytometry in different organs of diploid, triploid and tetraploid sugar-beet (Beta vulgaris L.) plants, in the first (at harvest) and the second (at the height of the blooming period) year of development. Of the organs/parts of organs of the vegetative plant that developed during the first year, only the leaf lamina did not contain endopolyploid cells; in all others, one to three endocycles had occurred. The second-year seed-crop plant was also highly polysomatic; even in reproductive organs such as the flower and pericarp the endopolyploid cells were present (up to 8C and 32C, respectively). At this stage of development no endocycles occurred in the leaf lamina, flower bract, and inflorescence bract. The parts of the plant with no endopolyploid cells are recommended for ploidy estimation, and as a material suitable for micropropagation and genetic manipulations. Endoreduplication, up to 32C (64Cx), was organ-specific and correlated negatively with plant ploidy. The highest mean C-value, over 7, was in the diploid, in the basal part of the oldest leaf petiole in the first-year plant, and in the storage parenchyma of the root in the second-year seed-crop plant. The results confirm that higher endopolyploidy occurs in plants with a smaller 2C DNA amount than in those with a larger one. The significance of endopolyploidization in development of sugar-beet plant organs is discussed.     

Interspecific somatic hybrids <Emphasis Type="Italic">Solanum bulbocastanum</Emphasis> (+) <Emphasis Type="Italic">S. tuberosum</Emphasis> H-8105

Interspecific somatic hybrids between a dihaploid potato clone H-8105 susceptible to Phytophthora infestans (Mont.) de Bary and a resistant diploid tuberizing species Solanum bulbocastanum were generated and analysed. Only ten regenerants displaying the intermediate morphology with dominating characteristics of the wild parent (simple leaves, anthocyanin pigmentation) were produced in 15 weeks after a single PEG-mediated fusion event. The RAPD patterns confirmed the hybridity of all of them. The hybrids rooted poorly and grew slowly in vitro. The cytological analysis revealed a high degree of aneuploidy in the hybrids with morphological and growth anomalies in vitro, while the morphologically normal hybrids were tetraploids. All the S. bulbocastanum (+) H-8105 hybrids were unstable in culture and three of them were consequently lost during three years of propagation in vitro. The possible reasons for instability of somatic hybrids between the distantly related species are discussed.     

兰花蕉属植物染色体新计数

首次报道了国产兰花蕉属植物2种1变种的体细胞染色体计数,其中兰花蕉及其变种长萼兰花蕉为2n=54,为六倍体;海南兰花蕉为2n=18,为二倍体。分析了世界范围内兰花蕉属植物染色体数及其倍性的地理学关系。     

盾叶薯蓣自然变异类型间的比较研究

对取自云南期纳的二倍体和三倍体盾叶薯蓣植株以及重庆城口的四倍体植株进行了形态学、染色体数目及同工酶的比较研究。结果表明,这3种类型植株在叶片形态上有明显的差异。二倍体的染色体数目是2n=2x=20,三倍体为2n=3x=30,四倍体为2n=4x=40;酯酶(EST)和超氧化物歧化酶(SOD)酶谱显示,3种类型植株之间具有明显的相关性,但多倍体较二倍体的酶带条数少且着色浅。这些差异除了有地理分布不同的因素外,倍性的不同也是很重要的因素。     

利用氟乐灵进行同源四倍体萝卜种质创制研究

本研究应用除草剂氟乐灵处理两叶一心幼苗生长点,进行同源四倍体萝卜种质诱导,对变异植株进行形态、细胞学鉴定和花粉母细胞染色体数目鉴定。结果表明,应用 0.2 mmol/L 和 1.0 mmol/L 氟乐灵处理,6个萝卜品种都获得同源四倍体植株,10 mmol/L 处理仅在 Nau-zhqh 得到同源四倍体;其中 0.2 mmol/L处理 Nau-dy 和 1.0 mmol/L 处理 Nau-xbch 获得四倍体最高诱导率(40%);四倍体种质与二倍体种质相比,形态性状、气孔大小、保卫细胞内叶绿体数目、花器官大小、花粉粒大小及花粉萌发率都存在显著差异,将形态、气孔鉴定和染色体计数结合可以准确确定变异株的倍性。研究表明利用氟乐灵诱导是进行萝卜同源四倍体种质创新的有效途径之一。本研究应用除草剂氟乐灵处理两叶一心幼苗生长点,进行同源四倍体萝卜种质诱导,对变异植株进行形态、细胞学鉴定和花粉母细胞染色体数目鉴定。结果表明,应用 0.2 mmol/L 和 1.0 mmol/L 氟乐灵处理,6个萝卜品种都获得同源四倍体植株,10 mmol/L 处理仅在 Nau-zhqh 得到同源四倍体;其中 0.2 mmol/L处理 Nau-dy 和 1.0 mmol/L 处理 Nau-xbch 获得四倍体最高诱导率(40%);四倍体种质与二倍体种质相比,形态性状、气孔大小、保卫细胞内叶绿体数目、花器官大小、花粉粒大小及花粉萌发率都存在显著差异,将形态、气孔鉴定和染色体计数结合可以准确确定变异株的倍性。研究表明利用氟乐灵诱导是进行萝卜同源四倍体种质创新的有效途径之一。     

Leaf epidermal characteristics of Asiatic Buddleja L. under scanning electron microscope: Insights into chromosomal and taxonomic significance

The leaf epidermis of all 23 species from Asian Buddleja was investigated with scanning electron microscopy (SEM). Characteristics of trichome type, stomatal shape, cuticular membrane on adaxial and abaxial epidermis, inner margin of outer stomatal ledge and ornamentation of outer stomatal ledge are presented in this study. Among the Buddleja species, some distinct epidermal patterns were observed. These can be used to characterize and identify different sections among the Asian Buddleja species, viz. Alternifoliae, Curviflorae and Rectiflorae. In general, stomatal length of Buddleja increases with ploidy level. This character can be used to distinguish diploids from polyploids without preparation of caryograms. Based on this correlation Buddleja microstachya, B. subcapitata and B. bhutanica are characterized to be diploids, as concluded from their stomatal dimensions. Leaf epidermis characters can also be used to differentiate species pairs that are easily confused with each other, viz., B. asiatica and B. bhutanica, B. albiflora and B. nivea, B. candida and B. fallowiana, B. delavayi and B. forrestii, B. japonica and B. lindleyana, B. officinalis and B. paniculata.     

三倍体和二倍体银鲫的精子发生

应用透射电子显微镜观察了行雌核发育生殖的三倍体(体细胞具有150±染色体)和二倍体 (2n=100)银鲫(Carassius auratus gibelio Bloch)的精子发生过程.两种倍性的雄性的精子发生过程中,染色体数和细胞核的体积均呈3∶2的关系;而精巢的结构、细胞的形态和细胞器的构成均无明显的区别.其精子发生经历了精原细胞、初级精母细胞、次级精母细胞和精子细胞几个阶段,精子细胞再经过精子形成过程成为精子;三倍体银鲫的精子发生与二倍体一样能正常完成减数分裂,形成形态和功能正常的雄性配子.正常的精子发生过程证明,体细胞具有150±条染色体的黑龙江银鲫是已经初步完成二倍化的三倍体,雄性个体在生殖群体中起着重要的作用;推测黑龙江银鲫的二倍体实际可能是四倍体,则三倍体的黑龙江银鲫为偶倍性的六倍体,因此其减数分裂可以正常进行,同时又经历了一定程度的二倍化,所以雄性可育,且参与繁殖后代 [动物学报 54(3):467-474,2008].     

木槿属几种植物的染色体数目及其倍性的研究

采用去壁低渗火焰干燥法进行染色体制片分析了木槿属Hibiscus植物裂瓣槿H. schizopetalus (Masters) Hook. f.)、木芙蓉H. mutabilis L.以及扶桑H. rosa sinensis L. 4个栽培变种的染色体数目.结果表明裂瓣槿染色体数目为2n=42木芙蓉2n=92扶桑2n=84重虹中玫槿2n=105; 橙黄中玫槿2n=138; 洋红中玫槿2n=147.裂瓣槿、扶桑、重虹中玫槿、洋红中玫槿之间存在倍性关系,其染色体基数为x=21.通过对植物形态特征以及染色体数目的观察分析推测红色中玫槿可能为洋红中玫槿和裂瓣槿的杂交种.     

Variation in the content of hypericins in four generations of seed progeny of <Emphasis Type="Italic">Hypericum perforatum</Emphasis> somaclones

The content of hypericins in in vitro regenerated Hypericum perforatum plants (R ₀) and four generations of their seed progeny (R ₁–R ₄) was compared. The mean content of hypericins in field-grown plants over the period 1992–2002 gradually increased under selection, and in the R ₄ generation it was almost seven-times higher than that in the R ₀ somaclones. Significant difference between hypericin content in diploids and tetraploids was detected in R ₀, R ₁ and R ₃ generations. Hypericin content in four diploid and tetraploid lineages originated from a single somaclone was genotype dependent. To eliminate the influence of environmental conditions during different growing seasons, we used seeds of selected R ₀–R ₃ plants to derive R′₁ to R′₄ generations cultivated during the same years. In this case no statistically significant difference in hypericin content was found between the R′₁–R′₄ generations. Apomictically and sexually derived plants were distinguished by PCR using variable numbers of tandem repeats (VNTR) primers. The content of hypericins in apomictically derived progenies was compared.     

Insight into the basis of root growth in Arabidopsis thaliana provided by a simple mathematical model

Plant organ growth changes under genetic and environmental influences can be observed as altered cell proliferation and volume growth. The two aspects are mutually dependent and intricately related. For comprehensive growth analysis, it is necessary to specify the relationship quantitatively. Here, we develop a simple mathematical model for this purpose. Our model assumes that the biological activity of a given organ is proportional to the cell number of the organ and is allocated into three aspects: cell proliferation, volume growth, and organ maintenance. We analyzed the growth of primary roots of Arabidopsis thaliana (L.) Heynh. in one tetraploid and four diploid strains using this model. The analysis determined various growth parameters, such as specific cost coefficients of cell proliferation and volume growth for each strain. The results provide insight into the basis of interstrain variations and ploidy effects in root growth.