云南山楂茎尖的离体培养及其无性系快速繁殖

用云南山楂(Crataegus scabrifolia(Franch.)Rehd.)成年树茎尖和实生芽两种不同发育阶段的材料为外殖体,诱导它们休眠芽萌动,丛生芽条并诱导芽条生根。实验结果如下:1.以成年态的云南山楂侧芽为外植体,培养在附加IAA 0.1—0.5mg/l+6-BA 1-2mg/l的MS培养基上可诱导芽的萌发;将芽继代培养在附加0.5—1mg/l 6-BA的SH或MS培养基上,40天后芽数增殖4—6倍;将芽条截下置于1/2MS培养基上,附加不同浓度的IAA或IBA,可得到50—80％的生根率。2.以实生芽为外殖体,在相同条件下,则20天后芽数增殖便可获4—6倍;98％以上生根。结果表明:云南山楂的幼年态要比成年态易脱分化和再分化。     

Physical map of chloroplast DNA of aerial yam,Dioscorea bulbifera L.

Summary A physical map of chloroplast DNA (ctDNA) of aerial yam, Dioscorea bulbifera L. was constructed using three restriction endonucleases, PstI, SalI, and SmaI. In addition, a clone bank of the BamHI-digested fragments were generated, and the locations of most BamHI fragments on the map were also determined. The ctDNA of D. bulbifera was found to be a circular molecule with a total size of ca. 152 kb involving two inverted repeats of ca. 25.5 kb, and small and large single copy regions of ca. 18.5 and 83.4 kb, respectively. The genes for the large subunit of the ribulose 1,5-bisphosphate carboxylase (rbcL) and the ATP-synthase subunits and (atpB/atpE) were mapped.Contribution from the Plant Germ-plasm Institute and the Laboratory of Genetics (No. 504), Faculty of Agriculture, Kyoto University, Japan. The work was supported in part by a Grant-in-Aid (No. 60400005) from the Ministry of Education, Science and Culture, Japan     

慈竹无性系种群生长发育规律初探

慈竹(Neosinocalamus affinis)系四川分布面积最大、产量高、用途广的重要经济竹种,对振兴四川经济具有很大的潜在作用。作者引用Harper的构件结构理论,将慈竹无性系作为一个种群进行研究。以慈竹幼竹为研究对象,通过对其生长发     

普通小麦与簇毛麦双二倍体的合成,育性及细胞遗传学研究

通过杂种幼胚无性系培养获得大量再生植株F_1,经秋水仙碱处理,合成了普通小麦与簇毛麦属间双二倍体(AABBDDVV)。其形态特征除株高、穗长、小穗数,籽粒大小和育性明显增加,生育期延长外,分别与各自的再生植株F_1相似。双二倍体的体细胞染色体数目变化范围为48—56。花粉母细胞减数分裂中期Ⅰ 2n=28Ⅱ的细胞占56.82％,每个细胞平均有27.10个二价体,1.44个单价体,0.08个三价体,0.03个四价体。经过连续两代单穗单株选择,结实率由15.91％提高到36.52％。     

伊贝母体细胞无性系的建立及其胚状体的发生

本文报道了伊贝母体细胞无性系的建立及其胚状体的发生。已继代培养三年零六个月共30多代的鳞芽愈伤组织,目前仍有分化能力。通过愈伤组织形态细胞学的观察,发现伊贝母体细胞无性系形成小鳞茎的途径有二:一是由特化了的愈伤组织表皮细胞。经多次分裂发育成不定芽而形成小鳞茎;二是由愈伤组织表层或内层特化了的胚性细胞,经多次分裂发育成胚状体而形成小鳞茎。不定芽和胚状体的形态发生是有区别的。     

人参多肽基因的化学合成和克隆

 本文报道了具有降血糖作用的人参多肽基因的设计及用固相亚磷酰胺法的合成。再以质粒pUC19作为克隆载体,以大肠杆菌JM101为受体菌,克隆了人参多肽基因,并成功地获得了克隆菌株。     

Detecting epistatic genetic variance with a clonally replicated design: models for lowvs high-order nonallelic interaction

A quantitative genetic model, that uses known family structure with clonal replicates to separate genetic variance into its additive, dominance and epistatic components, is available in the current literature. Making use of offspring testing, this model is based on the theory that components of variance from the linear model of an experimental design may be expressed in terms of expected covariances among relatives. However, if interactions between a pair of quantitative trait loci (QTLs) explain a large proportion of the total epistasis, it will seriously overestimate the additive and dominance variances but underestimate the epistatic variance. In the present paper, a new model is developed to manipulate this problem by combining parental and offspring material into the same test. Under the condition described above, the new model can provide an accurate estimate for additive x additive variances. Also, its accuracy in estimating dominance and total epistatic variances is much greater than the accuracy of the previous model. However, if there is obvious evidence showing the major contribution of high-order interactions, especially among 4QTLs, to the total epistasis, the previous model is more appropriate to partition the genetic variance for a quantitative trait. The re-analysis of an example from a factorial mating design in poplar shows large differences in estimating variance components between the new and previous models when two different assumptions (lowvs high-order epistatic interactions) are used. The new model will be an alternative to estimating the mode of quantitative inheritance for species, especially for longlived, predominantly outcrossing forest trees, that can be clonally replicated.     

Life histories and habitat selection in Daphnia: divergent life histories of D. magna clones differing in phototactic behaviour

To test the hypothesis of co-adaptation of life histories and daytime vertical distribution (vertical migration behaviour) in Daphnia, life history characteristics were analysed for two positively, three negatively, and four intermediately phototactic Daphnia magna clones. Clones with different phototactic behaviour were found to have divergent life history strategies, with positively phototactic clones being good exploiters under the non-limiting conditions provided in the laboratory, i.e. low density (1 ind./1), high food concentration (6,5–7 10⁵ Scenedesmus cells/ml, restored daily) and high temperature (20° C). They realized a high intrinsic rate of increase at a small adult body size through rapid development, at a cost of producing small neonates. Negatively and intermediately phototactic clones had larger adult body sizes, and produced larger neonates that were more starvation-resistant than those of positively phototactic clones. Selection for high intrinsic rate of increase in intermediately phototactic clones was mediated through the production of large clutches.     

蝮蛇毒碱性磷脂酶A_2基因的克隆

从蝮蛇毒腺中抽提总ＲＮＡ．利用人工合成寡核苷酸引物作逆转录,以ｃＤＮＡ为模板进行体外扩增,获得磷脂酶Ａ２（简称ＰＬＡ２）基因,克隆至ｐＢＳ－ｋｓ载体中。通过对３个碱性ＰＬＡ２（简称ＢＰＬＡ２）基因单独克隆分别作ＤＮＡ全序列分析,推导ｐｒｏ－ＢＰＬＡ２由１３８个氨基酸残基构成,与已测定的部分氨基酸序列比较,基本相符。该基因成功的克隆,不仅推导出ＢＰＬＡ２的蛋白质全序列,也为进一步开展蛇毒功能肽蛋白质工程的研究工作打下了良好的基础。