影响香根草体细胞胚胎发生和植株再生因素初探

为了探索提高香根草(Vetiveriazizanioides)遗传种质改良效率的有效途径,初步研究了影响香根草体细胞胚胎发生和植株再生的若干因素。以MS培养基为基本培养基,附加不同配比的生长素和细胞分裂素,对香根草的腋芽及无菌不定芽进行离体培养。结果表明,2,4-D是诱导体细胞胚胎发生的关键因素,当培养基中只含2,4-D而不含或少含细胞分裂素(6-BA)时,外植体经由体细胞胚胎发生途径形成再生植株。愈伤组织诱导频率在有的品种之间差异显著,最高的达到96.7%(cv.Zomba),最低的不到30%(cv.Malaysia);而有的品种之间差异不显著(例如cv.Kandy和cv.Sunshine)。胚性愈伤组织的再生能力可以长期保持,从未经继代培养的到持续继代第23代的胚性愈伤组织,再生频率都在80%以上,而且再生植株的生长良好。在3-7℃的低温下进行分化培养时,仍然有40.5%-50.0%不同世代的胚性愈伤组织还保持着再生能力。

甘蓝型杂交油菜种子胎萌发生特性的初步研究

本试验以甘蓝型杂交种秦油2号及其三系种子为材料，于1992～1993两年在浙江农业大学农场进行。试验结果表明，甘蓝型杂交油菜杂种秦油2号、不育系陕2A和保持系陕2B种子胎萌发生在开花后19天左右，并随着种子发育日趋成熟而有不断增多的趋势，而常规品种垦C1种子胎萌发生在成熟后期（开花后31天）。角果内位于果身中部的胎萌粒多于果身两端部。不同类型和品种、不同年份、具有胎萌特性同一植株的不同花序部位和同一品种不同个体（或株系）间胎萌率的变化较大。甘蓝型杂交油菜果壳对角果内发育种子具有保护作用。发育早期的果壳对种子的保护作用较强，而发育后期的果壳相对较弱，易胎萌品种的果壳对种子的保护作用较不易胎萌品种弱。

甘蓝型油菜种子胎萌发生的影响因子研究

以黄籽油菜‘410’‘456’‘552’和黑籽油菜‘492’为试验材料,采用花期标记、定期采样、形态和生理分析等方法,研究了种子胎萌发生时期、环境对胎萌的影响以及胎萌与种子的形态和相关生理指标的关系。结果表明:4个甘蓝型油菜品种种子胎萌发生在种胚充实阶段(花后27~36 d左右),初始胎萌率为2.44%~3.90%,胎萌发生时期越早的品种的胎萌率越高;种子千粒质量与胎萌率呈显著或极显著正相关(r为0.84~0.97),含水量与胎萌率呈极显著负相关(r为–0.93~–0.98);种胚充实初期高温高湿的外部环境、较薄的种皮及相对较高的脂肪酶活性、可溶性糖含量、呼吸强度均易导致种子胎萌的发生,而种子电导率、总糖含量与胎萌率的相关性不显著。

矮生菜豆种子胎萌发生特性的初步研究

研究了若干矮生菜豆品种在不同年份和采种设施下种子的胎萌发生特性。试验结果表明 :(1)品种间在种子胎萌发生率方面存在显著差异 ,有的品种不发生胎萌 ,有的品种其胎萌种子发生频率在 2 0 %以上 ;(2 )对于能够发生种子胎萌的品种而言 ,采种年份和设施对胎萌种子发生率有明显的影响 ;(3)种子胎萌一般在开花后 35 d左右开始发生 ;(4 )胎萌种子的发生部位具有明显的规律 ,即胎萌种子主要发生在植株的下部和豆荚的近喙端。

细胞分裂素类物质在植物体细胞胚发生中的作用

本文对细胞分裂素及其类似物在植物体细胞胚发生中的作用的研究历史、现状及前景进行了评述。

IVF—ET中授精方式及移植胚胎质量对妊娠结局的影响

目的探讨体外受精-胚胎移植中不同授精方式及移植胚胎情况对妊娠结局的影响。方法对2007年6～12月完成的116个体外受精-胚胎移植周期的病例，分别根据授精方式和移植胚胎数进行分组，统计学分析比较各组妊娠情况。结果①按授精方式分为常规体外受精-胚胎移植组、胞浆内单精子注射组和体外受精／胞浆内单精子注射组。与常规体外受精组66．23％的受精率比较，体外受精／胞浆内单精子注射组体外受精的受精率明显降低（X2=29．096，P〈0．01），仅为42．66％；3组继续妊娠率依次为29．69％、40．63％、20．00％，各组间比较无显著性差异（P〉0．05）；②按移植胚胎情况分组：无优质胚胎组及分别有1个、2个和3个优质胚胎组的继续妊娠率依次为10．00％、36．84％、34．78％和37．50％，无优质胚胎组较有优质胚胎各组继续妊娠率降低，但无统计学意义（X2分别为3．955、1．000、2．946，均P〉0．05），优质胚胎各组间比较亦无显著性差异（P〉0．05）；各组多胎发生率依次为0、14．29％、50．00％和33．33％，有1个优质胚胎组的多胎发生率低于其他优质胚胎组，但无统计学意义（X2分别为2．839、1．000、1．000，均P〉0．05）。结论授精方式及移植胚胎质量与妊娠结局有相关性，单优质胚胎移植可能会明显减少多胎发生率。

巧拆轮胎

轮胎在机车上用久了,外胎容易锈粘在钢圈上,如果轮胎发生了故障,很难从钢圈上取下,现介绍一种简易办法:先将轮胎(包括钢圈)从轮毂上拆下来平放在地面上。

奶牛难产和双胎的防控创新途径

奶牛难产和双胎状况直接关系到养殖业的健康发展,通过科学研究可以找到更有效的管理方法,提高奶牛的生产力和繁殖效率,有效促进养殖业的发展。通过研究如何有效预防和处理奶牛难产,如何改善双胎奶牛的管理,可以提高资源利用效率,减少能源和饲料的浪费,降低养殖成本,从而提高养殖业的经济效益,促进奶牛养殖行业的长期、稳定发展。

Histological Study on Soybean Somatic Embryogenesis

Soybean somatic cell could induce the development of embryoid which was similar to embryo morphologically and structurally. Somatic embryogenesis system of soybean was used to conduct genetic transformation of soybean because of its several advantages such as higher transformational efficiency, beetter synchronism and fewer plant chimeras among transgenic plants. After infected with agrobacterium tumefaciens,the initiation, differentiation and development of young cotyledon embryogenic cell of soybean which was cultured on selective culture medium with kanamycin were investigated through histological study. The result showed that somatic embryo was differentiated in non-bud differentiation way. The embryogenic cells were differentiated from epidermis of explant or cells in 1 layer or 2 layers, with the division of embryogenic cells and degradation and disorganization of surrounding cells, the embryogenic cells would form embryoid with analogous suspensor structure. Later, globular embryoid would extrude from epidermis then developed into heart-shape embryo. The experiment was expected to provide theoretical reference for the construction of high transformational system of using plant somatic embryogenesis induced by young cotyledon of soybean.

Fluctuations of Endogenous Hormones in Isolated Rice Embryos During Embryogenesis and Early Stages of Germination

Fluctuations of levels of several endogenous plant hormones in isolated rice ( Oryza sativa ssp. japonica) embryos during early and mid-embryogenesis and early stages of germination were studied by enzyme-linked immunosorbent assay (ELISA). Embryos were collected at different days after pollination (DAP) and different days after imbibition (DAI) of mature seeds. The contents of gibberellin(1) (GA(1)), abscisic acid (ABA), isopentenyladenine and isopentenyladenosine ( iPAs), zeatin and zeatin riboside ( ZRs) were immunochemically assayed. The GA(1) level was the highest among all hormones tested. The variations of GA(1) levels were opposite with the ABA levels, with some exceptions. During early and mid-embryogenesis, the levels of GA(1) and ABA were the highest at 4 DAP. From 8 to 18 DAP, GA(1) level declined, whereas the ABA level increased. During germination, GA(1) level increased at 2 DAI whereas simultaneously the ABA content decreased. The highest ratio of GA(1)/ABA was observed at 2 DAI The levels of iPAs and ZRs were maxima in the embryos at 4 DAP, decreased to a very low level and maintained constant thereafter. Our results provide further evidence that GA(1) plays an important role in the early stages of embryo development and germination. The balance between GA(1) and ABA, rather than their absolute contents, controls these processes throughout the development, whereas iPAs and ZRs may play important roles in early embryogenesis. The use of isolated embryos as starting material avoids the usual interferences with other tissues such as the endosperm. In addition, this is the first report dealing with the hormonal balance of early-embryos in rice.

The Structure of Oryza Embryos and Their Dimorphic Cotyledons

It has been generally held in botany that Oryza sativa L. is a monocotyledon. Based on studies of rice embryo development we confirmed that rice embryo has two dimorphic cotyledons rather than just one cotyledon. In the present study we attempt to know if the morphology of embryos in other species of Oryza differs from O. sativa and if these embryos have dimorphic cotyledon. Two types of embryo structures were observed in 22 species and/or subspecies of genus Oryza under the scanning electron microscope. Type 1, the O.sativa type, which is characterized by ventral scale and lateral scales, was found in 16 species. Type 2, the O. meyeriana (Zoll. et Mor. ex Steud.) Baill. ssp. tuberculata W. C. Wu et Y. G. Lu, G. C. Wang type, with no ventral scale and lateral scales, was found in 6 species and subspecies. The embryogenic process of O.sativa and O.meyeriana sub. tuberculata showed that the scutellum primordium, coleorhiza primordium, coleoptile primordium and shoot apical meristem directly differentiate from proembryo. The former two later develop into the embryo envelope, which is the outside cotyledon; the coleoptile primordium develops into the coleoptile with the shape of inverted empty cone surrounding and covering the growth cone, which is the apical cotyledon. Both types of rice embryos have dimorphic cotyledons. The structural difference between them is that the scutellum primordium of the young embryo in type 2 does not differentiate ventral scale and lateral scales while the embryo of type 1 does. The dimorphic cotyledons of embryo of Oryza plants originate from the dorsiventrality of proembryo.

Embryogenesis of Polyembryonic Rice ApⅢ: Structural and Histochemical Studies of Egg Apparatus Around Fertilization

The structural and histochemical changes of the egg apparatus in the polyembryonic rice ( Oryza sativa L.), ApⅢ with the highest frequence of additional embryos among the polyembryonic rice investigated, before and after fertilization were studied and compared with those of normal and other polyembryonic rices in a similar developmental period. A total of 2 932 ovules were observed and each of them contained only a single embryo sac with a set of egg apparatus. Among 1 655 embryo sacs, there were 1 643 embryo sacs (99.27%) with one normal egg apparatus in each embryo sac, and only 12 embryo sacs (0.73%) from the remainder with 4_celled egg apparatus, i.e. two eggs and two synergids. Neither the numerous poly_egg apparatus and egg_like cells, nor the double set of embryo sacs each containing one egg apparatus and other abnormal egg apparatus in single ovary, which were reported by earlier investigators to have high frequency of embryo production in SB_1 and ApⅣ, were observed. The egg cell was located at the subterminal site of the micropylar end of embryo sac. The cytoplasm of egg cell was rich in protein materials and polysaccharide grains, which did not disappear until the division of zygote. The prominent nucleus was closely surrounded by protein and polysaccharide grains, which did not disappear until the division of zygote. No cytological difference was found between egg cells from the normal and abnormal egg apparatus. The two synergids were fully developed and situated at the upper most part of the micropylar end of the mature embryo sac. In most embryo sacs, the synergids were flask_shaped with longer necks, and a widened cap_shaped top, in close contact with the micropyle. The synergids had a well developed filiform apparatus. The characteristic appearance of the filiform apparatus as well as the cap_neck region of synergids before and after pollen tube penetration were easily distinguishable from the egg cell. The structure, the stainability with Coomassie Brilliant Blue and PAS reaction, the process of accumulation, distribution and disapperance of the cytoplasmic protein materials and polysaccharide grains of the two synergids, the persistent and rarely the receptive synergids before and after pollen tube penetration, were closely similar to those of egg cell of the same developmental stage. In comparison with normal and other polyembryonic rice reported, the size of nucleus and nucleolus and their stainability also strongly resembled those of egg cell. Based on the results observed, the main conclusions are summarized as follows: (1) the additional embryos very frequently developed in the young and mature seed of polyembryonic rice ApⅢ were produced by one or two synergids of normal egg apparatus, rarely by 4_celled egg apparatus; (2) during fertilization, the synergids, in addition to the natural specific function of introducing pollen tube and transferring sperms to egg cell and central cell, could be closely associated with the potentiality to breed one or two additional embryos; and (3) as compared with that of normal or other polyembryonic rice it is firstly disclosed that in a few embryo sacs of ApⅢ, the cytoplasmic and nuclear structure, the active anabolism and catabolism of protein and polysaccharide materials and the delayed disorganization at the mid_basal region of the receptive and persistent synergid still remained unchanged before the division of zygote. Such salient features could be the predisposition for the origin of additional embryos in ApⅢ.

Embryogenesis and Development of Isolated Microspore in Chinese Cabbage

[Objective] The aim was to observe embryogenesis and development of isolated microspores in Chinese cabbage. [Method] Chinese cabbage F 1 hybrids were used as the experimental materials, and optical microspore was employed to observe the embryogenesis and development of isolated microspores. [Result] Cells swelled after heat shock treatment, which was the critical factor of embryoid induction. Three pathways equal division, unequal division and germination of microspores were discovered to lead to the embryogenesis from isolated microspores after swelling. Microspore could grow directly to embryoid through germination path way. Equally divided microspores formed the original embryos after successive multiple equal divisions. Original embryos could develop into cotyledon-shaped embryos via globular, heart-shaped and torpedo-shaped embryos. The large one of the two cells from unequally divided microspores continued to divide and finally formed a polar embryoid. [Conclusion] The study will provide cytological basis for high induction frequency and embryoid of Chinese cabbage.

Studies on Parameters Affecting Embryogenesis of Protoplasts Isolated from Suspension of Embryogenic Cells in Loblolly Pine

Protoplasts of embryogenic suspension cells of loblolly pine (Pinus taeda L).were isolated at exponential growth stage.Influences of various concentrations of basal medium,levels of BA,and concentrations of inositol on the differentiation of embryonal suspensor mass (ESM),early stage somatic embryos (ESE) ,and lae stage somatic embryos (LSE) were investigated .A study of the effect of various concentrations of LP basal medium sowed that the optimal basal medium concentration of ESM,ESE,and LSE differentiation was 1.25 LP medium.The effects of various levels of BA and inositol showed that the optimal concentrations of BA for the formation of ESM,ESE and LSE were 4 mg/L ,2mg/L and 1mg/L,respectively ,and the optimal concentrations of inositol for the ESM ,ESE and LSM formation were 400mg/L,800mg/L and 1,200mg/L,respectively.

Identification of Z-OTU protein during zebrafish oogenesis and early embryogenesis

Zebrafish（Danio rerio） Z-OTU,containing OTU and TUDOR domains,was predicted to be a member of OTU-related protease,a family of the deubiquitylating enzymes（DUBs）.A previous report from our laboratory clearly describes the expression patterns of z-otu mRNA.Here,we characterized the Z-OTU protein during zebrafish oogenesis and early embryogenesis.After prokaryotic expression,the recombinant protein of the OTU domain and GST was purified and injected into rabbits to obtain the polyclonal antibody-anti-Z-OTU,which was used for immunohistochemistry in zebrafish ovaries and embryos.Interestingly,obvious differences existed between the expression patterns of z-otu mRNA and its protein during oogenesis and early embryogenesis.In stage I oocytes,z-otu mRNA was detected in cytoplasm while its protein existed in the germinal vesicle.In addition,its protein was distributed during entire oogenesis,while mRNA was not detected in oocytes at stage IV or mature oocytes.The z-otu mRNA disappeared after midblastula transition（MBT） and its protein gradually decreased after this stage.We inferred that Z-OTU protein,like other OTU-related protease with DUB activity,was required for germinal vesicle breakdown of oocytes during meiosis,germinal vesicle migration,and embryo cleavage maintenance.

培养基中添加孕酮对牛体外受精卵的影响

上海农学院和日本京都大学合作在培养液中添加孕酮以研究外源性孕酮对牛体外受精卵发育的影响。结果表明,适量添加孕酮有助于胚胎的体外发育。其中10ng/ml孕酮添加组的8细胞胚胎发生率(55％)极显著高于对照组(39.0％)(P【0.01);囊胚发生率(18.9％)亦显著高于对照组(9.6％)

The Progress on Abnormal Development Mechanism

What summarized in this paper is the progress in recent years' in the causdive mechanism on study of developmental toxicants as chemical teratogenesis in three aspects.(1) It is about the phenomena and the possible reason of chemical teratogenesis in the preimplantation period. These research results are contrary to the past traditional concepts. (2) Due to using much more molecular biology methods, it can be observed more dead foetus phenomena before birth, which cannot be done previously and are of great value for reference. (3) When analyzing the genetic reason of chemical abnormal, a new research idea may be showed, i.e. the developmental abnormal due to chemical teratogenesis is induced with association of more relative genes and their expression abnormal. 13 references are involved in.

Rice bicoid-related cDNA sequence and its expression during early embryogenesis

Bicoid is one of the important Drosophila maternal genes involved in the control of embryo polarity and larvae segmentation. To clone and characterize the rice bicoid-related genes, one cDNA clone, Rb24 (EMBL accession number: AJ2771380), was isolated by screening of rice unmature seed cDNA library. Sequence analysis indicates that Rb24 contains a putative amino acid sequence, which is homologous to unique 8 amino acids sequence within Drosophila bicoid homeodomain (50% identity, 75% similarity) and involves a lys-9 in putative helix 3. Northern blot analysis of rice RNA has shown that this sequence is expressed in a tissue-specific manner. The transcript was detected strongly in young panicles, but less in young leaves and roots. This results are further confirmed with paraffin section in situ hybridization. The signal is intensive in rice globular embryo and located at the apical tip of the embryo, then, along with the development of embryo, the signal is getting reduced and transfers into both sides of embryo. The existence of bicoid-related sequence in rice embryo and the similarity of polar distribution of bicoid and Rb24 mRNA in early embryo development may implicates a conserved maternal regulation mechanism of body axis presents in Drosophila and in rice.

Auxin distribution and transport during embryogenesis and seed germi-nation of Arabidopsis

Auxin distribution during embryogenesis and seed germination were studied with transgenic Arabidopsis plants expressing GUS gene driven by a synthetic DR5 promoter,an auxin responsive promoter. The results showed that GUS activity is higher in ends of hypophysis and cotyledon primordia of heart-, torpedo- and cotyledon-stage embryos, leaf tip area, lateral root primordia, root apex and cotyledon of young seedlings. And GUS accumulated in root apex of the seedlings grown on auxin transport inhibitor containing media. All these suggested that above-mentioned part of the organs and tissues have a higher level of auxin, and auxin polar transport inhibitor could cause the accumulation of auxin in root apex. And auxin transport inhibitor also resulted in aberration of Arabidopsis leaf pattern formation, root gravitropism and elongation.