Development of fertilized ovules and their role in the growth of the pea pod

The histological development of fertilized ovules during fruit-set and development in pea ( Pisum sativum L. cv. Alaska) has been investigated. Killing the ovules on day 0 (anthesis) or day 1 prevented fruit-set and resulted in ovary degeneration. When the ovules were destroyed at later stages the ovaries developed, though the rate of growth of the pod was reduced significantly. Pollination in pea occurs normally the day before anthesis, and fertilization of the egg cell 32 to 48 h later. The first divisions of the zygote and endosperm nuclei started simultaneously (ca 48 h after pollination) but the endosperm developed more rapidly than the embryo; the embryo sac cavity was lined with free endosperm nuclei at the time of beginning suspensor elongation. Extracts of endosperm and ovule coats from ovules at day 7 after anthesis showed fruit-set activity in pea, the latter material having about 3 times more activity than the former per ovule basis. These results indicate that fertilization of the ovule is necessary for fruit-set in pea, and that compounds which induce fruit-set are probably synthesized in the ovules following fertilization.     

Identification and genetic analysis of semidwarfism-related proteins in rice (Oryza sativa L.)

Summary By transferring a semidwarf gene (sd-1) from Taichung Native 1 into a tall Japanese cultivar, Norin 29, through seven backcrosses, a semidwarf near-isogenic line SC-TN1 was obtained. The proteins of the embryo in Norin 29 and SC-TN1 were separated by two-dimensional electrophoresis. Most of the proteins showed the same electrophoretic pattern. However, it was found that there was a difference in the appearance of two basic glycoproteins designated as SRP-1 and SRP-2. These proteins exhibited the same molecular mass, but different isoelectric points. Hybridization results indicated that a single locus controls SRP-1 and SRP-2 with codominant alleles. The gene symbol Srp was given to this locus, with alleles Srp-1 and Srp-2 responsible for SRP-1 and SRP-2, respectively. Srp-2 was found in all of the semidwarf cultivars and lines having sd-1, except a tall cultivar Tsaiyuan-chung. This finding suggests that Srp-2 may be closely linked with sd-1. The amounts of these proteins markedly increased after water absorption of the seed, suggesting that these proteins may be related to the early development of the plant.     

Inhibition of rat yolk sac tumour growth in vivo by a monoclonal antibody to the retroviral molecule P15E

Summary A monoclonal mouse IgG2b antibody 19F8, directed towards a determinant on the retroviral transmembranous molecule p15E, binds selectively to certain rat tumours, including all tested yolk sac tumours, one rat colon carcinoma, one spontaneous kidney carcinoma and an adenovirus-type-9-induced rat breast tumour, as tested by antibody-dependent cellular cytotoxicity (ADCC) and immunohistochemistry. Groups of rats receiving yolk sac tumour F56 isografts intraperitoneally (i.p.) or subperitoneally (s.p.) were treated with this monoclonal antibody (mAb), 19F8, inoculated twice a week in doses of 100 µg. Parallel control groups received analogous inoculations of an isotype-matched monoclonal antibody. A significant growth inhibitory effect was observed with 19F8. In 5/10 rats isografted i.p., tumour outgrowth was completely inhibited and in the other 5 rats the outgrowth was delayed compared to the 10 rats in the control group, which all developed tumours. All rats of the control group developed large volumes of ascites, whereas the 5 rats in the therapy group with eventual tumour outgrowth had little or no ascites. In two experiments with rats carrying subperitoneal isografts and treated with the 19F8 mAb, tumour grew out in 4/5 and 5/10 rats, though growth was delayed compared to the control groups, in which 5/5 and 9/9 rats developed tumours. The tumours grew significantly more slowly in the therapy groups compared to the controls. All rats that developed tumours in the therapy groups showed an anti-idiotypic response against mAb 19F8. The single tumour-free rat in the first experiment and 1/5 tumour-free rats in the other showed no such response. The draining lymph node cells from the tumour-free animals showed a specific proliferative response to yolk sac tumour F56 cells in a mixed lymphocyte tumour cell culture (MLTC), and the MLTC-induced cells were cytotoxic to F56 but not to the natural-killer-sensitive rat T cell lymphoma G1—Tc1. The cytotoxic cell population was more than 90% CD4⁺. It is concluded that the two test systems for identification of the epitope of p15E detected by mAb 19F8 correlated well in detection of the epitope in the cells (immunohistochemistry) and at the cell surface (ADCC). It is also concluded that mAb 19F8 has a growth-inhibitory effect on yolk sac tumour F56 and that, as a result of the treatment, T cells with specificity for F56 are appearing in draining lymph nodes of tumour-free animals.     

Regeneration of peach plants from callus derived from immature embryos

Summary Peach plants were repeatedly regenerated from immature embryos but not from callus derived from mature embryos. A white, nodular, highly regenerative callus was obtained when friable, primary callus from immature embryos was transferred from medium containing 4.5 M 2,4-dichlorophenoxyacetic acid and 0.44 M benzyladenine (BA) to media containing 0.27 M -naphthaleneacetic acid (NAA) and 2.2 M BA. This callus retained its morphogenetic potential for a minimum of three subcultures. Green nodular callus, that lacked regenerative capacity, was produced from primary callus derived from mature embryos. Maximum regeneration of shoots occurred when highly regenerative callus was transferred to a medium in which the NAA concentration was reduced five times and the BA concentration was increased two times. Regenerated shoots were rooted in the dark on a medium containing 28.5 M indoleacetic acid. Cytogenetic analysis of regenerated plants indicated that all plants were diploid, 2n = 2x = 16. Phenotypic evaluation of regenerated plants, grown under field conditions, is now in progress.     

Hybridization in the genus Lens by means of embryo culture

Summary The cultivated lentil L. culinaris and the wild lentil L. ervoides are reproductively isolated from one another due to their hybrid embryo breakdowns. Using embryo culture, vegetatively normal hybrids were obtained. One specific hybrid, heterozygous for a reciprocal translocation, had about 50% gamete viability and produced aborted and viable embryos in a 11 ratio. In the F₂, vegetatively normal and highly fertile plants were selected. With the aid of embryo culture techniques, L. ervoides can be included in the wild gene pool of the cultivated lentil.     

Midbody sealing after cytokinesis in embryos of the sea urchin Arabacia punctulata

Summary Cytokinesis consists of a contractile phase followed by sealing of the connecting midbody to form two separated cells. To determine how soon the midbody sealed after cleavage furrow contraction, the fluorescent dye Lucifer Yellow CH(457.3 M.W.) was microinjected into cells at various intervals after cleavage had begun. Mitotic PtK₂ cells were recorded with video-microscopy so that daughter cells in the epithelial sheet could be identified for several hours after cell division. One daughter cell of each pair followed was microinjected to determine whether the dye diffused into the other daughter cell. For intervals up to four hours after the beginning of cytokinesis, diffusion took place between daughter cells. After this time the dye did not spread between daughter cells. In sea urchin blastomeres of the first, second and third divisions, Lucifer Yellow passed between daughter blastomeres only during the first 15 min after cytokinesis. If one cell of a two-cell, four-cell or eight-cell embryo was microinjected more than 15 min after the last cleavage, the dye remained in the injected cell and was distributed to all progeny of that cell, resulting in blastulae that were either one-half, one-quarter or one-eighth fluorescent, respectively. Thus, although cleavage furrow contraction takes approximately the same amount of time in sea urchin blastomeres and PtK₂ cells, the time of midbody sealing differs dramatically in the two cell types. Our results also indicate the importance of knowing the mitotic history of cells when injecting dyes into interphase cells for the purpose of detecting gap junctions.     

Systematic significance of mature embryo of bamboos

The mature embryo of seven species belonging to five genera of Indian bamboos is described. In all these the basic pattern of embryo organisation is same: the scutellar and coleoptilar bundles are not separated by an internode, the epiblast is absent, the lower portion of the scutellum and the coleorhiza are separated by a cleft and the margins of embryonic leaves overlap. The features unique to fleshy fruited bamboos are: presence of a massive scutellum, the juxtaposition of plumule and radicle and the occurrence of a bud in the axil of the coleoptile. The fleshy fruit bearing bamboos should be classified into one group, the tribeMelocanneae. Evidence is provided to recognise additional groups in the subfamilyBambusoideae.     

鸡胚视网膜发育中花生凝集素结合糖蛋白的图谱

我们应用微量(1—3微克蛋白)等电点聚焦和SDS双向电泳对鸡胚视网膜发育的第4天(E_4)到第16天(E_(16))总蛋白图谱进行分析,并结合印迹的PNA免疫酶标反应,分析了总蛋白中与PNA结合的糖蛋白图谱的变化。E_4时没有看到PNA结合糖蛋白的任何阳性反应的斑点,E_6时这种糖蛋白的种数突然增加,约占总蛋白数的20%。新的糖蛋白增加的速率在E_6时最快,存其后的发育阶段(E_8—E_(16))慢于总蛋白增加的速率。这种糖蛋白大都是等电点在中性pH范围内,中等大小分子量的糖肽。视神经的总蛋白中含PNA结合糖蛋白数的比例高于同一发育年龄视网膜中的比例,这说明糖蛋白可能主要存在于质膜上。视网膜的总蛋白图谱相似于前脑的,但与视顶盖的更相近。本文对这种能与PNA结合,即含有D-半乳糖残基的糖蛋白在视网膜发育中的意义进行了讨论。     

红皮树胚胎发育

本文报道红皮树(Styrax suberifoltus Hook.et Arn.)大小孢子发育和早期胚胎发生。子房具胚珠20—23枚,胚珠横生,珠被二层,薄珠心,孢原细胞直接起大孢子母细胞作用。合点端大孢子具功能。胚囊发育为正常型。成熟胚囊具大量淀粉粒。小孢子形成为同时型,成熟花粉为二细胞型。传粉后、受精前两个助细胞在形状和对苏木精着色程度上有显著区别。胚乳发育为细胞型。在合子分裂前,胚乳细胞增至约26个时,暂时停止分裂。苏木精对细胞质不易着色,似解体细胞。有胚乳吸器。