Fertile plants regenerated from suspension culture-derived protoplasts of an indica type rice (Oryza sativa L.)

Calluses were induced from immature embryos of an indica type rice and finely dispersed cell suspension cultures were initiated from the callus using modified AA medium (S₁ medium). The suspension cultures were maintained alternatively (1–2 passages in each medium) in S₁ medium and S₂ medium, the latter containing KNO₃, NH₄NO₃, proline and glutamine as nitrogen source. Protoplasts of high quality were isolated form suspension cells cultured in S₂ medium supplemented with ABA. Embedding the protoplasts in agarose blocks containing NH₄NO₃-free modified KM8P(PM₁) medium and immersing the blocks in NH₄NO₃-containing modified KM8P(PM₃) medium were most effective for obtaining protoplast division and callus formation. The protoplast-derived calluses were precultured in potato extract-aand/or ABA-containing N₆(D₁, D₂ or D₃) media and many embryo-like structures were formed. These structures developed into plantlets after being transferred to N₆ differentiation (D₄) medium. The regenerated plantlets grew into mature plants and beard seeds normally.Abbreviations AA medium amino acids based medium - ABA abscisic acid - BA benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - DF division frequency - IAA indoleacetic acid - KIN kinetin - NAA naphthaleneacetic acid - PE planting efficiency     

细叶黄芪叶肉原生质体发育早期几种细胞器的变化

在细叶黄芪叶肉原生质体发育早期,细胞器的变化较大。离体培养4h后,线粒体的嵴和基质物质开始增加。培养3—5天后,线粒体的数量增加5倍以上,此时可见大部分线粒体围绕细胞核分布。在培养24h后,高尔基体开始发育,它们主要分布在细胞质周边区域。多糖细胞化学染色表明,高尔基体内沉积着大量嗜银物质。培养1天后,粗面内质网开始发育。培养3天时,部分叶绿体边缘出现一些空隙结构。随着叶绿体内膜结构的消失,淀粉粒增大,叶绿体逐渐转变为造粉质体。     

Oxidative metabolism and protoplast culture

Summary Barley leaf blade protoplasts accumulate malonaldehyde, a product of lipid peroxidation, during culture. In addition, glutathione levels fall after protoplast isolation and the proportion of glutathione in the oxidized state rises. These data indicate oxidative stress after protoplast isolation and during culture. The cause of this phenomenon is revealed by data showing that the activities of enzymes associated with antioxidative processes including glutathione reductase and ascorbate peroxidase decrease after barley protoplast isolation. In contrast, protoplasts isolated from suspension cultured cells of bromegrass and soybean exhibit little evidence for oxidative stress and increased activities of glutathione reductase and ascorbate peroxidase. We suggest that an antioxidative response is associated with mitosis and colony formation from protoplasts, as exhibited by bromegrass and soybean. Conversely, failure of an antioxidative response is associated with low viability and absence of mitosis, as in barley. Increased viability of barley leaf protoplasts cultured on feeder layer cells is correlated with increased glutathione content and higher glutathione reductase activity.     

南苜蓿组织和原生质体培养及转化试验

主要探讨南苜宿子叶和下胚轴外植体,子叶原生岳体培养中的器官发生及遗传转化。南苜蓿子叶和下胚细外植体培养在附加１ＡＡ０．５－１ｍｇ／Ｌ和细胞分裂素（ＢＡ或ＺＴ）０．５－２ｍｇ／Ｌ的ＭＳ培养基上,在有当照的条件下诱导形成不定芽,进而再生成完整植株。子叶原生质体培养在附加２,４－Ｄ０．５ｍｇ／Ｌ和ＫＴ０．２ｍｇ／Ｌ的Ｂ５液体培养基中,细胞分裂频率可达３０－４１％,原生质全来源的愈伤组织在ＭＳＢ培养基（Ｍ     

Flower senescence in daylily (Hemerocallis)

This paper reviews recent developments in the use of molecular probes for analyzing the genetic makeup of somatic hybrids. Successful application of somatic hybridization to the interspecific transfer of traits encoded in the nucleus is still having limited success. A major difficulty is hybrid infertility, particularly in hybrids between sexually incompatible species. The formation of asymmetric hybrids is being explored as an approach for improving hybrid fertility. Evaluation of the degree of chromosome elimination and chromosome stability and instability in asymmetric hybrids is difficult when the traditional approaches of chromosome counting and isozyme analysis are used. Two new approaches are resolving this difficulty. The use of species-specific repetitive DNA probes in dot blotting and in situ hybridization to chromosomes is providing quantitative data on chromosome elimination and allows detection of translocations. Use of restriction fragment length polymorphism (RFLP) probes for analysis of hybrids between genetically mapped species makes it possible to account for the presence or absence of individual chromosomes and chromosomes arms. Wider use of such molecular probes should greatly improve our understanding of the genetics of both symmetric and asymmetric somatic hybrids and may lead to new strategies for the effective interspecific transfer of nucleus-encoded traits by protoplast fusion.     

Protoplasts as tools in cell biology

Studies of plant protoplasts using both fluorescent dyes and electron dense probes have demonstrated endocytosis in plants. Ultrastructural work with soybean protoplasts using cationized ferritin (CF) revealed an endocytotic pathway from coated pits at the plasma membrane to coated vesicles, the partially coated reticulum, Golgi bodies, multivesicular bodies and finally the vacuole. Endocytosis may be responsible for membrane retrieval from the cell surface or degradation of elicitors or toxins during host-pathogen interactions. Immunofluorescence studies of dividing plant protoplasts have provided new information about the preprophase band (PPB) of microtubules and the shape of spindles. Studies of PPBs in soybean protoplast cultures permitted detailed examination of PPB development and an assessment of the usefulness of the PPB index for identifying morphogenic cultures. In multinucleate protoplasts the size and number of PPBs were apparently not controlled by nuclear number. Research with conifer protoplasts resulted in the discovery of new features of gymnosperm spindles.     

MACROALGAE SURVIVE DIGESTION BY FISHES1

Small individuals (<15 cm long) of the clingfish Sicyases sanguineus consume as many as 18 seaweed species in Central Chile. Enteromorpha sp. was the only species able to survive digestion by fish recently collected from the field. Enteromorpha compressa and Gelidium chilense also survived by tissue regeneration when offered as food in the laboratory, but only E. compressa showed stimulation of swarmer production. In general, our results on a vertebrate species reproduce previous findings on diverse invertebrate species. Since fish are highly motile, their capacity to disperse algal species by defecation might be of great ecological importance.     

两种药用黄芪比较生物学研究

通过栽培实验,本文对两种药用黄芪的个体发育节律,根,茎,叶,花及种子的生物学特性进行了较系统的比较研究,为确定蒙古黄芪（ＡｓｔｒａｇａｌｕｓｍｏｎｇｈｏｌｉｃｕｓＢｕｎｇｅ）为独立的种,提供了更为全面的依据。     

Intergeneric hybridization between Pleurotus ostreatus and Schizophyllum commune by PEG-induced protoplast fusion

Intergeneric hybridization between Pleurotus ostreatus and Schizophyllum commune was studied using PEG-induced fusion. The fusion of protoplasts from auxotrophic mutant strains resulted in the formation of fusion hybrids in the frequencies of 3.6 to 7.3×10^–5. Most of these fusion hybrids were monokaryotic and sterile and no heterokaryosis occurred. Most fusants showed a significantly higher nuclear DNA content when compared to parental strains and no diploids (parent 1 genome plus parent 2 genome) were found. Some fusion hybrids revealed both parental fragments in nuclear and mitochondrial rDNA PCR profiles. AP-PCR (Arbitrarily-primed Polymerase Chain Reaction) fingerprints also indicated that most of the fusion products were recombinant hybrids.