共查询到19条相似文献,搜索用时 718 毫秒
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大黍无融合生殖现象的研究 总被引:1,自引:0,他引:1
大黍无融合生殖现象的研究冀朝辉,王景林(首都师范大学生物系,北京100037)大黍(Panicummaximum)是一种热带牧草。据报导,它具有无融合生殖特性。其无融合生殖类型为体细胞无孢子生殖,并且属于兼性无融合生殖。我们运用石蜡切片法和整体透明法... 相似文献
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雀稗属无融合生殖研究进展 总被引:1,自引:0,他引:1
雀稗属(Paspalum)为禾本科黍亚科多年生或一年生植物,是黍亚科内最有经济价值的类群之一。雀稗属植物种群极其复杂,大多数为多倍体。由于多倍体的存在及有性生殖的自交不亲和等原因,雀稗属植物表现出复杂多样的生殖特性,是禾本科中具备无融合生殖特性种类最多的属。对雀稗属无融合生殖的分布、无融合生殖相关的细胞学和胚胎学基础、无融合生殖的特点及其遗传学和分子生物学研究进展进行了综述。 相似文献
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水蔗草兼性无融合生殖胚胎学研究 总被引:4,自引:0,他引:4
对水蔗草 (ApludamuticaL .)的生殖方式进行研究 ,结果表明水蔗草进行兼性无融合生殖。胚囊发育分为两种类型 ,即有性生殖的蓼型和无孢子生殖的大黍型。无融合生殖胚囊频率为 6 0 .74%。在大孢子母细胞发育至四分体后 ,珠孔端的 3个大孢子解体。合点端的大孢子未解体时 ,邻近大孢子的 1个珠心细胞开始特化 ,形成无融合生殖的原始细胞 ,由该原始细胞发育形成有 1个卵细胞、1个助细胞和 2个极核的四核胚囊。 相似文献
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对水蔗草(Apluda mutica L.)的生殖方式进行研究,结果表明水蔗草进行兼性无融合生殖.胚囊发育分为两种类型,即有性生殖的蓼型和无孢子生殖的大黍型.无融合生殖胚囊频率为60.74%.在大孢子母细胞发育至四分体后,珠孔端的3个大孢子解体.合点端的大孢子未解体时,邻近大孢子的1个珠心细胞开始特化,形成无融合生殖的原始细胞,由该原始细胞发育形成有1个卵细胞、1个助细胞和2个极核的四核胚囊. 相似文献
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水稻与大黍不对称休细胞杂交再生植株 总被引:2,自引:0,他引:2
采用PEG(聚乙二醇)融合法,诱诱导水稻(Oryza sativa L.)原生质体与无融合生殖大黍(Panicum maximum Jacq.)原生质体融合,经过融合体筛选、培养,成功地获得了再生植株并移栽成活。在融合前水稻原生质体经过2.5mmol/L碘乙酰胺(IOA)在室温(22-25℃)条件下处理15min,大黍原生质体经过60Kr软X射线照射处理。对获得的28株融合再生植株进行初步检测发现 相似文献
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水稻与大黍不对称体细胞杂交再生植株 总被引:12,自引:0,他引:12
采用PEG(聚乙二醇)融合法,诱导水稻(Oryza sativa L.)原生质体与无融合生殖大黍(Panicummaximum Jacq.)原生质体融合,经过融合体筛选、培养,成功地获得了再生植株并移栽成活。在融合前,水稻原生质体经过2.5mmol/L碘乙酰胺(IOA)在室温(22~25℃)条件下处理15min,大黍原生质体经过60Kr软X射线照射处理。对获得的28株融合再生植株进行初步检查发现,在花器官形态、结构及生殖特性上与对照亲本水稻植株有显著的差异,出现多花药(一朵颖花具7~11枚甚至13枝花药)、多胚珠(1个子房内有2~3个胚珠)及“多胚囊”(1个胚珠内有2个以上类似胚囊的结构)等现象。雌、雄性育性显著降低或完全不育,仅有5株能够少量结实,I-KI溶液着色的花粉从0至68%不等。细胞胚胎学检查表明不能结实的植株雌性均不育,即不能分化出正常的胚囊结构。 相似文献
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植物的无融合生殖是指不经过雌雄配子融合而产生种子的一种特殊生殖方式。由于利用无融合生殖途径可以固定杂种优势,从而改良现有植物的育种策略,因此对无融合生殖的研究已成为生物学科的新生长点。本文主要从无融合生殖的概念和类型,无融合生殖在单子叶植物中的分布,无融合生殖的胚胎学,分子生物学和遗传学机制及创造新的无融合生殖种质资源的方法等6方面对单子叶植物的无融合生殖的研究进展进行了综述,并提出了今后开展无融合生殖研究的思路和设想。 相似文献
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Amanda L. Grusz 《植物分类学报:英文版》2016,54(6):656-665
This review provides a synopsis of apogamous reproduction in ferns and highlights important progress made in recent studies of fern apomixis. First, a summary of the apomictic fern life cycle is provided, distinguishing between two pathways to diploid spore production that have been documented in apomictic ferns (premeiotic endomitosis and meiotic first division restitution) and briefly discussing the evolutionary implications of each. Next, recent trends in fern apomixis research are discussed, exposing a shift in focus from the observation and characterization of apomixis in ferns to more integrated studies of the evolutionary and ecological implications of this reproductive mode. Peer-reviewed contributions from the past decade are then summarized, spanning the identification of new apomictic lineages through to the developmental, phylogenetic, and population genetic insights that have been made in studies of fern apomixis during that time. Gaps in our understanding are also discussed, including the extent and implications of recombinant apomixis in ferns, the possible reversibility of reproductive mode (from apomictic to sexual) in ferns, and the genomic causes and consequences of apomixis in seed free vascular plants. To conclude, future directions for fern apomixis research are proposed in the context of modern technological advances and recent insights from studies of apomixis in other groups. 相似文献
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Apomixis in agriculture: the quest for clonal seeds 总被引:8,自引:0,他引:8
Apomixis, or asexual reproduction through seeds, is a natural trait that could have an immense positive impact on crop production. Apomictic breeding strategies could allow the fixation and indefinite propagation of any desired genotype, however complex. Apomicts display a wide variety of developmental mechanisms, which can be viewed as a short-circuiting of sexual development. Gametophytic and sporophytic apomixis are distinguished by the developmental origin of apomictically derived embryos. Genetic studies suggest that individual elements of gametophytic apomixis, such as apomeiosis and parthenogenesis, are either controlled by one or two dominant Mendelian factors. As recombination around apomeiosis loci is suppressed, it is currently not known how complex these loci are. Much less is known regarding the genetic control of sporophytic apomixis but initial studies suggest a complex genetic control. Genetic analyses of sexual reproduction in plant model systems have identified genes that, when mutated, display elements of apomixis. Such studies help in the identification of candidate genes and promoters that can be used for the de novo engineering of apomixis through biotechnology. Molecular genetic studies in apomictic and sexual systems will generate the knowledge necessary for the engineering of conditional apomixis technology. Approaches encouraging collaboration and widespread dissemination of the acquired knowledge will constitute the most innovative route to the development, deployment and acceptance of apomixis technology in agriculture. 相似文献
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Hou W Lin S Li Y Pang X Zeng Y Wu R 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(5):681-691
Apomixis, or asexual reproduction through seeds, occurs in over 400 species of angiosperms. Although apomixis can favorably
perpetuate desired genotypes through successive seed generation, it may also bring about some difficulty for linkage analysis
and quantitative trait locus mapping. In this article, we explore the issue of how apomixis affects the precision and power
of linkage analysis with molecular markers. We derive a statistical model for estimating the linkage between different markers
when some progeny are derived from apomixis. The model was constructed within the maximum likelihood framework and implemented
with the EM algorithm. A series of procedures are formulated to test the linkage of markers, the rate of apomixis, and the
degree of genetic interference during meiosis. The model was examined and validated through simulation studies. The model
will provide a tool for linkage mapping and evolutionary studies for plant species that undergo apomixis. 相似文献
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Abstract Apomixis, the asexual reproduction via seed, has long been regarded a blind alley of evolution. This hypothesis was based on the assumption that apomixis is an irreversible, phylogenetically derived trait that would rapidly lead to extinction of the respective lineages. However, recent updates of the taxonomic distribution of apomixis in angiosperms suggest an alternative evolutionary scenario. Apomixis is taxonomically scattered and occurs in both early and late branching lineages, with several reversals from apomixis to obligate sex along phylogeny. Genetic control of apomixis is based on altered expression patterns of the same genes that control sexual development; epigenetic changes following polyploidization and/or hybridization may trigger shifts from sexuality to apomixis. Mendelian inheritance confirms the facultative nature and possible reversibility of apomixis to sexual reproduction. Apomixis, therefore, could represent a transition period in the evolution of polyploid complexes, with polyspory in paleopolyploids being a remnant of lost apomixis. In neopolyploids, apomixis helps to overcome sterility and allows for geographical range expansions of agamic polyploid complexes. The facultative nature of apomixis allows for reversal to sexuality and further speciation of paleopolyploid lineages. Thus, apomixis may facilitate diversification of polyploid complexes and evolution in angiosperms. 相似文献
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单子叶植物无融合生殖的研究进展 总被引:6,自引:0,他引:6
植物的无融合生殖是指不经过雌雄配子融合而产生种子的一种特殊生殖方式。由于利用无融合生殖途径可以固定杂种优势 ,从而改良现有植物的育种策略 ,因此对无融合生殖的研究已成为生物学科的新生长点。本文主要从无融合生殖的概念和类型 ,无融合生殖在单子叶植物中的分布 ,无融合生殖的胚胎学 ,分子生物学和遗传学机制及创造新的无融合生殖种质资源的方法等 6方面对单子叶植物的无融合生殖的研究进展进行了综述 ,并提出了今后开展无融合生殖研究的思路和设想 相似文献
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植物无融合生殖研究进展 总被引:1,自引:0,他引:1
本文综述了植物无融合生殖研究进展。无融合生殖能固定杂种优势,是新的研究热点。无融合合生殖转育研究取得长足进展。胚胎发生研究手段由切片技术逐渐发展为整体透明、组化荧光技术。大孢子母细胞(MMC)细胞壁无胼胝质(callose)及MMC哑铃状核是二倍性孢子形成区别于有性生殖的特征。DNA分子标记是无融合生殖研究的新的有效工具,狼尾草属、摩擦禾属的无融合生殖分子标记已被找到,并且后者已定位到玉米第6染色体长臂末端。 相似文献
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V. Brukhin 《Russian Journal of Genetics》2017,53(9):943-964
Apomixis is defined as the asexual plant reproduction through seeds that results in the production of genetically uniform progeny. In fact, apomixis could be considered as a natural way of cloning. Currently there are more than 400 plant species known to use apomixis as a strategy for their propagation. The primary fundamental aspects of apomixis are the bypassing of meiosis and parthenogenetic development of the embryo without fertilization Apomixis attracts special attention because of its potential value for agriculture, as it could be harnessed for plant breeding programs enabling the permanent fixation of heterosis in crop plants. A better understanding of the molecular and genetic regulation of apomixis is important for developmental and evolutionary perspectives but also for implementation of engineering of apomixis traits into agricultural crop plants. Despite apomixis is considered as one of the key technologies for the improving agriculture, it is currently not fully known how the genetic and molecular regulation of this important trait occurs. In this review, an up to date information on the biology of apomixis and the known genes and genetic loci associated with regulation of different components of apomixis is provided. 相似文献
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K. A. Geetha Aarti Kawane Ashok Kumar Bishoyi Arunkumar Phurailatpam C. Ankita S. K. Malik R. Srinivasan S. R. Bhat 《Trees - Structure and Function》2013,27(3):567-581
Guggul [Commiphora wightii (Arnot) Bhandari], a polygamous woody tree valued for its medicinal oleoresin gum rich in guggulsterone, is reported to reproduce via sporophytic apomixis. Details about its natural diversity, and mode and extent of sexual reproduction are, however, scanty. Therefore, a comprehensive investigation of guggul reproduction was made employing histology, controlled pollination, flow cytometry and RAPD analyses of progeny to assess the occurrence and extent of sexual reproduction. We report the discovery of obligate sexual female plants of guggul through these studies. Also, we document a unique pollen–pistil incompatibility that prevents all but one pollen tube growth into the style to effect fertilization. Consequently, obligate sexual female plants produced single-seeded fruit although each flower contains four ovules. In apomictic plants bearing more than one seed per fruit, at most only one seed was of sexual origin. Further, flow cytometric analysis conclusively demonstrated that endosperm development occurs either autonomously or following triple fusion. Autonomous endosperm development was invariably associated with endoreduplication, a unique feature of apomixis in guggul. Despite predominance of apomixis, a low frequency of sexual reproduction was found to persist in apomictic plants yielding new genetic variation. RAPD analysis clearly distinguished accessions and was useful in identifying sexual progenies. The implications of the novel pollen–pistil interaction on establishment and spread of apomixis in guggul are discussed. The study has not only revealed novel features of guggul reproduction but also opened new opportunities for molecular genetic analysis of sporophytic apomixis and breeding improvement of guggul. 相似文献