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苔藓植物是一类高等植物.没有维管组织,具颈卵器,以配子体为主要营养体,孢子体寄生或半寄生于配子体上.苔藓植物传统地分为苔纲和藓纲,近代一些学者将苔纲中的角苔目提升为纲,从而将苔藓植物分为三纲,即苔纲、角苔纲和藓纲.三纲的主要识别特征列表于下: 相似文献
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苔藓植物是体型较小的高等植物,分布广泛.苔藓植物的识别主要基于配子体的色泽、叶排列、叶形、叶细胞结构特点等形态结构资料以及配子体生长的生境、基质等环境特征,也适当考虑孢子体形态、结构等特征.重点对北京城区常见的苔藓植物做了介绍,以便相关人员在识别鉴定时参考. 相似文献
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葫芦藓(Funaria hygrometrica)配子体和孢子体重金属富集特性比较 总被引:1,自引:1,他引:1
通过对湘西茶田钒矿废弃冶炼厂矿渣上葫芦藓的野外生态调查和采集,利用原子吸收光谱仪、电感耦合等离子发射光谱仪和原子荧光光谱仪分析了葫芦藓配子体和孢子体及其基质重金属含量。结果表明葫芦藓配子体和孢子体富集了大量的重金属,各重金属元素在配子体和孢子体间的富集存在较大的差异,配子体比孢子体显著富集重金属元素(p<0.05),Zn和Mn在葫芦藓植物体中比其他重金属元素更高。同时也讨论了重金属在苔藓植物中的富集及生物阻抗的作用。 相似文献
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苔藓植物离体培养和多倍体研究 总被引:1,自引:0,他引:1
苔藓植物离体培养和多倍体研究陈阜东,刘家熙(首都师范大学生物系,北京100037)应用MS和无机培养基在24℃温度,12小时光照,3000Lx光强条件下离体培养苔藓植物茎段、茎尖,叶片和蒴帽可获得正常苔藓植物配子体(n)及孢子体(2n)。离体器官发育... 相似文献
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在调查和分类的基础上,发现小寨子沟自然保护区共有苔藓植物153种,分别属于92属,72科.通过对苔藓植物的优势类群、科属的区系成分、垂直分布以及群落类型的分析,结果表明:小寨子沟自然保护区苔藓植物(1)物种多样性丰富.(2)优势类群明显.(3)垂直分布显著.(4)温带分布为主. 相似文献
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Placental morphology is remarkably diverse between major bryophyte groups, especially with regard to the presence and distribution of transfer cells in the sporophyte and gametophyte. In contrast, with the exception of metzgerialean liverworts, placental morphology is highly conserved within major bryophyte groups. Here we examine the ultrastructure of the placenta in Monoclea forsteri and Treubia lacunosa, basal members of the marchantialean and metzgerialean liverwort lineages, respectively. In both species several layers of transfer cells are found on both sides of the placenta, with sporophytic transfer cells exhibiting prominent wall labyrinths. Consistent with previous reports of a similar placenta in other putatively basal and isolated liverwort genera such as Fossombronia, Haplomitrium, Blasia and Sphaerocarpos, this finding suggests that this type of placenta represents the plesiomorphic (primitive) condition in liverworts. Distinctive ultrastructural features of placental cells in Monoclea include branched plasmodesmata in the sporophyte and prominent arrays of smooth endoplasmic reticulum, seemingly active in secretion in the gametophyte. These arrays contain a core of narrow tubules interconnected by electron-opaque rods, structures with no precedent in plants. Analysis of the distribution of different types of placenta in major bryophyte groups provides valuable insights into their inter-relationships and possible phylogeny. 相似文献
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An improved method for the preparation of chromosomes from the male gametophyte of the alga Laminaria japonica Aresch. was described. The male gametophyte was pretreated with pDB (p-dichlorobenzene) and 8-hydroxyquinoline in order to clear cell wall and soften cytoplasm. The samples were treated by mordant iron alum [FeNH4 (SO4)2⋅6H2O] followed by staining with haemotoxylin. Well-spread and highly stained chromosomes were observed without precipitation. The chromosome number of male gametophyte of L. japonica was estimated to be 31. %
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Summary We examined the prospects for using the female gametophyte irradiation technique in cabbage to reduce the number of generations needed for cytoplasm transfer. Three different crosses were used with one nuclear and two cytoplasmic male-sterile lines as female parents. The doses applied ranged from 100 to 700 Gy. Differences between the genotypes were observed only in embryo and plant production with varying dose. Several plants derived from the various experiments exhibited one or two recessive paternal markers and an aneuploid number of chromosomes, which shows an irradiation-induced loss of maternal chromosomes. However, no androgenetic haploid plant was obtained. The aneuploid plants could sometimes be backcrossed, and in one case a shift in the segregation ratio towards the paternal (non-irradiated) phenotype was observed. We concluded that while the female gametophyte irradiation technique could reduce the number of generations necessary for cytoplasm transfer, the damage induced seems too restricted for this technique to be applied in cabbage breeding at present. 相似文献
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Xylans are known to be major cellulose-linking polysaccharides in secondary cell walls in higher plants. We used two monoclonal antibodies (LM10 and LM11) for a comparative immunocytochemical analysis of tissue and cell distribution of xylans in a number of taxa representative of all major tracheophyte and bryophyte lineages. The results show that xylans containing the epitopes recognized by LM10 and LM11 are ubiquitous components of secondary cell walls in vascular and mechanical tissues in all present-living tracheophytes. In contrast, among the three bryophyte lineages, LM11 binding was detected in specific cell-wall layers in pseudoelaters and spores in the sporophyte of hornworts, while no binding was observed with either antibody in the gametophyte or sporophyte of liverworts and mosses. The ubiquitous occurrence of xylans containing LM10 and LM11 epitopes in tracheophytes suggests that the appearance of these polysaccharides has been a pivotal event for the evolution of highly efficient vascular and mechanical tissues. LM11 binding in the sporophyte of hornworts, indicating the presence of relatively highly substituted xylans (possibly arabinoxylans), separates these from the other bryophytes and is consistent with recent molecular data indicating a sister relationship of the hornworts with tracheophytes. 相似文献
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Cell and molecular biology of bryophytes: ultimate limits to the resolution of phylogenetic problems 总被引:1,自引:0,他引:1
JEFFREY G. DUCKETT F.L.S. KAREN S. RENZAGLIA 《Botanical journal of the Linnean Society. Linnean Society of London》1988,98(3):225-246
Ultrastructure, biochemistry and 5S rRNA sequences link tracheophytes, bryophytes and charalean green algae, but the precise interrelationships between these groups remain unclear. Further major clarification now awaits primary sequence data. These are also needed to determine directionality in possible evolutionary trends within the bryophytes, but are unlikely to overturn current schemes of classification or phylogeny. Comparative ultrastructural studies of spermatogenesis, sporogenesis, the cytoskeleton and plastids reinforce biochemical and morphogenetic evidence for the wide phyletic discontinuities between mosses, hepatics and hornworts, and also rule out direct lines of descent between them. Direct ancestral lineages from charalean algae to bryophytes and to tracheophytes are also unlikely. EM studies of gametophyte/sporophyte junctions, plus immunological investigations of bryophyte cytoskeletons, are likely to accentuate the differences between mosses, hepatirs and hornworts. Other priorities for systematics include elucidation of oil body ultrastructure, analysis of the changes in nuclear proteins during spermatogenesis and a detailed comparison of bryophyte and charalean plastids. The combined evidence from ultrastrueture, biochemistry, morphology and morphogenesis warrants general acceptance of the polyphyletic origin of the bryophytes. Ultrastructural attributes should be more widely used in bryophyte systematics. 相似文献
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Factors that influence the distribution of ferns are poorly understood and likely reflect the ecology of both the sporophyte and the gametophyte generation. Little study has been done on the ecology of the gametophyte generation, especially in regard to tropical species. The goal of this study was to examine demography and the influence of light and disturbance on the distribution of the gametophytes of several tropical epiphytic, hemiepiphytic, and terrestrial fern species. Through a series of observational and experimental studies, we found that increased terrestrial gametophyte density and richness were related to both increased light and disturbance. By contrast, increased light had no influence, and increased disturbance negatively affected epiphytic density. Over a 25-mo demographic study, epiphytic and hemiepiphytic species had significantly greater longevities and lower recruitment rates than terrestrial species. Such unique strategies may have evolved in response to different disturbance regimens between the two habitats. Terrestrial species encounter and are adapted to more frequent disturbance and have invested in rapid gametophyte growth and recruitment. Epiphytic species may be more influenced by bryophyte competition, and in habitats of relatively low disturbance, they have invested in greater size and longevities. In such systems, gametophytes are able to survive for years waiting for favorable recruitment conditions. 相似文献
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E. M. Morozova 《Biology Bulletin》2002,29(2):192-195
Cytophotometric measurements of Feulgen-DNA were carried out in the nuclei of embryo sac cells of Haemanthus albiflos and Ornithogalum caudatum. It was found that the nuclei of the egg system, haploid in the number of chromosomes, became polyploid in DNA amount at the final stages of gametophyte development. 相似文献
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《The Plant cell》2022,34(10):3512
The liverwort Marchantia polymorpha has been utilized as a model for biological studies since the 18th century. In the past few decades, there has been a Renaissance in its utilization in genomic and genetic approaches to investigating physiological, developmental, and evolutionary aspects of land plant biology. The reasons for its adoption are similar to those of other genetic models, e.g. simple cultivation, ready access via its worldwide distribution, ease of crossing, facile genetics, and more recently, efficient transformation, genome editing, and genomic resources. The haploid gametophyte dominant life cycle of M. polymorpha is conducive to forward genetic approaches. The lack of ancient whole-genome duplications within liverworts facilitates reverse genetic approaches, and possibly related to this genomic stability, liverworts possess sex chromosomes that evolved in the ancestral liverwort. As a representative of one of the three bryophyte lineages, its phylogenetic position allows comparative approaches to provide insights into ancestral land plants. Given the karyotype and genome stability within liverworts, the resources developed for M. polymorpha have facilitated the development of related species as models for biological processes lacking in M. polymorpha.The model liverwort Marchantia polymorpha is now experiencing a Renaissance due to its facile forward and reverse genetics and its simple genome that includes sex chromosomes. 相似文献