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Embryogenic calli were initiated from embryonic explants of Pinus roxburghii using female gametophytes containing immature pre-cotyledonary embryos. Zygotic embryos were collected at different developmental
stages and cultured on various media. Initiation of embryogenic calli was achieved in pre-cotyledonary zygotic embryos of
a 0.1-mm to 1.2-mm embryonal head on Douglus fir cotyledon revised medium (DCR) medium supplemented with 2,4-D or NAA and
BA. Embryogenic callus development was initiated from the suspensor region of immature embryos. The method of immature embryo
culture was significant as rapid embryogenic callus development occurred in megagametophytes where the suspensor was stretched
onto the medium from the cut micropylar end. Sixty embryogenic lines were established from 2500 explants cultured during one
season. A pro-embryo with six to eight meristematic cells and suspensor of six to ten long, vacuolated cells dominated the
early phase of the callus development. Cleavage polyembryony occurred in proliferating callus, constituting a method of multiplication
of these somatic embryos. Somatic embryos developed to stage-I and stage-II embryos on DCR medium supplemented with 5 μM 2,4-D or 10 μM NAA.
Received: 30 June 1999 / Revision received: 15 November 1999 / Accepted: 3 December 1999 相似文献
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This review focuses on investigation in acquisition of embryogenic competence during somatic embryogenesis in the last five
decades. In tissue culture, differentiated somatic cells acquire embryogenic competence and proliferate as embryogenic cells
during the induction phase. These embryogenic cells are important because they differentiate to form somatic embryos at a
later time. Various molecular and structural markers for detecting embryogenic cells or enhancing embryogenic competence are
summarized and implications of the findings are discussed. 相似文献
5.
Genotypic control of peanut somatic embryogenesis 总被引:2,自引:0,他引:2
The protocol for obtaining a high frequency of plant development via somatic embryogenesis from mature zygotic embryo-derived
leaflets of peanut (Arachis hypogaea L.) involves multiple stages; these include the induction of embryogenic masses, development of embryos, radicle emergence/conversion
of embryos and the development of plants from rooted abnormal embryos. Sixteen genotypes were subjected to this protocol by
exposing mature zygotic embryo-derived leaflets to the common media sequence and comparing responses. Although the protocol
was effective for all the genotypes, variation in frequency of response at each stage of development indicated that, with
the exception of root meristem differentiation and subsequent radicle emergence, the whole process of somatic embryogenesis
depended on the genotypic constitution of the original plant. The failure of somatic embryos to undergo conversion to plantlets
could be a genotype-dependent characteristic.
Received: 5 June 1997 / Revision received: 2 December 1997 / Accepted: 12 December 1997 相似文献
6.
Somatic embryogenesis is a notable illustration of plant totipotency and involves reprogramming of development in somatic
cells toward the embryogenic pathway. Auxins are key components as their exogenous application recuperates the embryogenic
potential of the mitotically quiescent somatic cells. In order to unravel the molecular basis of somatic embryogenesis, cDNA
library was made from the regeneration proficient wheat leaf base segments treated with auxin. In total, 1440 clones were
sequenced and among these 1,196 good quality sequences were assembled into 270 contigs and 425 were singletons. By reverse
northern analysis, a total of 57 clones were found to be upregulated during somatic embryogenesis, 64 during 2,4-D treatment,
and 170 were common to 2,4-D treatment and somatic embryogenesis. A substantial number of genes involved in hormone response,
signal transduction cascades, defense, anti-oxidation, programmed cell death/senescence and cell division were identified
and characterized partially. Analysis of data of select genes suggests that the induction phase of somatic embryogenesis is
accompanied by the expression of genes that may also be involved in zygotic embryogenesis. The developmental reprogramming
process may in fact involve multiple cellular pathways and unfolding of as yet unknown molecular events. Thus, an interaction
network draft using bioinformatics and system biology strategy was constructed. The outcome of a systematic and comprehensive
analysis of somatic embryogenesis associated interactome in a monocot leaf base system is presented.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
7.
Callus induction and somatic embryogenesis of Phalaenopsis 总被引:23,自引:0,他引:23
Callus induction and plant regeneration through somatic embryogenesis in Phalaenopsis Richard Shaffer `Santa Cruz' were examined. Protocorm-like body (PLB) segments formed calli in Vacin and Went medium with
sucrose. The optimal concentration of sucrose was 40 g ⋅ l–1. Medium containing 200 ml ⋅ l–1 coconut water together with 40 g ⋅ l–1 sucrose was effective for callus induction. Gellan gum was suitable than agar as a gelling agent for callus induction. The
calli easily formed PLBs after being transferred to a medium without sucrose. Histological observation suggested that the
PLBs were somatic embryos. No variation was observed in the flowering plants regenerated through somatic embryogenesis.
Received: 11 June 1997 / Revision received: 6 October 1997 / Accepted: 18 October 1997 相似文献
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Regeneration of Acacia mangium through somatic embryogenesis 总被引:2,自引:0,他引:2
Somatic embryogenesis and whole plant regeneration were achieved in callus cultures derived from immature zygotic embryos
of Acacia mangium. Embryogenic callus was induced on MS medium containing combinations of TDZ (1–2 mg/l), IAA (0.25–2 mg/l) and a mixture of
amino acids. Globular embryos developed on embryogenic callus cultured on the induction medium. Nearly 42% of embryogenic
cultures with globular embryos produced torpedo- and cotyledonary-stage embryos by a two-step maturation phase. The first
stage occurred on 1/2-strength MS basal medium containing 30 g/l sucrose and 5 mg/l GA3 followed by the second stage on 1/2-strength MS basal medium containing 50 g/l sucrose. Of the cotyledonary-stage somatic
embryos, 11% germinated into seedlings that could be successfully transferred to pots. Light- and scanning electron microscopy
showed that the somatic embryos originated from single cells of the embryogenic callus. Further, a single cell layer could
be detected beneath the developing somatic embryos that appeared to be a demarcation layer isolating the somatic proembryonic
structure from the rest of the maternal callus. A suspensor-like structure connected the globular embryos to the demarcation
layer. This is the first successful report of plant regeneration through somatic embryogenesis for this economically important
tropical forest species.
Received: 20 January 2000 / Revision received: 28 September 2000 / Accepted: 29 September 相似文献
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Nucellar-derived cell cultures of sour orange (Citrus aurantium L.) proliferate as proembryogenic masses. By a change in the carbon source of the medium from sucrose to glycerol they are induced to undergo synchronous embryogenesis forming embryo initials that develop into globular embryos. The proembryogenic masses released glycoproteins to the medium. Exogenous addition of the glycoproteins to cells in glycerol-containing medium modified the course of embryo development in a dose-dependent manner. Addition of 20 g · ml–1 of glycoproteins blocked embryogenesis and resulted in an accumulation of embryo initials. When glycoproteins were added to cultures containing advanced globularstage embryos further development was suppressed. The inhibitory component of the glycoproteins was found to be a family of polypeptides with apparent molecular masses of 53–57 kDa. While these proteins normally accumulated only in cultures of proembryogenic masses, they could be induced to accumulate in glycerol-containing medium by the addition of the glycoproteins. Thus, their accumulation was not a direct consequence of the type of growth medium used or the developmental state of the cultures. The results indicate that the 53-to 57 kDa glycoproteins could play a regulatory role in in-vitro embryogenesis in sour orange. The normal progression of embryo development appears to depend, in an obligatory manner, on the absence of these glycosylated extracellular proteins from the medium.Abbreviations kDa
kilodalton
- PEM
proembryogenic masses
- SDS-PAGE
sodium dodecyl sulphate-polyacrylamide gel electrophoresis
- 2D-PAGE
Two-dimensional polyacrylamide gel electrophoresis
We thank Dr. S. Satoh (Institute of Biological Sciences, Tsukuba, Japan) for sending protein samples of the purified 57-kDa glycoprotein. This research was supported by a grant from the Charles H. Revson Foundation for Basic Research in the Life Sciences of the Israel Academy of Sciences. R.F. is a recipient of the Jack and Florence Goodman Career Development Chair. 相似文献
12.
Daucus carota L. cell lines secrete a characteristic set of arabinogalactan proteins (AGPs) into the medium. The composition of this set of AGPs changes with the age of the culture, as can be determined by crossed electrophoresis with the specific AGP-binding agent, β-glucosyl Yariv reagent. Addition of AGPs isolated from the medium of a non-embryogenic cell line to an expiant culture initiated the development of the culture to a non-embryogenic cell line. Without addition of AGPs or with addition of carrot-seed AGPs an embryogenic cell line was established. Three-month-old embryogenic cell lines usually contain less than 30% of dense, highly cytoplasmic cells, i.e. the embryogenic cells, but when carrot-seed AGPs were added this percentage increased to 80%. Addition of carrot-seed AGPs to a two-year-old, non-embryogenic cell line resulted in the re-induction of embryogenic potential. These results show that specific AGPs are essential in somatic embryogenesis and are able to direct development of cells. 相似文献
13.
Conditions for efficient direct somatic embryogenesis and plant regeneration of leaf explants from carnation cultivars Lena
(SIM group) and Bulgarian spray cultivars Nasslada, Yanita, Regina and Line 84 were established. Murashige and Skoog (MS)
liquid medium supplemented with 1 mg/l 2,4-dichlorophenoxyacetic acid and 0.2 mg/l 6-benzylaminopurine was used for direct
induction of embryoids without an additional callus phase. The first globular structures were observed after 20 days of cultivation.
Their further development to the torpedo stage was correlated with the presence of polyethylene glycol (PEG 6000). Somatic
embryo maturation was promoted by casein hydrolysate (1000 mg/l) in MS liquid media. The percentage conversion of embryos
and polyembryos to whole plants varied between 10 and 75% among studied cultivars. Plantlets regenerated by this procedure
were morphologically identical to the donor material and developed normally in a greenhouse.
Received: 29 November 1996 / Revision received: 28 April 1997 / Accepted: 28 May 1998 相似文献
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Segments taken from young leaves of an orchid (Oncidium Gower Ramsey) produced clusters of somatic embryos directly from epidermal and mesophyll cells of leaf tips and wound surfaces
without an intervening callus within 1 month when cultured on a GelriteTM-gelled 1/2-MS basal medium supplemented with a low dosage (0.3–1 mg/l) of thidiazuron. Subculturing of these embryo clusters
produced more embryos and subsequent plantlet formation on the same medium. The high-frequency embryogenesis of these leaf
cells in this orchid is strong evidence of their totipotency, and further modification of the protocol for plant formation
could be useful for the mass propagation and transformation of selected elite lines.
Received: 16 September 1998 / Revision received: 16 February 1999 / Accepted: 26 February 1999 相似文献
16.
Y. Henry J. -L. Marcotte J. De Buyser 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(2-3):344-350
The expression of essential genes during somatic embryogenesis can be analysed by inducing aneuploid cells to undergo embryogenesis during immature embryo culture and then determining whether defects occur. Triticum aestivum disomic and aneuploid stocks, including 36 ditelosomics and 7 nullitetrasomic Chinese Spring wheats, were compared for their ability to undergo somatic embryogenesis after 2 months of in vitro immature embryo culture. Their regeneration capacity was observed after 4 and 14 months of in vitro culture to determine which chromosome arms influence the process. The large range of variation found among the tested aneuploids suggested that genetic control of the somatic tissue culture ability is polygenic. Our results indicate that genes affecting somatic embryo-genesis and regeneration are located in all of the homoeologous chromosome groups. The lack of chromosome arms 1AL (DT 1AS) and 3DL (DT 3DS) practically suppresses somatic embryogenesis, demonstrating that major genes on wheat chromosome arms 1AL and 3DL control regeneration capacity. Results suggest that plants were mainly produced from somatic embryo development. Although the control of somatic embryogenesis and regeneration is polygenic, the genes located on the long arms of homoeologous group 3 chromosomes have a major effect. We also have evidence of chromosome arms that determine the time required for regeneration. 相似文献
17.
Factors affecting somatic embryogenesis in peanut (Arachis hypogaea L.) using leaflet explants of seedlings obtained from aseptically germinated embryo axes were evaluated. Somatic embryogenesis
was influenced by developmental stage, leaflet size, induction medium, and time on induction medium. Leaflets that were 5–7
mm long had a greater embryogenic response than smaller or larger leaflets. Percent embryogenesis and mean number of embryos
were related to the developmental stage of germinating seedlings. A greater response was obtained if leaflets were folded
and closely appressed. Preselection of leaflets increased percent embryogenesis from 21% up to 67%. As leaflets unfolded,
embryogenesis decreased; open leaflets lost the potential for embryogenesis. The optimal induction conditions were a 7-day
incubation period on Murashige and Skoog medium with 136 μm 2,4-dichlorophenoxyacetic acid and 0.93 μm kinetin. Somatic embryos germinated to form plants that exhibited a normal morphology.
Received: 29 December 1997 / Revision received: 9 April 1998 / Accepted: 24 April 1998 相似文献
18.
Embryogenic and non-embryogenic callus lines derived from the same diploid Cyclamen persicum genotype (`Purple Flamed') were analyzed by flow cytometry and compared to the initial plant material. The DNA content of
the diploid plant in the greenhouse was 1.12 pg DNA/2C as estimated in relation to the internal standards tomato nuclei and
chicken erythrocytes. In both callus lines the majority of cells contained the same amount of DNA as the initial plant, indicating
that no polyploidization has taken place after 5 years of culture on medium containing 2.0 mg/l 2,4-dichlorophenoxyacetic
acid (2,4-D) and 0.8 mg/l 6-(γ-γ-dimethylallylamino)purine(zip). Thus, our data suggest that in Cyclamen callus lines there was no strict correlation between the ploidy level and the ability to produce somatic embryos. Furthermore,
following the proportion of cells in the three phases of the cell cycle (G0/G1, S, G2/M) during one subculture period of 4
weeks revealed high division activity within the first 2 weeks for both callus lines cultured on the 2,4-D-containing medium.
However, when transferred to hormone-free medium, the division activity of the embryogenic cell line decreased markedly, corresponding
to the differentiation of somatic embryos. In contrast, for the non-embryogenic callus an increase in cells in the G2/M phase
was observed.
Received: 22 November 1996 / Revision received: 6 January 1997 / Accepted: 20 February 1997 相似文献
19.
Somatic embryogenesis and somaclonal variation in Norway spruce: morphogenetic, cytogenetic and molecular approaches 总被引:15,自引:0,他引:15
J.-L. Fourré P. Berger L. Niquet P. André 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(2):159-169
Four embryogenic clones of Norway spruce have been subcultivated and observed over several years to determine the evolution
of production of mature embryos and to assess the quality of the embryos produced. A wide range of intraclonal quantitative
and qualitative variability has been observed within this production. Certain morphologic deviations appeared at the immature
stage and after maturation, such as immature embryos with a diffuse organization, complete or part albino mature embryos or
acclimated somatic seedlings comparable to dwarf mutants. All of these phenotypic variations could be the result of a modification
of the genome itself or of only the expression of the genome. Two approaches, chromosome counting and RAPD (random amplified
polymorphic DNA), were chosen for their capacity to detect genotypic variations: respectively, genomic and chromosomic or
genic mutations. The cytogenetic approach revealed, for the first time in this species, three cases of mutated acclimated
somatic plants: one totally trisomic and two chimeras with trisomic buds and diploid roots. Other cases of 5-year-old trisomic,
double trisomic, tetraploid or mixoploid embryogenic masses were also detected. The molecular approach (RAPD) revealed no
somaclonal variation despite the large sample of DNA and primers used and the important interclonal variation observed.
Received: 9 June 1996 / Accepted: 21 June 1996 相似文献
20.
F. Toncelli G. Martini G. Giovinazzo V. Nuti Ronchi 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,70(4):345-348
Summary A permanent dicentric chromosome system was studied on carrot cultures and regenerated somatic embryos at different stages of development. The large chromosomal variability of the cultures and the presence of the breakage-fusion bridge cycle did not interfere with the initial developmental process up to the seedling stage but subsequent growth proceeded only if healing of the broken ends or dicentric loss had occurred. The behaviour of the dicentric chromosome in culture and during somatic embryogenesis is discussed in relation to chromosomal variability, abnormal development and the somaclonal variation that such mechanisms may generate in regenerated plants. 相似文献