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Single or a group of somatic cells could give rise to the whole plant, which require hormones, or plant growth regulators. Although many studies have been done during past years, how hormones specify cell fate during in vitro organogenesis is still unknown. To uncover this mechanism, Arabidopsis somatic embryogenesis has been recognized as a model for studying in vitro plant organogenesis. In this paper, we showed that establishment of auxin gradients within embryonic callus is essential for inducing stem cell formation via PIN1 regulation. This study sheds new light on how hormone regulates stem cell formation during in vitro organogenesis.Key words: auxin gradients, PIN proteins, stem cell, somatic embryogenesis 相似文献
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W. A. Parrott G. Dryden S. Vogt D. F. Hildebrand G. B. Collins E. G. Williams 《In vitro cellular & developmental biology. Plant》1988,24(8):817-820
Summary Somatic embryos of soybean [Glycine max (L.) Merr.] are induced on immature cotyledons explanted onto a medium containing moderately high levels of auxin. Germinability
of embryos is related to morphologic normality, and both are reduced by excessive exposure to auxin during the induction process.
Shoot meristem development was improved by reducing exposure of cotyledonary explants from 30 to 10 to 14 d on 10 mg/liter
α-naphthaleneacetic acid (NAA). A 3-d exposure was sufficient to induce embryos, and embryo frequency was not significantly
increased by exposures to NAA for more than 1 wk. Embryo frequency was enhanced, however, by transfer after 9 d to fresh medium
containing 10 mg/liter NAA. Germination of morphologically normal embryos was achieved without growth regulators, after maturation
for 1 mo. on hormone-free medium and desiccation for 1 wk in a sealed, dry container.
This research was funded by Lubrizol Genetics, Inc., Madison, WI. 相似文献
4.
Recent advances in conifer somatic embryogenesis: improving somatic embryo quality 总被引:18,自引:0,他引:18
Somatic embryogenesis of coniferous species was first reported more than 20 years ago. Since then, there has been an explosion of research aimed at developing and optimizing protocols for efficient regeneration of plantlets. Although routinely used both as a means of propagation, as well as a valuable model system for investigating the structural, physiological, and molecular events occurring during embryo development, in vitro embryogenesis is still problematic for some coniferous species. Major problems include: low number of embryos generated; and low frequency of mature embryos able to convert into viable plantlets. Until recent years, despite the fact that embryogenesis is comprised of a sequence of defined steps which include proliferation of embryogenic tissue, embryo maturation, and germination, attempts at improving the whole procedure have been made almost exclusively during the maturation stage. This strategy was based on the assumption that successful regeneration is related to treatments provided during the development of the embryos. Major optimizations of the maturation medium have involved judicious selections of type and concentration of growth regulators, namely abscisic acid, and adjustments of the osmoticum of the culture medium. Extensive work has been conducted in defining the effects of plasmolysing and non-plasmolysing osmoticum agents during maturation, as well as in improving desiccation techniques required for the completion of the maturation program. In the last 2 years, however, work on spruce has clearly demonstrated that the early events in embryogenesis are crucial for the successful completion of the overall embryogenic program. The use of cell tracking techniques, implemented by physiological and molecular studies, has revealed that manipulations of the culture conditions early in the process can increase both number and quality of embryos produced in culture. Additional manipulations of the germination medium can also enhance germination and conversion frequency of somatic embryos matured in a sub-optimal environment. These new findings, together with the unraveling of molecular mechanisms involved in the control/regulation of embryo development hold considerable promise for clonal propagation in conifers. 相似文献
5.
Somatic embryogenesis in soybean via somatic embryo cycling 总被引:4,自引:0,他引:4
Wennuan Liu Patricia J. Moore Glenn B. Collins 《In vitro cellular & developmental biology. Plant》1992,28(3):153-160
Summary The objectives of the present research were: a) to develop an efficient soybean embryogenic regeneration system characterized
by a high frequency of explant response and a large number of somatic embryos per explant; b) to evaluate the factors affecting
somatic embryogenesis via somatic embryo cycling; and c) to identify the origin of somatic embryos in the system. A highly
improved and efficient system for soybean somatic embryogenesis was established using somatic embryo cotyledons and somatic
embryo hypocotyl/radicle explants plated on α-naphthaleneacetic acid (NAA) or 2,4-dichlorophenoxyacetic acid (2,4-D) supplemented
MS basal media. The system included somatic embryo cycling between liquid and solid medium and it consistently gave rise to
a much higher frequency of explant response and a larger number of embryos per responding explant than those obtained from
zygotic cotyledon explant tissues. Genotype, differences were observed for response in some of the treatments with cv “Fayette”
being more responsive than “J103”. Histological studies revealed that somatic embryos induced in the somatic embryo cycling
system originated almost exclusively from epidermal cells on both 2,4-D and NAA inductive media. The cells of the epidermis
proliferated to produce somatic embryos directly without an intervening callus phase. A single-cell origin of somatic embryos
was observed in cultures on a 40 mg/liter 2,4-D treatment. A large number of responding cells in the epidermis was also observed
in the 10 mg/liter NAA treatment. The single-cell origin of somatic embryos from epidermal layers of the explant tissues should
facilitate development of an efficient transformation system for soybean. 相似文献
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The patterns of protein biosynthesis in the embryo and endosperm during embryogenesis in the Scots pine were studied using electrophoresis and biochemistry methods. Proteins of the albumin-globulin fraction were visualized already at the early embryonic stages. The main polypeptide components (48-60, 37-39, and 20-22 kDa) were gradually accumulated in the course of maturation. A high synchrony was noted between the stages of embryogenesis and molecular events related to protein biosynthesis and accumulation in the developing seed. 相似文献
8.
Comparison of somatic embryogenesis and embryo conversion in commercial soybean cultivars 总被引:4,自引:0,他引:4
Six commercially important soybean cultivars and one control cultivar were compared for differences in induction-efficiency of somatic embryogenesis, primary embryo yield, and embryo conversion. Cotyledons from immature seeds of similar developmental stage for all soybean cultivars were used for embryo induction. The experiments utilized a Latin square design to exclude the effect of differential lighting and position due to plate location in the growth chamber on the embryogenesis process. Results indicated that the efficiency of embryo induction and yield of primary somatic embryos were genotype-dependent. In contrast, no dependence on genotype was observed for the conversion of embryos to form roots and shoots. The percentage of cotyledons that gave a positive embryogenic response ranged from 26 to 89% for the soybean cultivars tested. The average number of primary globular-stage embryos per responding cotyledon after one month on induction medium ranged from 6 to 13 among the seven cultivars. Conversion frequencies for all genotypes ranged from 27 to 45%. 相似文献
9.
The developmental plasticity of plants is beautifully illustrated by the competence of the immature male gametophyte to change its developmental fate from pollen to embryo development when exposed to stress treatments in culture. This process, referred to as microspore embryogenesis, is widely exploited in plant breeding, but also provides a unique system to understand totipotency and early cell fate decisions. We summarize the major concepts that have arisen from decades of cell and molecular studies on microspore embryogenesis and put these in the context of recent experiments, as well as results obtained from the study of pollen and zygotic embryo development. 相似文献
10.
Alexander I. Kuklin Plamen D. Denchev Atanas I. Atanassov Alan H. Scragg 《Plant Cell, Tissue and Organ Culture》1994,38(1):19-23
A procedure for the development of alfalfa (Medicago falcata L.) somatic embryos to the torpedo stage in air-lift vessels is described. Embryos were initiated from chopped leaf explants and were formed by direct somatic embryogensis. The system produced a high number of torpedo stage embryos. The effect of various inoculation densities on embryo development was studied. A procedure for the development and maturation of embryos in aerated liquid media was established. The rate of conversion of the torpedo stage embryos formed in the vessels was 83%.Abbreviations ABA
abscisic acid
- B5
Gamborgs B5 medium (Gamborg et al. 1968)
- COT
cotyledon embryo state
- 2,4-d
2,4-dichlorophenoxyacetic acid
- FW
fresh weight
- ID
internal diameter
- MS
Murashige and Skoog medium (Murashige & Skoog 1962)
- PEG
polyethylene glycol
- POLY
polyembryos
- VVM
volume of gas/volume of bioreactor 相似文献
11.
Effects of cytokinins and auxins on cassava shoot organogenesis and somatic embryogenesis from somatic embryo explants 总被引:4,自引:0,他引:4
Somatic embryos of cassava (Manihot esculenta Crantz) cultivar ‘Nanzhi 188’ were isolated and cut into fragments to be cultured
on media with various cytokinins and auxins. Cytokinin induced of cassava shoot organogenesis, while auxin stimulated somatic
embryogenesis. The effectiveness on organogenesis was different based on different cytokinins and in combination with auxins.
Benzyladenine and thidiazuron stimulated more shoot organogenesis than kinetin and N-isopentenyladenine.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
12.
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
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Ljubinka Ćulafić SneŽana Budimir Radmila Vujičić Mirjana Nešković 《Plant Cell, Tissue and Organ Culture》1987,11(2):133-139
Axillary buds of the dioecious plant Rumex acetosella L. were isolated and cultured in vitro. The callus tissue which developed at the basal parts of the explants displayed a high capacity for shoot formation. This morphogenetic pattern was predominant on Murashige and Skoog (MS) medium supplemented with 2% sucrose, 2.2 mgl-1 benzylaminopurine and 0.17 mgl-1 indole-3-acetic acid. Somatic embryogenesis was induced when the osmolality of the medium was increased by adding 6% sucrose instead of 2%, or hexitols in addition to 2% sucrose. Most of the embryogenic calli were formed on the basal parts of leaf laminae and bracts. Development and maturation was strongly promoted by transferring the tissue to a solid or liquid medium lacking benzylaminopurine and indole-3-acetic acid and supplemented with 10 mgl-1 gibberellic acid. The embryos germinated and developed into normal rosette plants when transferred to vermiculite moistened with hormone-free, half-strength MS salt solution. The histology of successive embryogenic stages is presented. 相似文献
15.
NiDA WangLJ 《Cell research》2001,11(4):273-278
INTRODUCTIONAuxin plays an important role in regu1ating celldivision, e1ongation and differentiatiou, vascular tis-sue fOrmation[1], pollen deve1opment[2] and 1eafyhead fOrmation[3]. Adrin polar transport is be-1ieved to invohe in a variety of important growthand developmenial processes, including the patternfOrmation of eInbryO, leaf morphogenesis and theroot gravity response[4--8]. Auxin po1ar transportinhibitor has been proved essential illterference ofataln transport leading to patte… 相似文献
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Putrescine, spermidine, and spermine levels during somatic embryogenesis of interior spruce (Picea glauca x Picea engelmannii complex) were quantified On abscisic acid supplemented growth medium putrescine and spermidine levels increased two-fold coinciding with maturation of the early somatic embryos to globular embryos. Polyclonal antibodies raised against Escherichia coli arginine decarboxylase (ADC) and ornithine decarboxylase (ODC), following affinity purification specifically recognized spruce ADC and ODC, which corresponded to 85kD and 65kD bands on western blots of total protein extracts from embryogenic masses, Immunoassays using these antibodies showed increased ADC levels corresponding to embryo maturation while ODC levels remained the same. From these results it is concluded that polyamines are involved in the maturation of somatic embryos of interior spruce.Abbreviations ADC
arginine decarboxylase
- BSA
bovine serum albumin
- ODC
ornithine decarboxylase
- PBS
phosphate buffered saline
- PCA
perchloric acid
- SDS-PAGE
sodium dodecyl sulfateporyacrylamide gel electrophoresis 相似文献
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Control of direct and indirect somatic embryogenesis by exogenous growth regulators in immature zygotic embryo cultures of rose 总被引:3,自引:0,他引:3
Immature zygotic embryos of rose (Rosa hybrida L.; cv. Sumpath) did not form somatic embryos or embryogenic calluses when cultured on half-strength Murashige and Skoog's medium supplemented with various con-centrations of 2,4-dichlorophenoxyacetic acid (2,4-D) as the sole growth regulator. However, the zygotic embryos produced somatic embryos without an intervening callus phase at a frequency of 27.3% on medium with 4.44 M 6-benzyladenine (BA) alone. Immature zygotic embryos formed embryogenic calluses at a frequency of 25% on medium with a combination of 1.36 M 2,4-D and 4.44 M BA. Upon transfer to medium without growth regulators, embryogenic calluses produced numerous somatic embryos that subsequently developed into plantlets. Somatic embryos were induced directly from immature zygotic embryos, or indirectly via an intervening callus phase, by manipulating the exogenous growth regulators. Plantlets were successfully transplanted to potting soil and grown to maturity in a greenhouse. 相似文献
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Cécile Cabasson Patrick Ollitrault Francois-Xavier Côte Nicole Michaux-Ferriére Dominique Dambier Régine Dalnic Claude Teisson 《Physiologia plantarum》1995,93(3):464-470
Growth of willow-leaf mandarin ( Citrus deliciosa Ten.) nucellar callus cultures without embryo formation was supported on sucrose as the sole carbon source. Somatic embryogenesis was obtained by substituting galactose for sucrose at the same concentration (0.15 M ). A histocytological study revealed proliferation of young globular embryos during the first half of the 18-day culture cycle, irrespective of the carbon source. However, during the second half of the cycle, further embryo development failed in cell cultures on sucrose-containing medium. The rate of cell growth and the carbohydrate depletion of the medium were 3-fold higher on sucrose than on galactose-containing medium. Cell suspensions on sucrose differed by an increase in calcium, phosphorus, magnesium and potassium utilization soon after subculturing, followed by a sharp decrease. Finally, the phosphorus utilization rate per g dry weight formed was 2-fold higher in cell cultures on galactose during the second half of the culture cycle, coinciding with further embryo ontogenesis. 相似文献
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The objective of the current study was to simplify existing somatic embryogenesis systems in potato (Solanum tuberosum L.) cv. Desiree. The project targeted the agar-based induction phase of the potato somatic embryogenesis process as the key
area for improvement. Experiments were established to ascertain the effect of a 2,4-D (2,4 dichlorophenoxyacetic acid) pulse,
applied to the primary internodal section explant source and its subsequent effect on embryo induction. Parameters tested
were the duration of the auxin pulse in a range from 0 to 300 min, and the concentrations of 2,4-D applied, in a range from
0 to 5,120 μM. The mean number of somatic embryos formed per explant was recorded after 4 and 8 weeks culture. Our findings
indicated that the somatic embryogenesis in potato internodal segments could be evoked by an auxin (2,4-D) pulse treatment
over a wide concentration and duration range. The results further suggested that a simple 20 μM 2,4-D pulse treatment could
replace a lengthy 2 week induction phase in potato somatic embryogenesis and thus improve the system’s practicability for
wider uptake. 相似文献
20.
AtLTP1 luciferase expression during carrot somatic embryogenesis 总被引:4,自引:0,他引:4
Marcel A.J. Toonen John A. Verhees Ed D.L. Schmidt Ab van Kammen Sacco C. de Vries 《The Plant journal : for cell and molecular biology》1997,12(5):1213-1221
The carrot (Daucus carota L.) EP2 gene encodes a Lipid Transfer Protein (LTP) which is expressed during protoderm formation in developing embryos. To develop a vital reporter system for gene expression during somatic embryo development a 1.1 kB fragment of the Arabidopsis thaliana LTP1 promoter was fused to the firefly luciferase (LUC) coding sequence. The AtLTP1 luciferase expression pattern in transformed carrot suspension cultures was identical to the expression pattern of the endogenous carrot EP2 gene. Cell tracking experiments revealed that all somatic embryos were derived from AtLTP1 luciferase expressing cell clusters. However, not all cell clusters that expressed the AtLTP1 luciferase reporter gene developed into a somatic embryo, suggesting that initiation of an embryogenic pathway in tissue culture does not always lead to development of a somatic embryo. 相似文献