The Experts below are selected from a list of 21252 Experts worldwide ranked by ideXlab platform
Herve Etienne - One of the best experts on this subject based on the ideXlab platform.
-
cycle characteristics in a temporary immersion bioreactor affect regeneration morphology water and mineral status of coffee coffea arabica Somatic Embryos
Plant Cell Tissue and Organ Culture, 2005Co-Authors: J Albarran, Benoit Bertrand, Marc Lartaud, Herve EtienneAbstract:Mass regeneration of Coffea arabica L. Somatic Embryos using a temporary immersion bioreactor was improved by optimizing the immersion cycles, i.e. both the duration and the frequency of immersions. It was demonstrated that increasing the frequency of short immersions (1 min immersions every 24, 12 and 4 h) stimulated embryo production (480, 2,094 and 3,081 Embryos/1-l bioreactor, respectively) and improved quality (60, 79 and 85 of torpedo shaped Embryos, respectively). On the other hand, an increase in the immersion duration (1, 5 and 15 min) inhibited embryo regeneration (from 2,094 to 428 Embryos per 1-l bioreactor) and negatively affected their morphological quality (from 79 to 49 torpedo-shaped Embryos) and the conversion of Embryos into plants (from 70 to 33). A 15 min immersion duration applied every 4 h produced hyperhydric symptoms in 90 of the Embryos. Hyperhydric Embryos were characterized by higher fresh weight and water content, more negative values for water potential and higher K+ content when compared to normal torpedo-shaped Embryos. Micrographs showed structural problems in the globular stage, such as the existence of an irregular epidermis and an absence of reserves. Whatever the immersion cycle used, the Somatic Embryos exhibited water and mineral characteristics very different from those of their zygotic counterparts. The use of 1 min immersions every 4 h led to the production of the largest quantities of torpedo-shaped Embryos without hyperhydricity that succeeded in regenerating plants (75 conversion).
-
direct sowing of coffea arabica Somatic Embryos mass produced in a bioreactor and regeneration of plants
Plant Cell Reports, 1999Co-Authors: D Etiennebarry, Benoit Bertrand, N Vasquez, Herve EtienneAbstract:The effect of germination conditions on the morphology of Coffea arabica L. Somatic Embryos mass-produced in a 1-l temporary immersion bioreactor (RITA®) was studied with emphasis on direct sowing in soil. Using germinated Embryos, direct sowing resulted in a highly successful conversion of Embryos into plants. A culture density above 1600 Embryos per 1-l bioreactor positively affected embryo morphology by causing higher embryonic axis elongation (+4–5 mm). At this density, the addition of a high concentration of sucrose (234 mM) 2 weeks before sowing promoted an increase in effective plant conversion in soil (78%) and a vigorous vegetative growth of the resulting plants. Furthermore, direct sowing reduced handling time to 13% and shelving area requirements to 6.3% of the values obtained by conventional acclimatization of plants developed on gel media.
Patrick Von Aderkas - One of the best experts on this subject based on the ideXlab platform.
-
a novel method of cryopreservation without a cryoprotectant for immature Somatic Embryos of conifer
Plant Cell Tissue and Organ Culture, 2011Co-Authors: Lisheng Kong, Patrick Von AderkasAbstract:Cryopreservation of embryogenic tissue is an essential storage step in genotype selection and seedling production through Somatic embryogenesis. To date, immature conifer Somatic Embryos, at the proliferation step, were only able to tolerate ultra low temperature after prior cryoprotectant treatments. We report a novel cryopreservation method for conifer (interior spruce and Douglas-fir) embryogenic tissue focusing on the maturation step of developing Embryos that forgoes such cryoprotectant treatment. In this study, Somatic Embryos matured on culture media containing abscisic acid (ABA) at 20°C for 8 weeks. Typically, matured Embryos in this manner were able to survive cryopreservation. The embryogenicity, however, decreased with increasing embryo maturity. Non-freezing low temperatures, such as 5°C, not only inhibited cotyledon development but also maintained embryogenicity. Cryotolerance was successfully induced when Embryos were matured (or pretreated) under 5°C for a suitable culture period, typically 4–8 weeks. These Embryos were able to survive a rapid cooling process and liquid nitrogen storage without the addition of any cryoprotectants. After cryopreservation, embryogenic tissue was recovered in both interior spruce and Douglas-fir. Embryo maturation tests indicated no difference in mature embryo yields with or without cryopreservation in interior spruce. The key factors inducing cryotolerance included ABA supplementation in culture media and low temperature pretreatment. Optimum combinations of these factors can result in high rates of tissue survival and high embryogenicity after cryopreservation.
-
desiccation cryopreservation and water relations parameters of white spruce picea glauca and interior spruce picea glauca engelmannii complex Somatic Embryos
Tree Physiology, 2001Co-Authors: Robin E Percy, N J Livingston, Jonathan A Moran, Patrick Von AderkasAbstract:Effects of drying and cryopreservation on survival of spruce (Picea glauca (Moench) Voss and Picea glauca x engelmannii complex) Somatic Embryos (SEs) were investigated with the aim of developing simple and robust protocols for embryo storage. Somatic Embryos dried over salt solutions of known water potential (Psi) survived removal of virtually all free water, to a relative water content (RWC) of approximately 0.13, a value similar to that for spruce zygotic Embryos from dry seed. Desiccated SEs also survived subsequent freezing in liquid nitrogen, without the addition of cryoprotectant or pre-culture steps. Highest survival (> 80%) after freezing in liquid nitrogen was in Embryos pre-dried to Psi of -15 to -20 MPa, which yielded RWC close to predicted bound (apoplastic) water values. Low (< 35%) or no survival after freezing was observed in Embryos pretreated at higher Psi (above -5 MPa) or at very low Psi (-540 MPa, using silica gel), respectively.
Traud Winkelmann - One of the best experts on this subject based on the ideXlab platform.
-
metabolite profiling of Somatic Embryos of cyclamen persicum in comparison to zygotic Embryos endosperm and testa
Frontiers in Plant Science, 2015Co-Authors: Traud Winkelmann, Christina Rode, Svenja Ratjens, Melanie Bartsch, Karsten Niehaus, Hanna BednarzAbstract:Somatic embryogenesis has been shown to be an efficient in vitro plant regeneration system for many crops such as the important ornamental plant Cyclamen persicum, for which this regeneration pathway of Somatic embryogenesis is of interest for the vegetative propagation of parental lines as well as elite plants. However, Somatic embryogenesis is not commercially used in many crops due to several unsolved problems, such as malformations, asynchronous development, deficiencies in maturation and germination of Somatic Embryos. In contrast, zygotic Embryos in seeds develop and germinate without abnormalities in most cases. Instead of time-consuming and labor-intensive experiments involving tests of different in vitro culture conditions and plant growth regulator supplements, we follow a more directed approach. Zygotic Embryos served as a reference and were compared to Somatic Embryos in metabolomic analyses allowing the future optimization of the in vitro system. The aims of this study were to detect differences in the metabolite profiles of torpedo stage Somatic and zygotic Embryos of C. persicum. Moreover, major metabolites in endosperm and testa were identified and quantified. Two sets of extracts of two to four biological replicates each were analyzed. In total 52 metabolites were identified and quantified in the different tissues. One of the most significant differences between Somatic and zygotic Embryos was that the proline concentration in the zygotic Embryos was about 40 times higher than that found in Somatic Embryos. Epicatechin, a scavenger for reactive oxygen species, was found in highest abundance in the testa. Sucrose, the most abundant metabolite was detected in significantly higher concentrations in zygotic Embryos. Also, a yet unknown trisaccharide, was significantly enriched in zygotic Embryos.
-
from callus to embryo a proteomic view on the development and maturation of Somatic Embryos in cyclamen persicum
Planta, 2012Co-Authors: Christina Rode, Hanspeter Braun, Kathrin Lindhorst, Traud WinkelmannAbstract:In this study, the proteome structures following the pathway in Somatic embryogenesis of Cyclamen persicum were analysed via high-resolution 2D-SDS-PAGE with two objectives: (1) to identify the significant physiological processes during Somatic embryogenesis in Cyclamen and (2) to improve the maturation of Somatic Embryos. Therefore, the effects of maturation-promoting plant growth regulator abscisic acid (ABA) and high sucrose levels on torpedo-shaped Embryos were investigated. In total, 108 proteins of differential abundance were identified using a combination of tandem mass spectrometry and a digital proteome reference map. In callus, enzymes related to energy supply were especially distinct, most likely due to energy demand caused by fast growth and cell division. The switch from callus to globular embryo as well as from globular to torpedo-shaped embryo was associated with controlled proteolysis via the ubiquitin-26S proteasome pathway. Storage compound accumulation was first detected 21 days after transfer to plant growth regulator (PGR)-free medium in early torpedo-shaped Embryos. Increase in abundance of auxin-amidohydrolase during embryogenesis suggests a possible increase in auxin release in the late embryo stages of Cyclamen. A development-specific isoelectric point switch of catalases has been reported for the first time for Somatic embryogenesis. Several proteins were identified to represent markers for the different developmental stages analysed. High sucrose levels and ABA treatment promoted the accumulation of storage compounds in torpedo-shaped Embryos. Additionally, proteins of the primary metabolic pathways were decreased in the proteomes of ABA-treated Embryos. Thus, ABA and high sucrose concentration in the culture medium improved maturation and consequently the quality of Somatic Embryos in C. persicum.
-
germination of encapsulated Somatic Embryos of cyclamen persicum
Hortscience, 2004Co-Authors: Traud Winkelmann, L Meyer, Margrethe SerekAbstract:Somatic Embryos of cyclamen (Cyclamen persicum Mill.) were produced using a liquid culture system. Two encapsulation techniques, conventional alginate beads and alginate hollow beads, were tested for globular cyclamen Somatic Embryos with the aim of develop- ing synthetic seeds. Final germination from alginate beads was as high as observed for non encapsulated control Embryos (97%), but germination was delayed. In contrast, germination from hollow beads was lower (71%) and occurred later. In hollow beads Somatic Embryos developed within the capsule, and outgrowth seemed to be more diffi cult than from alginate. Storage at 4 °C for four weeks resulted in a reduction of viability for controls as well as for encapsulated Embryos. Incorporation of medium into the capsules improved the speed of germination for both capsule types. However, Somatic Embryos were not able to germinate on a medium-free support, even if encapsulated in beads containing medium.
-
the effect of oxygen partial pressure in bioreactors on cell proliferation and subsequent differentiation of Somatic Embryos of cyclamen persicum
Plant Cell Tissue and Organ Culture, 1999Co-Authors: Annette Hohe, Traud Winkelmann, Hansgeorg SchwenkelAbstract:The effect of the relative oxygen partial pressure (pO2) in bioreactors on cell proliferation and subsequent differentiation of Somatic Embryos from suspension cultures of Cyclamen persicum Mill. was investigated. The growth rate of cell line 3738-VIII in growth-regulator containing medium in bioreactors at 5% pO2 was slightly reduced in comparison to 10% and 20% pO2. Cultures growing at 40% pO2 had a lower growth rate, a markedly reduced cell viability and showed a decrease of the medium pH to 3.5. Because a pH-control with a setpoint of 3.3 caused cell death within 4 days, it was assumed, that the reason for the poor cell proliferation and viability in the cultures at 40% pO2 was an effect of medium acidification rather than of the high O2 partial pressure. A significantly higher number of germinating Embryos was obtained from the cultures grown at 40% pO2 than from those grown in flasks or in bioreactors at 5%, 10% and 20% pO2. These results were specific for cell line 3738-VIII. Another cell line, 3736-12, did not show marked differences in cell proliferation, viability, pH or subsequent regeneration of Somatic Embryos when grown at different O2 partial pressures.
Krystyna Klimaszewska - One of the best experts on this subject based on the ideXlab platform.
-
accumulation pattern and identification of seed storage proteins in zygotic Embryos of pinus strobus and in Somatic Embryos from different maturation treatments
Physiologia Plantarum, 2004Co-Authors: Krystyna Klimaszewska, Frederic Morency, Catherine Jonesoverton, Janice CookeAbstract:Somatic embryogenesis (SE) of Pinus strobus L. has been greatly improved over the last few years with respect to both the initiation frequencies from a number of seed families and production of mature Somatic Embryos that readily convert to plants. However, there are no data on biochemical characterization of Somatic Embryos in relation to zygotic Embryos of eastern white pine and on the optimal duration of the maturation stage. It is believed that Somatic Embryos closely resembling zygotic Embryos not only morphologically but biochemically would display more vigorous growth. Hence, in this study the accumulation pattern of the most abundant seed storage proteins in zygotic and Somatic Embryos were characterized by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and identified by amino acid sequencing and tandem mass spectrometry (MS/MS). This showed that Somatic Embryos accumulated storage proteins in a similar manner to zygotic Embryos and that the most abundant were the buffer-insoluble 11S- globulins MW 59.6 kDa, which dissociated under reduced conditions to 38.2-40.0 and 22.5-23.5 kDa range polypeptides, and buffer-soluble 7S vicilin-like proteins MW 46.0-49.0 kDa, which did not separate under reduced conditions. Other relatively abundant soluble proteins were in the ranges of 25-27 and 27-29 kDa. The only group of proteins that showed different migration profiles in the presence of β-mercaptoethanol (ME) were the low molecular mass proteins of 14.6-16.5 kDa. Somatic Embryos that matured for 9 weeks on medium with 6% sucrose accumulated more storage proteins than those matured on medium with 3% sucrose and the extension of the maturation period to 12 weeks resulted in significant reduction of the storage proteins on both media. As expected, Somatic Embryos matured on medium with 6% sucrose had lower water potential (Ψ) than those from medium with 3% sucrose. Nonetheless, the Somatic Embryos matured under the best of tested conditions (6% sucrose for 9 weeks) had slightly higher water content; 1.35 ± 0.28 g H 2 O g -1 DM (mean ± SD) than the mature non-dried zygotic Embryos; (1.16 ± 0.09 g H 2 Og -1 DM), and accumulated less storage proteins, whose amounts were either similar to (7S-vicilins) or below (11S-globulins) those found in the immature zygotic Embryos collected 2 weeks prior to the usual cone collection. The implications of these results for further research and development of viable artificial seed is discussed.
-
maturation of Somatic Embryos of pinus strobus is promoted by a high concentration of gellan gum
Physiologia Plantarum, 1997Co-Authors: Krystyna Klimaszewska, Dale R SmithAbstract:Application of Somatic embryogenesis to Pinus strobus clonal propagation and genetic improvement was hampered by the difficulty in achieving synchronous maturation of a large number of Somatic Embryos that would germinate and produce plants. Media containing abscisic acid (80 μM) and osmotic agents such as sucrose, polyethylene glycol and/or dextran did not sustain development of mature Somatic Embryos from plated embryonal masses. This indicated that factors other than osmotic agents might be involved in sustaining development of Pinus strobus Somatic Embryos to maturity. It was subsequently found that media lacking osmotica but containing a high concentration of gellan gum (1%) induced significant improvement in the development of mature Somatic Embryos in the presence of 80 or 120 μM abscisic acid. This positive effect was independent of the genotype and all four tested lines displayed similar responses. Media containing gellan gum at concentrations from 0.4 to 1.2% formed gels that varied in their strength. Gel strength was proportional to the concentration of gellan gum in the specific medium but varied depending on the medium formulation. Gel strength increased with the duration of storage of the culture medium by 46% (sD 14) after 14 days of storage. Preliminary results showed that Embryos matured on high gellan gum media displayed improved germination frequencies. These results indicate that in Pinus strobus the water status and possibly other medium characteristics that are influenced by increased concentration of gelling agent have stimulatory effects on maturation of Somatic Embryos.
Jan Salaj - One of the best experts on this subject based on the ideXlab platform.
-
initiation of embryogenic tissues and plantlet regeneration from Somatic Embryos of pinus nigra arn
Plant Science, 1999Co-Authors: Terezia Salajova, Jan Salaj, Andrej KormutakAbstract:Embryogenic cultures were derived from immature zygotic Embryos of Pinus nigra Arn. The zygotic Embryos at the time of collection were at the precotyledonary stage of development. To stimulate the maturation of early Somatic Embryos, abscisic acid (ABA; 25 mg/l) combined with maltose (3, 6, 9%) were used. The maturation process appeared to be cell line dependent. The best results were obtained in cell line E15. In this cell line high concentrations (6 and 9%) of maltose improved Somatic embryo maturation and well-formed cotyledonary Somatic Embryos developed. Two other cell lines tested (E7 and E16) showed prevailingly precotyledonary Somatic embryo development. Although in cell line E16 in the presence of 9% maltose few cotyledonary Embryos appeared, no plantlet regeneration occurred. Cotyledonary Somatic Embryos of cell line E15 germinated and regenerated plantlets with shoot and root meristem. The regenerated plantlets with root have been transferred to soil and at present are under observation.
-
developmental anatomy and ultrastructure of early Somatic Embryos in european black pine pinus nigra arn
Protoplasma, 1995Co-Authors: Jan Jasik, Terezia Salajova, Jan SalajAbstract:Embryogenic callus cultures of European black pine (Pinus nigra Arn.) were established on megagametophytes containing zygotic Embryos in early developmental stage. In addition to many elongated cells and disorganized growing clumps they contained early Somatic Embryos at various stages of development. At all stages of embryogenesis the Embryos were organized as bipolar structures. Cell pairs composed of one isodiametric cell with dense cytoplasm and a second large vacuolated cell were the simplest bipolar system. The vacuolated cell underwent senescence. The cytoplasm-rich cell and its derivates divided transversally, resulting in several cytoplasmic cells arranged in row. An early embryonal cylindrical mass was formed by longitudinal division of the cells in a filament. Proximally localized cells in the early embryonal mass became vacuolized and elongated gradually giving rise to the secondary suspensor. Distal cells remained cytoplasmic in character and formed an embryonal mass along the axis of long early Somatic Embryos. Differences in the proportion of organelles and heterochromatin clumps, thickness of cell walls and number of plasmodesmata between cells at various stages of early Somatic embryogenesis were described.
