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  • 1
    Electronic Resource
    Electronic Resource
    The role of sucrose during maturation of black spruce (Picea mariana) and white spruce (Picea glauca) somatic embryos (2001)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 111 (2001), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The present study was conducted to understand the role of sucrose in the medium on the maturation of black spruce and white spruce somatic embryos. A maturation medium containing 6% sucrose, which hydrolyzed into glucose and fructose, gave significantly more embryos than a medium containing 3.16% of each glucose and fructose. Preventing the complete sucrose hydrolysis by a daily transfer of the tissues onto fresh medium significantly decreased the yield of somatic embryos compared to when sucrose was allowed to complete its hydrolysis. This reduction was not due to the manipulation of the tissues during the transfer, since a daily in situ transfer did not affect embryo production. To verify if the better embryo production observed on a medium containing 6% sucrose was due to the increasing osmotic pressure of the medium, this increasing osmotic pressure was simulated with a sequence of media containing different concentrations of glucose and fructose. Unexpectedly and for both species, this simulation did not improve somatic embryo production, which stayed similar to the one obtained on constant osmotic pressure. To understand these results, embryos produced on the different treatments were analyzed in terms of sucrose, glucose, fructose and starch levels and protein contents. The embryo carbohydrate content was independent from the carbohydrate used in the maturation medium. However, embryos matured on 6% sucrose allowed to hydrolyze during the maturation period contained significantly more soluble and insoluble proteins than embryos matured on any other treatment. Furthermore, embryos with a higher protein content also exhibited a higher epicotyl appearance frequency. The role of sucrose as a regulatory factor during the maturation of spruce somatic embryos is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2001.1110316.x
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  • 2
    Electronic Resource
    Electronic Resource
    Kinetics of ethylene biosynthesis and its effects during maturation of white spruce somatic embryos (2000)
    Copenhagen : Munksgaard International Publishers
    Physiologia plantarum 109 (2000), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The objective of the current investigation was to study the role of ethylene in the maturation of white spruce (Picea glauca [Moench.] Voss) somatic embryos. This was carried out by examining the effects of (1) 1-aminocyclopropane-1-carboxylic acid (ACC), a direct precursor of ethylene in plant tissue, (2) silver nitrate (AgNO3), an inhibitor of ethylene action, (3) α-aminooxyamino acid (AOA), a potent inhibitor of ethylene biosynthesis, and (4) enrichment with ethylene. Ethylene biosynthesis was biphasic and gradually increased during embryo development, whereas endogenous ACC and N-malonylaminocyclopropane-1-carboxylic acid (mACC) decreased. Addition of ACC or AOA to the culture medium increased or decreased, respectively, ethylene biosynthesis by altering endogenous ACC levels during the culture period. In contrast to AOA and AgNO3, ACC and ethylene enrichment significantly decreased the production of mature somatic embryos and increased the browning of the cultures. However, the structure of the shoot apex in mature cotyledonary stage embryos formed under ethylene enrichment was similar to that in control systems. This shows that a reduction in ethylene is beneficial to maturation of white spruce somatic embryos. This is further substantiated by the finding that the inhibitory effects of AOA were partially reversed by the addition of ethylene. The possible effects of the interaction between ethylene and polyamines on somatic embryo development are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2000.100315.x
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  • 3
    Electronic Resource
    Electronic Resource
    Induction of tolerance to fast desiccation in black spruce 
(Picea mariana) somatic embryos: relationship between partial water loss, sugars, and dehydrins (2002)
    Oxford, UK : Blackwell Science, Ltd
    Physiologia plantarum 115 (2002), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Events associated with the induction of tolerance to fast desiccation in black spruce (Picea mariana) somatic embryos were investigated. An experimental approach using an initial period of partial water loss was developed to induce either no, partial, or complete tolerance to fast desiccation. Tolerance to subsequent fast desiccation was not promoted by decreasing embryo water content from 1.5 to 1.1 g H2O g−1 DW (g g−1) throughout the first 24 h of slow desiccation. However, tolerance increased from 10 to 95% germination during the second 24-h period of slow desiccation after partial water loss from 1 to 0.55 g g−1. Emphasis was also placed on the relationship between observed tolerance, and sugar and dehydrin contents. Compared to controls, sucrose content in embryos doubled after 24 h of slow desiccation and more than tripled after 48 h. Conversely, starch content was decreased by one half after 24 h and by three quarters after 48 h. Sucrose abundance and raffinose occurrence after 48 h of slow desiccation were congruent with complete tolerance to fast desiccation. The period of slow desiccation between 24 and 48 h also increased the content of a 24-kDa dehydrin and the appearance of a 42-kDa dehydrin. The relationship between partial water loss, sugars and dehydrins is discussed with respect to tolerance to fast desiccation in black spruce somatic embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2002.1150406.x
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  • 4
    Electronic Resource
    Electronic Resource
    Epidermal transpiration, ultrastructural characteristics and net photosynthesis of white spruce somatic seedlings in response to in vitro acclimatization (2003)
    Oxford, UK : Munksgaard International Publishers
    Physiologia plantarum 118 (2003), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Mortality of transplanted somatic seedlings at the stage of acclimatization is often high and likely due to rapid change in environmental conditions. To investigate the potential of in vitro acclimatization of somatic seedlings before soil transfer, somatic seedlings of white spruce (Picea glauca[Moench] Voss) were germinated on a liquid medium supplemented with sucrose. After 6 weeks in germination, sucrose was omitted from the medium for a supplementary 6 weeks at which time somatic seedlings were acclimatized in vitro in their germination tubes before transfer to soil. In vitro acclimatization of somatic seedlings was realized by transferring the test tubes containing the germinated somatic seedlings to the greenhouse for 9 days. During this period, the culture tube lids of acclimatized somatic seedlings were lifted progressively increasing air exchange between the tube and the greenhouse whereas, for non-acclimatized somatic seedlings the culture tubes were maintained closed during in vitro acclimatization. In vitro acclimatized somatic seedlings had higher asymptotic net photosynthesis (Pn) at light saturation than non-acclimatized seedlings (6 versus 4.5 µmol m−2 s−1). At the end of the in vitro acclimatization period, a lower rate of epidermal transpiration was also observed for acclimatized somatic seedlings (3.85 versus 4.75% h−1). Microscopic observations showed that starch granules were more abundant in needles of acclimatized somatic seedlings than in non-acclimatized somatic seedlings, probably as a result of their greater photosynthetic capacity. Needles from acclimatized somatic seedlings also showed more epicuticular wax projections than needles from non-acclimatized somatic seedlings. These structural changes may help somatic seedlings to restrict epidermal water loss and stomatal aperture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1399-3054.2003.00146.x
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  • 5
    Electronic Resource
    Electronic Resource
    Transient transformation of pollen and embryogenic tissues of white spruce (Picea glauca (Moench.) Voss) resulting from microprojectile bombardment (1994)
    Springer
    Plant cell reports 13 (1994), S. 661-665 
    Details
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Detailed analyses of the physical parameters inherent in the microprojectile bombardment technology necessary to produce optimum transient β-glucuronidase (GUS) expression were undertaken in pollen and embryogenic tissues of white spruce. Higher helium pressure used for microprojectile bombardment resulted in lower GUS expression in pollen, but in higher GUS expression in embryogenic tissues. Modification of the osmoticum of the culture medium had a limited effect on GUS transient expression in pollen but substantially increased the transient expression in embryogenic tissues. The viability of transformed pollen was not affected by the bombardment procedure. This is the first detailed analysis of microprojectile bombardment technology reporting the conditions needed for optimum transient transformation of pollen and embryogenic tissues of white spruce.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231619
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of desiccation to low moisture content on germination, synchronization of root emergence, and plantlet regeneration of black spruce somatic embryos (1999)
    Springer
    Plant cell, tissue and organ culture 56 (1999), S. 193-200 
    Details
    ISSN: 1573-5044
    Keywords: desiccation tolerance ; drying rate ; germination synchronization ; long-term preservation ; Picea mariana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A desiccation protocol was developed to evaluate the effect of different levels of desiccation on germination and plantlet regeneration of black spruce somatic embryos. Large desiccation chambers (80 l) with four liters of saturated salt solutions provided constant relative humidities (RH) of 63, 79, 88, and 97% (± 2%). Under these conditions, an embryo mass of 10 mg always dried fast even at 97% RH. In contrast, an embryo mass of 80 mg generated different kinetics of water loss, from fast drying at 63% RH to slow drying at 97% RH. Drying rates similar to those obtained with 80 mg embryos were also generated by combining 40 mg embryos with 40 mg water. The effects of drying rate and embryo MC on germination rate, root elongation, and plantlet regeneration were examined. A fast drying rate to 4–5% embryo MC, obtained under 63% RH, was detrimental to germination and plantlet development. However slower drying rates, obtained under 79–97% RH and generating 7–19% MC in the embryos, gave developmental responses similar to the control. Synchronization of root emergence was improved only for embryos desiccated to approx. 16% MC under 97% RH. The optimal desiccation protocol using large desiccation chamber at 97% RH and a constant embryo mass of 40 mg embryos plus 40 mg water was applied to five genotypes of black spruce. For all genotypes, desiccated embryos gave plantlet regeneration rates similar to the control undesiccated embryos.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006201414616
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  • 7
    Electronic Resource
    Electronic Resource
    Effects of sealed and vented gaseous microenvironments on the maturation of somatic embryos of black spruce with a special emphasis on ethylene (1999)
    Springer
    Plant cell, tissue and organ culture 56 (1999), S. 201-209 
    Details
    ISSN: 1573-5044
    Keywords: carbon dioxide ; ethylene ; oxygen ; Picea mariana ; somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Maturation of black spruce somatic embryos in sealed and vented microenvironments was investigated. The sealed microenvironment induced a larger number of well-formed mature embryos and less precocious germination than the vented microenvironment. Maturation rate of somatic embryos was not changed either by injection of ethylene into the culture vessel or by its removal by potassium permanganate traps. Increased as well as decreased ethylene concentrations, by the addition of either 1-aminocyclopropane-1-carboxylic acid (precursor of ethylene) or cobalt chloride (inhibitor of ethylene biosynthesis), resulted in a decreased number of embryos produced. However, inhibition of ethylene action by the addition of silver nitrate to the maturation medium did not affect either ethylene concentration or somatic embryo production. It was concluded that ethylene accumulation during maturation has no effect on somatic embryo production. Neither the microenvironment nor the modification of the ethylene metabolism affected conversion rate of somatic embryos into plantlets growing in soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006202827008
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  • 8
    Electronic Resource
    Electronic Resource
    Maturation of black spruce somatic embryos. Part I. Effect of l-glutamine on the number and germinability of somatic embryos (1995)
    Springer
    Plant cell, tissue and organ culture 41 (1995), S. 23-32 
    Details
    ISSN: 1573-5044
    Keywords: glutamine ; maturation ; nitrogen ; Picea mariana ; somatic embryogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Different concentrations of l-glutamine and different nitrogen sources in the medium were compared during maturation of black spruce (Picea mariana (Mill.) B.S.P.) somatic embryos. l-glutamine can be used as the sole nitrogen source for the maturation of Picea mariana somatic embryos at 2 to 3 gl-1. A significantly lower number of somatic embryos was obtained on a medium prepared with only inorganic nitrogen. Compared with a medium supplement to inorganic nitrogen resulted in a twofold increase in the number of embryos for six genotypes. The nitrogen source and concentration in the maturation medium significantly affected the germination sensus stricto of somatic embryos (radicle appearance), but not their development into plantlets; at the time of epicotyl appearance, an effect of the nitrogen source was no longer found. A comparison of the development of somatic embryos into plantlets from seven genotypes showed that the genotype had more effect in terms of epicotyl appearance and in conversion rate than the nitrogen source present in the maturation medium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00124083
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  • 9
    Electronic Resource
    Electronic Resource
    Requirements for in vitro propagation of seven nitrogen-fixing Alnus species (1984)
    Springer
    Plant cell, tissue and organ culture 3 (1984), S. 189-199 
    Details
    ISSN: 1573-5044
    Keywords: Actinorhizae ; Alnus ; Frankia ; in vitro culture ; micropropagation ; nitrogen fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Studies on the in vitro propagation of Alnus crispa, A. glutinosa, A. incana, A. japonica, A. rubra, A. sinuata and A. viridis indicated interspecific as well as intraspecific variations in their requirements for in vitro culture. The WPM and Blaydes media supported, respectively, growth of A. glutinosa and A. crispa but not that of both species, while the MS medium induced equal or significantly better growth than WPM and Blaydes media for both species. The optimum type and concentration of sugar to be used in the multiplication medium varied with species. Only A. glutinosa showed good growth on sucrose while glucose was optimum for all other species but at different concentrations. All species rooted in 3 weeks on half-strength MS medium including 1 μM IBA. All clones of A. glutinosa and A. rubra rooted 100%, whereas “easy-to-root” and “difficult-to-root” clones were observed in the other species. In the rooting medium, glucose promoted rooting of the “difficult-to-root” clones better than sucrose. Survival following transfer to an artificial substrate was 100% for all species. Nodulation tests using pure cultures of two Frankia strains showed 100% nodulation on all Alnus clones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00040337
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  • 10
    Electronic Resource
    Electronic Resource
    Maturation of black spruce somatic embryos: Sucrose hydrolysis and resulting osmotic pressure of the medium (1995)
    Springer
    Plant cell, tissue and organ culture 42 (1995), S. 39-46 
    Details
    ISSN: 1573-5044
    Keywords: Mannitol ; osmoticum ; Picea mariana ; somatic embryogenesis ; sugar analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The physiological and osmotic roles of sucrose during black spruce (Picea mariana (Mill.) B.S.P.) embryo maturation were investigated. The results showed that when both sucrose and mannitol were present in the medium, the optimum sucrose concentration varied between 4% and 6%. From these data, mannitol does not apparently replace sucrose during the maturation of somatic embryos and therefore it might not be a suitable osmoticum. For the media supplemented with 4% to 12% sucrose and various concentrations of mannitol, the osmotic pressure of the medium rose during maturation, particularly for the highest sucrose concentrations (7% to 12%). Medium containing 3% each of fructose and glucose produced fewer mature embryos compared to the medium with 6% sucrose. An increment in the osmotic potential was observed in medium with 6% sucrose in contrast to that containing 3% each of fructose and glucose. Sugar analysis revealed that the sucrose hydrolysis in the medium was detectable within 1 week of incubation and continued throughout the maturation period. Moreover, no significant uptake of the sugars was detected, since the total amount of fructose, glucose and sucrose remained constant. Our results indicate that the action of sucrose on embryo maturation is mostly achieved through an osmotic control.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00037680
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