Evaluation of Cold—Moist Stratification Treatments for Germinating Eastern and Carolina Hemlock Seeds for ex Situ Gene Conservation

2014 ◽  
Keyword(s):  
Ex Situ ◽  
Gene Conservation

scholarly journals The National Tree Seed Centre Celebrates 40 Years

2007 ◽  
Vol 83 (5) ◽  
pp. 719-722
Author(s):  
J D Simpson ◽  
B S.P. Wang
Keyword(s):  
Seed Storage ◽  
Ex Situ ◽  
Future Research ◽  
Gene Conservation ◽  
Forest Land ◽  
Seed Physiology ◽  
Technology Research Group ◽  
Insect Attack ◽  
Tree Seed

The National Tree Seed Centre has been providing seed of known origin and quality for research for 40 years. Seed is also stored for long-term gene conservation purposes to provide a source of germplasm for future research and restoration. This is particularly important for species facing such threats as insect attack, disease, climate change, or conversion of forest land to non-forest uses. The Centre's inventory focuses on native tree and shrub species, striving to store samples from throughout their ranges. Over 26 000 seed samples have been sent to researchers in 65 countries, 70% of these samples being distributed within Canada. Seed research has always been a component of the Seed Centre's program. One notable accomplishment is the development of the Petawawa Germination Box. The Seed Centre participates in and contributes to activities of the Association of Official Seed Analysts, the International Seed Testing Association, and the IUFRO Seed Physiology and Technology Research Group. Key words: collection, dormancy, ex situ gene conservation, germination, research, seed, storage

scholarly journals Setting priorities for conservation of the conifer genetic resources of British Columbia

1996 ◽  
Vol 72 (4) ◽  
pp. 406-415 ◽  
Author(s):  
Alvin D. Yanchuk ◽  
Donald T. Lester
Keyword(s):  
British Columbia ◽  
Genetic Resources ◽  
Protected Areas ◽  
Natural Regeneration ◽  
Ex Situ ◽  
Gene Conservation ◽  
Conifer Species ◽  
The Future ◽  
Ex Situ Collections

Gene conservation of native conifer species in British Columbia is considered necessary primarily to safeguard the future evolutionary potential of species to climate change, new biotic challenges and for commercial genetic improvement programs. The tactical options include: (i) maintaining existing protected areas, (ii) creating new reserves for in situ management, and (iii) ex situ collections of various types.A two-part strategy is presented, with emphasis on technical justifications, for the conservation of conifer tree genetic resources of 23 British Columbia species. Part I is a survey of the frequency of each species in current land reserves in BC. Part II outlines an approach that will aid in setting priorities for additional gene conservation activities for specific species. This process attempts to use information on: (i) levels of in situ protection, (ii) the status of each species in current provenance research and breeding programs, and (iii) the relative capabilities for natural regeneration for each species.Representation of the 23 native conifer species in the current network of protected areas is generally complete. For instance, western hemlock is under little threat, as extensive ex situ collections are in field tests; it is well protected in the current reserve network, and it has a great capacity for natural regeneration. At the other extreme, whitebark pine has no ex situ collections made to date, needs additional protection in some ecoregions of the province, and generally has poor natural regeneration potential. While implementation of our strategy will be an ongoing process (i.e. updating information from both new and old in situ reserves, and setting new priorities among species), several immediate issues have been noted. These include; (i) follow-up work in the area of population sampling for ex situ collections, (ii) "ground truthing" of current reserves where data are weak, and (iii) examining the merit of certain populations not located in BC (as they could be as important as those currently protected in BC).For the future, various broad management questions will need to be resolved, such as: (i) whether existing reserves will perpetuate the various gene pools, and what management will be appropriate for such areas, (ii) the impact of pollen migration from genetically improved production stands on reserve stands, and (iii) the role of commercially improved stands and the breeding populations themselves to meet gene conservation objectives. Key words: gene conservation, native conifers, British Columbia, tree genetics

Survival and regeneration of dormant silver birch buds stored at super-low temperatures

1996 ◽  
Vol 26 (4) ◽  
pp. 617-623 ◽  
Author(s):  
Leena Ryynänen
Keyword(s):  
Liquid Nitrogen ◽  
Silver Birch ◽  
Ex Situ ◽  
Gene Conservation ◽  
Survival And Growth ◽  
Ideal Method ◽  
Cooling Velocity ◽  
Female Catkin ◽  
Normal Laboratory

Cryopreservation was developed for the storage of in vivo buds of silver birch (Betulapendula Roth). The principles of the optimized method were the use of buds already acclimated in nature and slow freezing with a cooling velocity of 10 °C/h down to a terminal temperature of −38 °C. After 24 h at this temperature the buds were immersed in liquid nitrogen at − 196 °C for 8 days, 6 months, or 12 months. After fast thawing, 5 min in a water bath at 37 °C, the buds were surface sterilized and cultured according to the normal laboratory routine. The buds were examined after 2 and 4 weeks of cultivation. There were no significant differences in survival and growth between the unfrozen controls and buds stored in liquid nitrogen for different times. The growth percentage of buds without a female catkin was double that of buds with a catkin. These results indicate that cryopreservation would be an ideal method for the ex situ gene conservation of birch and retention of the juvenility of adult genotypes.

scholarly journals The recent state of cryopreservation techniques for ex-situ gene conservation and breeding purposes in small ruminants: A review

2020 ◽  
pp. 81-87
Author(s):  
Malam Abulbashar Mujitaba ◽  
Nóra Vass ◽  
Szilárd Bodó
Keyword(s):  
Assisted Reproductive Technologies ◽  
Small Ruminants ◽  
Reproductive Technologies ◽  
Ex Situ ◽  
Gene Conservation ◽  
High Concentration ◽  
The Caucasus ◽  
Cryopreservation Techniques ◽  
Almost All

The viewpoint of the recent cryopreservation techniques (CT) suggests the use of a reduced volume of cryopreservation solution, high concentration of cryoprotectants and ultra-rapid cooling and warming rates help to reduce cryo-injury and maximize the viability of the preserved animal genetic resources (AnGR). The CT had now become widely accepted as one of the best methods of choice for the ex-situ conservation of AnGR due to its high success rate recorded and no-invasive nature as compared to the conventional slow rate freezing (CSRF). Rapid advances and wide acceptability of the use of assisted reproductive technologies (ART’s) particularly artificial insemination (AI) in animal breeding had resulted in a greater loss of a large number of good quality genes in virtually almost all the native breeds of animals across the globe. Small ruminant (SR) animals are not an exception in such present predicaments situation of erosion and dilution of the valuable AnGR among the native breeds. As a result of this, 148 and 16 breeds of sheep and goats respectively have already become extinct in Europe and the Caucasus. In view of the aforementioned situation, the present review aimed at exploring some of the current states of development, roles played and potentials of CT in the conservation of SR genes and genome for the immediate and future breeding purposes for sustainable development. It basically covers; animal genetic resource, the need to conserve AnGR, tools for ex situ in vitro conservation of AnGR and recent developments in breeding and cryopreservation of SR AnGR. Cryopreservation is playing a pivotal role in ex-situ gene conservation of AnGR. Decline in genetic diversity among SR breed population was high in Europe and the Caucasus. There is therefore, need for improvent on current stringent measures on conservation of AnGR in this region of the world.

Gene conservation - in situ, ex situ and sampling strategies.

2009 ◽  
pp. 259-283 ◽  
Author(s):  
T. L. White ◽  
W. T. Adams ◽  
D. B. Neale
Keyword(s):  
Ex Situ ◽  
Sampling Strategies ◽  
Gene Conservation

scholarly journals Tree species of concern in New Brunswick, Canada. II. Guidelines for conservation of genetic resources

2007 ◽  
Vol 83 (3) ◽  
pp. 402-407
Author(s):  
J A Loo ◽  
T L Beardmore ◽  
J D Simpson ◽  
D A McPhee
Keyword(s):  
New Brunswick ◽  
Genetic Resources ◽  
Tree Species ◽  
Ex Situ Conservation ◽  
Ex Situ ◽  
Gene Conservation ◽  
American Beech ◽  
Bur Oak ◽  
Butternut Canker

Guidelines were developed by the New Brunswick Forest Gene Conservation Working Group for conserving genetic resources of four native tree species in New Brunswick. Gene conservation guidelines for three of these species aim to maintain sufficient gene pools of known or putatively resistant stock to retain or develop the potential for restoration. Natural populations of American beech (Fagus grandifolia) are known to have genotypes resistant to the beech scale at low frequencies. Gene conservation approaches include in situ and ex situ measures, including resistance breeding. White elm (Ulmus americana) demonstrates a degree of resistance to Dutch elm disease (DED), and will benefit from a mixture of in situ and ex situ conservation measures. Resistance to butternut canker has not yet been demonstrated in populations of butternut (Juglans cinerea), but ex situ conservation of putatively resistant genotypes will be of increasing importance as the frequency of butternut canker escalates. Bur oak (Quercus macrocarpa), threatened by small population size, habitat loss, and ongoing development, requires primarily in situ conservation and restoration efforts. Key words: American beech, bur oak, butternut, disease resistance, ex situ, gene conservation guidelines, genetic resources, in situ, restoration, white elm

scholarly journals Ex situ gene conservation for conifers in the Pacific Northwest.

2002 ◽  
Author(s):  
Sara R. Lipow ◽  
J. Bradley St. Clair ◽  
G.R. Johnson
Keyword(s):  
Pacific Northwest ◽  
Ex Situ ◽  
Gene Conservation ◽  
The Pacific

An in situ and ex situ TEM study of the formation of thin cobalt silicide films by molecular beam epitaxy on the silicon (100) surface

1988 ◽  
Vol 46 ◽  
pp. 884-885
Author(s):  
D. Loretto ◽  
J. M. Gibson ◽  
S. M. Yalisove ◽  
R. T. Tung
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Defect Density ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Metal Base ◽  
In Situ Experiments ◽  
Potential Applications

The cobalt disilicide/silicon system has potential applications as a metal-base and as a permeable-base transistor. Although thin, low defect density, films of CoSi2 on Si(111) have been successfully grown, there are reasons to believe that Si(100)/CoSi2 may be better suited to the transmission of electrons at the silicon/silicide interface than Si(111)/CoSi2. A TEM study of the formation of CoSi2 on Si(100) is therefore being conducted. We have previously reported TEM observations on Si(111)/CoSi2 grown both in situ, in an ultra high vacuum (UHV) TEM and ex situ, in a conventional Molecular Beam Epitaxy system.The procedures used for the MBE growth have been described elsewhere. In situ experiments were performed in a JEOL 200CX electron microscope, extensively modified to give a vacuum of better than 10-9 T in the specimen region and the capacity to do in situ sample heating and deposition. Cobalt was deposited onto clean Si(100) samples by thermal evaporation from cobalt-coated Ta filaments.

The use of transmission and analytical electron microscopy in studying reactions and phase transformations in thin film

1993 ◽  
Vol 51 ◽  
pp. 842-843
Author(s):  
K. Barmak
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transformations ◽  
Analytical Electron Microscopy ◽  
Ex Situ ◽  
Multilayer Thin Films ◽  
Absolute Concentration ◽  
Analytical Electron ◽  
Deposition Step

Generally, processing of thin films involves several annealing steps in addition to the deposition step. During the annealing steps, diffusion, transformations and reactions take place. In this paper, examples of the use of TEM and AEM for ex situ and in situ studies of reactions and phase transformations in thin films will be presented.The ex situ studies were carried out on Nb/Al multilayer thin films annealed to different stages of reaction. Figure 1 shows a multilayer with dNb = 383 and dAl = 117 nm annealed at 750°C for 4 hours. As can be seen in the micrograph, there are four phases, Nb/Nb3-xAl/Nb2-xAl/NbAl3, present in the film at this stage of the reaction. The composition of each of the four regions marked 1-4 was obtained by EDX analysis. The absolute concentration in each region could not be determined due to the lack of thickness and geometry parameters that were required to make the necessary absorption and fluorescence corrections.

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