17 research outputs found

    Potential Distribution of Six North American Higher-Attine Fungus-Farming Ant (Hymenoptera: Formicidae) Species

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    Ants are among the most successful insects in Earth’s evolutionary history. However, there is a lack of knowledge regarding range-limiting factors that may influence their distribution. The goal of this study was to describe the environmental factors (climate and soil types) that likely impact the ranges of five out of the eight most abundant Trachymyrmex species and the most abundant Mycetomoellerius species in the United States. Important environmental factors may allow us to better understand each species’ evolutionary history. We generated habitat suitability maps using MaxEnt for each species and identified associated most important environmental variables. We quantified niche overlap between species and evaluated possible congruence in species distribution. In all but one model, climate variables were more important than soil variables. The distribution of M. turrifex (Wheeler, W.M., 1903) was predicted by temperature, specifically annual mean temperature (BIO1), T. arizonensis (Wheeler, W.M., 1907), T. carinatus, and T. smithi Buren, 1944 were predicted by precipitation seasonality (BIO15), T. septentrionalis (McCook, 1881) were predicted by precipitation of coldest quarter (BIO19), and T. desertorum (Wheeler, W.M., 1911) was predicted by annual flood frequency. Out of 15 possible pair-wise comparisons between each species’ distributions, only one was statistically indistinguishable (T. desertorum vs T. septentrionalis). All other species distribution comparisons show significant differences between species. These models support the hypothesis that climate is a limiting factor in each species distribution and that these species have adapted to temperatures and water availability differently

    GERMPLASM PRESERVATION BY CRYOPRESERVATION: USE OF NEW BIOTECHNOLOGY TO MAINTAIN GENETIC DIVERSITY IN LABIATAE SPECIES

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    Many Labiatae species are of potential interest as medicinal and aromatic plants. Therefore, micropropagation was established, which includes clonal maintenance. Furthermore, some species are endangered. in vitro culture and cryopreservation increasingly contribute to the germplasm maintenance in genebanks, especially of vegetatively propagated germplasm, like in mint (Mentha spp.). Various cryopreservation methods are used worldwide. The germplasm collection of the German Central Crop Collection maintains 148 accessions of various mint species in vitro using slow growth conditions at 2°C and 10°C. Cryopreservation is applied using droplet vitrification with the cryoprotectant PVS2. At present, the cryopreserved mint collection consists of 24 accessions. The average regeneration rate is 62%. Regeneration is depending on the genotype. Recently was found that endophytes play a major role in cryopreservation success. Antibiotics are applied to support survival and regeneration in critical phases after rewarming. Despite good success of cryopreservation in various mint species, this method is still not fully applicable to another Labiatae genus, Orthosiphon. Here, regeneration rate is 82% in controls contrasting to 4% in cryopreserved samples. In vitro maintenance of these plants is possible but labour-intensive because they are not storable at low temperatures. Various measurements of the target organs were performed to elucidate the background of these differences. Differential scanning calorimetry informs about the thermal transitions of tissue water critical for storability. Its results revealed that the pretreatment time must be longer comparing to that needed for mint

    Different protocols - different situations - different genotypes from the research laboratory to application in genebanks Some subjects of discussion

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    Genebanks are application fields of preservation and maintenance methods, also of those for cryopreservation, in a broader scale. When moving some scientific method from the state of fundamental research in a university s laboratory into broader application, some aspects have to be considered. The main problems are: 1. In/stability of a given method. We need to be sure that the method developed under experimental conditions using a model genotype is applicable also under every-days laboratory conditions which may differ with the season, with the personnel, sometimes with fluctuations in surrounding technical parameters. They should be applicable with other genotypes than the models as well and they should be not too sensitive in circumstances when material is not grown or received under optimum conditions. Some factors which influence the results are the physiological conditions of the material and hidden endophytes. 2. Logistics using a method in a larger scale. Whereas the attention of a fundamental researcher can be drawn on every single step of the procedure, and it is no need to limit his time for one given part of the protocol, in routine work it is necessary to pass all the steps sufficiently quick to get an efficient amount of explants into cryopreservation. Therefore, the simplest and shortest protocol will always have priority when decision between several options is needed. Furthermore, the output of the whole procedure is depending on the number of acting persons. Should we have more persons available, specialisation could take place. This is especially important in regard of the explant preparation procedures. Participation of several persons will, on the other hand, increase the standardisation needs. 3. Genbanks are the most capable actors to compare aspects of cryopreservation in a range of taxa within a given systematic group. This potential is by far not fully utilised. It would be interesting to compare species in a given group which differ in certain parameters e. g. water content (e. g. there are genera where there is a full range from water plants to succulents, or use of resurrection plants), cold- or salt tolerance. Results obtained in routine screening in genebanks could, thus, give another feed-back link to fundamental research. 4. Finally, the existence of a well-elaborated method is only one prerequisite for success in genebanks. Collaboration between several laboratories will increase the general effect of these methods by mutual validation and chances to establish safety duplication systems.vokMyynti MTT, Tietopalvelut 31600 Jokioine
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