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- Andersen, Naja Steen, et al.
(författare)
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Processes affecting genetic structure and conservation: a case study of wild and cultivated Brassica rapa
- 2009
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Ingår i: Genetic Resources and Crop Evolution. - Dordrecht : Springer Science and Business Media LLC. - 0925-9864 .- 1573-5109. ; 56:2, s. 189-200
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Tidskriftsartikel (refereegranskat)abstract
- When planning optimal conservation strategies for wild and cultivated types of a plant species, a number of influencing biological and environmental factors should be considered from the outset. In the present study Brassica rapa was used to illustrate this: to develop Scandinavian conservation strategies for wild and cultivated B. rapa, DNA-marker analysis was performed on 15 cultivated and 17 wild accessions of B. rapa plus 8 accessions of the cross compatible B. napus. The B. rapa cultivars were bred in Sweden and Finland in 1944-1997 and the wild B. rapa material was collected from Denmark, Sweden and United Kingdom. The B. napus accessions were bred within the last 20 years in the Scandinavian countries. Results were based on scoring of 131 polymorphic ISSR markers in the total plant material. A Bayesian Markov chain Monte Carlo (MCMC) approach implemented in NewHybrids demonstrated a clear distinction of B. rapa and B. napus individuals except for three individuals that seemed to be backcrosses. The backcrossed hybrids descended from two Swedish populations, one wild and one escaped. The overall pattern of genetic variation and structure in B. rapa showed that cultivated and wild B. rapa accessions formed two almost separated clusters. Geographical origin and breeding history of cultivars were reflected in these genetic relationships. In addition, wild populations from Denmark and Sweden seemed to be closely related, except for a Swedish population, which seemingly was an escaped cultivar. The study point to that many processes, e.g. spontaneous introgression, naturalisation, breeding and agricultural practise affected the genetic structure of wild and cultivated B. rapa populations.
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- Boberg, Pelle, et al.
(författare)
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The effect of high temperatures on seed germination of one native and two introduced conifers in Patagonia
- 2010
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Ingår i: Nordic Journal of Botany. - Chichester : Wiley-Blackwell. - 0107-055X .- 1756-1051. ; 28:2, s. 231-239
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Tidskriftsartikel (refereegranskat)abstract
- We examined the effect of thermal shock on the germination of seeds of three conifers, two introduced (Pseudotsuga menziesii and Pinus ponderosa), and one native to Patagonia (Araucaria araucana). Previous research has suggested increased susceptibility to invasions in burnt areas, and therefore, the effect of simulated fire (heat) on seed germination in these native and introduced species was compared. Seeds were heated to two different heat intensities (50°C and 100°C) for 1 or 5 min, which is within the temperature range reached in the upper soil layers during forest fires. Germination tests were then carried out in a growth chamber. The heat treatments had a negative effect on the germination of P. menziesii at temperatures of 100°C, and a negative effect on the germination of P. ponderosa at the temperature of 100°C and the exposure of 5 min. The heat treatments had no affect at all on A. araucana. The species with larger seeds (A. araucana) had higher survival rates after the thermal shocks. Also intraspecific differences in seed sizes possibly point at larger seeds surviving thermal shocks better than smaller seeds. In addition, thermal shock caused a delay in the onset of germination in the two introduced species, while it did not change the time for germination in A. araucana. © The Authors. Journal compilation © Nordic Journal of Botany 2010.
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- de Vries, Franciska T., et al.
(författare)
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Soil food web properties explain ecosystem services across European land use systems
- 2013
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Ingår i: Proceedings of the National Academy of Sciences. - Washington, DC : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 110:35, s. 14296-14301
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Tidskriftsartikel (refereegranskat)abstract
- Intensive land use reduces the diversity and abundance of many soil biota, with consequences for the processes that they govern and the ecosystem services that these processes underpin. Relationships between soil biota and ecosystem processes have mostly been found in laboratory experiments and rarely are found in the field. Here, we quantified, across four countries of contrasting climatic and soil conditions in Europe, how differences in soil food web composition resulting from land use systems (intensive wheat rotation, extensive rotation, and permanent grassland) influence the functioning of soils and the ecosystem services that they deliver. Intensive wheat rotation consistently reduced the biomass of all components of the soil food web across all countries. Soil food web properties strongly and consistently predicted processes of C and N cycling across land use systems and geographic locations, and they were a better predictor of these processes than land use. Processes of carbon loss increased with soil food web properties that correlated with soil C content, such as earthworm biomass and fungal/bacterial energy channel ratio, and were greatest in permanent grassland. In contrast, processes of N cycling were explained by soil food web properties independent of land use, such as arbuscular mycorrhizal fungi and bacterial channel biomass. Our quantification of the contribution of soil organisms to processes of C and N cycling across land use systems and geographic locations shows that soil biota need to be included in C and N cycling models and highlights the need to map and conserve soil biodiversity across the world.
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- D'Hertefeldt, Tina, Universitetslektor, 1965-, et al.
(författare)
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Dead or dormant? Using vital stains to evaluate heat treatment of invasive Japanese knotweed
- 2023
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Ingår i: Swedish Oikos Meeting. ; , s. 8-8
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- One of the most widely established invasive alien plant species in Sweden is the Japanese knotweed. A range of control measures exist, and there is great need of methods to evaluate their effectiveness. No single method currently guarantees eradication of the Japanese knotweed, hence there is considerable interest to develop more efficient techniques. One is heat treatment using steam or hot water. The effects of heat on above-ground biomass are easy to evaluate but it has proven to be more problematic to evaluate vitality of below-ground rhizomes, which can stay dormant under unfavorable conditions. We have therefore evaluated rhizome vitality using combined greenhouse trials and fluorescence microscopy observations with the vital stains fluorescence diacetate (FDA) and propidium iodide (PI). Fluorescence diacetate was effective in separating live rhizomes from rhizomes that were autoclaved at 121°C. However, while propidium iodide is routinely used to identify dead cells by staining their nuclei, unexpectedly few nuclei were stained in the heat-treated rhizomes. When temperature was reduced to 80°C for 1 hour, FDA indicated some live meristems. However, at 80°C for longer periods, no fluorescence was visible which indicated dead rhizomes. This shows the importance of treatment longevity in order to terminate persistent rhizomes of Japanese knotweed. Type of presentation: Flash talk.
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- D'Hertefeldt, Tina, et al.
(författare)
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Escaped oilseed rape : Occurrence in the agricultural landscape and potential pollen-mediated gene flow from crop oilseed rape
- 2021
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Ingår i: Journal of Pollination Ecology. - Cambridge, ON : International Commission for Plant Pollinator Relations. - 1920-7603. ; 28, s. 127-137
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Tidskriftsartikel (refereegranskat)abstract
- To assess the role of feral oilseed rape (OSR) plants as resources for pollinators and avenues for gene flow, we compared occurrence of feral populations in standardized agricultural landscapes, using a landscape ecological approach. The occurrence of feral and volunteer populations was investigated in relation to differences in road length and width, number of OSR fields, and landscape scale. The potential for pollen-mediated gene flow from crop to feral oilseed rape was investigated with fluorescent dye in a field experiment. Moreover, greenhouse estimates of pollen germination rate and pollen tube growth rate were performed to get an indication of siring success in crop and feral plants. Escaped OSR occurred in 14 out of the 16 investigated landscapes, and feral populations were more common alongside large roads than small roads in large-scale landscapes. The number of plants in a habitat ranged from 1-160 individuals, with 1-19 habitats per landscape. In the field experiment with fluorescent dye, no transfer of dye was detected during early flowering in May. At the end of the flowering period in June, transfer of dye was found in 71.4% of the feral plants, showing that significant transfer, most likely by pollinators, occurred from the field to the feral plants. There was no difference in pollen germination rate between crop and feral plants. Pollen tube growth rate was significantly higher in feral oilseed rape than in the crop (P < 0.001). Our results contribute to increased understanding of i) the utilization of feral populations by pollinators in an intensively farmed agricultural landscape, and ii) crop-feral gene flow within OSR.
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- D'Hertefeldt, Tina, et al.
(författare)
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Extensive physiological integration in Carex arenaria and Carex disticha in relation to potassium and water availability
- 2002
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Ingår i: New Phytologist. - Chichester : Wiley. - 1469-8137 .- 0028-646X. ; 156:3, s. 469-477
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Tidskriftsartikel (refereegranskat)abstract
- Physiological integration between ramets is beneficial when acquiring heterogeneously distributed resources, and is hypothesized to occur when the benefits of resource sharing outweigh the costs. Our aim was to investigate if resource availability affected physiological integration in Carex arenaria and Carex disticha. Ramet systems were grown in high potassium and high water (K+ W+), high K and low water (K+ W-), or low K and high water (K- W+) for 1 month. Thereafter, water and K transport were traced with erythrosin and rubidium, respectively. Carex arenaria and C. disticha transported erythrosin over seven ramet generations and rubidium throughout the whole ramet system, but C. arenaria exported 20% more rubidium from the labelled shoot than C. disticha. A detailed analysis of subset of plants suggested that C. disticha in low K abundance shared more rubidium than in high K abundance, and that C. arenaria ramets in both K+ W- and K- W+ shared more resources than K+ W+ ramets. We demonstrated long-distance resource transport for K and water in C. arenaria and C. disticha. The distance of integration was not affected by resource availability in C. arenaria or C. disticha, but local concentrations of K showed marked and contrasting responses to nutrient and water treatment in both species.
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