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  • 351.
    Karis, Per Ola
    Stockholm University, Faculty of Science, Department of Botany.
    Tribe Arctotideae Cass.2007In: The families and genera of Vascular plants, Springer, Berlin , 2007, p. 223-229Chapter in book (Refereed)
  • 352.
    Karis, Per Ola
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Funk, Vicki A
    Smithsonian Institution, Washington, DC 20013, USA.
    McKenzie, Robert J
    Dept of Botany, Rhodes University, Grahamstown, South Africa.
    Barker, NP
    Dept of Botany, Rhodes University, Grahamstown, South Africa.
    Chan, Raymund
    Universiti Teknologi Malaysia, Johor, Malaysia.
    Arctotideae2009In: Systematics, Evolution and Biogeography of Compositae / [ed] Funk VA, Susanna A, Stuessy TF, Bayer RJ, Vienna: International Association for Plant Taxonomy , 2009, p. 285-310Chapter in book (Other academic)
  • 353.
    Karis, Per Ola
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Helme, N. A.
    Metalasia namaquana (Asteraceae-Gnaphalieae), a new species from the Kamiesberg (South Africa)2012In: South African Journal of Botany, ISSN 0254-6299, E-ISSN 1727-9321, Vol. 78, p. 281-284Article in journal (Refereed)
    Abstract [en]

    The new species Metalasia namaquana is described from the Kamiesberg, a well known centre of plant endemism in the Northern Cape Province of South Africa. The species is most similar to Metalasia fastigiata and Metalasia albescens. The morphology, ecology and conservation status of the new species are discussed.

  • 354.
    Karis, Per Ola
    et al.
    Stockholm University, Faculty of Science, Department of Botany. växtsystematik.
    Helme, Nick
    Metalasia helmei (Asteraceae-Gnaphalieae), a new member of a small clade from the Western Cape?2008In: Bothalia, Vol. 38, no 1Article in journal (Refereed)
    Abstract [en]

    The new species Metalasia helmei from the Kwadousberg in the Western Cape is described, and is most closely related to M. agathosmoides and M. fastigiata. This paper contains presentations of morphology, habitat preference, and conservation status for the new species.

  • 355.
    Karpinski, Stanislaw
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Gabrys, Helena
    Mateo, Alfonso
    Stockholm University, Faculty of Science, Department of Botany.
    Karpinska, Barbara
    Stockholm University, Faculty of Science, Department of Botany.
    Mullineaux, Philip M.
    Light perception in plant disease defence signalling2003In: Current opinion in plant biology, ISSN 1369-5266, E-ISSN 1879-0356, Vol. 6, no 4, p. 390-396Article in journal (Refereed)
    Abstract [en]

    Light is a predominant factor in the control of plant growth, development and stress responses. Many biotic stress responses in plants are therefore specifically adjusted by the prevailing light conditions. The plant cell is equipped with sophisticated light-sensing mechanisms that are localised inside and outside of the chloroplast and the nucleus. Recent progress has provided models of how the signalling pathways that are involved in light perception and in defence could operate and interact to form a plant defence network. Such a signalling network includes systems to sense light and regulate gene expression. Photo-produced H2O2 and other reactive oxygen species in the cell also play an essential role in this regulatory network, controlling biotic and abiotic stress responses

  • 356.
    Karpinski, Stanislaw
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Muhlenbock, Per
    Stockholm University, Faculty of Science, Department of Botany.
    Genetic, molecular and physiological mechanisms controlling cell death, defenses, and antioxidant network in response to abiotic and biotic stresses in plants2007In: Abstracts of the Annual Main Meeting of the Society for Experimental Biology, Glasgow, Scotland, 31st March - 4th April, 2007, 2007Conference paper (Other (popular science, discussion, etc.))
  • 357.
    Kautsky, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Lago-Lestón, Asunción
    Mota, Catarina
    Pearson, Gareth
    Functional divergence in heat shock response following rapid speciation of Fucus spp. in the Baltic Sea2010In: Marine Biology, ISSN 1432-1793, Vol. 157, no 3, p. 683-688Article in journal (Refereed)
    Abstract [en]

    In the Baltic Sea, the broadly distributed brown alga Fucus vesiculosus coexists in sympatry over part of its range (south west Gulf of Bothnia) with the Baltic endemic F. radicans sp. nov, while further north in colder and lower-salinity areas of the Baltic F. radicans occurs alone (north west Gulf of Bothnia). F. radicans appears to have arisen via rapid speciation from F. vesiculosus within the recent history of the Baltic (ca. 7500 BP). Possible functional divergence between the two species was investigated by comparing stress-responsive gene expression in a common-garden experiment. The experiment used two allopatric populations of Fucus vesiculosus from the Skagerrak (North Sea) and Central Baltic, as well as F. radicans from the same Central Baltic site. The two species in sympatry displayed divergent heat shock responses, while F. vesiculosus populations from allopatric sites did not. F. radicans was more sensitive to heat shock at 25°C, either alone or together with high irradiance and desiccation, than Baltic or Skagerrak F. vesiculosus. The results indicate that rapid functional divergence in the inducible heat shock response has occurred between sympatric species on a timescale of thousands of years.

  • 358.
    Kautsky, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Pereyra, Ricardo
    Bergström, Lena
    Johannesson, Kerstin
    Rapid speciation in a newly opened postglacial marine environment, the Baltic Sea2009In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 9, no 70Article in journal (Refereed)
    Abstract [en]

    Background: Theory predicts that speciation can be quite rapid. Previous examples comprise a wide range of organisms such as sockeye salmon, polyploid hybrid plants, fruit flies and cichlid fishes. However, few studies have shown natural examples of rapid evolution giving rise to new species in marine environments.

    Results: Using microsatellite markers, we show the evolution of a new species of brown macroalga (Fucus radicans) in the Baltic Sea in the last 400 years, well after the formation of this brackish water body ~8–10 thousand years ago. Sympatric individuals of F. radicans and F. vesiculosus (bladder wrack) show significant reproductive isolation. Fucus radicans, which is endemic to the Baltic, is most closely related to Baltic Sea F. vesiculosus among north Atlantic populations, supporting the hypothesis of a recent divergence. Fucus radicans exhibits considerable clonal reproduction, probably induced by the extreme conditions of the Baltic. This reproductive mode is likely to have facilitated the rapid foundation of the new taxon.

    Conclusion: This study represents an unparalleled example of rapid speciation in a species-poor open marine ecosystem and highlights the importance of increasing our understanding on the role of these habitats in species formation. This observation also challenges presumptions that rapid speciation takes place only in hybrid plants or in relatively confined geographical places such as postglacial or crater lakes, oceanic islands or rivers.

  • 359. Khan, Saleh
    et al.
    Razafimandimbison, Sylvain G
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Liede-Schumann, Sigrid
    Phylogeny and biogeography of Virectaria based on molecular and morphological data2008In: Plant Systematics and Evolution, Vol. 275, p. 43-58Article in journal (Refereed)
  • 360. Khan, Saleh
    et al.
    Razafimandimbison, Sylvain G
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Liede-Schumann, Sigrid
    Sabiceeae and Virectarieae : one or two tribes? – New tribal and generic limits of Sabiceeae (Rubiaceae) and biogeographical origin of Sabicea s.l.2008In: Taxon, Vol. 57, p. 7-23Article in journal (Refereed)
  • 361. Kim, Yun-Soo
    et al.
    Lim, Soon
    Kang, Kwon-Kyoo
    Jung, Yu-Jin
    Lee, Young-Hye
    Choi, Yong-Eui
    Sano, Hiroshi
    Stockholm University, Faculty of Science, Department of Botany.
    Resistance against beet armyworms and cotton aphids in caffeine-producing transgenic chrysanthemum2011In: PLANT BIOTECHNOLOGY, ISSN 1342-4580, Vol. 28, no 4, p. 393-395Article in journal (Refereed)
    Abstract [en]

    Transgenic chrysanthemum plants were constructed to simultaneously express three N-methyltransferases involved in caffeine biosynthetic pathways. Resulting plants produced caffeine at approximately 3 mu g g(-1) fresh tissue, and were tested for herbivore repellence. When starved second-instar caterpillars of beet armyworms (Spodoptera exigu) were allowed to feed, they ate up to 4.4 mm(2) of leaf discs from the wild type plants, while less than 1.5 mm(2) of those from the transgenic plants. When third-instars of cotton aphid (Aphis gossypii) were subjected to a choice-test, 27 gathered on wild type leaves, and 6 on transgenic leaves. These results indicate that caffeine-producing chrysanthemum is resistant against herbivores, lepidoptera caterpillars and aphids, both being one of the most serious pests in agriculture. We propose that the method can be practically applied to a variety of important plant species to confer resistance against biotic stresses.

  • 362.
    Kiviniemi Birgersson, Katariina
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Effects of fragment size and isolation on the occurrence of four short-lived plants in semi-natural grasslands2008In: Acta Oecologica, Vol. 33, p. 56-65Article in journal (Refereed)
    Abstract [en]

    Habitat fragmentation is predicted to lead to an area-related reduction in population size and a decreasing colonisation rate due to isolation. A reduction in grassland size may promote a “run-away-decline process” leading to reduced individual fitness and viability of the populations originally inhabiting the grassland. To circumvent the problems of time-lags associated with the slow response of long-lived plants to semi-natural grassland fragmentation, four short-lived grassland species were studied. During three years, data on population sizes were gathered for Carum carvi, Rhinanthus minor, Trifolium arvense and Viola tricolor in Swedish semi-natural grasslands varying in size and degree of isolation. A seed sowing experiment was conducted to assess dispersal and seed limitation at a local and regional scale, respectively. Overall, the presence/absence of species was not related to fragment size and isolation (connectivity). However, for the fragments where the species were present, positive relationships between grassland size and population size were detected for three species. No significant relationships between isolation and population size were detected for any species. This study thus demonstrates that short-lived plant species, confined to semi-natural grasslands, respond to decreases in fragment size by forming smaller populations. Seed sowing indicated that the species are both dispersal and seed limited in the study area, and that disturbances are important for establishment. In order to maintain characteristic grassland species in fragmented (isolated) semi-natural grasslands, it may therefore be of interest to preserve large intact fragments instead of several small ones.

  • 363.
    Kiviniemi Birgersson, Katariina
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Remnant population dynamics in the facultative biennial Carum carvi in fragmented semi-natural grasslands2009In: Population Ecology, Vol. 51, p. 197-208Article in journal (Refereed)
    Abstract [en]

    Transition matrix models were used to examine population dynamics in the facultative biennial Carum carvi L. in semi-natural grasslands, specifically to assess what life cycle stages that are important for population development and to evaluate effects of environmental stochasticity on population persistence and, hence, the ability to develop remnant populations.

    The demographic studies were conducted over a four year period in three moderately grazed grasslands that differed in onset and duration of grazing. Experimental seed sowing was also conducted in disturbed and undisturbed plots in the populations. Deterministic and stochastic models yielded overall negative population growth (λ < 1) for the populations. λ was sensitive to transitions in the most frequent vegetative stage classes. Elasticity analysis indicated that a large proportion of population growth could be ascribed to stasis of individuals in the largest vegetative stage class. LTREs showed that also progression to larger stage classes was important in explaining between-population variation in λ. The expected time to extinction was in the order of several decades for the study populations. Seed sowing indicated that seedling establishment was limited by both seed and micro-site availability. The populations of C. carvi seem to be able to persist for a rather long time in moderately grazed semi-natural grasslands, even in cases where populations are destined to go extinct. The results thus indicate that “biennials” are able to maintain remnant populations in managed semi-natural grasslands.

  • 364.
    Kiviniemi Birgersson, Katariina
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Löfgren, Anders
    Spatial (a)synchrony in population fluctuation of five plant species in fragmented habitats2009In: Basic and Applied Ecology, Vol. 10, p. 70-78Article in journal (Refereed)
    Abstract [en]

    The spatial scale at which populations show synchronous temporal fluctuations in abundance, relative to the spatial scale over which they can disperse, may influence the persistence of local and regional populations. There have been frequent demonstrations of spatial synchrony in population dynamics of animal populations. But few studies have investigated the degree of spatial synchrony in less mobile taxa, e.g. plants, where life history, dispersal and interaction with the environment would be different due to a sessile phase. This study has during three years investigated the synchrony in local population size changes in four short-lived species, and during a nine year period for one long-lived species, in a semi-natural grassland landscape in southern Sweden. The spatial scale of this study was less than 15 km, which is quite small in comparison with other studies, but the temporal scale was of similar magnitude as the few studies on plant abundances and synchrony. When using detrended estimates of population size change, a significant pattern of decreasing synchrony with increasing distance was found for the two short-lived species that were most confined to managed semi-natural grasslands. Spatial synchrony was detected up to a few km. However, the species displayed synchrony in different years. The degree of synchrony can thus vary considerably across years and among species. Spatially autocorrelated weather conditions could partly explain the spatial scale of synchrony found during certain time intervals. However, the prevailing asynchrony suggests that local factors dominate the dynamics of the populations at the investigated scale.

  • 365. Kleyer, Michael
    et al.
    Bekker, RM
    Knevel, IC
    Bakker, JP
    Thompson, K
    Sonnenschein, M
    Poschlod, P
    van Groenendael, JM
    Klimes, L
    Klimesova, J
    Klotz, S
    Rusch, G
    Hermy, M
    Adriens, D
    Boedeltje, G
    Bossuyt, B
    Dannemann, A
    Endels, P
    Götzenberger, L
    Hodgson, JG
    Jackel, A-K
    Kuhn, I
    Kunzmann, D
    Ozinga, WA
    Römermann, C
    Stadler, M
    Schlegelmilch, J
    Steendam, HJ
    Tackenberg, O
    Wilmann, B
    Cornelissen, JHC
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Garnier, E
    Peco, B
    The LEDA traitbase: a database of plant life-history traits of North West Europe2008In: Journal of Ecology, Vol. 96, p. 1266-1274Article in journal (Refereed)
  • 366.
    Klint, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ran, Liang
    Stockholm University, Faculty of Science, Department of Botany.
    Rasmussen, Ulla
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Birgitta
    Stockholm University, Faculty of Science, Department of Botany.
    Identification of developmentally regulated proteins in cyanobacterial hormogonia using a proteomic approach.2006In: Symbiosis, ISSN 0334-5114, Vol. 41, no 2, p. 87-95Article in journal (Refereed)
  • 367.
    Klint, Johan
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Rasmussen, Ulla
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Birgitta
    Stockholm University, Faculty of Science, Department of Botany.
    FtsZ may have dual roles in the filamentous cyanobacterium Nostoc/Anabaena sp. strain PCC 7120.2007In: J Plant Physiol, ISSN 0176-1617, Vol. 164, no 1, p. 11-8Article in journal (Refereed)
  • 368. Kodama, Y
    et al.
    Shinnya, T
    Sano, H
    Stockholm University, Faculty of Science, Department of Botany.
    Dimerization of /N/-methyltransferases involved in caffeine biosynthesis2008In: Biochemie, Vol. 90, p. 547-551Article in journal (Refereed)
  • 369. Kodama, Yutaka
    et al.
    Tamura, Takashi
    Hirasawa, Wataru
    Nakamura, Kimiyo
    Sano, Hiroshi
    Stockholm University, Faculty of Science, Department of Botany.
    A novel protein phosphorylation pathway involved in osmotic-stress response in tobacco plants2009In: Biochimie, ISSN 0300-9084, E-ISSN 1638-6183, Vol. 91, no 4, p. 533-539Article in journal (Refereed)
    Abstract [en]

    Osmotic stress is one of the severest environmental pressures for plants, commonly occurring under natural growing condition due to drought, salinity, cold and wounding. Plants sensitively respond to these stresses by activating a set of genes, which encode proteins necessary to overcome the crises. We screened such genes from tobacco plants, and identified a particular clone, which encoded a 45 kDa protein kinase belonging to the plant receptor-like cytoplasmic protein kinase class-VII, NAK (novel Arabidopsis protein kinase) group. The clone was consequently designated as NtNAK (Nicotiana tabacum AK, accession number: DQ447159). GFP-NtNAK fusion protein was localized in both cytoplasm and nucleus, and bacterially expressed NtNAK exhibited in vitro kinase activity. Its transcripts were clearly induced upon treatments of leaves with salt, mannitol, low temperature and also with abscisic and jasmonic acids and ethylene. These properties indicated NtNAK to be a typical osmo-stress-responsive protein kinase. Its target protein(s) were then screened by the yeast two-hybrid system, and one clone encoding a 32 kDa protein was identified. The protein resembled a potato stress-responsive protein CK251806, and designated as NtCK25 (accession number: DQ448851). Bacterially expressed NtCK25 was phosphorylated by NtNAK, and NtCK25-GFP fusion protein was exclusively localized in nucleus. The structure of NtCK25 was found to be similar to a human nuclear body protein, SP110, which is involved in DNA/protein binding regulation. This suggested that, perceiving osmo-stress signal, NtNAK phosphorylates and activates NtCK25, which might function in regulation of nucleus function. The present study thus suggests that NtNAK/NtCK25 constitutes a novel phosphorylation pathway for osmotic-stress response in plants.

  • 370.
    Kodandaramaiah, Ullasa
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Weingartner, Elisabet
    Stockholm University, Faculty of Science, Department of Botany.
    Janz, Niklas
    Stockholm University, Faculty of Science, Department of Zoology.
    Leski, Michael
    Slove, Jessica
    Stockholm University, Faculty of Science, Department of Zoology.
    Warren, Andrew
    Nylin, Sören
    Stockholm University, Faculty of Science, Department of Zoology.
    Investigating concordance among genetic data, subspecies circumscriptions and hostplant use in the nymphalid butterfly polygonia faunus2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 7, p. e41058-Article in journal (Refereed)
    Abstract [en]

    Subspecies are commonly used taxonomic units to formally describe intraspecific geographic variation in morphological traits. However, the concept of subspecies is not clearly defined, and there is little agreement about what they represent in terms of evolutionary units, and whether they can be used as reliably useful units in conservation, evolutionary theory and taxonomy. We here investigate whether the morphologically well-characterized subspecies in the North American butterfly Polygonia faunus are supported by genetic data from mitochondrial sequences and eight microsatellite loci. We also investigate the phylogeographic structure of P. faunus and test whether similarities in host-plant use among populations are related to genetic similarity. Neither the nuclear nor the mitochondrial data corroborated subspecies groupings. We found three well defined genetic clusters corresponding to California, Arizona and (New Mexico+Colorado). There was little structuring among the remaining populations, probably due to gene flow across populations. We found no support for the hypothesis that similarities in host use are related to genetic proximity. The results indicate that the species underwent a recent rapid expansion, probably from two glacial refugia in western North America. The mitochondrial haplotype network indicates at least two independent expansion phases into eastern North America. Our results clearly demonstrate that subspecies in P. faunus do not conform to the structuring of genetic variation. More studies on insects and other invertebrates are needed to better understand the scope of this phenomenon. The results of this study will be crucial in designing further experiments to understand the evolution of hostplant utilization in this species.

  • 371. Koksharova, Olga A
    et al.
    Klint, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Rasmussen, Ulla
    Stockholm University, Faculty of Science, Department of Botany.
    Comparative proteomics of cell division mutants and wild-type of Synechococcus sp. strain PCC 7942.2007In: Microbiology, ISSN 1350-0872, Vol. 153, no Pt 8, p. 2505-2517Article in journal (Refereed)
  • 372. Koksharova, Olga A
    et al.
    Klint, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Rasmussen, Ulla
    Stockholm University, Faculty of Science, Department of Botany.
    The first protein map of Synechococcus sp. strain PCC 79422006In: Mikrobiologiia, ISSN 0026-3656, Vol. 75, no 6, p. 765-74Article in journal (Refereed)
  • 373. Kolb, Annette
    et al.
    Dahlgren, Johan P.
    Stockholm University, Faculty of Science, Department of Botany.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Population size affects vital rates but not population growth rate of a perennial plant2010In: Ecology, ISSN 0012-9658, E-ISSN 1939-9170, Vol. 91, no 11, p. 3210-3217Article in journal (Refereed)
    Abstract [en]

    Negative effects of habitat fragmentation on individual performance have been widely documented, but relatively little is known about how simultaneous effects on multiple vital rates translate into effects on population viability in long-lived species. In this study, we examined relationships between population size, individual growth, survival and reproduction, and population growth rate in the perennial plant Phyteuma spicatum. Population size positively affected the growth of seedlings, the survival of juveniles, the proportion of adults flowering, and potential seed production. Analyses with integral projection models, however, showed no relationship between population size and population growth rate. This was due to the fact that herbivores and pathogens eliminated the relationship between population size and seed production, and that population growth rate was not sensitive to changes in the vital rates that varied with population size. We conclude that effects of population size on vital rates must not translate into effects on population growth rate, and that populations of long-lived organisms may partly be able to buffer negative effects of small population size on vital rates that have a relatively small influence on population growth rate. Our study illustrates that we need to be cautious when assessing the consequences of habitat fragmentation for population viability based on effects on only one or a few vital rates.

  • 374. Kolb, Annette
    et al.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Environmental context drives seed predator-mediated selection on a floral display trait2010In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 24, no 2, p. 433-445Article in journal (Refereed)
    Abstract [en]

    Linking trait selection to environmental context is necessary to move beyond the simple recognition that selection is spatially variable and to understand what ultimately drives this variation. Natural selection acts through differences among individuals in lifetime fitness and information about effects on fitness components is therefore often not sufficient to gain such an understanding. We investigated how environmental context influenced intensity of seed predation, flower abortion and selection on floral display traits in 44-52 populations of the perennial herb Primula veris over 2 years. Phenotypic selection on both inflorescence height and flower number varied among populations and was mediated partly by pre-dispersal seed predation and flower abortion in one of the years. Among-population variation in selection on inflorescence height, but not flower number, was linked to variation in canopy cover via its effects on seed predation. Lifetime fitness was less sensitive to seed predator damage in shaded environments but estimates of selection based on lifetime fitness agreed qualitatively with those based on seed output. Our results demonstrate that seed predators constitute an important link between environmental conditions and trait evolution in plants, and that selection on plant traits by seed predators can depend on environmental context.

  • 375.
    Kolb, Annette
    et al.
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany. växtekologi.
    Ecological and evolutionary consequences of spatial and temporal variation in pre-dispersal seed predation.2007In: Perspectives in Plant Ecology, Evolution and Systematics, Vol. 9, p. 79-100Article in journal (Refereed)
  • 376. Kolb, Annette
    et al.
    Leimu, Roosa
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Environmental context influences the outcome of a plant-seed predator interaction2007In: OIKOS, Vol. 116, no 5, p. 864-872Article in journal (Other (popular science, discussion, etc.))
  • 377.
    Kolb, Gundula
    Stockholm University, Faculty of Science, Department of Botany.
    The effects of cormorants on population dynamics and food web structure on their nesting islands2007Report (Other academic)
  • 378.
    Kolb, Gundula S.
    Stockholm University, Faculty of Science, Department of Botany.
    The impact of cormorant nesting colonies on plants and arthropods2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Seabirds concentrate large amounts of marine nutrients on their nesting islands. This nutrient input can have large consequences for island food webs and community structure. The high nutrient load may also cause runoff into surrounding waters and affect marine communities. In my thesis, I studied the effect of cormorant nesting colonies on the stoichiometry, abundance, species richness, and species composition of plants, algae, and invertebrates on land and in costal waters and investigated if differences in the elemental composition or homeostasis can explain differences in the numerical response among invertebrate groups. δ15N analysis indicated that ornithogenic nitrogen provided a significant nitrogen source for plants and arthropods on nesting islands and around high nest density islands also for brackish algae and invertebrates. Furthermore, nutrient runoff created a potential feed-back loop to spiders via chironomids. Cormorant nutrient input changed island vegetation and increased plant P and N content and epiphytic algae:Fucus ratio, but decreased plant species richness and vegetation cover. Invertebrates responded indirectly to these qualitative and quantitative changes in their food source and habitat, but also directly to cormorant subsidies. However not all taxonomic and feeding groups were affected and responses were both positive and negative. Differences in the numerical response among taxonomic groups could not be explained by differences in the level of homeostasis, since, generally, all invertebrates were strongly homeostatic. Similarly, consumer nutrient content was a poor predictor for displayed responses. I conclude that cormorant colonies have strong impacts on island vegetation and some consumer groups. However, even if they can decrease the species richness of some organism groups on their nesting islands, they increase the habitat heterogeneity in an archipelago and thus may increase the regional species diversity.

  • 379.
    Kolb, Gundula S.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ekholm, Janna
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    Effects of seabird nesting colonies on algae and aquatic invertebrates in coastal watersIn: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599Article in journal (Refereed)
    Abstract [en]

    Seabirds concentrate marine nutrients, from large marine areas, on their nesting islands. The high nutrient load may cause runoff into surrounding waters and affect marine communities in similar ways as reported from marine fertilization experiments. In order to test if cormorant colonies affect algae and invertebrates in surrounding coastal waters, we collected Fucus vesiculosus fronds, its epiphytic algae and associated invertebrate fauna near abandoned and active cormorant nesting islands and reference islands without nesting cormorants in the Stockholm archipelago in the northern Baltic Proper, Sweden. First, we showed, with δ15N analyses, that ornithogenic nitrogen provided a significant nitrogen source for algae and invertebrate consumers near islands with high nest density. Second, the nitrogen and phosphorus content of algae near active cormorant islands with high nest density was elevated and epiphytic algae increased relative to Fucus. Third, 3 of 5 invertebrate taxa (Jaera albifrons, Gammarus spp. and Chironomidae) showed increased biomasses near islands with high nest density, but contrary to earlier fertilization studies only J. albifrons increased in abundance compared to reference islands. We conclude that runoff from seabird colonies has a profound effect on primary producers and some consumers in the surrounding water, but only if the colonies exceed a certain nest density. Thus, seabirds not only affect marine communities via top-town forces as commonly assumed, but also via bottom-up forces by concentrating nutrients around their nesting islands. Consequently, seabird islands can be seen as natural fertilization experiments and give important insights in the effects of eutrophication of marine systems.

  • 380.
    Kolb, Gundula S.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ekholm, Janna
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    Effects of seabird nesting colonies on algae and aquatic invertebrates in coastal waters2010In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 417, p. 287-300Article in journal (Refereed)
    Abstract [en]

    Seabirds concentrate nutrients from large marine areas on their nesting islands. The high nutrient load may cause runoff into surrounding waters and affect marine communities in similar ways to those reported from marine fertilization experiments. In order to test if cormorant colonies affect algae and invertebrates in surrounding coastal waters, we collected Fucus vesiculosus fronds, its epiphytic algae, and associated invertebrate fauna near abandoned and active cormorant nesting islands as well as reference islands without nesting cormorants in the Stockholm archipelago in the northern Baltic Sea, Sweden. First, we showed, with delta N-15 analyses, that ornithogenic nitrogen provided a significant nitrogen source for algae and invertebrate consumers near islands with high nest density. Second, the nitrogen and phosphorus content of algae near active cormorant islands with high nest density was elevated, and epiphytic algae increased relative to F. vesiculosus. Third, 3 of 5 invertebrate taxa (Jaera albifrons, Gammarus spp., and Chironomidae) showed increased biomasses near islands with high nest density; but, contrary to former fertilization studies, only J. albifrons increased in abundance compared to reference islands. We conclude that runoff from seabird colonies has a profound effect on primary producers and some consumers in the surrounding water, but only if the colonies exceed a certain nest density. Thus, seabirds not only affect marine communities via top-town forces as commonly assumed, but also via bottom-up forces by concentrating nutrients around their nesting islands. Consequently, seabird islands can be seen as natural fertilization experiments and give important insights to the effects of eutrophication of marine systems.

  • 381.
    Kolb, Gundula S.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    Ecological stoichiometry and homeostasis of plants and invertebrates on and nearby heavily fertilized cormorant nesting islandsManuscript (preprint) (Other academic)
    Abstract [en]

    Ecological stoichiometry has generalized the fundamental role of individual nutrient demand in all ecological processes and interactions. It implies that the elemental composition (C:N:P) of a consumer relative to the C:N:P of its resource determines its growth rate and thus secondary productivity. A central, but recently questioned, principle of ecological stoichiometry is the assumption that heterotrophs, in contrast to autotrophs, keep their elemental composition strongly homeostatic. Since neither the relationship between consumer C:N:P and its numeric response to changes in resource C:N:P nor the C:N:P homeostasis of arthropods have been extensively studied for arthropods, we used a natural gradient of N and P loads, in form of seabird and non-seabird islands, to investigate the stoichiometry and homeostasis of primary producers and invertebrates, both on and around islands. We then looked for causal relationships between stoichiometry and the level of homeostasis of a taxonomic group, respectively, and observed numerical responses to seabird fertilization. We found in accordance to principal theories that invertebrates, generally, strongly regulated their stoichiometry while autotrophs were stoichiometrically plastic. Thus, we found no causal relationship between consumer homeostasis and displayed numeric responses. Furthermore, we found only weak support for the hypothesis that the C:N:P of a taxa determines its numeric response to increased resource nutrient content (lepidopteran larvae had high P:C and high abundance on P-rich cormorant islands). We conclude that other species traits than nutrient content mainly determine the success of a taxa in a certain environment. Additionally, due to the strong effects of different level of homeostasis on ecological interactions, food web dynamics and nutrient cycles, we underline the need of further studies on the homeostasis of arthropods.

  • 382.
    Kolb, Gundula S.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Jerling, Lenn
    Stockholm University, Faculty of Science, Department of Botany.
    Essenberg, Carolina
    Stockholm University, Faculty of Science, Department of Botany.
    Palmborg, Cecilia
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    The impact of nesting cormorants on plant and arthropod diversity2012In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 35, no 8, p. 726-740Article in journal (Refereed)
    Abstract [en]

    Seabirds can strongly affect several major factors correlated with species diversity by concentrating marine nutrients on their nesting islands and by physically disturbing island vegetation. In this study, we investigated the effects of nesting cormorants on the abundance, species richness, and composition of plants and arthropods (Coleoptera, Heteroptera, Araneae, and Chironomidae) on islands in Stockholm archipelago, Sweden. Nesting cormorants negatively affected plant species richness and vegetation cover and that changed plant species composition. The effect of nesting cormorants on island arthropods varied between feeding groups and sampling methods. Most orders did not change in abundance or species richness but some, such as coleopterans and spiders changed in species composition. Herbivorous coleopterans were generally negatively affected by cormorants whereas fungivorous species and scavengers were generally positively affected. In structural equation modeling we found that the effect of cormorants was sometimes direct, such as on scavengers, but many effects on island consumers were mediated by changes in vegetation caused by cormorant presence. Overall, arthropod communities were highly dissimilar between cormorant and reference islands, and we therefore conclude that nesting cormorants not only affect the diversity of their nesting islands but also of the archipelago as a whole. The total diversity in the archipelago may increase through regional increased habitat heterogeneity and by adding species which are favored by seabirds (e.g. scavenging and fungivorous coleopterans).

  • 383.
    Kolb, Gundula S.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Jerling, Lenn
    Stockholm University, Faculty of Science, Department of Botany.
    Essenberg, Caroline
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    The impact of nesting cormorants on plant and arthropod diversityArticle in journal (Refereed)
    Abstract [en]

    Seabirds can strongly affect major factors correlated with species diversity – primary productivity, heterogeneity, and disturbance – on their nesting islands through the concentration of marine nutrients and physical disturbing island vegetation. In this study, we investigated the effects of nesting cormorants on the abundance, species richness, and composition of plants and arthropods (Coleoptera, Heteroptera, Araneae, and Chironomidae) on islands in Stockholm archipelago, Sweden. We found that cormorants had a negative effect on plant species richness and vegetation cover and that they changed plant species composition. Plant biomass showed no linear correlation with nest density when considering all islands studied, but was negatively correlated with nest density when considering only cormorant islands. The effect of nesting cormorants on island arthropods varied across feeding groups and sampling methods. Coleopterans and cursorial spiders responded with shifts in species richness and composition, and several coleopteran feeding groups and chironomids also changed in abundance. The abundance and species richness of saprophagous and fungivorous coleopterans were higher on active cormorant islands than on reference islands, while the abundance and species richness of herbivorous coleopterans and the species richness of cursorial spiders were negatively correlated with nest density. In structural equation modeling we found that some feeding groups were directly affected by nest density, but that many of the effects of seabirds on island consumers were mediated by changes in vegetation. We conclude that nesting cormorants affect the diversity of their nesting islands and the archipelago as a whole. Although cormorant colonies can decrease the species diversity of plants and some invertebrate groups on their nesting islands, the total diversity in the archipelago may increase through regional increased habitat heterogeneity and by adding species which are favored by seabirds (e.g., saprophagous and fungivorous coleopterans).

  • 384.
    Kolb, Gundula S.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Jerling, Lenn
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    The impact of cormorants on plant–arthropod food webs on their nesting islands2010In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 13, no 3, p. 353-366Article in journal (Refereed)
    Abstract [en]

    This study investigated the effects of cormorant colonies on plant–arthropod island food webs, the consequences of nutrient-rich runoff on marine communities, and feedback loops from marine to terrestrial ecosystems. Terrestrial plant responses were as expected, with the highest plant biomass on islands with low nest density and the highest nitrogen (N) content on islands with high nest density. In contrast to our hypothesis, we found no uniform density response across guilds. Among herbivores, the variable responses may depend on the relative importance of plant quality or quantity. As expected, nutrient-rich runoff entered water bodies surrounding cormorant nesting islands, but only at high nest density, and increased the density of emerging insects. This created a potential feed-back loop to spiders (major terrestrial predators), where stable isotope analyses suggested great use of chironomids. Contrary to our expectation, this potential feed-back did not result in the highest spider density on islands with a high cormorant nest density. Web spiders showed no changes in density on active cormorant islands, and lycosids were actually less abundant on active cormorant islands compared to reference islands. The variable response of spiders despite increased dipteran densities, and also in other consumer groups, may be due to direct negative effects of cormorants on soil chemistry, vegetation cover, and other density regulating forces (for example, top–down forces) not studied here. This study highlights the importance of including processes in the surrounding marine ecosystem to understand the impacts of seabirds on the food web structures of their nesting islands. 

  • 385. Kool, Anneleen
    et al.
    de Boer, Hugo J.
    Krüger, Åsa
    Stockholm University, Faculty of Science, Department of Botany.
    Rydberg, Anders
    Abbad, Abdelaziz
    Björk, Lars
    Martin, Gary
    Molecular Identification of Commercialized Medicinal Plants in Southern Morocco2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 6, p. e39459-Article in journal (Refereed)
    Abstract [en]

    Background: Medicinal plant trade is important for local livelihoods. However, many medicinal plants are difficult to identify when they are sold as roots, powders or bark. DNA barcoding involves using a short, agreed-upon region of a genome as a unique identifier for species-ideally, as a global standard. Research Question: What is the functionality, efficacy and accuracy of the use of barcoding for identifying root material, using medicinal plant roots sold by herbalists in Marrakech, Morocco, as a test dataset. Methodology: In total, 111 root samples were sequenced for four proposed barcode regions rpoC1, psbA-trnH, matK and ITS. Sequences were searched against a tailored reference database of Moroccan medicinal plants and their closest relatives using BLAST and Blastclust, and through inference of RAxML phylograms of the aligned market and reference samples. Principal Findings: Sequencing success was high for rpoC1, psbA-trnH, and ITS, but low for matK. Searches using rpoC1 alone resulted in a number of ambiguous identifications, indicating insufficient DNA variation for accurate species-level identification. Combining rpoC1, psbA-trnH and ITS allowed the majority of the market samples to be identified to genus level. For a minority of the market samples, the barcoding identification differed significantly from previous hypotheses based on the vernacular names. Conclusions/Significance: Endemic plant species are commercialized in Marrakech. Adulteration is common and this may indicate that the products are becoming locally endangered. Nevertheless the majority of the traded roots belong to species that are common and not known to be endangered. A significant conclusion from our results is that unknown samples are more difficult to identify than earlier suggested, especially if the reference sequences were obtained from different populations. A global barcoding database should therefore contain sequences from different populations of the same species to assure the reference sequences characterize the species throughout its distributional range.

  • 386.
    Korall, Petra
    Stockholm University, Faculty of Science, Department of Botany.
    Phylogeny of Selaginellaceae2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The phylogeny of Selaginellaceae, a small, but historically important family of heterosporous lycopods, has been the focus of this thesis. The approximately 700 extant species are herbaceous and distributed all over the world, with most species in the tropics and subtropics. Lycopods constituted a dominant element of the Upper Carboniferous flora, but Selaginellaceae were probably established already in the Lower Carboniferous some 345 million years ago, as revealed by macrofossil data. Major patterns of relationships were investigated based on a representative sample of global diversity and molecular (plastid gene rbcL, nuclear region 26S rDNA) and morphological data. Analyses were performed using parsimony and Bayesian inference. A survey of megaspore surface and wall structures was carried out for living species and included in the phylogenetic analyses. The resulting phylogenetic trees were used to evaluate various hypotheses on the evolution of the group, including the origins of tropical and temperate species diversity, as well as the evolution of xerophytism. Results showed that Selaginellaceae are monophyletic, and many subclades were identified. In a basal dichotomy two species, Selaginella selaginoides (L.) Link and S. deflexa Brackenridge, appear in a strongly supported clade as sister group to a clade comprising all other species (rhizophoric clade). The rhizophoric clade is recognised by the presence of rhizophores, which are highly characteristic root-like organs, and on the presence of decussately arranged sporophylls. Within the rhizophoric clade a basal dichotomy is most often found resulting in two more or less equally sized sister groups. These and many other groupings within these clades are new and have not previously been recognized in any other systematic study. Some of the new groups seem to have corresponding morphological synapomorphies, such as aspects of rhizophore development and megaspore characteristics. Others share distinctive ecological traits (e.g., xerophytism). For many groups, however, no morphological, ecological, or physiological markers are yet known.

    The inclusion of megaspore fossils allowed for tentative ages to be assigned to certain clades within the family. The phylogenetic tree is inconclusive with regard to a tropical or temperate origin of modern species diversity, but there is clear evidence for multiple independent origins of xerophytic strategies. Besides the phylogenetic results, this study reveals exceptionally high levels of substitution rates and rate heterogeneity in Selaginellaceae.

  • 387.
    Korall, Petra
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Conant, David S.
    Metzgar, Jordan S.
    Schneider, Harald
    Pryer, Kathleen M.
    A molecular phylogeny of scaly tree ferns (Cyatheaceae)2007In: American Journal of Botany, ISSN 0002-9122, E-ISSN 1537-2197, Vol. 94, no 5, p. 873-886Article in journal (Refereed)
    Abstract [en]

    Tree ferns recently were identified as the closest sister group to the hyperdiverse clade of ferns, the polypods. Although most of the 600 species of tree ferns are arborescent, the group encompasses a wide range of morphological variability, from diminutive members to the giant scaly tree ferns, Cyatheaceae. This well-known family comprises most of the tree fern diversity (similar to 500 species) and is widespread in tropical, subtropical, and south temperate regions of the world. Here we investigate the phylogenetic relationships of scaly tree ferns based on DNA sequence data from five plastid regions (rbcL, rbcL-accD IGS, rbcL-atpB IGS, trnG-trnR, and trnL-trnF). A basal dichotomy resolves Sphaeropteris as sister to all other taxa and scale features support these two clades: Sphaeropteris has conform scales, whereas all other taxa have marginate scales. The marginate-scaled clade consists of a basal trichotomy, with the three groups here termed (1) Cyathea (including Cnemidaria, Hymenophyllopsis, Trichipteris), (2) Alsophila sensu stricto, and (3) Gymnosphaera (previously recognized as a section within Alsophila) + A. capensis. Scaly tree ferns display a wide range of indusial structures, and although indusium shape is homoplastic it does contain useful phylogenetic information that supports some of the larger clades recognised.

  • 388.
    Korall, Petra
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Schuettpelz, Eric
    Pryer, Kathleen M.
    ABRUPT DECELERATION OF MOLECULAR EVOLUTION LINKED TO THE ORIGIN OF ARBORESCENCE IN FERNS2010In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 64, no 9, p. 2786-2792Article in journal (Refereed)
    Abstract [en]

    Molecular rate heterogeneity, whereby rates of molecular evolution vary among groups of organisms, is a well-documented phenomenon. Nonetheless, its causes are poorly understood. For animals, generation time is frequently cited because longer-lived species tend to have slower rates of molecular evolution than their shorter-lived counterparts. Although a similar pattern has been uncovered in flowering plants, using proxies such as growth form, the underlying process has remained elusive. Here, we find a deceleration of molecular evolutionary rate to be coupled with the origin of arborescence in ferns. Phylogenetic branch lengths within the ""tree fern"" clade are considerably shorter than those of closely related lineages, and our analyses demonstrate that this is due to a significant difference in molecular evolutionary rate. Reconstructions reveal that an abrupt rate deceleration coincided with the evolution of the long-lived tree-like habit at the base of the tree fern clade. This suggests that a generation time effect may well be ubiquitous across the green tree of life, and that the search for a responsible mechanism must focus on characteristics shared by all vascular plants. Discriminating among the possibilities will require contributions from various biological disciplines, but will be necessary for a full appreciation of molecular evolution.

  • 389.
    Krüger, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum.
    Razafimandimbison, Sylvain G.
    Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum.
    Molecular phylogeny of the tribe Danaideae (Rubiaceae: Rubioideae): Another example of out-of-Madagascar dispersal2012In: Taxon, ISSN 0040-0262, E-ISSN 1996-8175, Vol. 61, no 3, p. 629-636Article in journal (Refereed)
    Abstract [en]

    Extensive efforts have been made to resolve the phylogeny of the large coffee family (Rubiaceae) based on molecular data. As a result, several small tribes have been described, but the phylogenies and generic delimitations for many of these groups remain unclear. This study focuses on the small tribe Danaideae that belongs to subfamily Rubioideae and whose generic limits have not previously been addressed with molecular data. It is the sole rubiaceous tribe distributed almost entirely in the Western Indian Ocean region, with the exception of the East African Danais xanthorrhoea. The tribe consists of three genera: Danais, Payera (including the monotypic genus Coursiana), and Schismatoclada. We present the first molecular phylogenetic study of Danaideae including representatives from all three genera and using Bayesian and maximum parsimony methods and sequence data from nuclear DNA (nrITS) and chloroplast DNA (petD, psbA-trnH, rpl32-trnL(UAG), rps16). Our main objectives were to rigorously test the monophyly of Danaideae as currently circumscribed and assess phylogenetic relationships within the tribe. The findings of this study shed light on the colonization history of the tribe. Our analyses reaffirm the monophyly of Danaideae and Danais but reveal the paraphyly of Payera and Schismatoclada. The close relationship between the three Danaideae genera and Coursiana is supported. However, we found very little support for the inclusion of the latter genus in Payera as proposed earlier. The tribe is resolved in two morphologically distinct major lineages, the highly supported Damns clade with lianescent habit (= Danais sensu Buchner & Puff) and the Payera-Schismatoclada clade with arborescent habit. The Malagasy and Mauritian specimens of Danais fragrans are not closely related, and we restrict D. fragrans to the Mauritian taxa and resurrect Danais lyallii Baker to accommodate the Malagasy D. fragrans. According to our analysis. Madagascar is the origin of all species of Danaideae occurring in the Comoro archipelago, East Africa, and Mauritius. The Mauritian and East African Danais each is the result of a single colonization event, while there were at least two independent colonization events to the Comoros.

  • 390. Kunze, H.
    et al.
    Wanntorp, L.
    Stockholm University, Faculty of Science, Department of Botany.
    Corona and anther skirt in Hoya (Apocynaceae, Marsdenieae)2008In: Plant Systematics and Evolution, ISSN 0378-2697, E-ISSN 1615-6110, Vol. 271, no 02-jan, p. 9-17Article in journal (Refereed)
    Abstract [en]

    The so called revolute margins of the corona in the genus Hoya (Marsdenieae) are homologous to the anther skirt. The anther skirt is primarily formed of two latero-basal lobes of the anther. In Hoya these lobes are fused with the underside of the basal process of the staminal corona and have evolved into a dominant structure of the gynostegium. Embedded in the anther skirt is the nectar tube, formed by the basal elongation of the guide rail. In many species, however, the function of nectar secretion for pollinator reward has been transferred to the anther skirt beneath the basal process of the corona. A survey of the Marsdenieae shows that the potential for developing an anther skirt is present in several other genera as well, though nowhere has it evolved into such elaborated structures as in Hoya.

  • 391.
    Källman, Stefan
    Stockholm University, Faculty of Science, Department of Botany.
    Näringsvärden i vilda svenska växter: analyser och fysiologiska studier av olika komponenter med tonvikt på kolhydrater, protein och vitamin C1983Doctoral thesis, monograph (Other academic)
    Abstract [en]

    In order to investigate the possibility of using wild plants as food in emergency situations and to provide results for further physiological studies, the content and seasonal variations of different nutritive components were investigated in 80 wild Swedish species, including 9 lichens. The plants were analysed for: glucose, fructose, galactose, sucrose, inulin, starch, crude protein, ascorbic acid, minerals, ash and amino acids. The carbohydrates were analysed with very specific enzymatic methods, which will be very suitable for further use in plant physiology. Storage organs had high carbohydrate contents. Fructosan storing organs from the family Asteraceae had the highest values, but the content in starch storing rhizomes from Typha latifolia were almost the same. Green plant parts had favourable amino acid compositions, fairly high starch levels, but no sucrose. Glucose and fructose dominated in meristematic tissues and in berries and fruits, but the berries and fruits showed considerably variations in carbohydrate composition. The lichens contained polysaccharides with a structure similar to starch. Young leaves and winter green plants were very rich in ascorbic acid, indicating the role of ascorbic acid in coldhardiness of plants. The results demonstrated the necessity of uniform investigations and appropriate methods, especially when analysing plant material. The investigated plants are potentially useful as food, and can supply enough carbohydrates for a correct physiological fat combustion in man during a trying survival march.

  • 392.
    Kårehed, Jesper
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany. Växtsystematik.
    Alseuosmiaceae2007In: Volume VIII, Flowering Plants. Eudicots: Asterales, Springer-Verlag, Berlin Heidelberg , 2007, p. 7-12Chapter in book (Other academic)
  • 393.
    Kårehed, Jesper
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany. Växtsystematik.
    Argophyllaceae2007In: Volume VIII, Flowering Plants. Eudicots: Asterales, Springer-Verlag, Berlin Heidelberg , 2007, p. 13-18Chapter in book (Other academic)
  • 394.
    Kårehed, Jesper
    et al.
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany. Växtsystematik.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany. Växtsystematik.
    The systematics of Knoxieae (Rubiaceae) - molecular data and their taxonomic consequences2007In: Taxon, ISSN 0040-0262, Vol. 56, no 4, p. 1051-1076Article in journal (Refereed)
    Abstract [en]

    The tribe Knoxieae consists of genera formerly included in (at least) four tribes of the Rubiaceae (the coffee family). Apart from Knoxia itself, which is mainly Indomalesian, the group is from Africa and Madagascar. Most genera are herbaceous or shrubby, but small trees are also present. They generally have fimbriate, colleter-tipped stipules and five-merous flowers with unequal calyx lobes. We present a molecular phylogeny of the group (based on two chloroplast markers, rps16 and trnT-F, and the nuclear ITS) and discuss the morphological support for the resulting groups and the taxonomic consequences of the phylogeny. Two hundred and sixty-one new sequences from 90 species have been obtained. Of the 19 genera of the Knoxieae, all but three (two monotypic and one with two species) are represented. The genera Calanda, Chlorochorion, Neopentanisia, and Paraknoxia are merged with Pentanisia. Pentas is shown to be not monophyletic and is split into the new genera Phyllopentas, Dolichopentas, and Rhodopentas. We also suggest the Pentas subgenera Megapentas and Chamaepentadoides be included in Chamaepentas. The genus Carphalea is also shown to be not monophyletic and for the African members of the genus (section Dirichletia) the name Dirichletia should be used. Placopoda is suggested to be merged with Dirichletia. Triainolepis is enlarged to include Paratriaina and Thyridocalyx. The tribal position of Lathraeocarpa is discussed. Twenty-nine new combinations for species and seven for infraspecific taxa are made. A key to the genera of Knoxieae is provided.

  • 395. Kårehed, Jesper
    et al.
    Groeninckx, Inge
    Dessein, Steven
    Motley, Timothy J
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    The phylogenetic utility of chloroplast and nuclear DNA markers and the phylogeny of the Rubiaceae tribe Spermacoceae.2008In: Mol Phylogenet Evol, ISSN 1095-9513, Vol. 49, no 3, p. 843-66Article in journal (Other academic)
  • 396.
    Landberg, Tommy
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Göthberg, Agneta
    Department of Applied Environmental Science (ITM).
    Neuschütz, Clara
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Nyquist, Johanna
    Stockholm University, Faculty of Science, Department of Botany. växtfysiologi.
    Dabrowska, Beata
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany. Växtfysiologi.
    Metal uptake in food plants and in phytoremediation2007In: JSPS colloquium “Frontiers in plant biotechnology” Stockholm, October, 2007, 2007Conference paper (Other (popular science, discussion, etc.))
  • 397.
    Landberg, Tommy
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Jensen, P.
    Greger, Maria
    Stockholm University, Faculty of Science, Department of Botany.
    Strategies of cadmium and zinc resistance in willow by regulation of net accumulation2011In: Biologia plantarum, ISSN 0006-3134, E-ISSN 1573-8264, Vol. 55, no 1, p. 133-140Article in journal (Refereed)
    Abstract [en]

    This work was performed to find out if metal resistant clones of Salix viminalis L. are capable to achieve high resistance to the metals by regulating their net accumulation. Salix clones with low or high resistance in combination with low or high accumulation capacity of either Zn or Cd were cultivated from cuttings in nutrient solution. The investigation included leakage and uptake experiments using (65)Zn or (109)Cd and analysis of root cation exchange capacity (CEC). Some plants were pre-treated with unlabeled 0.5 mu M Cd or 2.5 mu M Zn 24 h prior to the experiments to induce possible tolerance mechanisms. To find out if the regulation was a metabolic process, experiments were also performed with 2,4-dinitrophenol (DNP). Clones with high resistance and low Cd accumulation had higher efflux of Cd compared to the other clones, in both untreated and Cd pre-treated plants. This indicates a constitutive property to lower Cd accumulation by high Cd leakage. Pre-treatment with 0.5 mu M Cd diminished the Cd net uptake to a level near zero in all clones, likely to be due to decreased the Cd uptake. In contrast, resistant clones with high Cd accumulation had the highest root CEC, which may be used to bind up Cd in the free space. No clear regulation of Zn net uptake was found in Zn-resistant clones. Pre-treatment with Zn decreased the uptake of Zn into the free space in Zn-resistant clones. The resistant high-accumulating clones, however, showed the highest leakage of Zn in both untreated and pre-treated plants, a constitutive process not related to high accumulation. Neither the influx nor the efflux of Cd or Zn was affected by DNP indicating passive transport across the plasma membrane.

  • 398. Lantz, Henrik
    et al.
    Klackenberg, Jens
    Razafimandimbison, Sylvain
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany. Plant systematics.
    Mouly, Arnaud
    Three new species of Vanguerieae (Rubiaceae)2007In: Adansonia, ISSN 1280-8571, Vol. 29, no 1, p. 129-136Article in journal (Refereed)
  • 399.
    Larsson, John
    Stockholm University, Faculty of Science, Department of Botany.
    Cyanobacterial genome evolution subsequent to domestication by a plant (Azolla)2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Cyanobacteria are an ancient and globally distributed group of photosynthetic prokaryotes including species capable of fixing atmospheric dinitrogen (N2) into biologically available ammonia via the enzyme complex nitrogenase. The ability to form symbiotic interactions with eukaryotic hosts is a notable feature of cyanobacteria and one which, via an ancient endosymbiotic event, led to the evolution of chloroplasts and eventually to the plant dominated biosphere of the globe. Some cyanobacteria are still symbiotically competent and form symbiotic associations with eukaryotes ranging from unicellular organisms to complex plants. Among contemporary plant-cyanobacteria associations, the symbiosis formed between the small fast-growing aquatic fern Azolla and its cyanobacterial symbiont (cyanobiont), harboured in specialized cavities in each Azolla leaf, is the only one which is perpetual and in which the cyanobiont has lost its free-living capacity, suggesting a long-lasting co-evolution between the two partners. In this study, the genome of the cyanobiont in Azolla filiculoides was sequenced to completion and analysed. The results revealed that the genome is in an eroding state, evidenced by a high proportion of pseudogenes and transposable elements. Loss of function was most predominant in genetic categories related to uptake and metabolism of nutrients, response to environmental stimuli and in the DNA maintenance machinery. Conversely, function was retained in key symbiotic processes such as nitrogen-fixation and cell differentiation. A comparative analysis shows that the size of the cyanobiont genome has remained relatively stable, and that few genes have been completely eliminated, since the symbiotic establishment. Indications of genes acquired via horizontal gene transfer were discovered in thec yanobiont genome, some of which may have originated from the bacterial community in the Azolla leaf-cavities. It is concluded that the perpetual nature of the Azolla symbiosis has resulted in pronounced ongoing streamlining of the cyanobiont genome around core symbiotic functions, a process not described previously for complex cyanobacteria or for any bacterial plant symbiont. Further, the status of the genome indicates that the cyanobiont is at an early stage of adapting to its host-restricted environment and continued co-evolution with the plant may result in additional genome reductions. However, although a vertical transmission process is already established, the unusual extracellular location of the cyanobiont and the intricate nature of the symbiosis, may still impose restrictions on such a reductive process.

  • 400.
    Larsson, John
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Nylander, Johan A. A.
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Birgitta
    Stockholm University, Faculty of Science, Department of Botany.
    Genome fluctuations in cyanobacteria reflect evolutionary, developmental and adaptive traits2011In: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 11, p. 187-Article in journal (Refereed)
    Abstract [en]

    Background: Cyanobacteria belong to an ancient group of photosynthetic prokaryotes with pronounced variations in their cellular differentiation strategies, physiological capacities and choice of habitat. Sequencing efforts have shown that genomes within this phylum are equally diverse in terms of size and protein-coding capacity. To increase our understanding of genomic changes in the lineage, the genomes of 58 contemporary cyanobacteria were analysed for shared and unique orthologs. Results: A total of 404 protein families, present in all cyanobacterial genomes, were identified. Two of these are unique to the phylum, corresponding to an AbrB family transcriptional regulator and a gene that escapes functional annotation although its genomic neighbourhood is conserved among the organisms examined. The evolution of cyanobacterial genome sizes involves a mix of gains and losses in the clade encompassing complex cyanobacteria, while a single event of reduction is evident in a clade dominated by unicellular cyanobacteria. Genome sizes and gene family copy numbers evolve at a higher rate in the former clade, and multi-copy genes were predominant in large genomes. Orthologs unique to cyanobacteria exhibiting specific characteristics, such as filament formation, heterocyst differentiation, diazotrophy and symbiotic competence, were also identified. An ancestral character reconstruction suggests that the most recent common ancestor of cyanobacteria had a genome size of approx. 4.5 Mbp and 1678 to 3291 protein-coding genes, 4%-6% of which are unique to cyanobacteria today. Conclusions: The different rates of genome-size evolution and multi-copy gene abundance suggest two routes of genome development in the history of cyanobacteria. The expansion strategy is driven by gene-family enlargment and generates a broad adaptive potential; while the genome streamlining strategy imposes adaptations to highly specific niches, also reflected in their different functional capacities. A few genomes display extreme proliferation of non-coding nucleotides which is likely to be the result of initial expansion of genomes/gene copy number to gain adaptive potential, followed by a shift to a life-style in a highly specific niche (e. g. symbiosis). This transition results in redundancy of genes and gene families, leading to an increase in junk DNA and eventually to gene loss. A few orthologs can be correlated with specific phenotypes in cyanobacteria, such as filament formation and symbiotic competence; these constitute exciting exploratory targets.

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