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  • 1. Abbasi, Arshad Mehmood
    et al.
    Khan, Mir Ajab
    Khan, Nadeem
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Shah, Munir H
    Ethnobotanical survey of medicinally important wild edible fruits species used by tribal communities of Lesser Himalayas-Pakistan2013In: Journal of Ethnopharmacology, ISSN 0378-8741, E-ISSN 1872-7573, Vol. 148, no 2, 528-536 p.Article in journal (Refereed)
    Abstract [en]

    Ethnopharmacological relevance: Present survey was conducted to explore ethnomedicinal uses and cultural importance of wild edible fruits species by the inhabitants of Lesser Himalayas-Pakistan. Materials and methods: Information was obtained through informed consent semi-structured interviews, questionnaires, market survey, focus group conversation, unceremonious dialogue and village walks with key informants. Cultural significance of each species was calculated based on use report by participants at each study site. Results: A total of 35 wild edible fruits belonging to 21 genera and 17 families were used for the treatment of various ailments and consumed. Rosaceae was found dominating family with (8 spp.), followed by Moraceae (6 spp.), Rhamnaceae (5 spp.), Palmae and Vitaceae (2 spp. each) and remaining families were represented by one species each. Fruits (48%) were found highly utilized plant parts, followed by leaves (34%), bark, flowers and seeds (4% each), branches, latex and roots (2% each). Water was used as a medium for preparation while milk, ghee, oil, egg and butter are used for application. Modes of preparation were fall into seven categories like fresh parts eaten raw (38%), powder (24%), decoction (20%), extract (12 %), paste (4%), juice and latex (2% each). Based on cultural important index (CI) Morus nigra was found most significant species within top ten fruit plants followed by Morus alba, Olea ferruginea, Berberis lycium, Pyrus pashia, Ficus carica, Ficus palmata, Ziziphus mauritiana, Diospyros lotus and Ziziphus nummularia. Conclusions: Traditional uses of wild edible plant depend mainly on socio-economic factors rather than climatic conditions or wealth of flora. Use reports and citation demonstrated that there is a common cultural heritage regarding the gathered food plants. Further investigation is required for Antioxidant study, essential and toxic components, pharmacological applications; dietary requirements and biotechnological techniques to improve yields.

    (C) 2013 Elsevier Ireland Ltd. All rights reserved.

  • 2.
    Agić, Heda
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Moczydłowska, Małgorzata
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Canfield, Donald
    University of Southern Denmark .
    Reproductive cyst and operculum formation in the Cambrian-Ordovician galeate-plexus microfossils2016In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 138, no 2, 278-294 p.Article in journal (Refereed)
    Abstract [en]

    Unicellular organic-walled microfossils from the Cambrian-Ordovician transition in Estonia (ca. 490-480 million years ago) exhibit rare characters reflecting their function as reproductive algal cysts. The studied assemblages record the evolutionary history of phytoplankton in the early Paleozoic Era: novel morphologies appearing through the Cambrian and subsequently diversifying in the Ordovician. Well preserved specimens were extracted following a standard palynological method and studied by light transmitted microscopy. The galeate plexus acritarchs Caldariola, Priscogalea and Stelliferidium have revealed exceptionally preserved morphological elements and a rare structure among both fossil and extant protists – an opening with operculum (lid) in reproductive cysts, in addition to lavish vesicle ornamentation and sculpture. Analogous morphology is observed in the living dasycladalean alga Acetabularia (Chlorophyta), which possesses an intrinsic lid-forming apparatus used during organism’s reproductive stage. Based on the observations on the fossil material and studies on the Acetabularia lid-formation, we propose a model of operculum formation in the galeate plexus microorganisms. Due to strong morphological and ecological similarities between galeate fossils and dasycladalean cysts, and the antiquity of this algal order, galeates may be positioned within green algae, more specifically Dasycladales. Unique morphology of the operculum-bearing microbiota would have required a high degree of intracellular complexity for its development, suggesting that advanced intracellular machinery was present already in the early Paleozoic phytoplankton. Additionally, minute prasinophyte microfossils Reticella corrugata  are reported for the first time in the Upper Cambrian strata. 

  • 3.
    Akiyama, Reiko
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Life History and Tolerance and Resistance against Herbivores in Natural Populations of Arabidopsis thaliana2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In this thesis, I combined observational studies with field and greenhouse experiments to examine selection on life history traits and variation in tolerance and resistance against herbivores in natural populations of the annual herb Arabidopsis thaliana in its native range. I investigated (1) phenotypic selection on flowering time and plant size, (2) the effects of timing of germination on plant fitness, (3) the effect of leaf damage on seed production, and (4) correlations between resistance against a specialist and a generalist insect herbivore.

    In all three study populations, flowering time was negatively related to plant fitness, but in only one of the populations, significant selection on flowering time was detected when controlling for size prior to the flowering season. The results show that correlations between flowering time and plant fecundity may be confounded by variation in plant size prior to the reproductive season.

    A field experiment detected conflicting selection on germination time: Early germination was associated with low seedling survival, but also with large leaf rosette before winter and high survival and fecundity among established plants. The results suggest that low survival among early germinating seeds is the main force opposing the evolution of earlier germination, and that the optimal timing of germination should vary in space and time as a function of the relative strength of selection acting during different life-history stages.

    Experimental leaf damage demonstrated that tolerance to damage was lowest among vegetative plants early in the season, and highest among flowering plants later in the season. Given similar damage levels, leaf herbivores feeding on plants before flowering should thus exert stronger selection on defence traits than those feeding on plants during flowering.

    Resistance against larval feeding by the specialist Plutella xylostella was negatively correlated with resistance against larval feeding by the generalist Mamestra brassicae and with resistance against oviposition by P. xylostella when variation in resistance was examined within and among two Swedish and two Italian A. thaliana populations. The results suggest that negative correlations between resistance against different herbivores and different life-history stages of herbivores may contribute to the maintenance of genetic variation in resistance.

  • 4.
    Akiyama, Reiko
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Noack, Sibylle
    Department of Zoology, Stockholm University.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Genetic variation in leaf morphology and resistance against specialist and generalist insect herbivores in natural populations of Arabidopsis thalianaManuscript (preprint) (Other academic)
  • 5.
    Akiyama, Reiko
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Selection on flowering time in three natural populations of Arabidopsis thalianaManuscript (preprint) (Other academic)
  • 6.
    Akiyama, Reiko
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Conflicting selection on the timing of germination in a natural population of Arabidopsis thaliana2014In: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 27, no 1, 193-199 p.Article in journal (Refereed)
    Abstract [en]

    The timing of germination is a key life-history trait that may strongly influence plant fitness and that sets the stage for selection on traits expressed later in the life cycle. In seasonal environments, the period favourable for germination and the total length of the growing season are limited. The optimal timing of germination may therefore be governed by conflicting selection through survival and fecundity. We conducted a field experiment to examine the effects of timing of germination on survival, fecundity and overall fitness in a natural population of the annual herb Arabidopsis thaliana in north-central Sweden. Seedlings were transplanted at three different times in late summer and in autumn covering the period of seed germination in the study population. Early germination was associated with low seedling survival, but also with high survival and fecundity among established plants. The advantages of germinating early more than balanced the disadvantage and selection favoured early germination. The results suggest that low survival among early germinating seeds is the main force opposing the evolution of earlier germination and that the optimal timing of germination should vary in space and time as a function of the direction and strength of selection acting during different life-history stages.

  • 7.
    Akiyama, Reiko
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Ågren, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Magnitude and timing of leaf damage affect seed production in a natural population of Arabidopsis thaliana (Brassicaceae)2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 1, e30015- p.Article in journal (Refereed)
    Abstract [en]

    Background: The effect of herbivory on plant fitness varies widely. Understanding the causes of this variation is of considerable interest because of its implications for plant population dynamics and trait evolution. We experimentally defoliated the annual herb Arabidopsis thaliana in a natural population in Sweden to test the hypotheses that (a) plant fitness decreases with increasing damage, (b) tolerance to defoliation is lower before flowering than during flowering, and (c) defoliation before flowering reduces number of seeds more strongly than defoliation during flowering, but the opposite is true for effects on seed size.

    Methodology/Principal Findings: In a first experiment, between 0 and 75% of the leaf area was removed in May from plants that flowered or were about to start flowering. In a second experiment, 0, 25%, or 50% of the leaf area was removed from plants on one of two occasions, in mid April when plants were either in the vegetative rosette or bolting stage, or in mid May when plants were flowering. In the first experiment, seed production was negatively related to leaf area removed, and at the highest damage level, also mean seed size was reduced. In the second experiment, removal of 50% of the leaf area reduced seed production by 60% among plants defoliated early in the season at the vegetative rosettes, and by 22% among plants defoliated early in the season at the bolting stage, but did not reduce seed output of plants defoliated one month later. No seasonal shift in the effect of defoliation on seed size was detected.

    Conclusions/Significance: The results show that leaf damage may reduce the fitness of A. thaliana, and suggest that in this population leaf herbivores feeding on plants before flowering should exert stronger selection on defence traits than those feeding on plants during flowering, given similar damage levels.

  • 8. Aksmann, Anna
    et al.
    Shutova, Tatiana
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Samuelsson, Göran
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Tukaj, Zbigniew
    The mechanism of anthracene interaction with photosynthetic apparatus: A study using intact cells, thylakoid membranes and PS II complexes isolated from Chlamydomonas reinhardtii2011In: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 104, no 3-4, 205-210 p.Article in journal (Refereed)
    Abstract [en]

    Intact cells of Chlamydomonas reinhardtii as well as isolated thylakoid membranes and photosystem II complexes were used to examine a possible mechanism of anthracene (ANT) interaction with the photosynthetic apparatus. Since ANT concentrations above 1 mM were required to significantly inhibit the rate of oxygen evolution in PS II membrane fragments it may indicate that the toxicant did not directly interact with this photosystem. On the other hand, stimulation of oxygen uptake by ANT-treated thylakoids suggested that ANT could either act as an artificial electron acceptor in the photosynthetic electron transport chain or function as an uncoupler. Electron transfer from excited chlorophyll to ANT is impossible due to the very low reduction potential of ANT and therefore we propose that toxic concentrations of ANT increase the thylakoid membrane permeability and thereby function as an uncoupler, enhancing electron transport in vitro. Hence, its unspecific interference with photosynthetic membranes in vitro suggests that the inhibitory effect observed on intact cell photosynthesis is caused by uncoupling of phosphorylation. 

  • 9. Ali, Qasim
    et al.
    Haider, Muhammad Zulqurnain
    Iftikhar, Wasif
    Jamil, Sidra
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Department of Botany, Faculty of Science and Technology, Government College University, Faisalabad, Pakistan.
    Javed, M. Tariq
    Noman, Ali
    Iqbal, Muhammad
    Perveen, Rashida
    Drought tolerance potential of Vigna mungo L. lines as deciphered by modulated growth, antioxidant defense, and nutrient acquisition patterns2016In: Revista Brasileira de Botânica, ISSN 0100-8404, E-ISSN 1806-9959, Vol. 39, no 3, 801-812 p.Article in journal (Refereed)
    Abstract [en]

    Water shortage is one of the major environmental constraints that hamper the crop productivity worldwide. The present study was aimed to examine the drought tolerance potential of seven cultivars/lines of Vigna mungo L. depending upon their germination behavior, seedling growth, antioxidative defense mechanism, and nutrient acquisition. An experiment was conducted in the growth chamber using petri-plates and laid out in a completely randomized design (CRD). Hoagland's nutrient solution supplemented with 12 % PEG-8000 (drought treatment) or without PEG-800 (control) was used. Drought stress significantly altered the germination attributes as well as biomass production of all the studied cultivars/lines. Least adversative effects of drought stress were recorded in lines M-01001-1 and M-6036-21, respectively. The studied cultivars/lines exhibited differential response for various biochemical attributes under drought stress. The maximum increase in MDA and SOD activities and protein content was recorded in line M-603621, while the maximum AsA was recorded in line M-01001-1. Drought stress resulted in a significant reduction of plant N, P, K, Ca, and Mg contents, while the plant iron (Fe) contents remained unaffected. Results revealed that cultivars/lines M-01001-1 and M-6036-21 exhibited enhanced performance in terms of nutrient acquisition when stressed by drought. Based upon seed germination behavior, plant biomass production, biochemical attributes and mineral elements, the cultivars/lines M-01001-1 and M-6036-21 were identified as drought tolerant, while M-97 and Arroj-II were identified as drought sensitive.

  • 10. Amer, Ranya
    et al.
    Diez, Beatriz
    Stockholm University, Faculty of Science, Department of Botany.
    El-Shehawy, Rehab
    Stockholm University, Faculty of Science, Department of Botany.
    Diversity of hepatotoxic cyanobacteria in the Nile Delta, Egypt2009In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 11, no 1, 126-133 p.Article in journal (Refereed)
    Abstract [en]

    Optimized denaturing gradient gel electrophoresis (DGGE) fingerprinting and real-time PCR were performed to identify and quantify the potential hepatotoxic microcystin-and nodularin-producing cyanobacteria present in freshwater samples collected during different seasons at three different sites from the Nile River Delta. The combined use of molecular gene markers (targeting the aminotransferase domain of the hepatotoxin synthetase modules and the 16S rRNA gene) and light microscopy demonstrated the dominance of different freshwater Microcystis phylotypes, including the potential hepatotoxin producers M. wesenbergii and M. aeruginosa, several Synechococcus and Cyanobium phylotypes, as well as the presence of Nodularia spumigena and Cylindrospermopsis raciborskii in the samples ""collected during summer 2006 and winter 2007''. Certain seasonal changes (summer and winter) in Microcystis microdiversity were detected. Real-time PCR revealed no difference in the quantities of potential hepatotoxin-producing cyanobacterial communities between summer and winter, but did show differences between the three sampling sites investigated. The expression of the aminotransferase domain analyzed by DGGE fingerprinting demonstrated that all Microcystis phylotypes present in the samples might have been active at the time of the sampling. Statistical analysis showed a significant effect of TP, and not TN, on the relative abundance of the potentially hepatotoxic cyanobacterial community.

  • 11.
    Anderhag, Per
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Hepler, P. K.
    Lazzaro, M. D.
    Microtubules and microfilaments are both responsible for pollen tube elongation in the coniferPicea abies (Norway spruce)2000In: Protoplasma, ISSN 0033-183X, E-ISSN 1615-6102, Vol. 214, no 3, 141-157 p.Article in journal (Refereed)
    Abstract [en]

    InPicea abies (Norway spruce), microtubules and actin microfllaments both form a dense matrix throughout the tube mainly parallel to the direction of elongation. In these conifer pollen tubes the organization of this matrix is different from that in angiosperms. This study tests our hypothesis that differences in cytoskeletal organization are responsible for differences in tube growth and physiology. Pollen grains were germinated in media containing cytoskeletal disrupters and analyzed for germination, tube length, tube branching, and tip swelling. Disruption of microtubules significantly inhibits tube elongation and induces tube branching and tip swelling. Tip swelling is probably caused by disruption of the microtubules in the tip that are perpendicular to the direction of elongation. Confocal microscopy indicates that colchicine and propyzamide cause fragmentation of microtubules throughout the tube. Oryzalin and amiprophosmethyl cause a complete loss of microtubules from the tip back toward the tube midpoint but leave microtubules intact from the midpoint back to the grain. Disruption of microfilaments by cytochalasins B and D and inhibition of myosin by N-ethylmaleimide or 2,3-butanedione monoxime stops tube growth and inhibits germination. Microfilament disruption induces short branches in tubes, probably originating from defective microfilament organization behind the tip. In addition, confocal microscopy coupled with microinjection of fluorescein-labeled phalloidin into actively growing pollen tubes indicates that microfllament bundles extend into the plastid-free zone at the tip but are specifically excluded from the growing tip. We conclude that microtubules and microfilaments coordinate to drive tip extension in conifer pollen tubes in a model that differs from angiosperms.

  • 12.
    Andersson, Jenny
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Dissecting the photosystem II light-harvesting antenna2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In photosynthesis, sunlight is converted into chemical energy that is stored mainly as carbohydrates and supplies basically all life on Earth with energy.

    In order to efficiently absorb the light energy, plants have developed the outer light harvesting antenna, which is composed of ten different protein subunits (LHC) that bind chlorophyll a and b as well as different carotenoids. In addition to the light harvesting function, the antenna has the capacity to dissipate excess energy as heat (feedback de-excitation or qE), which is crucial to avoid oxidative damage under conditions of high excitation pressure. Another regulatory function in the antenna is the state transitions in which the distribution of the trimeric LHC II between photosystem I (PS I) and II is controlled. The same ten antenna proteins are conserved in all higher plants and based on evolutionary arguments this has led to the suggestion that each protein has a specific function.

    I have investigated the functions of individual antenna proteins of PS II (Lhcb proteins) by antisense inhibition in the model plant Arabidopsis thaliana. Four antisense lines were obtained, in which the target proteins were reduced, in some cases beyond detection level, in other cases small amounts remained.

    The results show that CP29 has a unique function as organising the antenna. CP26 can form trimers that substitute for Lhcb1 and Lhcb2 in the antenna structure, but the trimers that accumulate as a response to the lack of Lhcb1 and Lhcb2 cannot take over the LHC II function in state transitions. It has been argued that LHC II is essential for grana stacking, but antisense plants without Lhcb1 and Lhcb2 do form grana. Furthermore, LHC II is necessary to maintain growth rates in very low light.

    Numerous biochemical evidences have suggested that CP29 and/or CP26 were crucial for feedback de-excitation. Analysis of two antisense lines each lacking one of these proteins clearly shows that there is no direct involvement of either CP29 or CP26 in this process. Investigation of the other antisense lines shows that no Lhcb protein is indispensable for qE. A model for feedback de-excitation is presented in which PsbS plays a major role.

    The positions of the minor antenna proteins in the PS II supercomplex were established by comparisons of transmission electron micrographs of supercomplexes from the wild type and antisense plants.

    A fitness experiment was conducted where the antisense plants were grown in the field and seed production was used to estimate the fitness of the different genotypes. Based on the results from this experiment it is concluded that each Lhcb protein is important, because all antisense lines show reduced fitness in the field.

  • 13.
    Andersson, Petter
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    What shapes local density?: The importance of migration rates and local growth for density-patch size relationships in two Cionus weevils2012In: Ecological Entomology, ISSN 0307-6946, E-ISSN 1365-2311, Vol. 37, no 1, 90-98 p.Article in journal (Refereed)
    Abstract [en]

    1. The relative effect of migration and local growth on the spatio-temporal density-distribution of two co-existing herbivorous weevils, Cionus scrophulariae L. and C. tuberculosus Scop., in 32 host plant Scrophularia nodosa L. patches of varying sizes was investigated. 2. Predictions of the temporal development of the slope in the density-patch size relationships were derived from a basic population model with scale-dependent migration rates. The model indicated that the slopes in the density-patch size relationships during the early season should be reflected by the net scaling of immigration and emigration rates, whereas the slopes during the later season should increase as a result of local growth. 3. Emigration rates of the weevils were estimated in a field experiment, were the weevils coexisted in space and time. These results were then combined with a previous estimate of immigration rates in order to determine the net scaling of migration rates. 4. The emigration rate differed between species, caused by different movement rates in small patches, which could explain differences in the general slope of the density-patch size relationships of the weevils in the natural figwort patches throughout the summer. The slopes in the relationships in the early season were largely predicted by the net scaling of migration rates. The slope also increased in the later season for C. tuberculosus, whereas the slope decreased for C. scrophulariae. 5. It was concluded that the understanding of both inter- and intra-specific variations in density-patch size relationships of insect herbivores can be improved using population models incorporating scale-dependent migration and local growth.

  • 14.
    Andersson-Gunnerås, Sara
    et al.
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå.
    Hellgren, Jenny M
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå.
    Björklund, Simon
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå.
    Regan, Sharon
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå.
    Moritz, Thomas
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå.
    Sundberg, Björn
    Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå.
    Asymmetric expression of a poplar ACC oxidase controls ethylene production during gravitational induction of tension wood2003In: The Plant Journal, ISSN 0960-7412, E-ISSN 1365-313X, Vol. 34, no 3, 339-349 p.Article in journal (Refereed)
    Abstract [en]

    Ethylene is produced in wood-forming tissues, and when applied exogenously, it has been shown to cause profound effects on the pattern and rate of wood development. However, the molecular regulation of ethylene biosynthesis during wood formation is poorly understood. We have characterised an abundant 1-aminocyclopropane-1-carboxylic acid (ACC) oxidase gene (PttACO1) in the wood-forming tissues of Populus tremula (L.) × P. tremuloides (Michx). PttACO1 is primarily expressed in developing secondary xylem, and is specifically upregulated during secondary wall formation. Nevertheless, according to GC–MS analysis combined with tangential cryosectioning, the distribution of ACC was found to be fairly uniform across the cambial-region tissues. Gravitational stimulation, which causes tension wood to form on the upper side of the stem, resulted in a strong induction of PttACO1 expression and ACC oxidase activity in the tension wood-forming tissues. The ACC levels increased in parallel to the PttACO1 expression. However, the increase on the upper (tension wood) side was only minor, whereas large amounts of both ACC and its hydrolysable conjugates accumulated on the lower (opposite) side of the stem. This suggests that the relatively low level of ACC on the tension wood side is a result of its conversion to ethylene by the highly upregulated PttACO1, and the concurrent accumulation of ACC on the opposite side of the wood is because of the low PttACO1 levels. We conclude that PttACO1 and ACC oxidase activity, but not ACC availability, are important in the control of the asymmetric ethylene production within the poplar stem when tension wood is induced by gravitational stimulation.

  • 15. Andriamihajarivo, Tefy H.
    et al.
    Razafimandimbison, Sylvain G.
    Stockholm University, Faculty of Science, Department of Botany.
    Karehed, Jesper
    Phyllopentas flava (Rubiaceae), a New Morphologically Heterodistylous and Functionally Dioecious Species from Madagascar2011In: Systematic Botany, ISSN 0363-6445, E-ISSN 1548-2324, Vol. 36, no 4, 1024-1027 p.Article in journal (Refereed)
    Abstract [en]

    A new species of the Afro-Malagasy genus Phyllopentas Karehed & B. Bremer, Phyllopentas flava Razafim., T. Andriam. et Karehed, is described and illustrated. This plant is restricted to the Itremo region in southeastern Madagascar and is distinct morphologically from the other species of the genus by its pubescent, narrowly ovate to narrowly elliptic leaves, grey-whitish and thickly hairy midribs and secondary veins on the lower surfaces of leaves, and functionally dioecious and heterodistylous flowers. Summaries of distribution, phenology, habitat, and ecology are given and a conservation assessment is also provided.

  • 16. Andriamihajarivo, Tefy H.
    et al.
    Razafimandimbison, Sylvain G.
    Kårehed, Jesper
    Uppsala University, Music and Museums, The Linnean Gardens of Uppsala.
    Phyllopentas flava (Rubiaceae), a New Morphologically Heterodistylous and Functionally Dioecious Species from Madagascar2011In: Systematic Botany, ISSN 0363-6445, E-ISSN 1548-2324, Vol. 36, no 4, 1024-1027 p.Article in journal (Refereed)
    Abstract [en]

    A new species of the Afro-Malagasy genus Phyllopentas Karehed & B. Bremer, Phyllopentas flava Razafim., T. Andriam. et Karehed, is described and illustrated. This plant is restricted to the Itremo region in southeastern Madagascar and is distinct morphologically from the other species of the genus by its pubescent, narrowly ovate to narrowly elliptic leaves, grey-whitish and thickly hairy midribs and secondary veins on the lower surfaces of leaves, and functionally dioecious and heterodistylous flowers. Summaries of distribution, phenology, habitat, and ecology are given and a conservation assessment is also provided.

  • 17.
    Anfält, Tomas
    et al.
    Uppsala University, University Library.
    Nilsson, Örjan
    Uppsala University, Disciplinary Domain of Science and Technology.
    Little book of flowers: a bouquet from Rudbeck’s botanical project2000Book (Other academic)
  • 18.
    Anfält, Tomas
    et al.
    Uppsala University, University Library.
    Nilsson, Örjan
    Uppsala University, Disciplinary Domain of Science and Technology.
    Lilla blomboken: en bukett ur Rudbeckarnas botaniska projekt1999Book (Other academic)
  • 19.
    Angelcheva, Liudmila
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Mishra, Yogesh
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Antti, Henrik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kjellsen, Trygve D.
    Department of Biology, Norwegian University of Science and Technology.
    Funk, Christiane
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Strimbeck, Richard G.
    Department of Biology, Norwegian University of Science and Technology.
    Schröder, Wolfgang P.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Metabolomic analysis of extreme freezing tolerance in Siberian spruce (Picea obovata)2014In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 204, no 3, 545-555 p.Article in journal (Refereed)
    Abstract [en]

    Siberian spruce (Picea obovata) is one of several boreal conifer species that can survive at extremely low temperatures (ELTs). When fully acclimated, its tissues can survive immersion in liquid nitrogen. Relatively little is known about the biochemical and biophysical strategies of ELT survival. We profiled needle metabolites using gas chromatography coupled with mass spectrometry (GC-MS) to explore the metabolic changes that occur during cold acclimation caused by natural temperature fluctuations. In total, 223 metabolites accumulated and 52 were depleted in fully acclimated needles compared with pre-acclimation needles. The metabolite profiles were found to develop in four distinct phases, which are referred to as pre-acclimation, early acclimation, late acclimation and fully acclimated. Metabolite changes associated with carbohydrate and lipid metabolism were observed, including changes associated with increased raffinose family oligosaccharide synthesis and accumulation, accumulation of sugar acids and sugar alcohols, desaturation of fatty acids, and accumulation of digalactosylglycerol. We also observed the accumulation of protein and nonprotein amino acids and polyamines that may act as compatible solutes or cryoprotectants. These results provide new insight into the mechanisms of freezing tolerance development at the metabolite level and highlight their importance in rapid acclimation to ELT in P.obovata.

  • 20. Appelhans, M. S.
    et al.
    Smets, E.
    Razafimandimbison, Sylvain G.
    Stockholm University, Faculty of Science, Department of Botany.
    Haevermans, T.
    van Marle, E. J.
    Couloux, A.
    Rabarison, H.
    Randrianarivelojosia, M.
    Kessler, P. J. A.
    Phylogeny, evolutionary trends and classification of the Spathelia-Ptaeroxylon clade: morphological and molecular insights2011In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 107, no 8, 1259-1277 p.Article in journal (Refereed)
    Abstract [en]

    Background and Aims The Spathelia-Ptaeroxylon clade is a group of morphologically diverse plants that have been classified together as a result of molecular phylogenetic studies. The clade is currently included in Rutaceae and recognized at a subfamilial level (Spathelioideae) despite the fact that most of its genera have traditionally been associated with other families and that there are no obvious morphological synapomorphies for the clade. The aim of the present study is to construct phylogenetic trees for the Spathelia-Ptaeroxylon clade and to investigate anatomical characters in order to decide whether it should be kept in Rutaceae or recognized at the familial level. Anatomical characters were plotted on a cladogram to help explain character evolution within the group. Moreover, phylogenetic relationships and generic limits within the clade are also addressed. Methods A species-level phylogenetic analysis of the Spathelia-Ptaeroxylon clade based on five plastid DNA regions (rbcL, atpB, trnL-trnF, rps16 and psbA-trnH) was conducted using Bayesian, maximum parsimony and maximum likelihood methods. Leaf and seed anatomical characters of all genera were (re) investigated by light and scanning electron microscopy. Key Results With the exception of Spathelia, all genera of the Spathelila-Ptaeroxylon clade are monophyletic. The typical leaf and seed anatomical characters of Rutaceae were found. Further, the presence of oil cells in the leaves provides a possible synapomorphy for the clade. Conclusions The Spathelia-Ptaeroxylon clade is well placed in Rutaceae and it is reasonable to unite the genera into one subfamily (Spathelioideae). We propose a new tribal classification of Spathelioideae. A narrow circumscription of Spathelia is established to make the genus monophyletic, and Sohnreyia is resurrected to accommodate the South American species of Spathelia. The most recent common ancestor of Spathelioideae probably had leaves with secretory cavities and oil cells, haplostemonous flowers with appendaged staminal filaments, and a tracheidal tegmen.

  • 21. Armbruster, W. S.
    Pélabon, C
    Pérez-Barrales, R.
    Maad, Johanne
    Department of Biology, NTNU, NO-7491, Trondheim, Norway.
    The adaptive accuracy of flowers: Measurement and microevolutionary patterns2009In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 103, no 9, 1529-1545 p.Article in journal (Refereed)
  • 22. Arnqvist, L
    et al.
    Dutta, P C
    Jonsson, Lisbeth
    Södertörn University, Avdelning Naturvetenskap.
    Sitbon, F
    Reduction of cholesterol and glycoalkaloid levels in transgenic potato plants by overexpression of a type 1 sterol methyltransferase cDNA2003In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 131, no 4, 1792-1799 p.Article in journal (Refereed)
    Abstract [en]

    Transgenic potato (Solanum tuberosum cv Desiree) plants overexpressing a soybean (Glycine max) type 1 sterol methyltransferase (GmSMT1) cDNA were generated and used to study sterol biosynthesis in relation to the production of toxic glycoalkaloids. Transgenic plants displayed an increased total sterol level in both leaves and tubers, mainly due to increased levels of the 24-ethyl sterols isofucosterol and sitosterol. The higher total sterol level was due to increases in both free and esterified sterols. However, the level of free cholesterol, a nonalkylated sterol, was decreased. Associated with this was a decreased glycoalkaloid level in leaves and tubers, down to 41% and 63% of wild-type levels, respectively. The results show that glycoalkaloid biosynthesis can be down-regulated in transgenic potato plants by reducing the content of free nonalkylated sterols, and they support the view of cholesterol as a precursor in glycoalkaloid biosynthesis.

  • 23. Aronsson, Mora
    et al.
    Black-Samuelsson, Sanna
    Edqvist, Margareta
    Persson, Erik
    Nordiskt Genresurscenter (NordGen) och SLU.
    Ståhlberg, David
    Weibull, Jens
    Kulturväxtsläktingar: något att bry sig om2012In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 106, 309-318 p.Article in journal (Refereed)
  • 24.
    Ashelford, Kevin
    et al.
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Eriksson, Maria E
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Allen, Christopher M
    Applied Biosystems, part of Life Technologies, Warrington, UK.
    D’Amore, Linda
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Johansson, Mikael
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Gould, Peter
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Kay, Susanne
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Millar, Andrew J.
    Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
    Hall, Neil
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Hall, Anthony
    School of Biological Sciences, University of Liverpool, Liverpool, UK.
    Full genome re-sequencing reveals a novel circadian clock mutationin Arabidopsis2011In: Genome Biology, ISSN 1465-6906, E-ISSN 1465-6914, Vol. 12, R28- p.Article in journal (Refereed)
    Abstract [en]

    Background: Map based cloning in Arabidopsis thaliana can be a difficult and time-consuming process,specifically if the phenotype is subtle and scoring labour intensive. An alternative to map basedcloning would be to directly sequence the whole genome of a mutant to uncover the mutationresponsible for the phenotype.

    Results: Here, we have re-sequenced the 120 Mb genome of a novel Arabidopsis clock mutant earlybird (ebi-1), using massively parallel sequencing by ligation. This process was further complicated by the fact that ebi-1 is in Wassilewskija (Ws-2), not the reference accession ofArabidopsis. The approach reveals evidence of DNA strand bias in the ethyl methanesulfonate(EMS) mutation process. We have demonstrated the utility of sequencing a backcrossed line andusing gene expression data to limit the number of SNP considered. Using new SNP informationwe have excluded a previously identified clock gene, PRR7. Finally, we have identified a SNPin the gene AtNFXL-2 as the likely cause of the ebi-1 phenotype and validated this bycharacterising a further allele.

    Conclusion: In Arabidopsis, as in other organisms, the (EMS) mutation load can be high. Here wedescribe how sequencing a backcrossed line, using functional genomics and analysing new SNPinformation can be used to reduce the number EMS mutations for consideration. Moreover, theapproach we describe here does not require out-crossing and scoring F2 mapping populations, anapproach which can be compromised by background effects. The strategy has broad utility andwill be an extremely useful tool to identify causative SNP in other organisms.

  • 25.
    Asplund-Samuelsson, Johannes
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Birgitta
    Stockholm University, Faculty of Science, Department of Botany.
    Larsson, John
    Stockholm University, Faculty of Science, Department of Botany.
    Prokaryotic Caspase Homologs: Phylogenetic Patterns and Functional Characteristics Reveal Considerable Diversity2012In: PLoS ONE, ISSN 1932-6203, Vol. 7, no 11, e49888- p.Article in journal (Refereed)
    Abstract [en]

    Caspases accomplish initiation and execution of apoptosis, a programmed cell death process specific to metazoans. The existence of prokaryotic caspase homologs, termed metacaspases, has been known for slightly more than a decade. Despite their potential connection to the evolution of programmed cell death in eukaryotes, the phylogenetic distribution and functions of these prokaryotic metacaspase sequences are largely uncharted, while a few experiments imply involvement in programmed cell death. Aiming at providing a more detailed picture of prokaryotic caspase homologs, we applied a computational approach based on Hidden Markov Model search profiles to identify and functionally characterize putative metacaspases in bacterial and archaeal genomes. Out of the total of 1463 analyzed genomes, merely 267 (18%) were identified to contain putative metacaspases, but their taxonomic distribution included most prokaryotic phyla and a few archaea (Euryarchaeota). Metacaspases were particularly abundant in Alphaproteobacteria, Deltaproteobacteria and Cyanobacteria, which harbor many morphologically and developmentally complex organisms, and a distinct correlation was found between abundance and phenotypic complexity in Cyanobacteria. Notably, Bacillus subtilis and Escherichia coli, known to undergo genetically regulated autolysis, lacked metacaspases. Pfam domain architecture analysis combined with operon identification revealed rich and varied configurations among the metacaspase sequences. These imply roles in programmed cell death, but also e.g. in signaling, various enzymatic activities and protein modification. Together our data show a wide and scattered distribution of caspase homologs in prokaryotes with structurally and functionally diverse subgroups, and with a potentially intriguing evolutionary role. These features will help delineate future characterizations of death pathways in prokaryotes.

  • 26.
    Auffret, Alistair G.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Can seed dispersal by human activity play a useful role for the conservation of European grasslands?2011In: Applied Vegetation Science, ISSN 1402-2001, E-ISSN 1654-109X, Vol. 14, no 3, 291-303 p.Article in journal (Refereed)
    Abstract [en]

    Objective: To review the recent research into human-mediated dispersal (HMD) in the European rural landscape, and explore the potential positive aspect of HMD for grassland conservation, in contrast to it's common association with the spread of invasive species. Methods: A literature search was undertaken to identify HMD vectors in the rural landscape for discussion regarding dispersal potential past and present, implications for management, and the identification of future research needs. Results: Grazing animals are important propagule dispersers, but the reduced movement of livestock through the landscape has also meant a reduction in seeds dispersed in this way. Other, non-standard human-mediated dispersal vectors such as clothing and motor vehicles can also transport seeds of many species, and HMD vectors often transport seeds with a variety of dispersal specialisations. Recommendations: There should be a greater movement of grazing animals throughout the landscape, either within larger grazing areas or between existing grasslands. Where this is not possible, other, more directed dispersal of propagules from species-rich communities to target sites should be considered. The potential of non-standard HMD vectors to make a positive contribution to biodiversity should be considered, but more research into all types of HMD vectors is important if we are to fully understand their role in the dispersal of plant species in fragmented landscapes.

  • 27.
    Augusti, Angela
    Umeå University, Faculty of Science and Technology, Plant Physiology.
    Monitoring climate and plant physiology using deuterium isotopomers of carbohydrates2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Climate is changing and it is certain that this change is due to human activities. Atmospheric greenhouse gases have been rising in an unprecedented way during the last two centuries, although the land biosphere has dampened their increase by absorbing CO2 emitted by anthropogenic activities. However, it is unclear if this will continue in the future. This uncertainty makes it difficult to predict future climate changes and to determine how much greenhouse gas emissions must be reduced to protect climate.

    To understand the future role of plants in limiting the atmospheric CO2 level, the effect of increasing CO2 on plant photosynthesis and productivity has been studied. However, studies on trees showed contradictory results, which depended on the duration of the experiment. This revealed that an initial strong CO2 fertilization may be a transient response that disappears after a few years. Because climate changes over centuries, we must explore the response of vegetation to increasing CO2 on this time scale. Studying tree rings is a good alternative to impractical decade-long experiments, because trees have experienced the CO2 increase during the last 200 years and may already have responded to it.

    This thesis shows that the intramolecular distribution of the stable hydrogen isotope deuterium (deuterium isotopomer distribution, DID) of tree rings is a reliable tool to study long-term plant-climate adaptations. The premise for this is that the deuterium abundance in tree rings depends on environmental as well as physiological factors. Using newly developed methodology for DID measurements, the influences of both factors can be separated. Applied to tree rings, separating both factors opens a strategy for simultaneous reconstruction of climate and of physiological responses.

    The results presented show that DIDs are influenced by kinetic isotope effects of enzymes, allowing studies of metabolic regulation. We show that the abundances of specific D isotopomers in tree-ring cellulose indeed allow identifying environmental and physiological factors. For example, the D2 isotopomer is mostly influenced by environment, its abundance should allow better reconstruction of past temperature. On the other hand, the abundance ratio of two isotopomers (D6R and D6S) depends on atmospheric CO2, and might serve as a measure of the efficiency of photosynthesis (ratio of photorespiration to assimilation). The presence of this dependence in all species tested and in tree-ring cellulose allows studying adaptations of plants to increasing CO2 on long time scales, using tree-ring series or other remnant plant material.

  • 28.
    Backlund, Anders
    et al.
    Uppsala University.
    Bremer, Birgitta
    Uppsala University.
    Phylogeny of the Asteridae s. str. based on rbcL sequences, with particular reference to the Dipsacales1997In: Plant Systematics and Evolution, ISSN 0378-2697, E-ISSN 1615-6110, Vol. 207, no 3-4, 225-254 p.Article in journal (Refereed)
    Abstract [en]

    The rbcL gene of 15 taxa was sequenced and analyzed cladistically together with a large sample of genera representing all main clades of the subclass Asteridae in order to determine more precisely the delimitation of the order Dipsacales and to elucidate

  • 29.
    Backlund, Anders
    et al.
    Uppsala University.
    Bremer, Kåre
    Uppsala University.
    To be or not to be - principles of classification and monotypic plant families1998In: Taxon, ISSN 0040-0262, Vol. 47, no 2, 391-400 p.Article in journal (Refereed)
  • 30.
    Backlund, Anders
    et al.
    Uppsala University.
    Moritz, Thomas
    Uppsala University.
    Phylogenetic implications of an expanded valepotriate distribution in the Valerianaceae1998In: Biochemical Systematics and Ecology, ISSN 0305-1978, E-ISSN 1873-2925, Vol. 26, no 3, 309-335 p.Article in journal (Refereed)
    Abstract [en]

    A total of 27 taxa from the families Adoxaceae s.lat. (including Viburnaceae and Sambucaceae), Araliaceae, Caprifoliaceae, Dipsacaceae and Valerianaceae (including Triplostegia) have been analysed using thin-layer chromatography (TLC) and combined high pe

  • 31.
    Backlund, Anders
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Evolution, Genomics and Systematics, Systematic Botany.
    Nilsson, Siwert
    Naturhistoriska Riksmuséet.
    Pollen morphology and the systematic position of Triplostegia (Dipsacales)1997In: Taxon, ISSN 0040-0262, Vol. 46, no 1, 21-31 p.Article in journal (Refereed)
    Abstract [en]

    Triplostegia comprises two species of perennial herbs from southeast Asia, T. glandulifera and T. grandiflora. The systematic position of the genus has been debated ever since it was described, and it has been placed in either Dipsacaceae or Valerianaceae, or in a family of its own Triplo-stegiaceae. Pollen of Triplostegia, investigated by light microscopy and scanning electron micro-scopy, is similar to that of both Dipsacaceae and Valerianaceae. Presence of numerous branched and bent columellae as well as an aperturem argins tructurer esemblingt he halo found in Valeria-naceae indicates a closer relationship to the Valerianaceae. A sister-group relationship between Triplostegia and the Valerianaceae is furthermore supported by other studies of molecular and morphological data. In order to maximize information content in the framework of mandatory classificational ranks, Triplostegia is best included in the family Valerianaceae, as the sole mem-ber of a subfamily Triplostegioideae.

  • 32.
    Backlund, Anders
    et al.
    Uppsala University.
    Pyck, Nancy
    Catholic University, Leuven.
    Diervillaceae and Linnaeaceae, two new families of caprifolioids1998In: Taxon, ISSN 0040-0262, Vol. 47, no 3, 657-661 p.Article in journal (Refereed)
    Abstract [en]

    Two new families of caprifolioids, Diervillaceae and Linnaeaceae, are proposed. They correspond to the former subfamilies Diervilloideae and Linnaeoideae. A key to their genera and those remaining in Caprifoliaceae is provided.

  • 33.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Bog vegetation re-Mapped after sixty years: Studies on Skagershultamossen, central Sweden1972In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 23, no 3, 384-393 p.Article in journal (Refereed)
    Abstract [en]

    The author has re-mapped two areas on Skagershultamossen. The new maps have been compared with maps of the same areas from 1910, made by L. von Post. The vegetation changes are small. The open water surfaces have diminished in number and extent. The theory of cyclic succession on peat bogs finds no support from the maps. Plant communities have been delimited as to correspond to those on the old maps and defined through analysis of a number of sample plots

  • 34.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Gunnar Björkman och hans expedition till Lule lappmark 1924: Gunnar Björkman’s expedition to Swedish Lapland in 19242013In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 107, no 6, 354-358 p.Article in journal (Other academic)
    Abstract [en]

    Drawings by Torsten Höjer from Gunnar Björkman's botanical expedition to Swedish Lapland in 1924 are presented with some biographical notes on Björkman. The paleontologist  Birger Bohlin also participated.

  • 35.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Mossflora över Sankta Helena2013In: Myrinia, ISSN 1102-4194, Vol. 23, 84-87 p.Article in journal (Other academic)
    Abstract [en]

    A new bryophyte flora of St. Helena in the South Atlantic is presented. Of the known 110 species, 26 are (as presently known) endemic.

  • 36.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Hedlav, Cornicularia aculeata på mossar1983In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 77, 27-28 p.Article in journal (Refereed)
  • 37.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecological Botany.
    Milstolpe i västmanländsk botanik1982In: BergslagspostenArticle, book review (Other (popular science, discussion, etc.))
  • 38.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Swedish Biodiversity Centre. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Sankta Helena: en hotad endemisk flora. 1. Den ursprungliga floran och vegetationen och den historiska utvecklingen2014In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 108, no 3-4, 206-218 p.Article in journal (Other academic)
    Abstract [en]

    An overview of the endemic flora and the original vegetation of Saint Helena is given.

  • 39.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Swedish Biodiversity Centre. Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Sankta Helena: en hotad endemisk flora. 2. situationen i dag2014In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 108, no 5, 232-244 p.Article in journal (Refereed)
    Abstract [en]

    The present-day situation for the endemic flora of Saint Helena is described.

  • 40.
    Backéus, Ingvar
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Plant Ecology and Evolution.
    Ett etnobotaniskt livsverk2015In: Svensk Botanisk Tidskrift, ISSN 0039-646X, Vol. 109, no 6, 346-347 p.Article in journal (Refereed)
    Abstract [sv]

    Vagn J. Brøndegaard skrev mer än 1600 artiklar om allt som hade med relationen mellan växter och människor att göra. Många av dessa har nu ställts samman i två vackra volymer.

  • 41. Baena-González, Elena
    et al.
    Hanson, Johannes
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Shaping plant development through the SnRK1–TOR metabolic regulators2017In: Current opinion in plant biology, ISSN 1369-5266, E-ISSN 1879-0356, Vol. 35, 152-157 p.Article in journal (Refereed)
    Abstract [en]

    SnRK1 (Snf1-related protein kinase 1) and TOR (target of rapamycin) are evolutionarily conserved protein kinases that lie at the heart of energy sensing, playing central and antagonistic roles in the regulation of metabolism and gene expression. Increasing evidence links these metabolic regulators to numerous aspects of plant development, from germination to flowering and senescence. This prompts the hypothesis that SnRK1 and TOR modify developmental programs according to the metabolic status to adjust plant growth to a specific environment. The aim of this review is to provide support to this hypothesis and to incentivize further studies on this topic by summarizing the work that establishes a genetic connection between SnRK1-TOR and plant development.

  • 42.
    Bai, Bing
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Peviani, Alessia
    van der Horst, Sjors
    Gamm, Magdalena
    Snel, Berend
    Bentsink, Leónie
    Hanson, Johannes
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Extensive translational regulation during seed germination revealed by polysomal profiling.2017In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 214, no 1Article in journal (Refereed)
    Abstract [en]

    This work investigates the extent of translational regulation during seed germination. The polysome occupancy of each gene is determined by genome-wide profiling of total mRNA and polysome-associated mRNA. This reveals extensive translational regulation during Arabidopsis thaliana seed germination. The polysome occupancy of thousands of individual mRNAs changes to a large extent during the germination process. Intriguingly, these changes are restricted to two temporal phases (shifts) during germination, seed hydration and germination. Sequence features, such as upstream open reading frame number, transcript length, mRNA stability, secondary structures, and the presence and location of specific motifs correlated with this translational regulation. These features differed significantly between the two shifts, indicating that independent mechanisms regulate translation during seed germination. This study reveals substantial translational dynamics during seed germination and identifies development-dependent sequence features and cis elements that correlate with the translation control, uncovering a novel and important layer of gene regulation during seed germination.

  • 43.
    Bandau, Franziska
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Decker, Vicki Huizu Guo
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Gundale, Michael J.
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE 90183 Umeå, Sweden.
    Albrectsen, Benedicte Riber
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK 1871 Frederiksberg C, Denmark.
    Genotypic tannin levels in Populus tremula impact the way nitrogen enrichment affects growth and allocation responses for some traits and not for others2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 10, e0140971Article in journal (Refereed)
    Abstract [en]

    Plant intraspecific variability has been proposed as a key mechanism by which plants adapt to environmental change. In boreal forests where nitrogen availability is strongly limited, nitrogen addition happens indirectly through atmospheric N deposition and directly through industrial forest fertilization. These anthropogenic inputs of N have numerous environmental consequences, including shifts in plant species composition and reductions in plant species diversity. However, we know less about how genetic differences within plant populations determine how species respond to eutrophication in boreal forests. According to plant defense theories, nitrogen addition will cause plants to shift carbon allocation more towards growth and less to chemical defense, potentially enhancing vulnerability to antagonists. Aspens are keystone species in boreal forests that produce condensed tannins to serve as chemical defense. We conducted an experiment using ten Populus tremula genotypes from the Swedish Aspen Collection that express extreme levels of baseline investment into foliar condensed tannins. We investigated whether investment into growth and phenolic defense compounds in young plants varied in response to two nitrogen addition levels, corresponding to atmospheric N deposition and industrial forest fertilization. Nitrogen addition generally caused growth to increase, and tannin levels to decrease; however, individualistic responses among genotypes were found for height growth, biomass of specific tissues, root: shoot ratios, and tissue lignin and N concentrations. A genotype's baseline ability to produce and store condensed tannins also influenced plant responses to N, although this effect was relatively minor. High-tannin genotypes tended to grow less biomass under low nitrogen levels and more at the highest fertilization level. Thus, the ability in aspen to produce foliar tannins is likely associated with a steeper reaction norm of growth responses, which suggests a higher plasticity to nitrogen addition, and potentially an advantage when adapting to higher concentrations of soil nitrogen.

  • 44.
    Barros, Jaime
    et al.
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Serk, Henrik
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Granlund, Irene
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Pesquet, Edouard
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology. Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    The cell biology of lignification in higher plants2015In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 115, no 7, 1053-1074 p.Article, review/survey (Refereed)
    Abstract [en]

    Background Lignin is a polyphenolic polymer that strengthens and waterproofs the cell wall of specialized plant cell types. Lignification is part of the normal differentiation programme and functioning of specific cell types, but can also be triggered as a response to various biotic and abiotic stresses in cells that would not otherwise be lignifying.

    Scope Cell wall lignification exhibits specific characteristics depending on the cell type being considered. These characteristics include the timing of lignification during cell differentiation, the palette of associated enzymes and substrates, the sub-cellular deposition sites, the monomeric composition and the cellular autonomy for lignin monomer production. This review provides an overview of the current understanding of lignin biosynthesis and polymerization at the cell biology level.

    Conclusions The lignification process ranges from full autonomy to complete co-operation depending on the cell type. The different roles of lignin for the function of each specific plant cell type are clearly illustrated by the multiple phenotypic defects exhibited by knock-out mutants in lignin synthesis, which may explain why no general mechanism for lignification has yet been defined. The range of phenotypic effects observed include altered xylem sap transport, loss of mechanical support, reduced seed protection and dispersion, and/or increased pest and disease susceptibility.

  • 45.
    Bauer, Karolina
    Stockholm University, Faculty of Science, Department of Botany.
    Diazotrophy and diversity of benthic cyanobacteria in tropical coastal zones2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Discoveries in recent years have disclosed the importance of marine cyano-bacteria in the context of primary production and global nitrogen cycling. It is hypothesized here that microbial mats in tropical coastal habitats harbour a rich diversity of previously uncharacterized cyanobacteria and that benthic marine nitrogen fixation in coastal zones is substantial.

    A polyphasic approach was used to investigate cyanobacterial diversity in three tropical benthic marine habitats of different characters; an intertidal sand flat and a mangrove forest floor in the Indian Ocean, and a beach rock in the Pacific Ocean. In addition, nitrogenase activity was measured over diel cycles at all sites. The results revealed high cyanobacterial diversity, both morphologically and genetically. Substantial nitrogenase activity was observed, with highest rates at daytime where heterocystous species were present. However, the three habitats were dominated by non-heterocystous and unicellular genera such as Microcoleus, Lyngbya, Cyanothece and a large group of thin filamentous species, identified as members of the Pseudanabaenaceae family. In these consortia nocturnal nitrogenase activities were highest and nifH sequencing also revealed presence of non-cyanobacterial potential diazotrophs. A conclusive phylogenetic analysis of partial nifH sequences from the three sites and sequences from geographi-cally distant microbial mats revealed new clusters of benthic potentially ni-trogen-fixing cyanobacteria. Further, the non-heterocystous cyanobacterium Lyngbya majuscula was subjected to a physiological characterization to gain insights into regulatory aspects of its nitrogen fixation. The data demon-strated that nitrogenase activity is restricted to darkness, which called upon a re-evaluation of its diazotrophic behaviour.

  • 46.
    Beekman, Madeleine
    et al.
    Univ Sydney, Sch Life & Environm Sci, Sydney, NSW 2006, Australia..
    Nieuwenhuis, Bart
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
    Ortiz-Barrientos, Daniel
    Univ Queensland, Sch Biol Sci, St Lucia, Qld, Australia..
    Evans, Jonathan P.
    Univ Western Australia, Sch Anim Biol, Ctr Evolutionary Biol, Nedlands, WA 6009, Australia..
    Sexual selection in hermaphrodites, sperm and broadcast spawners, plants and fungi2016In: Philosophical Transactions of the Royal Society of London. Biological Sciences, ISSN 0962-8436, E-ISSN 1471-2970, Vol. 371, no 1706, 20150541Article, review/survey (Refereed)
    Abstract [en]

    Darwin was the first to recognize that sexual selection is a strong evolutionary force. Exaggerated traits allow same-sex individuals to compete over access to mates and provide a mechanism by which mates are selected. It is relatively easy to appreciate how inter-and intrasexual selection work in organisms with the sensory capabilities to perceive physical or behavioural traits that signal mate quality or mate compatibility, and to assess the relative quality of competitors. It is therefore not surprising that most studies of sexual selection have focused on animals with separate sexes and obvious adaptations that function in the context of reproductive competition. Yet, many sexual organisms are both male and female at the same time, often lack sexual dimorphism and never come into direct contact at mating. How does sexual selection act in such species, and what can we learn from them? Here, we address these questions by exploring the potential for sexual selection in simultaneous hermaphrodites, sperm-and broadcast spawners, plants and fungi. Our reviewreveals a range of mechanisms of sexual selection, operating primarily after gametes have been released, which are common in many of these groups and also quite possibly in more familiar (internally fertilizing and sexually dimorphic) organisms. This article is part of the themed issue 'Weird sex: the underappreciated diversity of sexual reproduction'.

  • 47.
    Bekele, Yared
    University of Gävle, Faculty of Engineering and Sustainable Development, Department of Industrial Development, IT and Land Management.
    GIS Based Factor Identification for the Change in Occurrence of Genista pilosa: a Case Study in Southern Sweden2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study has the objective of identifying the possible environmental constraints that has role for the continuous loss of heathland plant Genista pilosa. The study has assessed different environmental settings where the plant occurs by way of overlaying analysis based on multiple spatial data sets. Thereafter empirical change detection analyses on the land use of the study area have been performed on the GIS environment by combining temporal based remotely sensed spatial data. The result was then analyzed using land use dynamicity model and the rates of change on each land use type are identified. Expansion of human activity, especially the spreading of agricultural land and urbanization, is found to be the most determinant factor for the dramatic loss of the plant. Finally serious attention for the protection of the plant is recommended by mentioning the possible problem that would occur due to a loss of biodiversity.

  • 48.
    Benedict, Catherine
    Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    Cold Acclimation: Dissecting the plant low temperature signaling pathway using functional genomics2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The physiological process of cold acclimation protects plants native to the temperate regions of the world from the deleterious effects of low and freezing temperatures. This is achieved by a series of transcriptional, regulatory, and metabolic changes that enable continued growth and survival. Within minutes of exposure to temperatures below ca. 10°C, a complex cascade of transcriptional events is initiated to accomplish these changes. The initial alarm phase favors the rapid induction of a library of stress proteins with protective functions (e.g. COR proteins). This is followed by a cold hardened phase, characterized by maximal freezing tolerance, which continues until either the stress is removed, or the plant's metabolic and/or developmental state can no longer support maximal resistance.

    We have studied some of the important transcription factors and transcriptional changes associated with the initial alarm and later hardened phases of cold acclimation in the herbaceous annual Arabidopsis thaliana and the woody perennial Populus spp. We confirmed the functionality of the CBF-mediated signaling cascade in Poplar overexpressing AtCBF1, but noted that regulon composition and endogenous poplar CBF ortholog induction appeared to be tissue-specific. The lack of statistically significant DRE enrichment in the Poplar AtCBF1 regulons led us to investige cis-element abundance in the cold-associated transcription factor regulons of publicly available microarray data from Arabidopsis, leading to the development of a gene voting method of microarray analysis that we used to test for regulatory associations between transcription factors and their downstream cis-elements and gene targets. This analysis resulted in a new transcriptional model of the ICE1-mediated signaling cascade and implicated a role for phytochrome A. Application of this same method to microarray data from arabidopsis leaves developed at low temperature allowed us to identify a new cis-element, called DDT, which possessed enhancer-blocking function during the alarm stage of cold stress, but was enriched in the promoters of genes upregulated during the later cold hardened stages. As leaf growth and development at low temperature correlated with the enhancement freeze tolerance in Arabidopsis, we compared the transcriptomes of rapidly growing and fully grown poplar leaves at night (when both low temperatures and PhyA status might play important roles in nature), in the hopes of comparing this data with that of cold-treated leaves in the future. We identified the nocturnal mode of leaf growth in Populus deltoides as predominantly proliferative as opposed to expansive, and potentially linked to cellular carbohydrate status.

  • 49.
    Benedict, Catherine
    et al.
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC).
    Skinner, J. S.
    Meng, R.
    Chang, Y.
    Bhalerao, R.
    Finn, C.
    Chen, T. H. H.
    Umeå University, Faculty of Science and Technology.
    Hurry, Vaughan
    Umeå University, Faculty of Science and Technology, Umeå Plant Science Centre (UPSC). Umeå University, Faculty of Science and Technology, Department of Plant Physiology.
    The Role of the CBF-dependent Signalling Pathway in Woody Perennials2006In: Cold Hardiness in Plants: Molecular Genetics, Cell Biology and Physiology / [ed] T Chen, M Uemura, S Fujikawa, Wallingford: CABI Publishing, 2006, 167-180 p.Chapter in book (Other academic)
  • 50.
    Bengtson, Annika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Systematics and biogeography of the South African Metalasia clade (Asteraceae-Gnaphalieae)2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Metalasia clade (Asteraceae–Gnaphalieae) consisting of the genera Metalasia, Atrichantha, Calotesta, Dolichothrix, Hydroidea, Lachnospermum, Phaenocoma, and Planea is endemic to South Africa with a main distribution within the Cape Floristic Region (CFR), a region known for its remarkable botanical diversity.

    The monophyly of the Metalasia clade, the relationships of its genera, and the circumscription of these as well as their position within the tribe Gnaphalieae is investigated using molecular data. The study confirms the Metalasia clade to be a monophyletic group, untangling the relationships between the included genera.

    Five new Metalasia species have been described since the latest revision of the genus, three of which are described in the present work. An updated key to all 57 species of the genus is also provided.

    A phylogenetic study of the genus Metalasia, including all 57 species, based on a combination of morphological and molecular data shows that Metalasia consists of two sister clades, Clade A and Clade B, morphologically separated by the papillose cypselas of Clade A. Metalasia is, however, not supported as monophyletic, and Lachnospermum is placed together with the Metalasia species of Clade B. Further, the monotypic Planea, originally described as Metalasia schlechteri, is placed well within Clade B.

    A biogeographical study reveals Metalasia to have evolved in the CFR around 6.9 Ma. Ancestral area estimations present a possible scenario for the radiation of Metalasia and show a difference between Clade A and B, correlated to the different rainfall regimes of southern Africa. The results show that Clade B began to diversify around 6.4 Ma in the winter rainfall area, whereas the diversification of the Clade A crown group, which is estimated to only 3.3 Ma, was initiated in the all-year rainfall area.

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