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  • 51. Björkman, Maria
    et al.
    Hopkins, Richard
    Hambäck, Peter
    Stockholm University, Faculty of Science, Department of Botany.
    Rämert, Birgitta
    Effects of plant competition and herbivore density on the development of the turnip root fly (Delia floralis) in an intercropping system2009In: Arthropod-plant interactions, ISSN 1872-8855, Vol. 3, p. 55-62Article in journal (Refereed)
    Abstract [en]

    In this study, interactive effects of plant competition and herbivory on plant quality and herbivore development were examined in a greenhouse experiment where cabbage plants [Brassica oleracea L. var. capitata (Brassicaceae)] were intercropped with red clover [Trifolium pratense L. (Fabaceae)]. Cabbages were grown with two red clover densities and attack rates by the root feeding herbivore the turnip root fly, Delia floralis Fall. (Diptera: Anthomyiidae). Above ground and below ground cabbage biomass was reduced through intercropping and larval damage. Intercropping also resulted in lower nitrogen and higher carbon root levels compared with levels in the roots of monocultured cabbage. Furthermore, both root nitrogen and carbon levels increased with herbivory. Root neutral detergent fibre (NDF) and lignin content increased in response to both increased plant competition and higher egg densities. For lignin, an interaction effect was observed in the form of elevated levels in intercropped plants subjected to larval damage, while levels in roots of monocultured cabbage remained unchanged. The quality changes brought about by clover competition affected D. floralis development negatively, which resulted in reduced pupal weight. In addition, increased egg density also decreased larval growth. The effects on the development of D. floralis in relation to host plant quality are discussed.

  • 52. Blackmore, Stephen
    et al.
    Wortley, Alexandra H.
    Skvarla, John J.
    Gabarayeva, Nina I.
    Rowley, John R.
    Stockholm University, Faculty of Science, Department of Botany.
    Developmental origins of structural diversity in pollen walls of Compositae2010In: Plant Systematics and Evolution, ISSN 0378-2697, E-ISSN 1615-6110, Vol. 284, no 02-jan, p. 17-32Article in journal (Refereed)
    Abstract [en]

    Compositae exhibit some of the most complex and diverse pollen grains in flowering plants. This paper reviews the evolutionary and developmental origins of this diversity in pollen structure using recent models based on the behaviour of colloids and formation of micelles in the differentiating microspore glycocalyx and primexine. The developmental model is consistent with observations of structures recovered by pollen wall dissolution. Pollen wall diversity in Compositae is inferred to result from small changes in the glycocalyx, for example ionic concentration, which trigger the self-assembly of highly diverse structures. Whilst the fine details of exine substructure are, therefore, not under direct genetic control, it is likely that genes establish differences in the glycocalyx which define the conditions for self-assembly. Because the processes described here for Compositae can account for some of the most complex exine structures known, it is likely that they also operate in pollen walls with much simpler organisation.

  • 53. Blackmore, Stephen
    et al.
    Wortley, Alexandra H
    Skvarla, John J
    Rowley, John R
    Stockholm University, Faculty of Science, Department of Botany.
    Pollen wall development in flowering plants.2007In: New Phytol, ISSN 0028-646X, Vol. 174, no 3, p. 483-98Article, review/survey (Other (popular science, discussion, etc.))
  • 54.
    Boalt, Elin
    Stockholm University, Faculty of Science, Department of Botany.
    Ecology and evolution of tolerance in two cruciferous species2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Tolerance to herbivory is the ability of plants to maintain fitness in spite of damage. The goal of this thesis is to investigate the genetic variation and expression of tolerance within species, determine whether and in what conditions tolerance has negative side-effects, and how tolerance is affected by different ecological factors. Tolerance is investigated with special focus on the effects of different damage types, competitive regimes, history of herbivory, and polyploidization in plants. Studies are conducted as a literature review and three experiments on two cruciferous species Raphanus raphanistrum and Cardamine pratensis.

    In the tolerance experiments, plants are subjected to artificial damage solely, or in a combination with natural damage. A literature review was conducted in order to investigate the effects of damage method. We found that traits related to tolerance, such as growth and fitness were not as sensitive in regard to damage method as measures of induced chemical traits, or measures of secondary herbivory.

    Genetic variation of tolerance was demonstrated within populations of R. raphanistrum and between subspecies of C. pratensis. In R. raphanistrum, traits involved in floral display and male fitness were positively associated with plant tolerance to herbivore damage. A potential cost of tolerance was demonstrated as a negative correlation between levels of tolerance in high and low competitive regimes. I found no evidence of other proposed costs of tolerance in terms of highly tolerant plants suffering of reduced fitness in the absence of herbivores or trade-offs in terms of a negative association between tolerance to apical and leaf damage, or between tolerance and competitive ability. In C. pratensis, higher ploidy level in plants involved higher levels of tolerance measured as clonal reproduction. Furthermore, populations exposed to higher levels of herbivory had better tolerance than populations exposed to lower levels of herbivory. In this thesis, I demonstrate evidence of different components for the evolution of tolerance in plants: genotypic variation, selective factors in terms of costs and ploidization, and selective agents in terms of changing environment or herbivore pressure.

  • 55. Boalt, Elin
    et al.
    Arvanitis, Leena
    Stockholm University, Faculty of Science, Department of Botany.
    Lehtila, Kari
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    The association among herbivory tolerance, ploidy level, and herbivory pressure in cardamine pratensis2010In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 24, no 5, p. 1101-1113Article in journal (Refereed)
    Abstract [en]

    We tested whether differences in ploidy level and previous exposure to herbivory can affect plant tolerance to herbivory. We conducted a common garden experiment with 12 populations of two ploidy levels of the perennial herb Cardamine pratensis (five populations of tetraploid ssp. pratensis and seven populations of octoploid ssp. paludosa). Earlier studies have shown that attack rates by the main herbivore, the orange tip butterfly Anthocharis cardamines, are lower in populations of octoploids than in populations of tetraploids, and vary among populations. In the common garden experiment, a combination of natural and artificial damage significantly reduced seed and flower production. We measured tolerance based on four plant-performance metrics: survival, growth, seed production and clonal reproduction. For three of these measurements, tolerance of damage did not differ between ploidy levels. For clonal reproduction, the octoploids had a higher tolerance than the tetraploids, although they experience lower herbivore attack rates in natural populations. Populations from sites with high levels of herbivory had higher tolerance, measured by seed production, than populations with low levels of herbivory. We did not detect any significant costs of tolerance. We conclude that high intensity of herbivory has selected for high tolerance measured by seed production in C. pratensis.

  • 56.
    Boalt, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Arvanitis, Leena
    Lehtilä, Kari
    Ehrlén, Johan
    Effects of ploidy level and herbivore pressure on tolerance to herbivory in Cardamine pratensis.Manuscript (Other academic)
  • 57.
    Boalt, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Lehtilä, Kari
    Tolerance to apical and foliar damage: costs and mechanisms in Raphanus raphanistrum.2007In: Oikos, Vol. 116, no 12, p. 2071-2081Article in journal (Refereed)
  • 58.
    Boalt, Elin
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Lehtilä, Kari
    Tolerance to apical and leaf damage of Raphanus raphanistrum in different competitive regimes.Manuscript (Other academic)
  • 59. Bolmgren, K.
    et al.
    Vanhoenacker, Didrik
    Stockholm University, Faculty of Science, Department of Botany. Swedish Natural History Museum.
    Miller-Rushing, A. J.
    One man, 73 years, and 25 species. Evaluating phenological responses using a lifelong study of first flowering dates2013In: International journal of biometeorology, ISSN 0020-7128, E-ISSN 1432-1254, Vol. 57, no 3, p. 367-375Article in journal (Refereed)
    Abstract [en]

    Phenological shifts linked to global warming reflect the ability of organisms to track changing climatic conditions. However, different organisms track global warming differently and there is an increasing interest in the link between phenological traits and plant abundance and distribution. Long-term data sets are often used to estimate phenological traits to climate change, but so far little has been done to evaluate the quality of these estimates. Here, we use a 73-year long data series of first flowering dates for 25 species from north-temperate Sweden to evaluate (i) correlations between first flowering dates and year for different time periods and (ii) linear regression models between first flowering date and mean monthly temperatures in preceding months. Furthermore, we evaluate the potential of this kind of data to estimate the phenological temperature sensitivities (i.e. number of days phenological change per degree temperature change, beta(60)) in such models. The sign of the correlations between first flowering dates and year were highly inconsistent among different time periods, highlighting that estimates of phenological change are sensitive to the specific time period used. The first flowering dates of all species were correlated with temperature, but with large differences in both the strength of the response and the period(s) of the year that were most strongly associated with phenological variation. Finally, our analyses indicated that legacy data sets need to be relatively long-term to be useful for estimating phenological temperature sensitivities (beta(60)) for inter-specific comparisons. In 10-year long observation series only one out of 24 species reached a parts per thousand yen80 % probability of estimating temperature sensitivity (beta(60)) within a +/- 1 range, and 17 out of 24 species reached a parts per thousand yen80 % probability when observation series were 20 years or shorter. The standard error for beta(60) ranged from 0.6 to 2.0 for 10-year long observation series, and 19 out of 24 species reached SE < 1 after 15 years. In general, late flowering species will require longer time series than early flowering species.

  • 60.
    Bolmgren, Kjell
    Stockholm University, Faculty of Science, Department of Botany.
    Adaptation and Constraint in the Plant Reproductive Phase2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Conservatism is a central theme of organismic evolution. Related species share characteristics due to their common ancestry. Some concern have been raised among evolutionary biologists, whether such conservatism is an expression of natural selection or of a constrained ability to adapt.

    This thesis explores adaptations and constraints within the plant reproductive phase, particularly in relation to the evolution of fleshy fruit types (berries, drupes, etc.) and the seasonal timing of flowering and fruiting. The different studies were arranged along a hierarchy of scale, with general data sets sampled among seed plants at the global scale, through more specific analyses of character evolution within the genus Rhamnus s.l. L. (Rhamnaceae), to descriptive and experimental field studies in a local population of Frangula alnus (Rhamnaceae). Apart from the field study, this thesis is mainly based on comparative methods explicitly incorporating phylogenetic relationships. The comparative study of Rhamnus s.l. species included the reconstruction of phylogenetic hypotheses based on DNA sequences.

    Among geographically overlapping sister clades, biotic pollination was not correlated with higher species richness when compared to wind pollinated plants. Among woody plants, clades characterized by fleshy fruit types were more species rich than their dry-fruited sister clades, suggesting that the fleshy fruit is a key innovation in woody habitats. Moreover, evolution of fleshy fruits was correlated with a change to more closed (darker) habitats.

    An independent contrast study within Rhamnus s.l. documented allometric relations between plant and fruit size. As a phylogenetic constraint, allometric effects must be considered weak or non-existent, though, as they did not prevail among different subclades within Rhamnus s.l. Fruit size was correlated with seed size and seed number in F. alnus. This thesis suggests that frugivore selection on fleshy fruit may be important by constraining the upper limits of fruit size, when a plant lineage is colonizing (darker) habitats where larger seed size is adaptive.

    Phenological correlations with fruit set, dispersal, and seed size in F. alnus, suggested that the evolution of reproductive phenology is constrained by trade-offs and partial interdependences between flowering, fruiting, dispersal, and recruitment phases. Phylogenetic constraints on the evolution of phenology were indicated by a lack of correlation between flowering time and seasonal length within Rhamnus cathartica and F. alnus, respectively. On the other hand, flowering time was correlated with seasonal length among Rhamnus s.l. species. Phenological differences between biotically and wind pollinated angiosperms also suggested adaptive change in reproductive phenology.

  • 61.
    Bolmgren, Kjell
    Stockholm University, Faculty of Science, Department of Botany.
    Constraints, conservatism and adaptation in the evolution of fleshy fruits and flowering phenology of Rhamnus s.l. (Rhamnaceae).Article in journal (Refereed)
  • 62.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Eriksson, Ove
    Seed mass and the evolution of fleshy fruits in angiosperms2010In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 119, no 4, p. 707-718Article, review/survey (Refereed)
    Abstract [en]

    Fleshy fruits, like drupes and berries, have evolved many times through angiosperm history. Two hypotheses suggest that fleshy fruit evolution is related to changes in the seed mass fitness landscape. The reduced dispersal capability following from an increase in seed mass may be counterbalanced by evolution of traits mediating seed dispersal by animals, such as fleshy fruits. Alternatively, increasing availability and capabilities of frugivores promote evolution of fleshy fruits and allow an increase in seed size. Both these hypotheses predict an association between evolution of fleshy fruits and increasing seed size. We investigated patterns of fruit and seed evolution by contrasting seed mass between fleshy and non-fleshy fruited sister clades. We found a consistent association between possession of fleshy fruits and heavier seeds. The direction of fruit type change did not alter this pattern; seed mass was higher in clades where fleshy fruits evolved and lower in clades where non-fleshy fruits evolved, as compared to their sister clades. These patterns are congruent with the predictions from the two hypotheses, but other evidence is needed to distinguish between them. We emphasize the need to integrate studies of seed disperser effectiveness, seed morphology, and plant recruitment success to better understand the frugivores' role in fleshy fruit evolution.

  • 63.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ove, Eriksson
    Stockholm University, Faculty of Science, Department of Botany.
    Fleshy fruits – origins, niche shifts, and diversification.2005In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 109, no 2, p. 255-272Article in journal (Refereed)
    Abstract [en]

    We examined shifts in fruit type, fleshy vs non-fleshy, in relation to habitat-related niche shifts, species richness, and historical distribution, in 50 phylogenetically independent plant lineages. Each lineage consisted of a sister-group pair of fleshy vs non-fleshy taxa and their outgroup. Niche shifts were assessed based on plant community characteristics. Two niche dimensions assumed to reflect community dynamics were derived: spatial predictability of disturbances and canopy closure. Phylogenetically independent origins of fleshy fruit types (1) were correlated with changes to habitats characterized by more shaded and spatially more unpredictable disturbances, (2) had an opposite effect on species richness in woody and herbaceous clades, enhancing species richness in woody clades, and (3) were continuously distributed over a period covering the last 70 million years. These results support the hypothesis that fleshy fruit evolution is driven by vegetation dynamics, and suggest that the strength of frugivore mediated selection on fleshy fruits increases when recruitment sites are spatially unpredictable and/or characterized by low light conditions.

  • 64.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ove, Eriksson
    Phenology and ovule fate in Frangula alnus (Rhamnaceae) – interdependence or decoupling of flowering, fruiting, dispersal, and early recruitment phases?Manuscript (Other academic)
  • 65.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ove, Eriksson
    Linder, H. Peter
    Contrasting flowering phenology and species richness in abiotically and biotically pollinated angiosperms2003In: Evolution, ISSN 0014-3820, Vol. 57, no 9, p. 2001-2011Article in journal (Refereed)
  • 66.
    Bolmgren, Kjell
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Oxelman, Bengt
    Generic limits in Rhamnus s.l. L. (Rhamnaceae) inferred from nuclear and chloroplast DNA sequence phylogenies.2004In: Taxon, ISSN 0040-0262, E-ISSN 1996-8175, Vol. 53, no 2, p. 383-390Article in journal (Refereed)
    Abstract [en]

    This study tested the monophyly of the previously proposed genera Alaternus, Frangula, Oreoherzogia, and Rhamnus s.str., and the phylogenetic relations suggested by Grubov (1949), within the Rhamnus s.l. clade.Based on a global sample of 22 species, we derived phylogenetic hypotheses using parsimony analysis of variation in trnL-F (chloroplast) and ITS (nuclear) DNA regions. Both Alaternus, Frangula, and Oreoherzogia gained strong support, and our results further support recognition of Frangula as a monophyletic genus. The resolution between Alaternus, Oreoherzogia, and the rest of Rhamnus s.str. was less clear, and the mainly Mediterranean Oreoherzogia was strongly grouped with the American R. crocea. Therefore, we consider it as unjustified to split the rest of Rhamnus into smaller genera. Regarding Grubov's phylogenetic hypothesis, our study could only support the dichotomy between Frangula and the rest of Rhamnus.

  • 67.
    Borg, Agneta Julia
    Stockholm University, Faculty of Science, Department of Botany.
    Evolutionary relationships in Thunbergioideae and other early branching lineages of Acanthaceae2012Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Acanthaceae as circumscribed today consists of the three subfamilies Acanthoideae (Acanthaceae sensu stricto), Thunbergioideae and Nelsoniodieae, plus the genus Avicennia. Due to the morphological dissimilarities of Thunbergioideae and Nelsonioideae, the delimitation of the family has been controversial. The mangrove genus Avicennia was only recently associated with Acanthaceae for the first time, based on molecular evidence, but without morphological support. In this thesis, phylogenetic analyses of nuclear and chloroplast DNA sequences were used to test the monophyly and exact positions of Thunbergioideae and Nelsonioideae, and to infer detailed phylogenetic relationships within these subfamilies and among major lineages of Acanthaceae. Floral structure and development were comparatively studied in Avicennia and other Acanthaceae using scanning electron microscopy and stereo microscopy. Phylogenetic analyses strongly support monophyly of Thunbergioideae and Nelsonioideae, and place the latter clade with strong support as sister to all other plants treated as Acanthaceae. Thunbergioideae and Avicennia are moderately supported as sister taxa, and together they are sister to Acanthoideae. The general morphology of Avicennia can be easily accommodated in the Acanthaceae, and three synapomorphies support the suggested sister group relationship of Avicennia and Thunbergioideae: (1) collateral ovule arrangement, (2) vertical orientation of ovule curvature, and (3) an exposed nucellus that is contiguous with the ovary wall. Within Thunbergioideae and Nelsonioideae, support values for major lineages are generally high. With some exceptions, the constituent genera are supported as monophyletic. Evolutionary relationships among and within genera are discussed in a morphological and biogeographical context.

  • 68.
    Borg, Agneta Julia
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    McDade, Lucinda
    Schönenberger, Jürg
    Stockholm University, Faculty of Science, Department of Botany.
    Molecular phylogenetics and morphological evolution of Thunbergioideae (Acanthaceae)2008In: Taxon, Vol. 57, no 3, p. 811-822Article in journal (Refereed)
  • 69.
    Borg, Agneta Julia
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Schoenenberger, Juerg
    Comparative floral development and structure of the black mangrove genus Avicennia L. and related taxa in the Acanthaceae2011In: International journal of plant sciences, ISSN 1058-5893, E-ISSN 1537-5315, Vol. 172, no 3, p. 330-344Article in journal (Refereed)
    Abstract [en]

    Phylogenetic relationships of Avicennia have been difficult to trace because of the presence of convergent characters related to the mangrove environment. Recent molecular data suggest a close relationship to Thunbergioideae, a subfamily within Acanthaceae (Lamiales), but morphological support for the new findings has been equivocal. Floral structure and development are comparatively studied here in three species of Avicennia, with special attention given to the ovary and the ovules, which are also studied in Thunbergioideae. The suggested sister group relationship of Avicennia and Thunbergioideae is supported by three synapomorphies: (1) collateral ovule arrangement, (2) vertical orientation of ovule curvature, and (3) an exposed nucellus that is contiguous with the ovary wall, at least during early stages of ovule development. We interpret the latter character as a neotenic feature that is retained in the anthetic ovules of Avicennia. We confirm that the apparently tetramerous flowers of Avicennia have a basically pentamerous floral ground plan. Additional floral characters shared between Avicennia and Thunbergioideae include left contort corolla aestivation, thickened filament bases with glandular hairs, presence of pollen sac placentoids, and various aspects of fruit morphology and embryology. However, these features are either symplesiomorphic or are not known well enough to allow for unequivocal conclusion on character evolution in Acanthaceae.

  • 70.
    Borg, Agneta Julia
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Schönenberger, Jürg
    Department of Structural and Functional Botany, Faculty Centre of Biodiversity, University of Vienna.
    Phylogenetic relationships in Acanthaceae based on nuclear and chloroplast sequences with particular focus on the ThunbergioideaeManuscript (preprint) (Other academic)
    Abstract [en]

    Phylogenetic analyses using maximum parsimony and Bayesian inference of one nuclear (ETS) and three chloroplast DNA regions (rpl16, rps16, trnT-trnL) were used to infer detailed phylogenetic relationships within the tropical and subtropical subfamily Thunbergioideae and among major lineages of Acanthaceae. For the first time, sequencing of the monotypic genus Anomacanthus is reported and its position as sister to Mendoncia gains strong support. Relationships among South and Central American Mendoncia species are poorly resolved, most likely reflecting an earlier rapid radiation. The clade with Anomacanthus and Mendoncia is sister to the clade comprising Pseudocalyx and Thunbergia. Relationships within the larger genus Thunbergia are generally well resolved. Two species (Thunbergia heterochondros and T. colpifera) appear morphologically intermediate between Pseudocalyx and Thunbergia. We discuss evolutionary relationships, including unclear species boundaries revealed by the molecular data, in a morphological context. Relationships among and within the four genera shed light on the biogeographic history of the group. All four genera are represented in Africa, from where Mendoncia appears to have dispersed to South and Central America and subsequently diversified into a large number of closely related species. The geographic origin of Thunbergia is uncertain, and the data point to interesting biogeographical patterns in this genus.

  • 71.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum.
    A review of molecular phylogenetic studies of Rubiaceae.2009In: Annals of the Missouri Botanical Garden, ISSN 0026-6493, E-ISSN 2162-4372, Vol. 96, p. 4-26Article in journal (Refereed)
    Abstract [en]

    Rubiaceae is one of the five largest families of flowering plants with over 13,000 species. We have seen a tremendousincrease in our understanding of the phylogeny of the family through studies on molecular data during the 15-year period from1991 to 2005; some new relationships are completely unexpected and different from traditional classification. At the end of2005, ca. 50 phylogenetic reconstructions from the family had been published based on more than 4400 sequences. Moststudies are based on ITS and rbcL sequences, but 13 different markers have been used. Most sequences available in GenBank(as of 2005) are from rps16, trn(T)L-F, rbcL, and ITS. We can now see a framework of the family phylogeny with support forthree subfamilies and over 43 tribes; subfamily Cinchonoideae (Chiococceae, Cinchoneae, Guettardeae, Hamelieae, Hillieae,Hymenodictyeae, Isertieae, Naucleeae, Rondeletieae), subfamily Ixoroideae (Alberteae, Bertiereae, Coffeeae, Condamineeae,Cremasporeae, Gardenieae, Ixoreae, Mussaendeae, Octotropideae, Pavetteae, Posoquerieae, Retiniphylleae, Sabiceeae,Sipaneeae, Vanguerieae), and subfamily Rubioideae (Anthospermeae, Argostemmateae, Coussareeae, Craterispermeae,Danaideae, Gaertnereae, Knoxieae, Lasiantheae, Morindeae, Ophiorrhizeae, Paederieae, Psychotrieae, Putorieae, Rubieae,Schradereae, Spermacoceae, Theligoneae, Urophylleae), and tribe Coptosapelteae, which is placed outside the threesubfamilies. Two of these tribes, Gardenieae and Morindeae, are paraphyletic/polyphyletic. Only about half of the tribes havebeen the focus of specific investigations. However, we have seen increased interest in using Rubiaceae phylogenies for studiesof ecology, evolution, and biogeography, e.g., and also for morphological and anatomical investigations. Evolution of fruittraits, flower types, and myrmecophytism has been investigated, and biogeographic patterns for specific taxa in Africa, theCaribbean, and the Pacific have been studied. In addition, distribution of pollen types, chemical substances, and woodcharacteristics have been compared with molecular phylogenies.Key words:

  • 72.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum.
    Asterids2009In: The Timetree of life / [ed] S. B. Hedges and S. Kumar, Oxford: Oxford University Press , 2009, p. 177-187Chapter in book (Other academic)
  • 73.
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Linnaeus’ sexual system and flowering plant phylogeny2007In: Nordic Journal of Botany, Vol. 25, p. 5-6Article in journal (Other academic)
    Abstract [sv]

    Carl Linnaeus brought order to the knowledge of plants and animals by arranging all known species in encyclopaedic

    works. He proposed a system of plants, the sexual system, based on the number and arrangement of male and female

    organs. His artificial sexual system has since long been replaced by ‘natural’ or phylogenetic systems but there has never

    been a comprehensive comparison of the sexual system with modern plant classification. The currently most often used

    classification of flowering plants is the APG-system. It is based on comprehensive phylogenies of flowering plants,

    reconstructed by analyses of DNA data. The APG-system covers all flowering plants which are classified in 453 families

    and these are classified in 45 orders. Most of the species were not known at time of Linnaeus. Families and orders in the

    APG-system are arranged in larger informal groups representing major branches in the flowering plant phylogenetic tree.

    Three such groups are the monocots, the rosids, and the asterids.

    I have examined all genera published in Species plantarum (1753) and classified them according to order and major

    groups in the APG-system. All classes except one, number 15 Tetradynamia, comprises groups of unrelated plants. Not

    surprisingly, the sexual system does not display what we know today about plant relationships. As is evident from this

    analysis, there is little correspondence between the sexual system and the APG-system. This does not mean that the sexual

    system has been useless or misleading. When it was introduced, it formed the basis for much intensified research and

    increased knowledge of plants.

  • 74.
    Bremer, Birgitta
    et al.
    Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum. Stockholm University, Faculty of Science, Department of Botany.
    Bremer, Kåre
    Chase, Mark
    Fay, Mike
    Reveal, James
    Soltis, Douglas
    Soltis, Pamella
    Stevens, Peter
    An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III.2009In: Botanical Journal of the Linnean Society, Vol. 161, no 2, p. 105-121Article in journal (Refereed)
    Abstract [en]

    A revised and updated classification for the families of flowering plants is provided. Many recent studies have yielded increasingly detailed evidence for the positions of formerly unplaced families, resulting in a number of newly adopted orders, including Amborellales, Berberidopsidales, Bruniales, Buxales, Chloranthales, Escalloniales, Huerteales, Nymphaeales, Paracryphiales, Petrosaviales, Picramniales, Trochodendrales, Vitales and Zygophyllales. A number of previously unplaced genera and families are included here in orders, greatly reducing the number of unplaced taxa; these include Hydatellaceae (Nymphaeales), Haptanthaceae (Buxales), Peridiscaceae

    (Saxifragales), Huaceae (Oxalidales), Centroplacaceae and Rafflesiaceae (both Malpighiales), Aphloiaceae, Geissolomataceae and Strasburgeriaceae (all Crossosomatales), Picramniaceae (Picramniales), Dipentodontaceae and Gerrardinaceae (both Huerteales), Cytinaceae (Malvales), Balanophoraceae (Santalales), Mitrastemonaceae (Ericales) and Boraginaceae (now at least known to be a member of lamiid clade). Newly segregated families for genera previously understood to be in other APG-recognized families include Petermanniaceae (Liliales), Calophyllaceae (Malpighiales), Capparaceae and Cleomaceae (both Brassicales), Schoepfiaceae (Santalales), Anacampserotaceae, Limeaceae, Lophiocarpaceae, Montiaceae and Talinaceae (all Caryophyllales) and Linderniaceaeand Thomandersiaceae (both Lamiales). Use of bracketed families is abandoned because of its unpopularity, and in most cases the broader circumscriptions are retained; these include Amaryllidaceae, Asparagaceace and Xanthorrheaceae (all Asparagales), Passifloraceae (Malpighiales), Primulaceae (Ericales) and several other smaller families. Separate papers in this same volume deal with a new linear order for APG, subfamilial namesthat can be used for more accurate communication in Amaryllidaceae s.l., Asparagaceace s.l. and Xanthorrheaceae s.l. (all Asparagales) and a formal supraordinal classification for the flowering plants. 

  • 75.
    Bremer, Birgitta
    et al.
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Bremer, Kåre
    Heidari, Nahid
    Erixon, Per
    Olmstead, Richard G
    Anderberg, Arne A
    Källersjö, Mari
    Barkhordarian, Edit
    Phylogenetics of asterids based on 3 coding and 3 non-coding chloroplast DNA markers and the utility of non-coding DNA at higher taxonomic levels.2002In: Mol Phylogenet Evol, ISSN 1055-7903, Vol. 24, no 2, p. 274-301Article in journal (Other academic)
  • 76.
    Bremer, Birgitta
    et al.
    Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum. Stockholm University, Faculty of Science, Department of Botany.
    Eriksson, Torsten
    Stockholm University, Faculty of Science, The Bergius Botanical Garden Museum. Stockholm University, Faculty of Science, Department of Botany.
    Timetree of Rubiaceae - Phylogeny and dating the family, subfamilies and tribes2009In: International journal of plant sciences, ISSN 1058-5893, E-ISSN 1537-5315, Vol. 170, no 6, p. 766-793Article in journal (Refereed)
    Abstract [en]

    Rubiaceae are one of the largest families of plants, with ;13,000 species. In this study, we have estimated the phylogeny for 534Rubiaceae taxa from329 generawith up to five different chloroplast regions by Bayesian analysis. It resulted in a highly resolved tree with many strongly supported nodes. There is strong support for the three subfamilies (Cinchonoideae, Ixoroideae, Rubioideae) and most of the 44 included tribes. A scaled-down data set of 173 Rubiaceae taxawas usedwith a Bayesian approach to estimate divergence times for clades classified as tribes and subfamilies. Four fossils were used as minimum age priors, one inside each subfamily and one for Rubiaceae as a whole (Faramea-type pollen, Scyphiphora pollen, Cephalanthus pusillus fruits, and Paleorubiaceophyllum eocenicum leaves). The estimated lineage (stem) divergence time for Rubiaceae is 90.4Ma. The estimated lineage divergence times for the subfamilies are 84.4 (86.6)Ma for Rubioideae, 73.1Ma for Ixoroideae, and 73.1Ma for Cinchonoideae.The estimated lineage divergence times for the tribes vary between 86.6 and 14.2Ma. Classification, relationships, geographical distribution, and age estimates are presented and discussed for all tribes.

  • 77.
    Bremer, Birgitta
    et al.
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Jansen, R K
    Oxelman, B
    Backlund, M
    Lantz, H
    Kim, K J
    More characters or more taxa for a robust phylogeny--case study from the coffee family (Rubiaceae).1999In: Syst Biol, ISSN 1063-5157, Vol. 48, no 3, p. 413-35Article in journal (Other academic)
  • 78. Bremer, Kare
    et al.
    Friis, Else Marie
    Bremer, Birgitta
    Stockholm University, Faculty of Science, Bergianska botaniska trädgården (tills m Kungl. Vet. Ak.). Department of Botany.
    Molecular phylogenetic dating of asterid flowering plants shows early Cretaceous diversification.2004In: Syst Biol, ISSN 1063-5157, Vol. 53, no 3, p. 496-505Article in journal (Other academic)
  • 79.
    Bremer, Kåre
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Barreda, V. D.
    Palazzesi, L.
    Katinas, L.
    Crisci, J. V.
    Telleria, M. C.
    Passala, M. G.
    Bechis, F.
    Corsolini, R.
    An extinct Eocene taxon of the daisy family (Asteraceae): evolutionary, ecological and biogeographical implications2012In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 109, no 1, p. 127-134Article in journal (Refereed)
    Abstract [en]

    Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina.

    Methods: The fossil was collected from the 47.5 million-year-old Huitrera Formation at the Estancia Don Hipolito locality, Rio Negro Province, Argentina.

    Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriate-imbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively.

    Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of Mutisioideae-Carduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47.5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.

  • 80.
    Brindefalk, Björn
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Dessailly, Benoit H.
    Yeats, Corin
    Orengo, Christine
    Werner, Finn
    Poole, Anthony M.
    Evolutionary history of the TBP-domain superfamily2013In: Nucleic Acids Research, ISSN 0305-1048, E-ISSN 1362-4962, Vol. 41, no 5, p. 2832-2845Article in journal (Refereed)
    Abstract [en]

    The TATA binding protein (TBP) is an essential transcription initiation factor in Archaea and Eucarya. Bacteria lack TBP, and instead use sigma factors for transcription initiation. TBP has a symmetric structure comprising two repeated TBP domains. Using sequence, structural and phylogenetic analyses, we examine the distribution and evolutionary history of the TBP domain, a member of the helix-grip fold family. Our analyses reveal a broader distribution than for TBP, with TBP-domains being present across all three domains of life. In contrast to TBP, all other characterized examples of the TBP domain are present as single copies, primarily within multidomain proteins. The presence of the TBP domain in the ubiquitous DNA glycosylases suggests that this fold traces back to the ancestor of all three domains of life. The TBP domain is also found in RNase HIII, and phylogenetic analyses show that RNase HIII has evolved from bacterial RNase HII via TBP-domain fusion. Finally, our comparative genomic screens confirm and extend earlier reports of proteins consisting of a single TBP domain among some Archaea. These monopartite TBP-domain proteins suggest that this domain is functional in its own right, and that the TBP domain could have first evolved as an independent protein, which was later recruited in different contexts.

  • 81. Buckley, Thomas R.
    et al.
    Attanayake, Dilini
    Nylander, Johan A. A.
    Stockholm University, Faculty of Science, Department of Botany.
    Bradler, Sven
    The phylogenetic placement and biogeographical origins of the New Zealand stick insects (Phasmatodea)2010In: Systematic Entomology, ISSN 0307-6970, E-ISSN 1365-3113, Vol. 35, no 2, p. 207-225Article, review/survey (Refereed)
    Abstract [en]

    The Lanceocercata are a clade of stick insects (Phasmatodea) that have undergone an impressive evolutionary radiation in Australia, New Caledonia, the Mascarene Islands and areas of the Pacific. Previous research showed that this clade also contained at least two of the nine New Zealand stick insect genera. We have constructed a phylogeny of the Lanceocercata using 2277 bp of mitochondrial and nuclear DNA sequence data to determine whether all nine New Zealand genera are indeed Lanceocercata and whether the New Zealand fauna is monophyletic. DNA sequence data were obtained from mitochondrial cytochrome oxidase subunits I and II and the nuclear large subunit ribosomal RNA and histone subunit 3. These data were subjected to Bayesian phylogenetic inference under a partitioned model and maximum parsimony. The resulting trees show that all the New Zealand genera are nested within a large New Caledonian radiation. The New Zealand genera do not form a monophyletic group, with the genus Spinotectarchus Salmon forming an independent lineage from the remaining eight genera. We analysed Lanceocercata apomorphies to confirm the molecular placement of the New Zealand genera and to identify characters that confirm the polyphyly of the fauna. Molecular dating analyses under a relaxed clock coupled with a Bayesian extension to dispersal-vicariance analysis was used to reconstruct the biogeographical history for the Lanceocercata. These analyses show that Lanceocercata and their sister group, the Stephanacridini, probably diverged from their South American relatives, the Cladomorphinae, as a result of the separation of Australia, Antarctica and South America. The radiation of the New Caledonian and New Zealand clade began 41.06 million years ago (mya, 29.05-55.40 mya), which corresponds to a period of uplift in New Caledonia. The main New Zealand lineage and Spinotectarchus split from their New Caledonian sister groups 33.72 (23.9-45.62 mya) and 29.9 mya (19.79-41.16 mya) and began to radiate during the late Oligocene and early Miocene, probably in response to a reduction in land area and subsequent uplift in the late Oligocene and early Miocene. We discuss briefly shared host plant patterns between New Zealand and New Caledonia. Because Acrophylla sensu Brock & Hasenpusch is polyphyletic, we have removed Vetilia Stal from synonymy with Acrophylla Gray.

  • 82. Buckley, Yvonne M.
    et al.
    Ramula, Satu
    Blomberg, Simon P.
    Burns, Jean H.
    Crone, Elizabeth E.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Knight, Tiffany M.
    Pichancourt, Jean-Baptiste
    Quested, Helen
    Stockholm University, Faculty of Science, Department of Botany.
    Wardle, Glenda M.
    Causes and consequences of variation in plant population growth rate: a synthesis of matrix population models in a phylogenetic context2010In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 13, no 9, p. 1182-1197Article, review/survey (Refereed)
    Abstract [en]

    Explaining variation in population growth rates is fundamental to predicting population dynamics and population responses to environmental change. In this study, we used matrix population models, which link birth, growth and survival to population growth rate, to examine how and why population growth rates vary within and among 50 terrestrial plant species. Population growth rates were more similar within species than among species; with phylogeny having a minimal influence on among-species variation. Most population growth rates decreased over the observation period and were negatively autocorrelated between years; that is, higher than average population growth rates tended to be followed by lower than average population growth rates. Population growth rates varied more through time than space; this temporal variation was due mostly to variation in post-seedling survival and for a subset of species was partly explained by response to environmental factors, such as fire and herbivory. Stochastic population growth rates departed from mean matrix population growth rate for temporally autocorrelated environments. Our findings indicate that demographic data and models of closely related plant species cannot necessarily be used to make recommendations for conservation or control, and that post-seedling survival and the sequence of environmental conditions are critical for determining plant population growth rate.

  • 83. Buerki, S
    et al.
    Forest, F
    Acevedo-Rodríguez, P
    Callmander, M. W.
    Nylander, Johan
    Stockholm University. Stockholm University, Faculty of Science, Department of Botany.
    Harrington, M
    Sanmartín, I
    Küpfer, P
    Alvarez, N
    Plastid and nuclear DNA markers reveal intricate relationships at subfamilial and tribal levels in the soapberry family (Sapindaceae)2009In: Molecular Phylogenetics and Evolution, ISSN 1055-7903, E-ISSN 1095-9513, Vol. 51, p. 238-258Article in journal (Refereed)
  • 84. Buerki, Sven
    et al.
    Forest, Felix
    Alvarez, Nadir
    Nylander, Johan A. A.
    Stockholm University, Faculty of Science, Department of Botany.
    Arrigo, Nils
    Sanmartin, Isabel
    An evaluation of new parsimony-based versus parametric inference methods in biogeography: a case study using the globally distributed plant family Sapindaceae2011In: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 38, no 3, p. 531-550Article in journal (Refereed)
    Abstract [en]

    Aim Recently developed parametric methods in historical biogeography allow researchers to integrate temporal and palaeogeographical information into the reconstruction of biogeographical scenarios, thus overcoming a known bias of parsimony-based approaches. Here, we compare a parametric method, dispersal-extinction-cladogenesis (DEC), against a parsimony-based method, dispersal-vicariance analysis (DIVA), which does not incorporate branch lengths but accounts for phylogenetic uncertainty through a Bayesian empirical approach (Bayes-DIVA). We analyse the benefits and limitations of each method using the cosmopolitan plant family Sapindaceae as a case study. Location World-wide. Methods Phylogenetic relationships were estimated by Bayesian inference on a large dataset representing generic diversity within Sapindaceae. Lineage divergence times were estimated by penalized likelihood over a sample of trees from the posterior distribution of the phylogeny to account for dating uncertainty in biogeographical reconstructions. We compared biogeographical scenarios between Bayes-DIVA and two different DEC models: one with no geological constraints and another that employed a stratified palaeogeographical model in which dispersal rates were scaled according to area connectivity across four time slices, reflecting the changing continental configuration over the last 110 million years. Results Despite differences in the underlying biogeographical model, Bayes-DIVA and DEC inferred similar biogeographical scenarios. The main differences were: (1) in the timing of dispersal events - which in Bayes-DIVA sometimes conflicts with palaeogeographical information, and (2) in the lower frequency of terminal dispersal events inferred by DEC. Uncertainty in divergence time estimations influenced both the inference of ancestral ranges and the decisiveness with which an area can be assigned to a node. Main conclusions By considering lineage divergence times, the DEC method gives more accurate reconstructions that are in agreement with palaeogeographical evidence. In contrast, Bayes-DIVA showed the highest decisiveness in unequivocally reconstructing ancestral ranges, probably reflecting its ability to integrate phylogenetic uncertainty. Care should be taken in defining the palaeogeographical model in DEC because of the possibility of overestimating the frequency of extinction events, or of inferring ancestral ranges that are outside the extant species ranges, owing to dispersal constraints enforced by the model. The wide-spanning spatial and temporal model proposed here could prove useful for testing large-scale biogeographical patterns in plants.

  • 85. Buerki, Sven
    et al.
    Lowry, Porter P., II
    Alvarez, Nadir
    Razafimandimbison, Sylvain G.
    Stockholm University, Faculty of Science, Department of Botany.
    Kuepfer, Philippe
    Callmander, Martin W.
    Phylogeny and circumscription of Sapindaceae revisited: molecular sequence data, morphology and biogeography support recognition of a new family, Xanthoceraceae2010In: Plant Ecology and Evolution, ISSN 2032-3913, Vol. 143, no 2, p. 148-159Article in journal (Refereed)
    Abstract [en]

    Background and aims Recent studies have adopted a broad definition of Sapindaceae that includes taxa traditionally placed in Aceraceae and Hippocastanaceae, achieving monophyly but yielding a family difficult to characterize and for which no obvious morphological synapomorphy exists. This expanded circumscription was necessitated by the finding that the monotypic, temperate Asian genus Xanthoceras, historically placed in Sapindaceae tribe Harpullieae, is basal within the group. Here we seek to clarify the relationships of Xanthoceras based on phylogenetic analyses using a dataset encompassing nearly 3/4 of sapindaceous genera, comparing the results with information from morphology and biogeography, in particular with respect to the other taxa placed in Harpullieae. We then re-examine the appropriateness of maintaining the current broad, morphologically heterogeneous definition of Sapindaceae and explore the advantages of an alternative family circumscription. Methods Using 243 samples representing 104 of the 142 currently recognized genera of Sapindaceae s. lat. (including all in Harpullieae), sequence data were analyzed for nuclear (ITS) and plastid (matK, rpoB, trnD-trnT, trnK-matK, trnL-trnF and trnS-trnG) markers, adopting the methodology of a recent family-wide study, performing single-gene and total evidence analyses based on maximum likelihood (ML) and maximum parsimony (MP) criteria, and applying heuristic searches developed for large datasets, viz, a new strategy implemented in RAxML (for ML) and the parsimony ratchet (for MP). Bootstrap analyses were performed for each method to test for congruence between markers. Key results Our findings support earlier suggestions that Harpullieae are polyphyletic: Xanthoceras is confirmed as sister to all other sampled taxa of Sapindaceae s. lat.; the remaining members belong to three other clades within Sapindaceae s. lat., two of which correspond respectively to the groups traditionally treated as Aceraceae and Hippocastanaceae, together forming a clade sister to the largely tropical Sapindaceae s. str., which is monophyletic and morphologically coherent provided Xanthoceras is excluded. Conclusion To overcome the difficulties of a broadly circumscribed Sapindaceae, we resurrect the historically recognized temperate families Aceraceae and Hippocastanaceae, and describe a new family, Xanthoceraceae, thus adopting a monophyletic and easily characterized circumscription of Sapindaceae nearly identical to that used for over a century.

  • 86. Bukovinszky, Tibor
    et al.
    Gols, Rieta
    Kamp, Andre
    de Oliveira-Domingues, Filipe
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Botany.
    Jongema, Yde
    Bezemer, T. Martijn
    Dicke, Marcel
    van Dam, Nicole M.
    Harvey, Jeffrey A.
    Combined effects of patch size and plant nutritional quality on local densities of insect herbivores2010In: Basic and Applied Ecology, ISSN 1439-1791, E-ISSN 1618-0089, Vol. 11, no 5, p. 396-405Article in journal (Refereed)
    Abstract [en]

    Plant-insect interactions occur in spatially heterogeneous habitats. Understanding how such interactions shape density distributions of herbivores requires knowledge on how variation in plant traits (e.g. nutritional quality) affects herbivore abundance through, for example, affecting movement rates and aggregation behaviour. We studied the effects of plant patch size and herbivore-induced differences in plant nutritional quality on local densities of insect herbivores for two Brassica oleracea cultivars, i.e. white cabbage and Brussels sprouts. Early season herbivory as a treatment resulted in measurable differences in glucosinolate concentrations in both cultivars throughout the season. Herbivore induction and patch size both influenced community composition of herbivores in both cultivars, but the effects differed between species. Flea beetles (Phyllotreta spp.) were more abundant in large than in small patches, and this patch response was more pronounced on white cabbage than on Brussels sprouts. Herbivore-induction increased densities in all patches. Thrips tabaci was also more abundant in large patches and densities of this species were higher on Brussels sprouts than on white cabbage. Thrips densities were lower on induced than on control plants of both cultivars and this negative effect of induction tended to be more pronounced in large than in small patches. Densities of the cabbage moth (Mamestra brassicae) were lower on Brussels sprouts than on white cabbage and lower on herbivore-induced than on uninduced plants, with no effect of patch size. No clear effects of patch size and induction were found for aphids. This study shows that constitutive and herbivore-induced differences in plant traits interact with patch responses of insect herbivores.

  • 87. Burns, Jean H.
    et al.
    Blomberg, Simon P.
    Crone, Elizabeth E.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Knight, Tiffany M.
    Pichancourt, Jean-Baptiste
    Ramula, Satu
    Wardle, Glenda M.
    Buckley, Yvonne M.
    Empirical tests of life-history evolution theory using phylogenetic analysis of plant demography2010In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 98, no 2, p. 334-344Article in journal (Refereed)
    Abstract [en]

    1. A primary goal of evolutionary ecology is to understand factors selecting for the diversity of life histories. Life-history components, such as time-to-reproduction, adult survivorship and fecundity, might differ among species because of variation in direct and indirect benefits of these life histories in different environments or might have lower-than-expected variability because of phylogenetic constraints. Here, we present a phylogenetic examination of demography and life histories using a data base of 204 terrestrial plant species. 2. Overall, statistical models without phylogeny were preferred to models with phylogeny for vital rates and elasticities, suggesting that they lacked phylogenetic signal and are evolutionarily labile. However, the effect of phylogeny was significant in models including sensitivities, suggesting that sensitivities exhibit greater phylogenetic signal than vital rates or elasticities. 3. Species with a greater age at first reproduction had lower fecundity, consistent with a cost of delayed reproduction, but only in some habitats (e.g. grassland). We found no evidence for an indirect benefit of delayed reproduction via a decrease in variation in fecundity with age to first reproduction. 4. The greater sensitivity and lower variation in survival than in fecundity was consistent with buffering of more important vital rates, as others have also found. This suggests that studies of life-history evolution should include survival, rather than only fecundity, for the majority of species. 5. Synthesis. Demographic matrix models can provide informative tests of life-history theory because of their shared construction and outputs and their widespread use among plant ecologists. Our comparative analysis suggested that there is a cost of delayed reproduction and that more important vital rates exhibit lower variability. The absolute importance of vital rates to population growth rates (sensitivities) exhibited phylogenetic signal, suggesting that a thorough understanding of life-history evolution might require an understanding of the importance of vital rates, not just their means, and the role of phylogenetic history.

  • 88.
    Carr, H
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Axelsson, L
    Photosynthetic utilization of HCO3- in Laminaria saccharina depends on ATP from respirationManuscript (Other academic)
  • 89.
    Carr, H
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Axelsson, L
    Utilisation of HCO3- in Zostera marina is supported by ATP from respirationManuscript (Other academic)
  • 90.
    Carr, H
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Björk, M
    A methodological comparison of photosynthetic oxygen evolution and estimated electron transport rate in tropical ULVA (Chlorophyceae) species under different light and inorganic carbon conditions2003In: Journal of Phycology, ISSN 0022-3646, Vol. 39, no 6, p. 1125-1131Article in journal (Refereed)
  • 91.
    Carr, H
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Björk, M
    Degradation of D1 protein and changes in photosynthetic capacity in the green macroalgae Ulva fasciata Delile during exposure to high irradiance: Damage or down regulation within an hour?Article in journal (Refereed)
  • 92.
    Carr, Herman
    Stockholm University, Faculty of Science, Department of Botany.
    Energy balance during active carbon uptake and at excess irradiance in three marine macrophytes2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The marine environment is an important habitat where many processes occur that affect life conditions on earth. Macrophytes and planktonic oxygen evolvers are an essential component for almost all marine life forms and have developed in an environment that differs largely from the terrestrial habitats. For instance in regards to available ionic forms of inorganic carbon and moving water masses which affects incoming light. It is therefore relevant to examine the physiology of algae and marine plants to identify their unique features and differences to terrestrial plants that once orginated from algae. By using chlorophyll fluorescence measurements alone or combined with measurements of oxygen evolution and protein analysis photosynthetic strategies to withstand excess energy have been evaluated under a variety of experimental conditions. Furthermore metabolic pathways involved in energy transfer from photosynthesis to the site of active carbon uptake have been examined. The following was found:

    * The ratio between photosynthetic gross oxygen evolution and estimated electron transport rate varies in Ulva spp depending on previous history of light and dark exposures. To obtain P/I curves with ratios close to the theoretical 1:4 value, measurements should be performed on separate pieces of tissue at each irradiance level.

    * Under carbon deficient conditions, the estimated ETR is larger than the gross oxygen evolution, which may be due to the so called “water-water” cycle and absorption changes in PSII which are not corrected for in the calculation of ETR.

    * Upon exposure to high irradiances (1500 µmol photons m-2s-1) the PSII core protein D1 is broken down with a concomittant reduction in ETR in Ulva spp. With the decrease in electron transport between PSII and PSI the acidification of the lumen decreases and the ability to dissipate excess energy as heat. At prolonged irradiance, an acclimation occurs with a lesser or no breakdown of D1 indicating an additional photo-protective strategy other than heat dissipation.

    * Laminaria saccharina is dependent on mitochondrial respiration for active utilization of bicarbonate. By extruding protons outside the plasmalemma an acidification takes place that favors the conversion of bicarbonate into carbon dioxide that then can diffuse in to the cell. These proton pumps are driven by ATP supplied to a large degree from mitochondria, likely through the reductant NADPH produced photochemically.

    * The marine angiosperm Zostera marina is dependent on mitochondrial respiration for utilization of bicarbonate in a manner similar to that in Laminaria saccharina . However, the water-water cycle may supply additional ATP to the proton pumps in Zostera marina. Both species exhibit a lag-phase at the onset of illumination after a dark incubation period and at least part of this lag-phase is due to a lag in an activation of mitochondrial supported bicarbonate utilization. It is clear that the marine environment holds complex plant and algae species and much is still to discover about the oxygen evolvers that grow beneath the water surface.

  • 93.
    Carr, Herman
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Axelsson, Lennart
    Photosynthetic utilization of bicarbonate in Zostera marina is reduced by inhibitors of mitochondrial ATPase and electron transport2008In: Plant Physiology, ISSN 0032-0889, E-ISSN 1532-2548, Vol. 147, no 2, p. 879-885Article in journal (Refereed)
    Abstract [en]

    When Zostera marina was irradiated after a period of darkness, initiation of photosynthetic O-2 evolution occurred in two phases. During a lag phase, lasting 4 to 5 min, photosynthesis was supported by a diffusive entry of CO2. Photosynthesis then rapidly increased to its full rate. Tris buffer, at a concentration of 50 mM, completely inhibited this increase without affecting CO2-supported photosynthesis during the lag phase. These results verify that the increase in photosynthesis after the lag phase depended on an activation of bicarbonate (HCO3-) utilization through acid zones generated by proton pumps located to the outer cell membrane. In similar experiments, 6.25 mu M of the mitochondrial ATPase blocker oligomycin inhibited photosynthetic HCO3- utilization by more than 60%. Antimycin A, a selective blocker of mitochondrial electron transport, caused a similar inhibition of HCO3- utilization. Measurements at elevated CO2 concentrations verified that neither oligomycin nor antimycin interfered with linear photosynthetic electron transport or with CO2 fixation. Thus, a major part of the ATP used for the generation of acid zones involved in HCO3- utilization in Z. marina was derived from mitochondrial respiration.

  • 94.
    Carr, Herman
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, Department of Botany. Fysiologi.
    Björk, Mats
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, Department of Botany. Fysiologi.
    Parallel changes in non-photochemical quenching properties, photosynthesis and D1 levels at sudden, prolonged irradiance exposures in Ulva fasciata Delile.2007In: Journal of Photochemistry and Photobiology B: Biology, Vol. 87Article in journal (Refereed)
  • 95. Caruso, Alexandro
    et al.
    Rudolphi, Jörgen
    Stockholm University, Faculty of Science, Department of Botany.
    Rydin, Håkan
    Positive edge effects on forest-interior cryptogams in clear-cuts2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 11, p. e27936-Article in journal (Refereed)
    Abstract [en]

    Biological edge effects are often assessed in high quality focal habitats that are negatively influenced by human-modified low quality matrix habitats. A deeper understanding of the possibilities for positive edge effects in matrix habitats bordering focal habitats (e.g. spillover effects) is, however, essential for enhancing landscape-level resilience to human alterations. We surveyed epixylic (dead wood inhabiting) forest-interior cryptogams (lichens, bryophytes, and fungi) associated with mature old-growth forests in 30 young managed Swedish boreal forest stands bordering a mature forest of high conservation value. In each young stand we registered species occurrences on coarse dead wood in transects 0–50 m from the border between stand types. We quantified the effect of distance from the mature forest on the occurrence of forest-interior species in the young stands, while accounting for local environment and propagule sources. For comparison we also surveyed epixylic open-habitat (associated with open forests) and generalist cryptogams. Species composition of epixylic cryptogams in young stands differed with distance from the mature forest: the frequency of occurrence of forest-interior species decreased with increasing distance whereas it increased for open-habitat species. Generalists were unaffected by distance. Epixylic, boreal forest-interior cryptogams do occur in matrix habitats such as clear-cuts. In addition, they are associated with the matrix edge because of a favourable microclimate closer to the mature forest on southern matrix edges. Retention and creation of dead wood in clear-cuts along the edges to focal habitats is a feasible way to enhance the long-term persistence of epixylic habitat specialists in fragmented landscapes. The proposed management measures should be performed in the whole stand as it matures, since microclimatic edge effects diminish as the matrix habitat matures. We argue that management that aims to increase habitat quality in matrix habitats bordering focal habitats should increase the probability of long-term persistence of habitat specialists.

  • 96. Chakravarthy, Suma
    et al.
    Velasquez, Andre C.
    Ekengren, Sophia K.
    Stockholm University, Faculty of Science, Department of Botany.
    Collmer, Alan
    Martini, Gregory B.
    Identification of Nicotiana benthamiana Genes Involved in Pathogen-Associated Molecular Pattern-Triggered Immunity2010In: Molecular Plant-Microbe Interactions, ISSN 0894-0282, E-ISSN 1943-7706, Vol. 23, no 6, p. 715-726Article in journal (Refereed)
    Abstract [en]

    In order to identify components of pathogen-associated molecular pattern triggered immunity (PTI) pathways in Nicotiana benthamiana, we conducted a large-scale forward-genetics screen using virus-induced gene silencing and a cell-death-based assay for assessing PTI. The assay relied on four combinations of PTI-inducing nonpathogens and cell-death-causing challenger pathogens and was first validated in plants silenced for FLS2 or BAK1. Over 3,200 genes were screened and 14 genes were identified that, when silenced, compromised PTI as judged by the cell-death-based assay. Further analysis indicated that the 14 genes were not involved in a general cell death response. A subset of the genes was found to act downstream of FLS2-mediated PTI induction, and silencing of three genes compromised production of reactive oxygen species in leaves exposed to fig22. The 14 genes encode proteins with potential functions in defense and hormone signaling, protein stability and degradation, energy and secondary metabolism, and cell wall biosynthesis and provide a new resource to explore the molecular basis for the involvement of these processes in PTI.

  • 97.
    Chang, Christine Chi-Chen
    Stockholm University, Faculty of Science, Department of Botany.
    Mechanisms and genes controlling the signalling network for biotic and abiotic stress defences in Arabidopsis thaliana (L.) Heyhn: Functional cross-talk between photo-produced reactive oxygen species, photosynthesis and plant disease defence responses2005Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Excess excitation energy, mechanical injury and defence against pathogens, each trigger rapid production of reactive oxygen species (ROS) in Arabidopsis thaliana leaves. ROS, such as hydrogen peroxide (H2O2), are required for the induction of systemic acquired acclimation and may lead to redox changes in photosynthetic electron transport (PET). On one hand, enhanced ROS production during stress can destroy cells, and on the other, ROS can also act as signals for the activation of stress responsive and defensive pathways.

    In this work, physiological and molecular analyses of Arabidopsis mutants and transgenic lines were applied to investigate the signalling network controlling biotic and abiotic stress responses. A key enzyme of the antioxidant network is encoded by ASCORBATE PEROXIDASE 2 (APX2). Wounded leaves showed low induction of APX2 expression and when exposed to excess light, APX2 expression was increased synergistically. Signalling pathways dependent upon jasmonic acid, chitosan and abscisic acid were not involved in the wound-induced expression of APX2, but PET was required, and APX2 induction was preceded by a depressed rate of CO2 fixation.

    Analysis of lsd1 (LESION SIMULATING DISEASE 1) strongly suggests that light acclimatory processes and pathogen defences are genetically and functionally linked. It is important to know that LSD1 type of mutants have mainly been studied with regard to pathogenesis. From this work, it reveals that association of LSD1 with hypersensitive response may only be supplementary.

    GLUTATHIONE PEROXIDASES (GPXs) are another major family of ROS scavenging enzymes. Analysis of the Arabidopsis genome database revealed a new open-reading frame, thus increasing the total number of AtGPX gene family to eight (AtGPX1-AtGPX8). Arabidopsis thaliana transgenic lines with reduced expression of both putative chloroplastic isoforms (AtGPX1 and AtGPX7) and AtGPX7 knock-out mutant (ko-GPX7) were more sensitive to photo-oxidative stress but had a reduced bacterial growth rate when inoculated with virulent strains Pseudomonas syringae pv. tomato DC3000 and P.s.t. maculicola strain ES4326, indicating increased resistance to pathogenesis. This, to our knowledge, is the first functional and genetic analysis of chloroplastic GPXs in plants, and confirms that light and chloroplastic ROS metabolism is important for basal resistance against virulent pathogens.

    The above results confirm that light sensing, light acclimatory processes and photo-produced ROS also govern pathogen defence pathways. This has a great ecological relevance for Darwinian fitness of plants growing in the natural environment, where simultaneous pathogen attack and fluctuations in light, temperature and other environmental factors make rapid acclimation a constant necessity. Molecular, biochemical and physiological analysis of pathogen responses in mutants impaired in light sensing, EEE-dissipatory mechanisms, and similar analysis of light acclimatory processes in mutants impaired in pathogen defences may prove to be seminal.

  • 98.
    Chang, Christine Chi-Chen
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Ball, Louise
    Fryer, Michael J.
    Baker, Neil R.
    Karpinski, Stanislaw
    Mullineaux, Philip M.
    Induction of ASCORBATE PEROXIDASE 2 expression in wounded Arabidopsis leaves does not involve known wound-signalling pathways but is associated with changes in photosynthesis2004In: Plant Journal, Vol. 38, no 3, p. 499-511Article in journal (Refereed)
  • 99.
    Chang, Christine Chi-Chen
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Jorda, Lucia
    Slesak, Ireneusz
    Melzer, Michael
    Miszalski, Zbigniew
    Moritz, Thomas
    Mullineaux, Philip M.
    Parker, Jane
    Karpinska, Barbara
    Karpinski, Stanislaw
    Functional analysis of chloroplastic glutathione peroxidases (cpGPXs) in Arabidopsis thaliana provides a direct link between photo-oxidative stress and basal pathogen resistance mechanismsManuscript (Other academic)
  • 100.
    Chang, Christine Chi-Chen
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Slesak, Ireneusz
    Sotnikow, Alexej
    Mullineaux, Philip M.
    Karpinski, Stanislaw
    Karpinska, Barbara
    Functional characterization of the chloroplastic glutathione peroxidases (cpGPXs) in Arabidopsis thaliana: its role in light acclimatory mechanismsManuscript (Other academic)
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