| 1. |
- Arup, Ulf, et al.
(författare)
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A new taxonomy of the family Teloschistaceae
- 2013
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 31:1, s. 16-83
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Forskningsöversikt (refereegranskat)abstract
- The lichen family Teloschistaceae is one of the larger families of lichenized fungi. Currently it includes one very large heterogenous genus, Caloplaca, with some 1000 or more species with a vast variation in morphology, anatomy and chemistry. The rest of the family is split into 1015 smaller genera, each with 20 or fewer species. There is no modern classification of the family based on molecular data. Here we attempt a first phylogenetic evaluation of a large part of the family, including a total of 337 species. Of these, 162 were used in a combined phylogenetic analysis of the ribosomal RNA sequence markers nrITS, nrLSU and mrSSU, using Bayesian inference. We also analysed all species using nrITS data, split into four different analyses. As a result we propose a new classification of the family, where a total of 39 genera are recognized, of which 31 are newly described or resurrected. The new genera are: Athallia, Austroplaca, Bryoplaca, Calogaya, Cerothallia, Flavoplaca, Gondwania, Haloplaca, Orientophila, Pachypeltis, Parvoplaca, Rufoplaca, Shackletonia, Scutaria, Sirenophila, Solitaria, Squamulea, Stellarangia, Teloschistopsis, Usnochroma, Variospora, Villophora and Wetmoreana. Resurrected genera are Blastenia, Dufourea, Follmannia, Gyalolechia, Leproplaca, Polycauliona, Pyrenodesmia and Xanthocarpia. The species Orientophila subscopularis is described as new. A third subfamily, Teloschistoideae, is proposed to accommodate the genus Teloschistes and related genera, parallel to the two previously recognized subfamilies Xanthorioideae and Caloplacoideae. We also show the large plasticity in both morphological and anatomical characters between closely related species within genera, indicating the low value of these as evolutionary markers. The secondary chemistry is a better marker in some parts of the family. We recognize a large number of geographically delimited clades with clear centres of evolution, but often showing large variation in morphology and anatomy.
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| 2. |
- Athanasiadis, Athanasios, et al.
(författare)
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The genera Melyvonnea gen.nov. and Mesophyllum s.s. (Melobesioideae, Corallinales, Rhodophyta) particularly from the central Atlantic Ocean
- 2014
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 32:4, s. 385-436
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Tidskriftsartikel (refereegranskat)abstract
- We propose the new genus Melyvonnea to accommodate species previously included in Mesophyllum having: a) perithallial protuberances that may branch and dominate over the encrusting base, b) monoecious gametophytes with gametangial conceptacles occasionally developed in superimposition, c) spheroid carposporangial chambers (lacking a central pedestal), and d) filaments lining canals of multiporate roofs composed of 3 to 5 cells with distinctively elongate basal cells. The new genus shares with Mesophyllum the development of a predominantly coaxial hypothallium. Melyvonnea presently accommodates three species in the Central Atlantic, viz. the generitype Melyvonnea canariensis (Foslie) comb. nov. from the Canary Islands, Melyvonnea erubescens (Foslie) comb. nov. (= Mesophyllum incertum; type locality: Bermuda) from the western Atlantic, Melyvonnea aemulans (Foslie & Howe) comb. nov. from Puerto Rico, and one Indo-Pacific species, Melyvonnea madagascariensis (Foslie) comb. nov. We also emend Mesophyllum Lemoine to encompass Northern Hemisphere species that lack the above apomorphies of Melyvonnea and in addition develop a central pedestal in carposporangial conceptacles (via dissolution of the surrounding cells) with gonimoblasts bending down to fill the empty space. Mesophyllum sensu stricto currently includes six species in the NE Pacific (M. aleuticum, M. conchatum, M. crassiusculum, M. lamellatum, M. megagastri, M. vancouveriense), two species in the western Atlantic (M. mesomorphum and M. syntrophicum), and three species in the NE Atlantic and the Mediterranean Sea (M. expansum, M. lichenoides, M. philippii). Gametophytic species of each genus show a mainly disjunct distribution being restricted to the tropics-subtropics (Melyvonnea) and the temperate waters of the Northern Hemisphere (Mesophyllum s.s.). This classification is supported by a consensus of studies of all well-known species of Mesophyllum sensu Adey (1970), and is based on a phylogenetic analysis of morphological and anatomical characters in addition to molecular evidence.
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| 3. |
- Bakker, Jan P., et al.
(författare)
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Shading results in depletion of the soil seed bank
- 2014
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 32:5, s. 674-679
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Tidskriftsartikel (refereegranskat)abstract
- To what extent is the decline of characteristic dry alvar species related to the decline in the soil seed bank during scrub encroachment? We recorded the number of flower stems in the vegetation in relation to light attenuation along an encroachment series progressing from open alvar through small gaps inside dense scrub of Juniperus communis (cover of 60%) to intact dense scrub (cover of 100%) on the island of oland, Sweden. This measurement of potential reproduction (number of flower stems) was then compared to the number of species in the soil seed bank at each site along the alvar encroachment series. Scrub encroachment results in light attenuation between and under the shrubs. The total number of flower stems averaged over all species was similar between gaps and open alvar, but that of alvar species was significantly lower in the gaps, indicating that light attenuation could reduce their seed set. Shading in gaps is related to depletion of the soil seed bank and loss of alvar species, particularly those that do not form a persistent soil seed bank.
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| 4. |
- Birgander, Johanna, et al.
(författare)
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Activity of temperate grassland plants and symbiotic fungi during the winter - implications for community structure and carbon cycling in a changing climate
- 2012
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 30:5, s. 513-521
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Tidskriftsartikel (refereegranskat)abstract
- Several investigations have revealed surprisingly high activities during the winter in vegetation and soil in temperate and subarctic areas. Plants have been found to photosynthesize even under snow cover and at temperatures below freezing, and decomposer microorganisms can function, at low rates, all year around. In temperate grasslands, the vegetation includes winter annual herbs as well as bryophytes, which have the potential to be active and are thus susceptible to changing temperatures during winter. If temperatures stay below freezing and there is a snow cover, an increase in temperatures could in fact decrease the soil temperature due to reduced insulation by snow cover. On the other hand, if winter temperatures initially fluctuate around the freezing point, an increase by a few degrees might produce frost-free conditions. Based on available data, the composition of plant communities are strongly influenced by temperature conditions in the preceding winter. We conclude that the winter season in grasslands needs more research attention, to start to resolve which species are active and how they respond to a changing climate.
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| 5. |
- Boberg, Pelle, et al.
(författare)
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The effect of high temperatures on seed germination of one native and two introduced conifers in Patagonia
- 2010
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Ingår i: Nordic Journal of Botany. - Chichester : Wiley-Blackwell. - 0107-055X .- 1756-1051. ; 28:2, s. 231-239
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Tidskriftsartikel (refereegranskat)abstract
- We examined the effect of thermal shock on the germination of seeds of three conifers, two introduced (Pseudotsuga menziesii and Pinus ponderosa), and one native to Patagonia (Araucaria araucana). Previous research has suggested increased susceptibility to invasions in burnt areas, and therefore, the effect of simulated fire (heat) on seed germination in these native and introduced species was compared. Seeds were heated to two different heat intensities (50°C and 100°C) for 1 or 5 min, which is within the temperature range reached in the upper soil layers during forest fires. Germination tests were then carried out in a growth chamber. The heat treatments had a negative effect on the germination of P. menziesii at temperatures of 100°C, and a negative effect on the germination of P. ponderosa at the temperature of 100°C and the exposure of 5 min. The heat treatments had no affect at all on A. araucana. The species with larger seeds (A. araucana) had higher survival rates after the thermal shocks. Also intraspecific differences in seed sizes possibly point at larger seeds surviving thermal shocks better than smaller seeds. In addition, thermal shock caused a delay in the onset of germination in the two introduced species, while it did not change the time for germination in A. araucana. © The Authors. Journal compilation © Nordic Journal of Botany 2010.
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| 6. |
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| 7. |
- Göransson, Pernilla, et al.
(författare)
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Deschampsia cespitosa and soil acidification: general and trait-specific responses to acid and aluminium stress in a solution experiment
- 2011
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 29:1, s. 97-104
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Tidskriftsartikel (refereegranskat)abstract
- Genetically based adaptation and phenotypic plasticity represent important means of coping with natural or human-induced increases in soil acidity. In the present study, we examined the role of phenotypic plasticity in the grass Deschampsia cespitosa by testing for general and trait-specific responses to acid and aluminium (Al) stress. We sampled tussocks (genets) from sites in southern Sweden differing in their exposure to acid deposition, and quantified the performance of each genet under low pH and high Al levels in a solution experiment using the length and biomass of both shoots and roots as response variables. In agreement with results from a previous solution experiment, the overall performance (expressed as total biomass) declined under acid and Al stress, and there was no evidence for local genetic adaptation with respect to acidity. Three Oland populations showed signs of being stimulated by high Al levels, despite originating from relatively basic soils. We observed a significant increase in root length under high Al levels and hypothesize that this response may be adaptive in the natural soil environment, allowing growing roots to "escape" patches of soil with toxic concentrations of this element. Our results for D. cespitosa indicate that phenotypic plasticity has the potential to mitigate the negative effects of soil acidity in this species.
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| 8. |
- Hedrén, Mikael, et al.
(författare)
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Systematics and conservation genetics of Dactylorhiza majalis ssp elatior (Orchidaceae) on Gotland
- 2012
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 30:3, s. 257-272
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Tidskriftsartikel (refereegranskat)abstract
- A tall allotetraploid member of the Dactylorhiza incarnata/maculata complex with unspotted leaves and large pinkish flowers from the island of Gotland in the Baltic was examined for molecular variation patterns at five nuclear microsatellite loci, nuclear ITS and in plastid haplotypes. The allotetraploid was well separated from allopatric allotetraploids of similar appearance, including the western European D. majalis ssp. integrata (syn. D. praetermissa) and forms of D. majalis ssp. lapponica from mainland Sweden. It also differed from other allotetraploids distributed in the Baltic Sea region, including D. majalis ssp. baltica and D. majalis ssp. lapponica. It is here recognized as D. majalis ssp. elatior (Fr.) Hedren & H. A. Pedersen. Dactylorhiza osiliensis Pikner, described from Saaremaa (Estonia) is regarded as a synonym. The distribution covers Gotland, Saaremaa and possibly Hiiumaa. Dactylorhiza majalis ssp. elatior may have one or several recent origins within its present distribution area, and it contains no other molecular markers than those found in the parental D. incarnata var. incarnata and D. maculata ssp. fuchsii in the same area. It appears to have weak barriers towards secondary hybridization with its parental lineages. The situation is reminiscent to that of other young allotetraploids in the D. majalis s.l. complex, suggesting that introgression may be an underestimated process explaining the accumulation of genetic diversity in evolving allopolyploid plants.
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| 9. |
- Hydbom, Sofia, et al.
(författare)
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The effects of pH and disturbance on the bryophyte flora in calcareous sandy grasslands
- 2012
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X. ; 30:4, s. 446-452
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Tidskriftsartikel (refereegranskat)abstract
- The unique flora and fauna of calcareous sandy grasslands is threatened by acidification, eutrofication and changed land use. Restoration experiments in such grasslands in southern Sweden, including deep and shallow soil perturbation, allowed us to examine the effects of pH and disturbance on the bryophyte flora. We also studied natural pH and disturbance gradients in order to compare the natural pH and disturbance variation with the responses of experimental manipulation. We found that increased pH due to soil perturbation resulted in increased species richness. However, in naturally disturbed areas, pH seemed to have a lower effect, and instead, the location of the site and possibly the site history had a larger influence on species richness. We also found that some of the species that were common at naturally high pH (mainly acrocarps) were favoured by experimental pH manipulation. Our results pointed out Syntrichia ruraliformis as a sensitive pH indicator, being almost exclusively restricted to pH values above 7. The species can also serve as an indicator of sand steppe vegetation.
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| 10. |
- Johansson, Veronika A., et al.
(författare)
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Dust seed production and dispersal in Swedish Pyroleae species
- 2014
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 32:2, s. 209-214
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Tidskriftsartikel (refereegranskat)abstract
- Dust seeds are the smallest seeds in angiosperms weighing just about a few micrograms. These seeds are characteristic of most orchids, and several studies have been performed on seed features, fecundity and dispersal of orchid dust seeds. In this study we examine seed features, seed production and seed dispersal in another plant group with dust seeds, the Pyroleae (Monotropoideae, Ericaceae), focusing on six species: Pyrola chlorantha, P. minor, P. rotundifolia, Chimaphila umbellata, Moneses uniflora and Orthilia secunda. Seed production per capsule among these species was in the range between ca 1000 and 7800, and seed production per capsule bearing shoot was in the range between ca 7000 and 60 000. Combining our results with published information on pollen-ovule ratios suggests that these Pyroleae species have a generally efficient pollination system. The most fecund species was P. minor, the only species among the investigated that is probably largely self-pollinating. The investigated Pyroleae species have a seed production comparable to the less fecund orchid species. We studied seed dispersal in the field in one of the species, P. chlorantha. Despite the extremely small and potentially buoyant seeds, the vast majority of seeds are deposited close to the seed source, within a few meters. Further studies on the recruitment ecology of the investigated Pyroleae species are currently under way.
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