Role of black alder (Alnus glutinosa) in vegetation dynamics in West Norway

In Norway black alder (Alnus glutinosa) has an 'optimal' area along the western coast where it acts as a pioneer species in secondary successions on Calluna and grass heaths, pastures, formerly cultivated land and in hydroseres. Black alder is dominant or co–dominant with birch in oligotrophic grazing forests, most of which belong to the ass. Corno suecicae–Betuletum where black alder seems to be able to survive for a long time. It is also found in a variety of other woodland communities, some of which are stable Alnetea glutinosae or Alno–Padion communities. Others are successional stages towards meso– or eutrophic deciduous forests. The new Alnetea glutinosae ass. Carici nigrae–Alnetum glutinosae is described. The ecology of black alder in West Norway is compared to its ecology in other areas, especially on the British Isles. The humid climate and recent changes in agricultural practice are the main reasons for the present abundance of black alder in West Norway.     

Morphological and anatomical characterisation of black alder Alnus glutinosa (L.) Gaertn. ectomycorrhizas

 Ectomycorrhizal types of black alder [Alnus glutinosa (L.) Gaertn.] collected over a 3-year period within an alder forest were characterised by morphological and anatomical features. Of the total of 16 types, 14 are described for the first time in this paper. Eight identified types belong to the genera Russula, Lactarius, Naucoria, and Cortinarius, while eight further types remained unidentified. In some cases, similarities of mantle features indicate relationships to identified mycorrhizas. Mycorrhizas of Naucoria escharoides and N. subconspersa were not distinguished. Two unidentified mycorrhizal types exhibited hyphal mantle structures very similar to these Naucoria species. Within the genus Cortinarius, mycorrhizas of C. cf. helvelloides were easily distinguished from all other Cortinarius-like mycorrhizas described on Alnus, which in general showed little anatomical variation. Two further unidentified mycorrhizas, "Alnirhiza lilacina" and "A. violacea", probably also belong to Cortinarius. The ectomycorrhiza of Russula pumila was the only identified type within the genus Russula, but the unidentified type "Alnirhiza cremicolor" also likely belongs to this genus. Three Lactarius species were present in the experimental plot. Two species (L. obscuratus and L. omphaliformis) had indistinguishable mycorrhizal types, but were easily differentiated from the mycorrhizas of L. lilacinus, which caused intracellular penetration of Hartig net hyphae into epidermal and cortical cells. All other mycorrhizal types of black alder exhibited a paraepidermal Hartig net without penetration of root cells. Two unidentified mycorrhizal types "Alnirhiza atroverrucosa" and "A. cystidiobrunnea", already described from North American Alnus rubra as unnamed morphotypes, showed no similarity to identified mycorrhizas. All 16 mycorrhizal types appeared to be specific or at least typical for alders, since they have not yet been reported from other tree species. Accepted: 29 August 1997     

Comparison of random and SSR-enriched shotgun pyrosequencing for microsatellite discovery and single multiplex PCR optimization in Acacia harpophylla F. Muell. Ex Benth

Streamlining the development and genotyping of microsatellites in species for which no genetic information is available represents an important technical challenge to overcome in order to enable mainstream application of state-of-the-art population genetic analysis techniques in nonmodel organisms. Using the example of Acacia harpophylla, an acacia tree endemic of north-eastern Australia, we show that high-throughput shotgun pyrosequencing technology, so-called second-generation sequencing, reduces time and cost of microsatellite marker discovery in nonmodel organisms and of their large-scale typing in natural populations. We found that 0.5% of short sequence reads generated on 454 Genome Sequencer FLX Titanium from random genome sampling and 2.2% of reads generated with prior microsatellite enrichment yielded microsatellite markers with designed polymerase chain reaction (PCR) primers, suggesting that enrichment increases efficiency of pyrosequencing when microsatellite discovery is the primary goal. Using stringent selection criteria to facilitate downstream PCR multiplex design, we identified 1435 microsatellite loci with designed primers from a total of 200,908 short sequence reads. From a subset of 96 loci tested for amplification, 38 were validated for population genetics applications, leading to the optimization of a cost-effective multiplex PCR protocol for the simultaneous typing of nine microsatellites in natural populations of A. harpophylla.     

Gall mite (Eriophyes laevis) infestation and leaf removal affect growth of leaf area in black alder (Alnus glutinosa) short shoots

Summary We measured the effects ofEriophyes laevis mite galls on the relative growth of short shoot leaf area ofAlnus glutinosa. A portion of leaves was artificially removed from a set of short shoots with both high and low gall density to cause local stress conditions. Nontreated high and low gall density short shoots were used as controls. The results show that the relative growth of leaf area measured for short shoots is negatively affected by high gall density. Artificial leaf removal, on the other hand, had positive effects on leaf area growth. Interestingly, the growth of leaf area did not differ for high gall density short shoots with leaf removal and noninfested short shoots with no leaf removal. This result may be caused by the combined, opposite effects of leaf removal and gall infestation.     

Characterization of polymorphic microsatellite markers for the Carnaby's cockatoo (Calyptorhynchus latirostris) and related black cockatoo species

Microsatellite loci were isolated from Carnaby's black cockatoo (Calyptorhynchus latirostris: Aves), a highly valued, endangered, and endemic species of bird from Western Australia. This study describes three dinucleotide and one tetranucleotide microsatellite loci for which the primers produced clear and polymorphic amplification patterns with between two and nine alleles and moderate levels of variability. Two additional dinucleotide markers which were monomorphic in the Carnaby's cockatoo were able to amplify and were polymorphic in two other species of black cockatoo, greatly increasing the utility of these markers.     

Development of microsatellite markers in Fosterella rusbyi (Bromeliaceae) using 454 pyrosequencing

? Premise of the study: Polymorphic microsatellite markers were developed for Fosterella rusbyi (Bromeliaceae) to evaluate the population genetic structure and genetic diversity of natural populations of F. rusbyi and other Fosterella species in Bolivia. ? Methods and Results: 454 pyrosequencing technology was used to generate 73027 sequence reads from F. rusbyi DNA, which together contained 2796 perfect simple sequence repeats (SSRs). Primer pairs were designed for 30 loci, of which 15 were used to genotype 30 F. rusbyi plants from two geographical areas in Bolivia. All markers were polymorphic, with two to nine alleles in the overall sample. Cross-species amplification was tested in 10 additional Fosterella species. Seven loci showed consistent amplification in six or more species. ? Conclusions: The 15 SSR markers developed for F. rusbyi are promising candidates for population genetic analyses within F. rusbyi and other species of Fosterella.     

Glutamine synthetase in alder (Alnus glutinosa) root nodules. Purification, properties and cytoimmunochemical localization

Chromatographic, kinetic and regulatory properties of glutamine synthetase (GS) were investigated in root nodules of Alnus glutinosa L. (Gaertn) grown in a culture chamber. By DEAE Sephacel column chromatography and polyacrylamide gel electrophoresis, a major form of the enzyme was identified. Molecular weight was about 360 000 for the native protein and 43 000 for the subunits. Optimum pH was about 7.3 and Km for glutamate and ATP were 0.9 m M and 0.5 m M , respectively. By immunofluorescent techniques GS was localized in the inner cortical cells but not in vesicles of alder root nodules.     

Isolation and characterization of microsatellite markers for turbot (Scophthalmus maximus) by screening SSR-enriched library

Turbot (Scophthalmus maximus), important economical flatfish species, is famous for its rapid growth and good taste. Ten microsatellite loci were isolated and examined the population structure of two turbot strains, respectively from Dalian and Beidaihe. The number of alleles ranged from 3 to 11 with the expected heterozygosity ranged from 0.5700 to 0.8973. These sets of microsatellite markers are likely to be used as studies of genome mapping, parentage determination and population genetics in this species.     

Development of microsatellite markers for white spruce (Picea glauca) and related species

We report the development of 13 primer pairs that allow the unambiguous amplification of 15 microsatellite (SSR) loci in white spruce (Picea glauca). Fourteen of these loci were polymorphic in trees sampled at three geographically separated regions of western Canada. Segregation analysis carried out on these loci confirmed a Mendelian inheritance pattern for all except two, which showed significant segregation distortion. All of these primer pairs amplified SSR loci in at least one of the other Picea species tested [black spruce (P. mariana), red spruce (P. rubens), Norway spruce (P. abies), Colorado spruce (P. pungens), sitka spruce (P. sitchensis) and Engelmann spruce (P. engelmannii)]. Given the important commercial and ecological roles of these species, this set of markers will be invaluable for their management, the improvement of commercially important traits, and the study of their ecology and genetics. Received: 18 August 2000 / Accepted: 28 September 2000     

Refining the statistical parameters for constructing tree-ring chronologies using short-lived species: Alder (Alnus glutinosa Gaertn)

The dendrochronological potential of short-lived species has had varying degrees of success in the past. Where there has been a level of success with short sequenced assemblages, the focus has been on visual comparisons, based on the occurrence of signature rings. Of vital importance to alder’s ability to be cross-correlated is that it produces a significant amount of distinguishable signature rings. Between 2012 and 2013, a large artificial island (crannog) of medieval date was excavated at Drumclay, County Fermanagh, Northern Ireland, and revealed a site of significant longevity, dating from the 9th century AD to the Post-Medieval period. This excavation exposed a vast number of well-preserved waterlogged archaeological features, resulting in the retention of over 9,000 individual wood samples. Oak timbers were used scarcely in the construction of the crannog, with the dominant wood species identified during excavation being alder. While the oak timbers have proved successful in providing spot dates and indicating phases of activity, the full chronological potential of the wood assemblage lies in the ring patterns of the principal species, alder, particularly with respect to understanding construction phases and site evolution. Previous failures to build chronologies using alder have been attributed to the short-lived and site specific nature of the species. Here, we test whether the measurement of large numbers of samples from a single context within a single site overcomes the limitations posed by alder. We measured the ring-widths of 90 alder samples from archaeological features within the crannog’s infrastructure to test if a robust context chronology could be built. The average ring sequence length ranged from 30 to 60 rings, with one timber extending to 108 rings. Visual correlations were used to aid ring pattern matching in conjunction with statistical correlation. We used radiocarbon wiggle-matching to test the robustness of our constructed chronology and to anchor it to an absolute timescale. Our results to date show that problems of autocorrelation can arise when long alder sequences (>100 rings) are used in conjunction with short sequences (30 to 60 rings). Establishing a rigorous protocol for sample selection has enabled us to develop a more statistically refined methodology that has produced t-values as high as 8.3. We show that in order to construct the best possible alder chronology, multiple ring patterns need to be examined from each context. We recommend examining short-lived assemblages on their own merits; the best approach in these cases is not to look for the longest sequences but instead to focus on the those from the mean sequence range.     

Sensitivity of black alder (Alnus glutinosa [L.] Gaertn.) growth to hydrological changes in wetland forests at the rear edge of the species distribution

Functional responses of riparian species can be used as surrogates for their vulnerability to climate-driven changes. In particular, black alder (Alnus glutinosa [L.] Gaertn.) might be highly susceptible to changes in habitat at the southern limit of its biogeographical distribution in the Mediterranean Basin. In this study, the long-term environmental signal of black alder on a river system in southern Portugal was determined on trees located in different geomorphological position across the floodplain. For all sampled trees, we related radial growth to monthly precipitation, temperature and streamflow. Tree growth responded to some degree to climatic variables, while a marked reduction of tree-ring growth was observed after extreme hydrologic events leading to mechanical damage and uprooting, especially when located near and downstream on the active channel. Similarly, during the first years of life, tree-ring width tended to be narrower near to the active channel, whereas trees at far and less disturbed sites grew faster and, therefore, showed wider rings. Our results confirm the potential of black alder growth as a proxy for hydrologic conditions in a semi-arid basin, and the possibility of using the response of this species to track environmental changes. Given the ecological and economic importance of black alder, and the potential for rapid changes in its distribution, the identification of those areas the most at risk of flood damage, and the adequate management of high priority alder populations will become progressively more important over coming years.     

Stem photosynthesis not pressurized ventilation is responsible for light-enhanced oxygen supply to submerged roots of alder (Alnus glutinosa)

BACKGROUND AND AIMS: Claims that submerged roots of alder and other wetland trees are aerated by pressurized gas flow generated in the stem by a light-induced thermo-osmosis have seemed inconsistent with root anatomy. Our aim was to seek a verification using physical root-stem models, stem segments with or without artificial roots, and rooted saplings. METHODS: Radial O2 loss (ROL) from roots was monitored polarographically as the gas space system of the models, and stems were pressurized artificially. ROL and internal pressurization were also measured when stems were irradiated and the xylem stream was either CO2 enriched or not. Stem photosynthesis and respiration were measured polarographically. Stem and root anatomy were examined by light and fluorescence microscopy. KEY RESULTS: Pressurizing the models and stems to 相似文献   

Leaf water relations of black alder [Alnus glutinosa (L.) Gaertn.] growing at neighbouring sites with different water regimes

 The tree species black alder [Alnus glutinosa (L.) Gaertn.] typically inhabits wet sites in central Europe but is also successful on well drained soils. To test the physiological adjustment of the species in situ, conductances, transpiration rates and water potentials (Scholander pressure chamber) of black alder leaves were investigated at two neighbouring sites with different water regimes: alder trees at an occasionally water logged alder forest and alder shrubs in a nearby, much drier hedgerow. Additional experiments with alder cuttings in nutrient culture showed that leaf conductances and gas exchange were both strongly influenced by the substrate water potential. In situ however, there was little spatial variability within the different parts of a crown and we found that physiological regulation at leaf level was hardly influenced by different site water regimes or different tree sizes. Diurnal courses of leaf water relations as well as their regulation at the leaf level (e.g. the hyperbolic relationship between conductances and ΔW) were strikingly similar at both sites. Leaf water potential in black alder was shown to be a consequence of immediate transpiration rates, which were high in comparison to other tree species (up to 4 mmol H₂O m^–2 s^–1), rather than the water potentials being a factor that influenced conductance and, therefore, transpiration. The always high leaf conductances and consequent high transpiration rates are interpreted as a strategy to maximise productivity through low stomatal limitation at sites where water supply is usually not limited. However, at the same time this behaviour restricts black alder to sites where at least the deep-going roots can exploit water. Received: 10 September 1998 / Accepted: 12 January 1999     

Development and multiplexing of microsatellite markers using pyrosequencing in the clonal plant Comarum palustre (Rosaceae)

Microsatellites represent one of the most commonly used genetic markers for population genetic studies. Traditionally, their development is quite time consuming, requiring construction of a genomic library enriched for repeated motifs. Using pyrosequencing, a fast and cost-effective new generation sequencing technique, we produced 24,340,862 bases in 63,860 short fragment reads, including 1170 dinucleotide motifs with a minimum of six repeats and 1383 trinucleotide motifs with a minimum of four repeats for the Marsh Cinquefoil, Comarum palustre L., an endangered marsh pioneer species. We selected 58 loci with SSR (Short Sequence Repeat) segments (at least 10 repeats) for a preliminary screening. Out of them, we screened 29 loci on a capillary sequencer after ligation in a vector and PCR using T7 forward primer labelled with FAM fluorescent dye and the specific unlabeled reverse primers. This procedure allowed us to screen large number of candidate loci with the same labelled primer and unlabelled specific primers. Finally, we characterized 20 polymorphic microsatellite markers, nine dinucleotides and 11 trinucleotides. We used these markers to assess genetic diversity and clonal structure in two Belgian populations. All loci showed a maximum of two alleles per individual, suggesting that they are from a diploid genome. One genet was detected in a newly extending population while 53 different genets in a long-term ecologically managed population. The number of alleles per locus ranged from 6 to 14 in this old population with an expected heterozygosity, ranging from 0.5964 to 0.8278. These preliminary results show a genet size up to 7.2 m.