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Pekka E. Kauppi Aapo Rautiainen Kari T. Korhonen Aleksi Lehtonen Jari Liski Pekka Nöjd Sakari Tuominen Markus Haakana Tarmo Virtanen 《Forest Ecology and Management》2010,259(7):1239-1244
The growing stock more than doubled from 1.6 to 3.4 million m3 between 1912 and 2005 in forests on an area of 387 km2 in southern Finland. The stock expansion continued for 93 years noting interim results, which were available for 1959, 1982, 1994 and 1999. Forested area in the region hardly changed. Carbon sequestration was mainly a result of a long-term recovery from forest degradation, a legacy of land use in the 18th and 19th centuries. Tree demography responded to management change especially of mature stands: Average tree size and stocking density of stands increased. On average the expanding biomass stock sequestered 18 tons C annually per km2 (18 g C per m2). In comparison, the emissions of fossil carbon in the region were estimated at 12 tons C per km2 (12 g C per m2) on average. However, fossil CO2 emissions exceeded biomass sequestration in recent decades. The powerful and persistent expansion of the carbon stock was an unintended co-benefit of forestry, which was motivated by the intention to improve timber yield. On the more negative side the change in management introduced clear-cuts, and a loss of diverse elements of the pre-industrial biota. 相似文献
3.
Jeff R. Powell Rachel G. Campbell Kari E. Dunfield Robert H. Gulden Miranda M. Hart David J. Levy-Booth John N. Klironomos K. Peter Pauls Clarence J. Swanton Jack T. Trevors Pedro M. Antunes 《Applied soil ecology》2009,41(1):128-136
Most soybeans grown in North America are genetically modified (GM) to tolerate applications of the broad-spectrum herbicide glyphosate; as a result, glyphosate is now extensively used in soybean cropping systems. Soybean roots form both arbuscular mycorrhizal (AM) and rhizobial symbioses. In addition to individually improving host plant fitness, these symbioses also interact to influence the functioning of each symbiosis, thereby establishing a tripartite symbiosis. The objectives of this study were to (1) estimate the effects of glyphosate on the establishment and functioning of AM and rhizobial symbioses with GM soybean, and (2) to estimate the interdependence of the symbioses in determining the response of each symbiosis to glyphosate. These objectives were addressed in two experiments; the first investigated the importance of the timing of glyphosate application in determining the responses of the symbionts and the second varied the rate of glyphosate application. Glyphosate applied at recommended field rates had no effect on Glomus intraradices or Bradyrhizobium japonicum colonization of soybean roots, or on soybean foliar tissue [P]. N2-fixation was greater for glyphosate-treated soybean plants than for untreated-plants in both experiments, but only when glyphosate was applied at the first trifoliate soybean growth stage. These data deviate from previous studies estimating the effect of glyphosate on the rhizobial symbiosis, some of which observed negative effects on rhizobial colonization and/or N2-fixation. We did observe evidence of the response of one symbiont (stimulation of N2-fixation following glyphosate) being dependent on co-inoculation with the other; however, this interactive response appeared to be contextually dependent as it was not consistent between experiments. Future research needs to consider the role of environmental factors and other biota when evaluating rhizobial responses to herbicide applications. 相似文献
4.
Thorleifsson G Magnusson KP Sulem P Walters GB Gudbjartsson DF Stefansson H Jonsson T Jonasdottir A Jonasdottir A Stefansdottir G Masson G Hardarson GA Petursson H Arnarsson A Motallebipour M Wallerman O Wadelius C Gulcher JR Thorsteinsdottir U Kong A Jonasson F Stefansson K 《Science (New York, N.Y.)》2007,317(5843):1397-1400
Glaucoma is a leading cause of irreversible blindness. A genome-wide search yielded multiple single-nucleotide polymorphisms (SNPs) in the 15q24.1 region associated with glaucoma. Further investigation revealed that the association is confined to exfoliation glaucoma (XFG). Two nonsynonymous SNPs in exon 1 of the gene LOXL1 explain the association, and the data suggest that they confer risk of XFG mainly through exfoliation syndrome (XFS). About 25% of the general population is homozygous for the highest-risk haplotype, and their risk of suffering from XFG is more than 100 times that of individuals carrying only low-risk haplotypes. The population-attributable risk is more than 99%. The product of LOXL1 catalyzes the formation of elastin fibers found to be a major component of the lesions in XFG. 相似文献
5.
Minor KM Patterson EE Keating MK Gross SD Ekenstedt KJ Taylor SM Mickelson JR 《Veterinary journal (London, England : 1997)》2011,189(2):214-219
The impact of the mutation causing dynamin 1 (DNM1)-associated exercise-induced collapse (d-EIC) was determined in a retrospective genetic survey. The frequency of DNM1 mutant allele carriers in Labrador retrievers from conformation show, field trial/hunt test, pet or service lines ranged from 17.9% to 38.0% and the frequency of homozygous mutant (EE genotype) individuals ranged from 1.8% to 13.6%; 83.6% of these EE Labradors were reported to have collapsed by 4 years of age. DNM1 mutation carriers and EE dogs with a collapse phenotype were also detected in Chesapeake Bay retrievers, Curly-coated retrievers, Boykin spaniels, Pembroke Welsh corgis and mixed breed dogs thought to be Labrador retriever crosses. The DNM1 mutation was not identified in Golden, Flat-coated, or Nova Scotia duck tolling retrievers, or 15 other non-retrieving breeds. Veterinarians and breeders should be aware that the DNM1 EE genotype is not completely penetrant and that d-EIC is a widespread health concern in several very popular breeds, as well as breeds whose genetic similarity to retrievers is not obvious. 相似文献
6.
Robert H. Gulden David Levy-Booth Jeff R. Powell Kari E. Dunfield K. Peter Pauls Clarence J. Swanton 《Soil biology & biochemistry》2007,39(8):1956-1967
Recent advances in molecular techniques have allowed for the routine examination of nucleic acids in environmental samples. Although current methodologies are very sensitive, accurate target DNA quantification from environmental samples remains challenging. To facilitate high-throughput DNA quantification from environmental samples, we developed a novel DNA quantification method based on a non-linear curve-fitting approach to extract additional information from quantitative PCR amplification curves and used the fitted parameters to develop multiple regression standard equations for target DNA quantification. A 3-parameter sigmoidal function performed superior to a 4-parameter Weibull function for generating the multiple regression standard equations. In a verification experiment, target DNA was quantified in a series of ‘unknown’ samples in three soils using this approach and the results were compared to target DNA values determined using corrected and uncorrected Ct-based (threshold cycle) methods. For each method, the deviations from the expected target DNA content were determined. Results clearly showed that over all DNA concentrations, target DNA content determined by the non-linear curve-fitting method was more accurate and more precise than values predicted by all other methods. Analysis of variance conducted on the predicted DNA contents also revealed fewer statistical artifacts with the non-linear curve fitting method compared to the conventional Ct-based methods. The novel approach described here is accurate, inexpensive, and very amenable for automation and high-throughput applications. 相似文献
7.
Nissinen A Ibrahim M Kainulainen P Tiilikkala K Holopainen JK 《Journal of agricultural and food chemistry》2005,53(22):8631-8638
The effect of carrot psyllid (Trioza apicalis F?rster) feeding and limonene and methyl jasmonate (MeJA) treatments on the essential oil composition and headspace volatiles of carrot (Daucus carota ssp. sativus), cvs. Parano and Splendid, leaves was studied. Carrot psyllid feeding significantly increased the concentrations of sabinene, beta-pinene, and limonene, whereas limonene treatment increased the concentration of (Z)-beta-ocimene in the leaves of both cultivars. The limonene treatment significantly increased the concentration of total phenolics in the leaves of both cultivars, and MeJA treatment increased phenolic concentration in the leaves of Parano. Exogenous limonene spray did not decrease the number of carrot psyllid eggs laid either 2 or 24 h after treatment. The results suggest that carrot psyllid feeding induces changes in the endogenous monoterpene pool in the carrot leaves. Limonene and MeJA treatments affect some induced defenses of the carrot, but the exogenous limonene spray is not an effective oviposition deterrent against carrot psyllid. 相似文献
8.
Siw T. Killengreen Nigel G. Yoccoz Kari Anne Bråthen John-André Henden Tino Schott 《Biological conservation》2007,135(4):459-472
We conducted a large-scale, campaign-based survey in Finnmark, northern Norway to evaluate the proposition that declining Arctic fox populations at the southern margin of the Arctic tundra biome result from fundamental changes in the state of the ecosystem due to climatic warming. We utilized the fact that the decline of the Arctic fox in Finnmark has been spatially heterogeneous by contrasting ecosystem state variables between regions and landscape areas (within regions) with and without recent Arctic fox breeding.Within the region of Varanger peninsula, which has the highest number of recorded dens and the most recent breeding records of Arctic fox, we found patterns largely consistent with a previously proposed climate-induced, bottom-up trophic cascade that may exclude the Arctic fox from tundra. Landscape areas surrounding dens without recent Arctic breeding were here more productive than areas with recent breeding in terms of biomass of palatable and climate sensitive plants, the number of insectivorous passerines and predatory skuas. Even the frequency of unspecified fox scats was the highest in landscape areas where arctic fox breeding has ceased, consistent with an invasion of the competitively dominant red fox. The comparisons made at the regional level were not consistent with the results within the Varanger region, possibly due to different causal factors or to deficiencies in Arctic fox monitoring at a large spatial scale. Thus long-term studies and adequate monitoring schemes with a large-scale design needs to be initiated to better elucidate the link between climate, food web dynamics and their relations to Arctic and red foxes. 相似文献
9.
Synthetic chelating agents such as EDTA form strong complexes with heavy metals and therefore have the potential to remobilize metals from sediments and aquifers. In natural waters EDTA is present almost exclusively in the form of metal-complexes. Therefore, remobilization of metals is always a metal-metal-EDTA exchange reaction. We have investigated, to our knowledge for the first time, the remobilization of metals from the surface of synthetic iron oxides and from a river sediment by different metal-EDTA complexes. The metals are exchanged as follows:MeEDTAdissolved + Meast
adsorbed MeastEDTAdissolved + Meadsorbed
The order of the remobilization rate of Zn2+ from goethite is CaEDTA > Fe(III)EDTA, reflecting the slow exchange reaction of Fe(III)EDTA. For the remobilization of Pb2+ from goethite, the rate was found to be Fe(III)EDTA > CaEDTA > ZnEDTA. Here, Fe(III)EDTA has surprisingly the fastest exchange rate. Only very limited remobilization of Pb2+ is possible from hydrous ferric oxide at pH 8 due to the very strong adsorption of Pb2+. The order of remobilization of Zn2+ from a natural river sediment was found to be CaEDTA > CuEDTA > Fe(III)EDTA. The remobilization rate of Zn2+ with Fe(III)EDTA is only 12% of the rate with CaEDTA, illustrating the importance of EDTA speciation for assessing remobilization. 相似文献
10.
Kilpeläinen A Peltola H Ryyppö A Sauvala K Laitinen K Kellomäki S 《Tree physiology》2003,23(13):889-897
Impacts of elevated temperature and carbon dioxide concentration ([CO2]) on wood properties of 15-year-old Scots pines (Pinus sylvestris L.) grown under conditions of low nitrogen supply were investigated in open-top chambers. The treatments consisted of (i) ambient temperature and ambient [CO2] (AT+AC), (ii) ambient temperature and elevated [CO2] (AT+EC), (iii) elevated temperature and ambient [CO2] (ET+AC) and (iv) elevated temperature and elevated [CO2] (ET+EC). Wood properties analyzed for the years 1992-1994 included ring width, early- and latewood width and their proportions, intra-ring wood density (minimum, maximum and mean, as well as early- and latewood densities), mean fiber length and chemical composition of the wood (cellulose, hemicellulose, lignin and acetone extractive concentration). Absolute radial growth over the 3-year period was 54% greater in AT+EC trees and 30 and 25% greater in ET+AC and ET+EC trees, respectively, than in AT+AC trees. Neither elevated temperature nor elevated [CO2] had a statistically significant effect on ring width, early- and latewood widths or their proportions. Both latewood density and maximum intra-ring density were increased by elevated [CO2], whereas fiber length was increased by elevated temperature. Hemicellulose concentration decreased and lignin concentration increased significantly in response to elevated temperature. There were no statistically significant interaction effects of elevated temperature and elevated [CO2] on the wood properties, except on earlywood density. 相似文献