Artikkelit jotka sisältää sanan 'drought'
Kasvualustan kuivumisen vaikutukset rahkasaraturpeeseen istutettujen männyntaimien ensikehitykseen.
English title: High and dry: Consequences of drought exposure in Scots pine seedlings grown in authentic peat soil.
Original keywords:
männyntaimet;
Pinus sylvestris;
kuivuus;
rahkasaraturve;
fotosynteesin tehokkuus (Fv/ Fm);
mykorritsat;
polyamiinit;
juurten ja versojen kasvu
English keywords:
drought;
Fv/Fm;
mycorrhizal colonization;
Pinus sylvestris seedlings;
poly-amines;
root and shoot growth;
Sphagnum-Carex peat
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Tekijät
Should the frequency of drought increase in boreal forests due to climate change, seedlings planted in prepared peat mounds could become more susceptible to soil desiccation. The resistance of Scots pine (Pinus sylvestris L.) seedlings to drought will thus be a key factor in the regeneration success of pine-dominated, forestry-drained peatlands. In this study, we evaluated the physiological, metabolic, and morphological responses of year-old seedlings gradually exposed to extreme drought in highly decomposed Sphagnum-Carex peat blocks. Drought clearly suppressed root and shoot growth as well as fractional colonization of ectomycorrhizal fungi. Sustained declines in photochemical efficiency (Fv/Fm) of previous-year and current-year needles did not occur until the volumetric soil water content had dropped to 30% and 10%, respectively. Polyamine analysis revealed that new needles are preferred in protecting the different parts of the seedlings against drought stress. Despite growth losses, the maintenance of rather high photochemical efficiency in current-year needles under severe water stress would appear to indicate a potential for seedling recovery if water availability in the peat improved. Given the high tolerance exhibited by Scots pine seedlings, death by drought seems a lesser concern.
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Pearson,
Finnish Forest Research Institute, Parkano Research Unit, Kaironiementie 15, FI-39700 Parkano, Finland
Sähköposti:
ei.tietoa@nn.oo
- Saarinen, Sähköposti: ei.tietoa@nn.oo
- Heiskanen, Sähköposti: ei.tietoa@nn.oo
- Sarjala, Sähköposti: ei.tietoa@nn.oo
- Laine, Sähköposti: ei.tietoa@nn.oo
Arokosteikot: ekologia, esiintyminen ja suojelutilanne Pohjois-Pohjanmaalla ja Kainuussa.
English title: Aro wetlands: ecology, occurrence and conservation in north-central Finland.
Avainsanat:
Nature conservation;
aapa mire;
ecological gradient;
Finnish mire site type system;
groundwater;
mire complex;
peatland morpology;
seasonal drought;
wetland classification
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The present paper introduces and describes a poorly known wetland type – aro wetland – in well permeable mineral soil substratum in Northern Ostrobothnia and Kainuu (between 64° – 66° N lat.). Field observations (linked with the interpretation of aerial photographs) were made in 32 localities, whose conservation status is presented. We define boreal aro wetlands ecologically as a seasonal wetland type of their own which occur on well-drained mineral soil, which are mainly characterised by treeless, mire expanse fen vegetation and in which the peat accumulation is (almost) totally hampered by the vigorous decomposition of the organic matter resulting from an extremely unstable water regime (flood and seasonal drought) and small plant production. Aro wetlands in the western part of the study area occur on sandy substratum (the largest in parts of mire complexes split by ancient raised beach ridges), whereas in the eastern part the aro wetlands known so far are small pond-like depressions in till substratum. Carex lasiocarpa (mostly) dominates the vegetation on sandy substratum. Juncus filiformis and Carex nigra are typical, and Rhynchospora fusca and Molinia caerulea a bit rarer. Sphagnum cover is usually minimal. Considering aro wetlands an extreme case of suo (mire) makes the stability of water regime (stable – unstable) a direction of variation in the traditional Finnish mire site type system, which is based on several ecological gradients.
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Laitinen,
University of Oulu, Department of Biology, Botany, P.O.Box 3000, FI-90014, Finland
Sähköposti:
ei.tietoa@nn.oo
- Rehell, Sähköposti: ei.tietoa@nn.oo
- Huttunen, Sähköposti: ei.tietoa@nn.oo
- Eurola, Sähköposti: ei.tietoa@nn.oo
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