Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2006
Forfattere
T. Larssen E. Lydersen D. Tang Yi He Jixi Gao H. Liu Lei Duan H.M. Seip R.D. Vogt Jan Mulder M. Shao Yan-Hui Wang H. Shang X. Zhang Svein Solberg Wenche Aas Tonje Økland O. Eilertsen V. Angell Quanru Liu D. Zhao Renjun Xiang J. Xiao J. LuoSammendrag
Acid rain emerged as an important environmental problem in China in the late 1970s. Many years of record economic growth have been accompanied by increased energy demand, greater coal combustion, and larger emissions of pollutants. As a result of significant emissions and subsequent deposition of sulfur, widespread acid rain is observed in southern and southwestern China. In fact, the deposition of sulfur is in some places higher than what was reported from the ?black triangle? in central Europe in the early 1980s. In addition, nitrogen is emitted from agriculture, power production, and a rapidly increasing number of cars. As a result, considerable deposition of pollutants occurs in forested areas previously thought to be pristine. Little is known about the effects of acid deposition on terrestrial and aquatic ecosystems in China. In this article, we present the current situation and what to expect in the future, largely on the basis of results from a five-year Chinese?Norwegian cooperative project. In the years ahead, new environmental challenges must be expected if proper countermeasures are not put into place.
Forfattere
Jørgen Aleksander Mølmann Olavi Junttila Øystein Johnsen Jorunn Elisabeth OlsenSammendrag
Seedlings of trees with a free growth pattern cease growth when night-lengths become shorter than a critical value, and this critical night-length (CNL) decreases with increasing latitude of origin. In northern populations, the light quality also appears to play an important role and a clinal variation in requirement for far-red (FR) light has been documented. In this study we dissected the light quality requirements for maintaining growth in different latitudinal populations of Norway spruce (Picea abies (L.) H. Karst.) using light emitting diodes for red (R), FR and blue (B) light, as 12 h day extension to provide 24 h photoperiod. At equal spectral photon flux, FR light was more effective than R light in maintaining growth, and the requirement of both R and FR increased with northern latitude of origin. One-to-one mixtures of R and FR light were more effective in maintaining growth than either FR or R light alone, indicating a possible interaction between R and FR light maintaining growth. Using the blue light as day extension could not prevent growth cessation in any of the populations, but delayed the bud set slightly in all populations. Our results suggest that phytochrome(s) are the primary photoreceptors in high irradiance responses maintaining growth in Norway spruce seedlings.
Sammendrag
Conventional farmers converting to organics have contributed to most of the rapid expansion of organic farming in recent years. The new organic farmers may differ from their more established colleagues, which may have implications for the development of the organic farming sector and its distinctiveness vis-a-vis conventional production and marketing practices. The aim of this study was to explore Norwegian organic dairy farmers' personal and farm production characteristics, farming goals, conversion motives, and attitudes to organic farming, grouped by year of conversion (three groups). A postal survey was undertaken among organic dairy farmers (n=161). The results show that the newcomers (converted in 2000 or later) were less educated than the early entrants (the so-called 'old guard') who converted in 1995 or earlier. The frequency of activities like vegetable growing and poultry farming among the old guard was high. The late-entry organic herds were fed with more concentrates and had a higher milk production intensity, showed a higher incidence of veterinary treatments and less frequent use of alternative medicine than the herds of the two earlier converting groups. For all groups of farmers, the highest ranked farming goals were sustainable and environment-friendly farming and the production of high-quality food. Late entrants more often mentioned goals related to profit and leisure time. On average, the most frequently mentioned motives for conversion were food quality and professional challenges. The old guard was more strongly motivated by food quality and soil fertility/pollution issues than the others, whereas financial reasons (organic payments included) were relatively more important among the newcomers. All groups held very favorable views about the environmental qualities of organic farming methods, albeit with different strengths of beliefs. Even though trends towards more pragmatic and business-oriented farming were found, the majority of the newcomers were fairly committed.
Sammendrag
We have made and partially sequenced two subtracted cDNA libraries, one representing genes predominantly expressed in a tree from an early-flushing family of Norway spruce (early-flushing library; EFL) and the second from a late flushing family (late flushing library; LFL), during 4 weeks before bud burst. In the EFL, expressed sequence tags (ESTs) encoding proteins of the photosynthetic apparatus and energy metabolism and proteins related to stress (abiotic and biotic) and senescence were abundant. ESTs encoding metallothionein-like and histone proteins as well as transcription factors were abundant in the LFL. We used quantitative real-time reverse transcription polymerase chain reaction to study the expression patterns of 25 chosen genes and observed that the highest levels of activity for most genes were present when plants were still ecodormant. The results indicate that the late flushing is not a result of a delay in gene activity, but is rather associated with an active transcriptional process. Accordingly, certain metabolic processes may be turned on in order to prevent premature flushing. We discuss the putative role of the studied genes in regulation of bud burst timing. Among the candidate genes found, the most interesting ones were the DNA-binding proteins, water-stress- related genes and metallothioneins. Expression patterns of some genes involved in chemical modification of DNA and histones indicate that epigenetic factors are involved in the timing of bud burst. In the obtained transcriptomes, we could not find genes commonly believed to be involved in dormancy and bud set regulation (PHY, CRY, ABI etc.) in angiosperm plants.
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Forfattere
Line E. Sverdrup Roar Linjordet Gjermund Strømman Snorre Hagen Cornelis A.M. van Gestel Åsa Frostegård Roald SørheimSammendrag
The effect of zinc on soil nitrification and composition of the microbial community in soil was investigated using a full factorial experiment with five zinc concentrations and four levels of biological complexity (microbes only, microbes and earthworms (Eisenia fetida), microbes and Italian ryegrass (Lolium multiflorum var. Macho), and microbes, ryegrass and earthworms). After 6 weeks of exposure, the activity of soil nitrifying bacteria was measured and the microbial community structure was characterized by phospholipid fatty acid (PLFA) analysis. Soil nitrification and several PLFA markers were significantly influenced by either zinc addition and/or the presence of earthworms or ryegrass, and one of the most pronounced changes was the increase of fungi and decrease of bacteria with increasing concentrations of zinc. Of particular interest, however, was the potential interaction between the presence of plants and/or earthworms and the effect of zinc, which the factorial study design allowed us to explore. Such an effect was observed in two cases: Earthworms reduced the positive effect of zinc on the fungal biomass (ANOVA, p = 0.03), and the effect of earthworms on the soil nitrification activity depended on zinc concentration (ANOVA, p < 0.05). The effect of earthworm presence was not very large, but it does show that multispecies tests might give information about metal toxicity, or bioavailability that cannot be predicted from single-species tests. (c) 2006 Elsevier Ltd. All rights reserved.
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