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.
2011
Forfattere
Axel Schmidt Raimund Nagel Trygve Krekling Erik Christiansen Jonathan Gershenzon Paal KrokeneSammendrag
Norway spruce (Picea abies) defends itself against herbivores and pathogens by formation of traumatic resin ducts filled with terpenoid-based oleoresin. An important group of enzymes in terpenoid biosynthesis are the short-chain isoprenyl diphosphate synthases which produce geranyl diphosphate (C10), farnesyl diphosphate (C15), and geranylgeranyl diphosphate (C20) as precursors of monoterpenes, sesquiterpenes, and diterpene resin acids, respectively. After treatment with methyl jasmonate (MJ) we investigated the expression of all isoprenyl diphosphate synthase genes characterized to date from Norway spruce and correlated this with formation of traumatic resin ducts and terpene accumulation. Formation of traumatic resin ducts correlated with higher amounts of monoterpenes, sesquiterpenes and diterpene resin acids and an upregulation of isoprenyl diphosphate synthase genes producing geranyl diphosphate or geranylgeranyl diphosphate. Among defense hormones, jasmonate and jasmonate-isoleucine conjugate accumulated to higher levels in trees with extensive traumatic resin duct formation, whereas salicylate did not. Jasmonate and ethylene are likely to both be involved in formation of traumatic resin ducts based on elevated transcripts of genes encoding lipoxygenase and 1-aminocyclopropane-1-carboxylic acid oxidase associated with resin duct formation. Other genes involved in defense signalling in other systems, mitogen-activated protein kinase3 and nonexpressor of pathogenesis-related gene1, were also associated with traumatic resin duct formation. These responses were detected not only at the site of MJ treatment, but also systemically up to 60 cm above the site of treatment on the trunk.
Sammendrag
The species composition of wood-inhabiting fungi (polypores and corticoids) was investigated on 1138 spruce logs and 992 pine logs in 90 managed and 34 natural or near-natural spruce and pine forests in SE Norway. Altogether, the study included 290 species of wood-inhabiting fungi. Comparisons of logs with similar properties (standardized tree species, decay class, dimension class) in natural and managed forests showed a significant reduction in species number per log in managed spruce forests, but not in managed pine forests. The species number per log in managed spruce forests was 10–55% lower than on logs from natural spruce forests. The reduction was strongest on logs of large dimensions. A comparison of 200–400 spruce logs from natural and managed forests showed a 25% reduction in species richness corresponding to a conservative loss of ca. 40 species on a regional scale. A closer inspection revealed that species confined to medium and very decayed spruce logs were disfavored in managed forests, whereas species on early decay classes and decay generalists were unaffected. Similarly, species preferring large spruce logs were disfavored in managed forests. Forest management had strongest impact on low-frequent species in the spruce forests (more than 50% reduction), whereas common species were modestly affected. Corticoid fungi were more adversely affected than polypore fungi. These results indicate that wood-decaying fungi in pine forests are more adapted to forest disturbances than spruce-associated species. Management measures securing a continuous supply of dead wood are more important in spruce forests than in pine forests.
Forfattere
Stine Gregersen Vhile Nils Petter Kjos Aud Kari Fauske Henning Sørum Randi Seljåsen Margareth ØverlandSammendrag
Det er ikke registrert sammendrag
Forfattere
Christer MagnussonSammendrag
Nematodes, commonly known as round worms, are the most common multicellular animals on planet Earth. After 1000 million years of evolution members of the phylum Nematoda have a high bionomic diversity. As habitants of the soil and rhizosphere nematodes are involved en energy fluxes, and affect carbon and nutrient cycles. As plant parasites, either alone or in synergism with other pathogens, nematodes are responsible for plant disease complexes and major crop losses. A growth depression in a field of potato (Solanum tuberosum) cv. Saturna [resistant to pathotype Ro1 of potato cyst nematode (PCN) Globodera rostochiensis], suggestive of potato cyst nematode damage, was detected in Grue, eastern Norway. Analyses of soil samples did not detect PCN, but demonstrated the occurrence of a large number of lesion nematodes Pratylenchus penetrans .Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium Streptomyces scabies. Potato yield was reduced by 50% in the affected area of the field. Transect-sampling showed plant growth to be negatively correlated with densities of P. penetrans and suggested a damage threshold of potato to the nematode of 100 specimens per250 g of soil. Common scab (Streptomyces scabies) occurred frequently in the affected area. P. penetrans was present in roots, underground stems, stolons and tubers. Tubers from the depressed part of the field had severe symptoms similar to those caused by the common scab bacterium. In tubers, nematodes were detected inside cross-lesions typical symptoms of common scab, and occurred also in the outermost 0.5 mm tissue associated with such lesions. In pots with sterile sand, micro-tubers of potato cv. Saturna, produced from meristems, were grown in a green-house infected with, P. penetrans, S. scabies, and a combination of P. penetrans and, S. scabies. P. penetrans alone induced tuber lesions similar to those of common scab. Also, the combined inoculation of the bacterium and the nematode seemed to enhance symptom expression. Similar scab symptoms, in connection with lesion nematode infections, have been observed on potato tubers cv. Oleva, which also is relatively tolerant to common scab. Symptomatic tubers cv. Saturna first stored at 4o C for 20 weeks were transferred to pots with sterile sand and grown for 3 months in the green-house. In these cultures P. penetrans was first detected in soil 8 weeks after planting. Examination at harvest of soil, roots, stolons, tubers demonstrated symptoms typical of P. penetrans. Interestingly, P. penetrans survives storage of potatoes, from which new infections may develop. Hence, potato tubers do appear to be an important means for the spread of P. penetrans to new areas. The fact that the symptoms induced by this nematode may be mistaken for symptoms of common scab suggests that the frequency of S. scabies might have been overestimated in regular surveys. Infections by P. penetrans have important implications for scab control. This pertains in particular to recommended maintenance of high soil moisture at and during 4-9 weeks after tuber set. If symptoms are related to nematode infection rather than to the scab bacterium, this recommendation would allow for a rapid build-up of lesion nematodes resulting in a decrease in both yield and marketability of the tubers. Further studies are needed to investigate the extent of this problem.
Sammendrag
Recent research on how the structure and physiological development of red raspberry (Rubus idaeus L.) plants are controlled by genotype and the climatic environment is reviewed. Some older work, specially on plant structure relations, is also included. Physiological differences between annual- and biennial-fruiting plant types are highlighted. One major difference is the different requirements for flower formation. While biennial-fruiting cultivars have an absolute low temperature (≤ approx. 15°C) requirement for floral initiation, annual-fruiting cultivars readily initiate floral primordia at temperatures as high as constant 30°C. Also, while biennial-fruiting cultivars are facultative short-day plants with a critical photoperiod of 15 h at intermediate temperatures, flowering is promoted by long photoperiods in at least some annual-fruiting cultivars. However, the essential difference that determines whether the shoot life-cycle becomes annual or biennial is that, in biennial-fruiting genotypes, floral initiation is linked to the induction of bud dormancy, whereas in annual-fruiting cultivars, floral initiation is followed by direct flower development. Although this is genetically determined, it is a plastic trait that is subject to modification by the environment. Thus, at low temperatures and short photoperiods, the majority of initiated buds do enter dormancy also in annual-fruiting cultivars, with tip-flowering as a result. Practical applications are discussed, and it is concluded that our present physiological knowledge-base provides excellent opportunities for manipulation of raspberry crops for out-of-season production and high yields. It also provides a firm platform for further exploration of the underlying molecular genetics of plant structures and response mechanisms.
Sammendrag
The collapse of the Soviet Union in the Central Asian countries has led to enormous challenges for them in ensuring a sustainable environment. Weak economies and lack of expertise in environmental sciences were important reasons for the Norwegian support to the environmental sector in this region. The State Forest Service of the Kyrgyz Republic and the Norwegian Forestry Group initiated the TEMP project, later renamed TEMP-CA, in the Kyrgyz Republic in 2004. Activities in the Republic of Tajikistan were included in 2007 and in the Republic of Uzbekistan from 2008. The forestry sectors in the Kyrgyz Republic and neighbouring countries in Central Asia, surrounding the Fergana Valley, are closely linked to the environmental and emergency planning sectors. Overgrazing and overharvesting have contributed to a dramatic decline in forest cover. The TEMP-CA project contributes to a better understanding of environmental problems and sustainable forestry in Central Asia. The TEMP-CA project has promoted institutional co-operation between Norway and the Central Asian countries as well as between different institutions both within and between the countries of Central Asia. Increased expertise for scientists, fieldworkers, laboratory staff and staff in different forest departments as well as institutional development in general are important outputs from the TEMP-CA project. The Gauyan monitoring site in Batken oblast in the Kyrgyz Republic was the seventh of ten monitoring sites established in forests in Central Asia: 1: ”Kara-Koi” in the Osch oblast, the Kyrgyz Republic. 2: ”Sogot in the Jalal-Abad oblast, the Kyrgyz Republic. 3: “Dugoba” in Batken oblast, the Kyrgyz Republic. 4: “Besh-Tash” Talas oblast, the Kyrgyz Republic. 5: “Sary-Chelek”, in Jalal-Abad oblast, the Kyrgyz Republic. 6: “Navobod” in Sogdi oblast, the Republic of Tajikistan. 7: “Gauyan” in Batken oblast, the Kyrgyz Republic. 8: “Zaamin” in Djizak region, the Republic of Uzbekistan. 9: “Urumbash” in Jalal-Abad oblast, the Kyrgyz Republic. 10: “Umalak Teppa”, Tashkent region, the Republic of Uzbekistan.
Forfattere
Mats HøglindSammendrag
To develop mechanistic models for winter survival of grasses under climate change, more knowledge is needed of photosynthetic activity at low irradiance and temperature. Photosynthetic activity of small stands of Lolium perenne was continuously studied for up to two weeks under low photosynthetic photon flux density (PPFD) in the air temperature range from -3°C to +9°C. The photosynthetic rate of plants growing at 2, 6 and 9°C was similar at 120 µmol m-2 s-1 PPFD but the rate increased with increasing PPFD at all temperatures, particularly 9°C. Light saturation of photosynthesis was reached at approx. 300 µmol m-2 s-1 at 2 and 6°C, and at approx. 600 µmol m-2 s-1 at 9°C. At 300 µmol m-2 s-1, the CO2 exchange rate (CER) at 2°C was approx. 60% of that at 9°C. When the temperature increased gradually from 0°C at start to +5°C at the end of the 8-h photoperiod, CER decreased by about 20% compared with that at constant 5°C. Changing the temperature from constant +5°C to a diurnal variation between -2 and +2 °C gradually decreased daytime CER to approx. 10% after five days, partly due to leaf area losses (~50% loss) when the poorly acclimatised plants were exposed to frost. At start of the photoperiod at -2°C CER was negative, but became slightly positive when temperature exceeded -1°C after two hours. Total daily photosynthesis was negative due to night-time respiration in this treatment. Soil heating to avoid freezing when the diurnal air temperature fluctuated between -3 and + 3°C had no effect on CER at this low PPFD level (150 µmol m-2 s-1). In contrast to the -2/+2°C treatment, total daily photosynthesis was slightly positive in the -3/+3°C treatment, where the plants were better acclimatised to frost. Increasing the CO2 concentration from 350 to 600 µmol mol-1 had no effect on CER at 2 and 6°C, but increased it by 20% at 9°C. The data indicate that the minimum temperature for photosynthesis in the cultivar studied is about -4°C. The results can be applied in different photosynthesis models.
Sammendrag
Norwegian lamb meat production is mainly based on free grazing in mountainous pastures during the summer. Prior to slaughter in the autumn, some lambs not big enough for slaughter are finished on e.g. cultivated pastures. This study looked at the feed quality of different forages, and the effect on lamb meat quality. Lambs grazed on mountain pastures at Kvaløya in Northern Norway (69°N) and Sør-Fron in Mid Norway (58°N) in 2007, and a subgroup at each location was finished on cultivated pastures for 6 weeks prior to slaughter in September. The fiber content was significantly higher in the cultivated pasture in Mid Norway compared to the mountain pasture while no differences between pastures in Northern Norway were found. In Mid Norway the content of polyunsaturated fatty acid (18:3) was significantly higher in meat from lambs grazing the mountain pasture compared to lamb grazing the cultivated pasture. For Northern Norway, the opposite pattern was observed. The higher 18:3 content may be attributable to lower fiber content at the mountain pasture. In our study, there appears to be an effect of fiber content on the fatty acid composition in lamb meat.
Forfattere
Vibeke LindSammendrag
Norwegian lamb meat production is mainly based on free grazing in mountainous pastures during the summer. Prior to slaughter in the autumn, some lambs not big enough for slaughter are finished on e.g. cultivated pastures. This study looked at the feed quality of different forages, and the effect on lamb meat quality. Lambs grazed on mountain pastures at Kvaløya in Northern Norway (69°N) and Sør-Fron in Mid Norway (58°N) in 2007, and a subgroup at each location was finished on cultivated pastures for 6 weeks prior to slaughter in September. The fiber content was significantly higher in the cultivated pasture in Mid Norway compared to the mountain pasture while no differences between pastures in Northern Norway were found. In Mid Norway the content of polyunsaturated fatty acid (18:3) was significantly higher in meat from lambs grazing the mountain pasture compared to lamb grazing the cultivated pasture. For Northern Norway, the opposite pattern was observed. The higher 18:3 content may be attributable to lower fiber content at the mountain pasture. In our study, there appears to be an effect of fiber content on the fatty acid composition in lamb meat.
Populærvitenskapelig – Många nyheter bland skånska blommossor
Torbjörn Tyler, Hans Haavardsholm Blom
Forfattere
Torbjörn Tyler Hans Haavardsholm BlomSammendrag
[A lot of novelities in Schistidium in the province of Skne, southern-most Sweden.] Based on revision of c. 200 collections of Schistidium made during the ongoing survey of the bryophyte flora of the province of Skne, it is concluded that although S. apocarpum (s.str.) and S. crassipilum are by far the most frequent species a fair number of other taxa occure in the province.Thus, single collections of four species not previously documented from the province, viz. S. boreale, S. dupretii, S. robustum and S. trichodon, have been revealed. For all of these species this makes an extention of their known range of more than 500 km, indicating that also species not known from adjacent regions have to be considered when identifying material of this genus.A combination of efficient long-range dispersal and an ability to colonize virgin substrates may explain their, possibly short-lived, emergence far outside their established range: Further surveying is needed to document their distribution and frequency in the province, and their ability to persist at the localities.In total, 13 taxa of the genus are now documented from the province.