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
Sammendrag
Food production is the largest consumer of mined phosphorus (P) worldwide.
Forfattere
Anne BøenSammendrag
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Forfattere
Anne Falk ØgaardSammendrag
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Forfattere
Bjørn FrantzenSammendrag
7 pictures of Arctic landscapes.
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
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Forfattere
Tor J. JohansenSammendrag
Production of healthy, vigorous potato plants and a high yield of good quality under varied environmental conditions require quality seed tubers. Quality may be divided in two important factors, tuber health and physiological quality. Physiological quality (number and vigour of sprouts and stems, growth and yield potential) is determined by the size of the seed tuber, the physiological status of the seed and interactions between these two factors. The physiological status of the seed is usually called physiological age. This may be defined as “the stage of development of a tuber, which is modified progressively by increasing chronological age, depending of growth history and storage conditions” (Struik and Wiersema 1999, Seed potato technology). The sequence of stages of development are dormancy, apical sprouting, normal sprouting with a few or multiple branched sprouts, senility and finally incubation with direct formation of daughter tubers on the seed tuber. Each stage has a strong influence on vigour and yield potential of the seed. Temperature is the most important environmental factor that affects physiological age in seed potatoes, either during growth of the mother plant, or during storage. Unfortunately, physiological age is hard to measure directly, and indirect methods, based on sprout development, sprout characteristics and sprouting capacity are normally used. In Norway, several studies of the impact of geographic origin, growth temperatures, day-lengths, and pre-storing temperatures on vigour and yield potential have been performed the last10 years. One of the aims has been to study the “northern vigour claims”, which implies superiority of seed produced in northern latitudes over seed produced in southern latitudes. In summary the results showed: Low temperature (9 ºC) gave a small but positive effect on progeny growth vigour and yields compared to a higher temperature (15 ºC) in cv. ‘Troll’. Day-length (12 or 24 hrs) did not affect the results significantly. In a study with average temperatures of 9, 15 and 18 ºC, 12 and 24 hrs day-lengths, the physiologically oldest tubers originated from the lowest growth temperatures. In a three-year field study at distant sites in Norway (lat. 59-70) the results showed no superiority of seed from any latitude, regarding vigour and yields. In a controlled climate study at 9, 15 and 21 °C, results showed that dormancy may be shortened by low grow temperatures, and similarly by low post-harvest temperatures (4 °C). The scientific fundament of “northern vigour” is still not clear, but as a statement it may call attention to the generally good quality of northern seed.
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.
Forfattere
Maria Björkman Ingeborg Klingen ANE Birch Atle M. Bones Toby Bruce Tor J. Johansen Richard Meadow Jørgen A.B. Mølmann Randi Seljåsen Lesley Smart Derek StewartSammendrag
In this review, we provide an overview of the role of glucosinolates and other phytochemical compounds present in the Brassicaceae in relation to plant protection and human health. Current knowledge of the factors that influence phytochemical content and profile in the Brassicaceae is also summarized and multi-factorial approaches are briefly discussed. Variation in agronomic conditions (plant species, cultivar, developmental stage, plant organ, plant competition, fertilization, pH), season, climatic factors, water availability, light (intensity, quality, duration) and CO2 are known to significantly affect content and profile of phytochemicals. Phytochemicals such as the glucosinolates and leaf surface waxes play an important role in interactions with pests and pathogens. Factors that affect production of phytochemicals are important when designing plant protection strategies that exploit these compounds to minimize crop damage caused by plant pests and pathogens. Brassicaceous plants are consumed increasingly for possible health benefits, for example, glucosinolate-derived effects on degenerative diseases such as cancer, cardiovascular and neurodegenerative diseases. Thus, factors influencing phytochemical content and profile in the production of brassicaceous plants are worth considering both for plant and human health. Even though it is known that factors that influence phytochemical content and profile may interact, studies of plant compounds were, until recently, restricted by methods allowing only a reductionistic approach. It is now possible to design multi-factorial experiments that simulate their combined effects. This will provide important information to ecologists, plant breeders and agronomists.
Forfattere
Venche TalgøSammendrag
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