Hopp til hovedinnholdet

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

Til dokument

Sammendrag

Conifers and other trees are constantly adapting to changes in light conditions, water/nutrient supply and temperatures by physiological and morphological modifications of their foliage. However, the relationship between physiological processes and anatomical characteristics of foliage has been little explored in trees. In this study we evaluated needle structure and function in Norway spruce families exposed to different light conditions and transpiration regimes. We compared needle characteristics of sun-exposed and shaded current-year needles in a control plot and a thinned plot with 50% reduction in stand density. Whole-tree transpiration rates remained similar across plots, but increased transpiration of lower branches after thinning implies that sun-exposed needles in the thinned plot were subjected to higher water stress than sun-exposed needles in the control plot. In general, morphological and anatomical needle parameters increased with increasing tree height and light intensity. Needle width, needle cross-section area, needle stele area and needle flatness (the ratio of needle thickness to needle width) differed most between the upper and lower canopy. The parameters that were most sensitive to the altered needle water status of the upper canopy after thinning were needle thickness, needle flatness and percentage of stele area in needle area. These results show that studies comparing needle structure or function between tree species should consider not only tree height and light gradients, but also needle water status. Unaccounted for differences in needle water status may have contributed to the variable relationship between needle structure and irradiance that has been observed among conifers.

Sammendrag

Camelina is an underexploited oilseed crop that may be well suitable for cropping innorthern areas. The oil is particularly high in the omega-3 fatty acid alpha-linolenic acid (C18:3n-3). The aim of the present study was to evaluate the potential for secure production of high quality edible oil from organically grown camelina (Camelina sativa L. Crantz), focusing on the effects ofenvironmental parameters on oil content, fatty acid composition and contents of phytosterols and tocopherols. Field experiments with pre-crop barley were conducted in the growing seasons 2007, 2008 and 2009. Trials were fully randomized with two levels of Nitrogen (N) fertilization, 0 and 120 kg total Nha-1, and two levels of Sulphur (S) fertilization, 0 and 20 kg total S ha-1. Additional experiments were performed in 2009 in order to evaluate the effects of replacing pre-crop barley with pre-crop pea. Crude oils were obtained by usinga pilot press and the fatty acid composition and contents of phytosterols and tocopherols were analyzed by GC-MS and LC-MS. The results showed significantseasonal variations in the contents of fatty acids, tocopherols andphytosterols. Furthermore, significant effects of N-fertilization were observed, with increased contents of C18:3n-3, erucic acid (C22:1) and γ-tocopherol at the highest level of N-fertilization. Pea compared to barley as pre-crop also increased the content of C18:3n-3. There were no effects of S-fertilization. Principal component analysis revealed positive correlations between the contents of C18:3, C22:1, γ-tocopherol and phytosterols, in particular brassicasterol. In conclusion, camelina seems to be well suitable for organic cropping. The oil quality was influenced by season and N-fertilization, still, the variation in nutrient content was small.