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.
2005
Sammendrag
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Forfattere
Guro BrodalSammendrag
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Sammendrag
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Sammendrag
Søtkirsebærproduksjonen i Sør-Afrika er prega av pioner-ånd. Dyrkarane satsar stort, men har mange utfordingar slik som klimatiske avgrensingar, redusert tilgang på rett plantemateriale og plantevern-rådgjerder, og dei manglar både offentleg støtta forskings- og utviklingsprogram og rådgjeving. Økonomisk er dette likevel interessant, sidan det vert betalt gode prisar for søtkirsebær i ein periode med lite utbod av denne vara.
Sammendrag
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Forfattere
Paivi L.H. Rinne Carl Gunnar Fossdal Sissel Torre Heather Danforth Aksel Granhus Gunnhild Søgaard John Einset Harald Kvaalen Øystein Johnsen Christiaan van der SchootSammendrag
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Forfattere
Marit Almvik Ole Martin Eklo Randi Bolli Marianne Stenrød Christophe Moni Jens Kværner Tore Sveistrup Espen HauglandSammendrag
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Sammendrag
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Sammendrag
Many different species of microorganisms have one or more hydrogenase enzymes that reduce protons to molecular hydrogen under certain conditions. Upon sulfur deprivation, green algae can produce relatively large amounts of hydrogen in a sustainable process. The majority of research in this field has focused on Chlamydomonas reinhardtii, but other species of green algae are also able to produce hydrogen under sulfur deprivation. Using PCR reactions, we examined the presence of hydrogenase genes in marine and fresh water species of green algae that were able to produce hydrogen under sulfur deprived conditions. Primers were designed from conserved regions of the sequence of the two hydrogenase genes in C. reinhardtii, and used to screen for the presence of similar gene sequences in other species. PCR products that were sequenced suggest that genes for hydrogenase are present in C. noctigama and other species. Similarities and differences in the sequences of hydrogenase genes between C. reinhardtii and other species, will be presented.
Sammendrag
Various needle discolorations, often due to lack of uptake of certain nutrients are frequently observed in nordmann fir (Abies nordmanniana) in Norwegian Christmas tree plantations. Most common are the yellow to necrotic needle tips on older needles caused by magnesium (Mg) deficiency (confirmed by chemical analysis of foliage). Even though chemical analysis of soil samples show that Mg is present in sufficient amount, various soil factors may cause Mg-deficiency; too high or too low pH, excess potassium (K) or too wet or too dry conditions. Antagonism, causing imbalance in nutrient uptake, can lead to negative effects. High pH may give Ca2+/Mg2+ antagonism, too low pH NH4+/Mg2+ antagonism, and abundant K K+/Mg2+ antagonism. During wet conditions K+ and other monovalent cations may leave the colloids to regain equilibrium between liquid and solid material. Then Mg2+ may easily bind to the free spaces on the colloids, and thereby becomes unavailable for the plants. If the soil is very dry there may not be enough liquid for the nutrients to be dissolved, and thus uptake inhibited. Nordmann fir is mainly grown in the southwestern coastal region of Norway since the climate there is fairly mild and suitable for this plant species. The yearly rainfall is high in that region, so a main cause for Mg deficiency on nordmann fir is probably related to wet soil conditions. Uptake of Mg after foliage application has proved to be ineffective due to the wax layer on the fir needles. However application on young needles and shoots has been reported by the Norwegian extension service to be successful. K deficiency also results in discoloration of older needles, but symptoms can easily be distinguished from Mg deficiency. Both deficiencies results in yellowing of the needles, but different from K deficiency, the base remains green on needles suffering from Mg deficiency. Both Mg and K are very mobile nutrients in plants, and they are therefore easily translocated from older to younger needles. Samples with yellow discoloration of the youngest needles have been observed to be low in iron (Fe) and manganese (Mn), especially when the trees have grown in soil with high pH. Both nutrients are nearly immobile in plants after they have been transported to the cells, and they are therefore not available for the young shoots. Nitrogen (N) deficiency is seen as a uniform, pale green discolouration of both young and old needles.