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
Trygve S. Aamlid Arild AndersenSammendrag
Det er ikke registrert sammendrag
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
Det er ikke registrert sammendrag
Sammendrag
Det er ikke registrert sammendrag
Forfattere
Tatsiana EspevigSammendrag
Det er ikke registrert sammendrag
Forfattere
Johannes DeelstraSammendrag
Det er ikke registrert sammendrag
Forfattere
Tatsiana Espevig Michelle DaCosta Lindsey Hoffman Trygve S. Aamlid Anne Marte Tronsmo Bingru Huang Chenping XuSammendrag
Winter injury of temperate grasses used for turf is a significant problem in northern climatic regions. Field trials at two locations in Norway previously demonstrated differences in winter survival between two Agrostis species, velvet bentgrass (Agrostis canina L.) and creeping bentgrass (Agrostis stoloniferaL.). The freezing tolerance is an important component of winter hardiness of turfgrasses and it was studied under controlled environments. We also determined the crown carbohydrate and protein changes at different stages of cold acclimation of velvet bentgrass and creeping bentgrass and assessed their relationship to freezing tolerance. Similar freezing tolerance in velvet bentgrass and creeping bentgrass was associated with similar levels of sucrose in crown tissue of acclimated plants. Significantly higher crown fructan content in creeping bentgrass than in velvet bentgrass had no significantimpact on LT50 and suggested negligible direct contribution of fructans to freezing tolerance. Increased freezing tolerance in response to cold acclimation was associated with enhanced amino acid synthesis, since serine hydroxymethyltrasfernse and methionine synthase were up-regulated by acclimation. The first acclimation stage caused more changes in the crown protein composition than subzero cclimation.
Forfattere
Eldrid Lein MoltebergSammendrag
Det er ikke registrert sammendrag
Forfattere
Trygve S. AamlidSammendrag
Det er ikke registrert sammendrag
Forfattere
Helge SjursenSammendrag
Rugfaks hører til den biologiske gruppen toårige. Den voksne planten er 30-135 cm høy. Strået er opprett, tynt eller kraftig uten hår. Leddknutene er skinnende og fint håret. Bladene er 4-10 mm breie, oversiden og kantene er spredt håret og ru. Slirehinnen er 1-2 mm lang, tannet, lysebrun eller gul. Bladører mangler. Bladsliren er rørformet, men sprekker tidlig opp, er håret eller snau, ofte gulrød. Blomstene sitter i en 5-20 cm lang topp, til å begynne med opprett, seinere nikkende, åpen eller sammenklemt, grønn eller fiolett. Småaksene er 5-20 cm lange, flatklemt, oftest snaue. Formeringen og spredningen skjer utelukkende med frø. Rugfaks lager bare en liten bladtust første året, men blomstrer og setter frø tidlig andre året. Forekommer i dyrket mark og på avfallsplasser. Liker tyngre og gjerne noe sur jord, men vokser godt på lettere jord også. Opptrer som ugras i høstkorn, men på grunn av dagens effektive metoder for frørensing, er den praktisk talt uten betydning. Rugfaks (som lodnefaks) kan motarbeides ved å hindre frøspredning, og ved bruk av reine såvarer og ugrasrein gjødsel.