Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
1991
Authors
Halvor SolheimAbstract
The Eurasian sprucc bark beetle, Ips typogaphus carries spores of several fungi induding Ophiostoma bicolor, O. pellicillatum and O. polonicum. However, after attack on Norway spruce trees O. polonicum is the pioneer invader of the sapwood while other species follow. To determine the causes behind this distinct succession experiments were performed comparing growth rate, tolerance to oxygen-deficient conditions and to spruce resin between these early invaders. In sealed tubes with limited oxygen. O. polonicum grew for a longer time than three other species regularly associated with I. typagraphus in Norway. The non-volatile components of lesion resin induced by fungal attack, as opposed to preformed resin, inhihited the growth of all species, but partirularly O. polonicum. O. polonicum grew rapidly on malt agar, but not faster than some of the other species associated with I. typographus. It is concluded that rapid growth and the abilily lo tolerate low oxygen pressure are important attributes for primary invaders, allowing tree resistance mechanisms to be overcome following mass inoculation.
Abstract
No abstract has been registered
Authors
Oddvar SkreAbstract
Support is given for the dark respiration as a limiting factor for growth at low temperatures. The existence of a so-called alternative respiration that is not linked to the growth process, supports this hypothesis, because of its possible function as a stabilizing factor (overflow function). Physiological mechanisms influencing plant survival in a cold environment and tree-line forming processes are discussed.
Authors
Bjørn LangerudAbstract
No abstract has been registered
Authors
Paal KrokeneAbstract
No abstract has been registered
Authors
Bjørn Langerud Martin SandvikAbstract
No abstract has been registered
Authors
Arne Grønlund Rune SolbergAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Oddvar SkreAbstract
Large differences were found in survival stratey among species and ecotypes. The maple and elm populations and the two southern birch populations all responded to high temperatures by rapid leaf expansion as a possible compensation for increased respiration loss, and themaple and birch also by increasing their stem elongation rates, thereby competing more efficiently for available light. In the northern subalpine birch population, however, the seedlings developed leaves with high net assimilation rates instead of increasing their leaf areas and stem elongation rates. In this population abiotic climatic factors rather than competition therefor seem to be the most important adaptive force.
Authors
Gunnar Ogner Magne Opem Gabriele Remedios Gro Sjøtveit Britt SørlieAbstract
No abstract has been registered