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.
1994
Authors
Øystein Johnsen Gunnar Haug Ola Gram Dæhlen Borgny Sveen Grønstad Anne Tove RognstadAbstract
No abstract has been registered
Authors
Tryggve PerssonAbstract
No abstract has been registered
Authors
Øystein Johnsen Geir ØstrengAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
H.F. van DobbenAbstract
No abstract has been registered
Authors
Tor K. SpidsøAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Harald KvaalenAbstract
Ethylene production from an embryogenic culture of Norway spruce (Picea abies L.) was generally low, ca 2.5 nl g(-1) h(-1), whereas 1-aminocycloprapane-1-carboxylic acid (ACC) concentration was high, fluctuating between 50 and 500 nmol g(-1) during the 11-day incubation period. Hypoxia (2.5 and 5 kPa O-2) rapidly inhibited ethylene production without subsequent accumulation of ACC. Exogenous ACC (1, 10 and 100 mu M) did not increase ethylene production, but the highest concentrations inhibited tissue growth. Ethylene (7 mu l l(-1)) did not inhibit growth either when supplied as ethephon in the medium or in a continuous flow system. Benzyladenine (BA) had little effect on ethylene production, although it was necessary for sustaining the ACC level. Omission of 2,4-dichloro-phenoxyacetic acid (2,4-D) from the medium caused ethylene production to increase from about 2.5 to 7 nl g(-1) h(-1) within the 11-day incubation period. Although 2,4-D did not specifically alter the endogenous level of ACC, the lowest ACC level, 33 nmol g(-1), was observed in tissue treated with 2,4-D (22.5 mu M) and no BA for 11 days. Data from this treatment were used to estimate the kinetic constants for ACC oxidase, the apparent K-m was 50 mu M and V-max 2.7 nl g(-1) h(-1). Growth of the tissue was strongly inhibited by 2,4-D in the absence of BA, but weakly in the presence of BA (4.4 mu M). The results suggest that ethylene or ACC may be involved in the induction of embryogenic tissue and in the early stages of embryo maturation.
Authors
Richard HorntvedtAbstract
No abstract has been registered
Abstract
No abstract has been registered