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.

1993

Abstract

The relationships between temperature and growth and between growth and and carbon exchange rates are reviewed and evaluated, and supplied with experimental evidence from field and greenhouse studies on birch provenances. Adaptations to changing temperature and photoperiod are shown on birch from different altitudes and latitudes in Scandinavia.

Abstract

Root dieback disease of Norway spruce (Picea abies) seedlings is a serious problem in Scandinavian forest nurseries. We have chosen spruce seedlings infected with one of the most pathogenic fungi associated with this disease, Pyrhium sp., as an experimental system to study the interaction between root ceUs and fungi. In this experimental system the infection is efficient, resulting in root necrose within 1-2 days, growth retardation and complete wilting within 10 days. Anatomical studies of the infected roots revealed that within 4 days ceU waUs around the inner cortex ceUs were thicker compared to non-infected cells. Staining with methyl red indicated that deposition of lignin or lignin like substances were associated with this thickening of the ceU walls. Neither pectin nor suberin appeared to be deposited in these ceU walls since staining with rhutenium red and Sudan IV were negative.Already1 day after infection several pathogenesis related (PR) proteins with both basic and acidic pIs appeared. Three days after infection the number and amount of PRproteins increased considerably. On the fourth day the num ber of induced proteins were more then 40. The number and also the amount of these proteins remained stable after this day. Two acidic chitinases were present in non-infected roots. Already the first day after infection both of these were strongly induced and were accompanied by four other acidic and two basic chitinases. At day two the activity of the chitinases already mentioned increased and they were accompanied by two chitinases with a more neutral pl. On the third day after infection the chitinase activities stabilized on a steady level This steady state level was maintained to the 10th day. Also 6-1 ,3-glucanases were induced by the infection with Pyrhium sp. While no 6-1 glucanase activity was detected in non-infected roots, one acidic 6-1,3-glucanase was detected the first day after infection. On the second day after infection an additional acidic 6-1,3-glucanase was detected. The number and amount of B-l,3-glucanases, like the chitinases, stabilized on the level of the third day and was maintained unril day 10. These results show that Norway spruce, a gymnosperm, has a response to pathogen infection with many similarities to the angiosperms. They also show that roots respond to the infection in a way similar to the aerial parts.