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.
1995
Authors
B. R Singh R. P. Narwal Alhaji S. Jeng Åsgeir R. AlmåsAbstract
No abstract has been registered
Abstract
Roots of Picea abies seedlings were inoculated with pathogenic Pythium dimorphum. The ongoing lignification process, the accumulation of lignin, and the distribution of flavanols and condensed tannins (CT), were related to the concurrent visual disease symptoms, hyphal colonization, and cellular changes. The hyphae ramified in both the cortex and the stele within 24 h. Three days after inoculation the concentration of lignin had increased to a level twice that in noninfected tissues. With histochemical staining, the accumulation of lignin and the ongoing lignification were co-located in the inner cortex layer 4-6 days after infection. Comparison of temporal onset of lignification with the timing of the intruding hyphae shows that this defense response occurs too late to effectively prevent the pathogen from spreading. Flavanols and CT were also detected in both infected and noninfected roots.Increased staining of these compounds in infected roots was often detected in the inner cortex. Electron microscopic studies revealed that at least some of these phenolic compounds were localized either as spherules or as a layer appressed to the tonoplast of the central vacuole.
Abstract
No abstract has been registered
Authors
Bjørn ØklandAbstract
No abstract has been registered
Authors
Bjørn ØklandAbstract
No abstract has been registered
Authors
Torild Wickstrøm W. Lund R. ByeAbstract
An alkaline sample solution in combination with the complexing agent diethylenetriaminepentaacetic acid (DTPA) was employed to minimize interference from Ni and Co in the determination of As and Te by hydride generation inductively coupled plasma atomic emission spectrometry. Tetrahydroborate was also added to the sample solution, before the hydride was generated by acidification vith HCl in a continuous-flow system. The masking method was used for the determination of As and Te in the reference material NIST SRM 899 Nickel Ahoy. For the determination of As in a copper sample, the interference from Cu was removed by precipitation of the hydroxide and filtration. The precipitation method was used for the determination of As in the reference material NIST SRM 398 Unalloyed Copper V; hydride generation atomic absorption spectrometry was employed to determine the concentration of As.
Authors
Dan Aamlid Hans Tømmervik Michael L. Gytarsky Rodion Karaban Kåre Olav Venn Tord K. Rindal Natalya Vassilieva Galina N. Koptsik E.M. LøbersliAbstract
No abstract has been registered
Authors
Torild Wickstrøm W. Lund R. ByeAbstract
The use of an alkaline sample solution for the determination of Se by the hydride generation technique offers the possibility of eliminating the interference from very high concentrations of Ni2, CO2, Fe3 and Cr3. In order to achieve this, complexing agents were employed to mask the interfering metal ions, After addition of the masking agent, the pH was adjusted to 12-13 with NaOH, and sodium tetrahydroborate was finally added in order to reduce selenite to selenide ions. The selenium hydride was generated by acidifying the solution with HCl in a flow system.Ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid (DTPA) were found to be effective masking agents for Ni2 and Co2; the, interference from up to 8000 mg l(-1) of Ni2 or Co2 was eliminated. Tartrate was found to be a suitable masking agent for Fe3 and Cr3 UP to 5000 mg l(-1). Accurate results were obtained for the National Institute of Standards and Technology Standard Reference Materials 671 Nickel Oxide and 364 Low-alloy Steel, using combinations of DTPA and tartrate as masking agents. The detection limits were 0.1 mu g g(-1) for the Nickel Oxide and 0.3 mu g g(-1) for the Low-alloy Steel.
Authors
Halldór SverrissonAbstract
No abstract has been registered
Authors
Arja Lilja Risto HeikkiläAbstract
No abstract has been registered