Bernadette Nanayakkara

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The enzyme hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HCT) is involved in the production of methoxylated monolignols that are precursors to guaiacyl and syringyl lignin in angiosperm species. We identified and cloned a putative HCT gene from Pinus radiata, a coniferous gymnosperm that does not produce syringyl lignin. This gene was(More)
Enzymatic and topochemical aspects of lignification were studied in a Pinus radiata D. Don cell culture system that was induced to differentiate tracheary elements and sclereids with lignified secondary cell walls. The activities of the lignin-related enzymes phenylalanine ammonia lyase (PAL; EC and cinnamyl alcohol dehydrogenase (CAD; EC(More)
Young P. omorika trees subjected to static bending showed a severe compression wood response as characterized by fluorescence spectroscopy/microscopy, which decreased in severity with height correlated with a decrease in bending moment. This investigation is aimed at understanding the reaction wood response in a slow-growing conifer species under conditions(More)
Cell wall fluorescence and immunocytochemistry demonstrate that xylem parenchyma cell walls do not show changes in structure and composition related to gravitropic response comparable to those of tracheids, even when they have lignified secondary cell walls. Tracheid cell walls in compression wood have altered composition and structure which generates the(More)
A novel approach for the quantification of the degree of condensation at the C(5) position of etherified and phenolic phenylpropane (C-9) units of in situ lignin is described. This is achieved by degrading unmethylated and methylated wood by thioacidolysis and analyzing the resultant product mixtures by quantitative (31)P NMR spectroscopy. Applying this new(More)
A technique whereby whole mounts of delicate tissues of differentiating xylem are imaged directly by polishing and block-face imaging of embedded microcores. Autofluorescence and image analysis aids identifying the stages of xylogenesis. Stem microcores from fast-growing trees, such as Pinus radiata (D. Don) with wide zones of cambium and differentiating(More)
A cross-correlation time-of-flight method for measuring the sound speed in a seedling in a non-destructive and non-damaging way is described. The method uses two miniature accelerometers coupled to the bark of a growing seedling stem to record the acoustic signals and a small striker to generate an acoustic pulse. The two acoustic signals are then(More)
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