3 results for Altaner, CM

  • Distribution of (1 -> 4)-beta-galactans, arabinogalactan proteins, xylans and (1 -> 3)-beta-glucans in tracheid cell walls of softwoods

    Altaner, CM; Tokareva, EN; Jarvis, MC; Harris, Philip (2010-06)

    Journal article
    The University of Auckland Library

    Polysaccharides were located in the walls of normal and compression wood tracheids of Pinus radiata (radiata pine), Picea sitchensis (Sitka spruce) and Picea abies (Norway spruce) by transmission electron microscopy using immunogold labelling with monoclonal antibodies to (1→4)-β-galactan (LM5), (1→3)-β-glucan, arabinogalactan proteins (AGPs) (MAC207) and heteroxylans (LM10 and LM11). In fully differentiated compression wood tracheids, (1→4)-β-galactan was found in the S2(L) layer and, to a smaller extent, at the interface between the compound middle lamella and the S1 layer. (1→4)-β-Galactan appeared to be displaced from, or modified in, the S1 layer during cell wall formation. (1→3)-β-Glucan (callose) was confined to the helical cavities in the inner S2 layer of severe compression wood. MAC207 AGP glycan epitope was found exclusively in the S1 and S3 layers of normal wood tracheids and in the S1 and inner S2 layers of compression wood tracheids. Binding of LM10, which specifically recognizes unsubstituted or low-substituted xylans, occurred at similar locations to the MAC207 epitope, whereas binding of LM11, which recognizes more highly substituted as well as unsubstituted xylans, occurred throughout the tracheid walls with the exception of the primary wall. Immunogold labelling showed that the different wall layers of softwood tracheids have different polysaccharide compositions which change abruptly during cell wall formation.

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  • Wood quality assessment of Pinus radiata (radiata pine) saplings by dynamic mechanical analysis

    Sharma, M; Brennan, M; Chauhan, SS; Entwistle, KM; Altaner, CM; Harris, Philip (2015-11)

    Journal article
    The University of Auckland Library

    The use of dynamic mechanical analysis was explored as a possible method of screening for wood quality in breeding programmes. Viscoelastic properties along the grain of wood from 18-month-old Pinus radiata saplings were measured using a humidity-controlled dynamic mechanical analyser. Storage modulus and tanδ were determined independently for opposite wood (OW) and compression wood (CW) in 25 trees in the temperature range from 10 to 45 °C at 5 °C intervals at three frequencies (0.1, 1 and 10 Hz) at constant moisture content of 9 %. Storage modulus and tanδ were frequency and temperature dependent. The two wood types did not differ significantly in their storage modulus. But OW exhibited significantly higher tanδ values than CW. The relationship of viscoelastic properties with physical (acoustic velocity, basic density and longitudinal shrinkage) and chemical wood properties was explored. There was a strong correlation (R = 0.76) between storage modulus and dynamic MOE (measured by acoustics). In addition, tanδ was positively correlated with longitudinal shrinkage. Monosaccharide compositions of the cell wall polysaccharides and lignin contents were determined and showed significant differences in the relative proportion of major cell wall components in OW and CW. Correlations between tanδ and xylose, originating from heteroxylans, and lignin content were found for CW, suggesting that the damping behaviour of cell walls is controlled by the matrix between cellulose fibril aggregates.

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  • Wood quality - what can we learn from cell-wall chemistry?

    Harris, Philip; Altaner, CM (2015-02)

    Journal article
    The University of Auckland Library

    Compression wood is chemically different from normal, opposite and flexure wood. Based on these chemical differences, we have investigated several techniques that could potentially be developed into methods that could be used in commercial situations to identify and segregate compression wood. The leading contender is near infrared spectroscopy.

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