Inorganic compounds in the marine borer resistant timber turpentine (Syncarpia glomulifera)

Abstract

Turpentine wood is renowned for its resistance to attack by molluskan marine borers. This resistance is thought to be due to its high silica content, and possibly the presence of other, as yet unknown, compounds. Silica in turpentine wood is present as particles in rays, but in many plant species silica also occurs in cell walls. We hypothesized that Si is present in cell walls of turpentine, but when we tested this hypothesis using synchrotron XFM, we serendipitously observed several biocidal heavy metals in its heartwood. We found that turpentine heartwood contains a far greater diversity of these and other metals than previously thought. The concentrations of some of the heavy metals collectively reach levels previously shown to be toxic in vitro to the embryos and larvae of mollusks. This paper focuses on these inorganic components of turpentine wood and discusses their possible contribution to its marine borer resistance.

Keywords:

• Turpentine heartwood
• Syncarpia glomulifera
• silica
• marine borer resistance
• synchrotron X-ray fluorescence microscopy
• X-ray micro-computed tomography
• biocidal metals

Acknowledgements

This research was conducted in part at the XFM beamline at the Australian Synchrotron, part of ANSTO. We thank the Centre for Advanced Microscopy and National Laboratory for X-ray Micro-Computed Tomography at The Australian National University for giving us access to their instrumentation and for the expert technical assistance of Drs’ Frank Brink, Hua Chen and Levi Beeching; Gary Hopewell of Department of Agriculture and Fisheries, Queensland, Australia for a sample of turpentine heartwood; Dr Andrew Kingston for his encouragement and assistance with synchrotron X-ray fluorescence microscopy. PDE thanks Viance, Tolko, FPInnovations and Faculty of Forestry at University of British Columbia for their support of his BC Leadership Chair at the University of British Columbia.

Dedication

This paper is dedicated to the centenary of the birth of W. E. (Ted) Hillis (1921-2008) who with fellow scientists at the Commonwealth Scientific Industrial Research Organization (CSIRO) in Melbourne, Australia did so much to further our understanding of wood chemistry and its diverse impacts on the properties and processing of wood.

Additional information

Funding

Australian Research Council Grants, LP150101040, IC1801000080, LEO668019.