Growing stronger timber for use in construction? New means of observing wood formation could hold the key

New research into wood formation led by the University of Copenhagen (UCPH) has resulted in a means of observing how woody cell walls develop in plants, in real-time.

Wood is formed deep inside the plant, while microscopes work best when observing the surface of an object. For that reason, the process by which woody cell walls are formed has long eluded scientists.

However, this latest breakthrough may hold the key to solving the mystery, and could carry the potential to support the growth of sturdier timber for construction, as well as more climate efficient trees.

The ability of trees to grow to heights of 100 metres or more relies on a number of factors including water and light, as well as cell walls sturdy enough to keep the tree upright and able to handle the pressure created by water rising from the root, through the trunk, and into the leaves. This is where the development of ‘secondary cell walls’ come into play.

By using a genetic switch to modify the plants, a team of international researchers, including Professor Staffan Persson of UCPH’s Department of Plant and Environmental Sciences, was able to activate wood formation in all cells of the plant, including those on the surface. This allowed for detailed observation of the biological process involved with wood formation as it happens, using a microscope.

This new ability brings with it potential for manipulating the process and making secondary cell walls even stronger.

Cell walls in plants consist mainly of cellulose, produced by enzymes found on the surface of the cells. The process involves the development of protein tubes (or microtubules) on the cell surface, which serve as tracks or rails along which the enzyme producing wall can deposit the cellulose.

“Interestingly, during the formation of woody cell walls these ‘rails’ need to change their organisation completely to make patterned walls — a process that we now can follow directly under our microscopes," explained Persson.

"We now have a better understanding of the mechanisms that cause the microtubules to rearrange and form the patterns. The next step is to identify ways that allow us to make changes to the system. For example, by changing patterns," said Persson.

“Changing the patterns can alter the ways in which a plant grows or distributes water within it, which can then go on to influence a plant’s height or biomass,” said First Author, Dr Rene Schneider of the Max Planck Institute of Molecular Plant Physiology in Germany.

In the longer term, the team sees one of the most obvious applications as the manipulation of this biological process to grow trees that will provide stronger timber for use in construction.

"If we can change both the chemical composition of cell walls, which we and other researchers are already working on, and the patterns of cell walls, we can probably alter wood strength,” said Persson.

“Sturdier construction materials made of wood don’t just benefit the construction industry, but the environment and climate as well. They have a smaller carbon footprint, a longer service life, and can be used for manifold purposes. In some cases, they may even be able to replace energy-intensive materials like concrete.”

This is good news for the forestry industry, as it continues its efforts to position timber as a viable construction material for an increasing number of applications.