̽��ֱ�� of Cambridge - Raymond Wightman

Scientists discover entirely new wood type that could be highly efficient at carbon storage

kjg45 — Wed, 31 Jul 2024 15:14:49 +0000

Scientists from the Sainsbury Laboratory at Cambridge ̽��ֱ�� and Jagiellonian ̽��ֱ��, Poland made the discovery while undertaking an evolutionary survey of the microscopic structure of wood from some of the world’s most iconic trees and shrubs. 

They found that Tulip Trees, which are related to magnolias and can grow over 30 metres (100 feet) tall, have a unique type of wood. This discovery may explain why the trees, which diverged from magnolias when earth's atmospheric CO₂ concentrations were relatively low, grow so tall and so fast. This opens new opportunities to improve carbon capture and storage in plantation forests by planting a fast-growing tree more commonly seen in ornamental gardens, or breeding Tulip Tree-like wood into other tree species.

̽��ֱ��discovery was part of an evolutionary survey of the microscopic structure of wood from 33 tree species from the Cambridge ̽��ֱ�� Botanic Garden’s Living Collections. ̽��ֱ��survey explored how wood ultrastructure evolved across softwoods (gymnosperms such as pines and conifers) and hardwoods (angiosperms including oak, ash, birch, and eucalypts). 

̽��ֱ��wood samples were collected from trees in the Botanic Garden in coordination with its Collections Coordinator. Fresh samples of wood, deposited in the previous spring growing season, were collected from a selection of trees to reflect the evolutionary history of gymnosperm and angiosperm populations as they diverged and evolved. 

Using the Sainsbury Laboratory's low temperature scanning electron microscope (cryo-SEM), the team imaged and measured the size of the nanoscale architecture of secondary cell walls (wood) in their native hydrated state.

Microscopy Core Facility Manager at the Sainsbury Laboratory, Dr Raymond Wightman, said: “We analysed some of the world’s most iconic trees like the Coast Redwood, Wollemi Pine and so-called 'living fossils' such as Amborella trichopoda, which is the sole surviving species of a family of plants that was the earliest still existing group to evolve separately from all other flowering plants.

“Our survey data has given us new insights into the evolutionary relationships between wood nanostructure and the cell wall composition, which differs across the lineages of angiosperm and gymnosperm plants. Angiosperm cell walls possess characteristic narrower elementary units, called macrofibrils, compared to gymnosperms.” 

̽��ֱ��researchers found the two surviving species of the ancient Liriodendron genus, commonly known as the Tulip Tree (Liriodendron tulipifera) and Chinese Tulip Tree (Liriodendron chinense) have much larger macrofibrils than their hardwood relatives.

Hardwood angiosperm macrofibrils are about 15 nanometres in diameter and faster growing softwood gymnosperm macrofibrils have larger 25 nanometre macrofibrils. Tulip Trees have macrofibrils somewhere in between, measuring 20 nanometres.

Lead author of the research published in New Phytologist, Dr Jan Łyczakowski from Jagiellonian ̽��ֱ��, said: “We show Liriodendrons have an intermediate macrofibril structure that is significantly different from the structure of either softwood or hardwood. Liriodendrons diverged from Magnolia Trees around 30-50 million years ago, which coincided with a rapid reduction in atmospheric CO2. This might help explain why Tulip Trees are highly effective at carbon storage.”

̽��ֱ��team suspect it is the larger macrofibrils in this 'midwood' or 'accumulator-wood' that is behind the Tulip Trees’ rapid growth.

Łyczakowski added: “Both Tulip Tree species are known to be exceptionally efficient at locking in carbon, and their enlarged macrofibril structure could be an adaptation to help them more readily capture and store larger quantities of carbon when the availability of atmospheric carbon was being reduced. Tulip Trees may end up being useful for carbon capture plantations. Some east Asian countries are already using Liriodendron plantations to efficiently lock in carbon, and we now think this might be related to its novel wood structure.” 

Liriodendron tulipifera are native to northern America and Liriodendron chinense is a native species of central and southern China and Vietnam.

Łyczakowski said: “Despite its importance, we know little about how the structure of wood evolves and adapts to the external environment. We made some key new discoveries in this survey – an entirely novel form of wood ultrastructure never observed before and a family of gymnosperms with angiosperm-like hardwood instead of the typical gymnosperm softwood. 

“ ̽��ֱ��main building blocks of wood are the secondary cell walls, and it is the architecture of these cell walls that give wood its density and strength that we rely on for construction. Secondary cell walls are also the largest repository of carbon in the biosphere, which makes it even more important to understand their diversity to further our carbon capture programmes to help mitigate climate change.”

This research was funded by the National Science Centre Poland and ̽��ֱ��Gatsby Charitable Foundation.

Reference: Lyczakowski, J L and Wightman, R. "Convergent and adaptive evolution drove change of secondary cell wall ultrastructure in extant lineages of seed plants." July 2024, New Phytologist.  DOI: 10.1111/nph.19983

All cryo-SEM images from the wood survey are publicly available. 

Revealing the nanostructure of wood could help raise height limits for wooden skyscrapers

jg533 — Wed, 23 Oct 2019 04:00:00 +0000

There is increasing interest around the world in using timber as a lighter, more sustainable construction alternative to steel and concrete. While wood has been used in buildings for millennia, its mechanical properties have not, as yet, measured up to all modern building standards for major superstructures. This is due partly to a limited understanding of the precise structure of wood cells.

̽��ֱ��research, published today in the journal Frontiers in Plant Science, has also identified the plant Arabidopsis thaliana as a suitable model to help direct future forestry breeding programmes.

Dr Jan Lyczakowski, the paper’s first author from Cambridge ̽��ֱ��’s Department of Biochemistry, who is now based at Jagiellonian ̽��ֱ��, said, “It is the molecular architecture of wood that determines its strength, but until now we didn’t know the precise molecular arrangement of cylindrical structures called macrofibrils in the wood cells. This new technique has allowed us to see the composition of the macrofibrils, and how the molecular arrangement differs between plants, and it helps us understand how this might impact on wood density and strength.”

̽��ֱ��main building blocks of wood are the secondary walls around each wood cell, which are made of a matrix of large polymers called cellulose and hemicellulose, and impregnated with lignin. Trees such as the giant sequoia can only achieve their vast heights because of these secondary cell walls, which provide a rigid structure around the cells in their trunks.

̽��ֱ��team from Cambridge ̽��ֱ��’s Department of Biochemistry and Sainsbury Laboratory (SLCU) adapted low-temperature scanning electron microscopy (cryo-SEM) to image the nanoscale architecture of tree cell walls in their living state. This revealed the microscopic detail of the secondary cell wall macrofibrils, which are 1000 times narrower than the width of a human hair.

To compare different trees, they collected wood samples from spruce, gingko and poplar trees in the Cambridge ̽��ֱ�� Botanic Garden. Samples were snap-frozen down to minus 200°C to preserve the cells in their live hydrated state, then coated in an ultra-thin platinum film three nanometres thick to give good visible contrast under the microscope.

“Our cryo-SEM is a significant advance over previously used techniques and has allowed us to image hydrated wood cells for the first time”, said Dr Raymond Wightman, Microscopy Core Facility Manager at SLCU. “It has revealed that there are macrofibril structures with a diameter exceeding 10 nanometres in both softwood and hardwood species, and confirmed they are common across all trees studied.”

Cryo-SEM is a powerful imaging tool to help understand various processes underlying plant development. Previous microscopy of wood was limited to dehydrated wood samples that had to be either dried, heated or chemically processed before they could be imaged.

̽��ֱ��team also imaged the secondary cell walls of Arabidopsis thaliana, an annual plant widely used as the standard reference plant for genetics and molecular biology research. They found that it too had prominent macrofibril structures. This discovery means that Arabidopsis could be used as a model for further research on wood architecture. Using a collection of Arabidopsis plants with different mutations relating to their secondary cell wall formation, the team was able to study the involvement of specific molecules in the formation and maturation of macrofibrils.

Dr Matthieu Bourdon, a research associate at SLCU, said, “ ̽��ֱ��variants of Arabidopsis allowed us to determine the contribution of different molecules - like cellulose, xylan and lignin - to macrofibril formation and maturation. As a result, we are now developing a better understanding of the processes involved in assembling cell walls.”

̽��ֱ��wealth of Arabidopsis genetic resources offers a valuable tool to further study the complex deposition of secondary cell wall polymers, and their role in defining the fine structure of cell walls and how these mature into wood.

“Visualising the molecular architecture of wood allows us to investigate how changing the arrangement of certain polymers within it might alter its strength,” said Professor Paul Dupree, a co-author of the study in Cambridge’s Department of Biochemistry. “Understanding how the components of wood come together to make super strong structures is important for understanding both how plants mature, and for new materials design.”

“There is increasing interest around the world in using timber as a lighter and greener construction material,” added Dupree. “If we can increase the strength of wood, we may start seeing more major constructions moving away from steel and concrete to timber.”

Professor Dupree and Dr Lyczakowski are involved in the Leverhulme Trust funded Natural Material Innovation Centre where a team of biochemists, plant scientists, architects, mathematicians and chemists at the ̽��ֱ�� of Cambridge is working towards better understanding of wood structure, modification and application. ̽��ֱ��researchers are hoping they can make wooden skyscrapers, and even wooden cars, a reality by re-engineering the structure of wood in order to make better materials for construction and manufacturing. Their work was recently showcased at the Royal Society Summer Science Exhibition in London.

This study was supported by the Leverhulme Trust Centre for Natural Material Innovation, US Department of Energy, BBSRC, ERC and Gatsby Charitable Foundation.

Reference

J. Lyczakowski et al. ‘Structural imaging of native cryo-preserved secondary cell walls reveals the presence of macrofibrils and their formation requires normal cellulose, lignin and xylan biosynthesis.’ Frontiers in Plant Science (2019) DOI:10.3389/fpls.2019.01398

Cambridge researchers have captured the visible nanostructure of living wood for the first time using an advanced low-temperature scanning electron microscope.

Understanding how the components of wood come together to make super strong structures is important for understanding both how plants mature, and for new materials design.

Paul Dupree

Microscopic structure of spruce wood

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

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Rare mineral discovered in plants for first time

Anonymous — Mon, 05 Mar 2018 13:58:12 +0000

Scientists at Sainsbury Laboratory Cambridge ̽��ֱ�� have found that the mineral vaterite, a form (polymorph) of calcium carbonate, is a dominant component of the protective silvery-white crust that forms on the leaves of a number of alpine plants, which are part of the Garden’s national collection of European Saxifraga species.

Naturally occurring vaterite is rarely found on Earth. Small amounts of vaterite crystals have been found in some sea and freshwater crustaceans, bird eggs, the inner ears of salmon, meteorites and rocks. This is the first time that the rare and unstable mineral has been found in such a large quantity and the first time it has been found to be associated with plants.

̽��ֱ��discovery was made through a ̽��ֱ�� of Cambridge collaboration between the Sainsbury Laboratory Cambridge ̽��ֱ�� microscopy facility and Cambridge ̽��ֱ�� Botanic Garden, as part of an ongoing research project that is probing the inner workings of plants in the Garden using new microscopy technologies. ̽��ֱ��research findings have been published in the latest edition of Flora.

̽��ֱ��laboratory’s Microscopy Core Facility Manager, Dr Raymond Wightman, said vaterite was of interest to the pharmaceutical industry: “Biochemists are working to synthetically manufacture vaterite as it has potential for use in drug delivery, but it is not easy to make. Vaterite has special properties that make it a potentially superior carrier for medications due to its high loading capacity, high uptake by cells and its solubility properties that enable it to deliver a sustained and targeted release of therapeutic medicines to patients. For instance, vaterite nanoparticles loaded with anti-cancer drugs appear to offload the drug slowly only at sites of cancers and therefore limit the negative side-effects of the drug.”

Other potential uses of vaterite include improving the cements used in orthopaedic surgery and as an industrial application improving the quality of papers for inkjet printing by reducing the lateral spread of ink.

Dr Wightman said vaterite was often associated with outer space and had been detected in planetary objects in the Solar System and meteorites: “Vaterite is not very stable in the Earth’s humid atmosphere as it often reverts to more common forms of calcium carbonate, such as calcite. This makes it even more remarkable that we have found vaterite in such large quantities on the surface of plant leaves.”

Botanic Garden Alpine and Woodland Supervisor, Paul Aston, and colleague Simon Wallis, are pioneering studies into the cellular-level structures of these alpine plants with Dr Wightman. Mr Wallis, who is also Chairman of the international Saxifrage Society, said: “We started by sampling as wide a range of saxifrage species as possible from our collection. ̽��ֱ��microscope analysis of the plant material came up with the exciting discovery that some plants were exuding vaterite from “chalk glands” (hydathodes) on the margins of their leaves.

"We then noticed a pattern emerging. ̽��ֱ��plants producing vaterite were from the section of Saxifraga called Porphyrion. Further to this, it appears that although many species in this section produced vaterite along with calcite, there was at least one species, Saxifraga sempervivum, that was producing pure vaterite.”

Dr Wightman said two new pieces of equipment at the microscopy facility were being used to reveal the inner workings of the plants and uncovering cellular structures never before described: “Our cryo-scanning electron microscope allows us to view, in great detail, cells and plant tissues in their “native” fully hydrated state by freezing samples quickly and maintaining cold under a vacuum for electron microscopy.

"We are also using a Raman microscope to identify and map molecules. In this case, the microscope not only identified signatures corresponding to calcium carbonate as forming the crust, but was also able to differentiate between the calcite and vaterite forms when it was present as a mixture while still attached to the leaf surface.”

So why do these species produce a calcium carbonate crystal crust and why are some crusts calcite and others vaterite?

̽��ֱ��Cambridge ̽��ֱ�� Botanic Garden team is hoping to answer this question through further analysis of the leaf anatomy of the Saxifraga group. They suspect that vaterite may be present on more plant species, but that the unstable mineral is being converted to calcite when exposed to wind and rain. This may also be the reason why some plants have both vaterite and calcite present at the same time.

̽��ֱ��microscopy research has also turned up some novel cell structures. Mr Aston added: “As well as producing vaterite, Saxifraga scardica has a special tissue surrounding the leaf edge that appears to deflect light from the edge into the leaf. ̽��ֱ��cells appear to be producing novel cell wall structures to achieve this deflection. This may be to help the plant to collect more light, particularly if it is growing in partly shaded environments.”

̽��ֱ��team believes the novel cell wall structures of Saxifrages could one day help inform the manufacture of new bio-inspired optical devices and photonic structures for industry such as communication cables and fibre optics.

Mr Aston said these initial discoveries were just the start: “We expect that there may be other plants that also produce vaterite and have special leaf anatomies that have evolved in harsh environments like alpine regions. ̽��ֱ��next species we will be looking to study is Saxifraga lolaensis, which has super tiny leaves with an organisation of cell types not seen in a leaf before, and which we think will reveal more fascinating secrets about the complexity of plants.”

There is a risk that some of these tiny but amazing alpine plants could potentially disappear due to climate change, damage from alpine recreation sports and over-collecting. There is still much to learn about these plants, but the collaborative work of the Sainsbury Laboratory and Cambridge ̽��ֱ�� Botanic Garden team is revealing fascinating insights into leaf anatomy and biochemistry as well as demonstrating the potential for Saxifrages to supply a new range of biomaterials.

Story by Kathy Grube, Communications Manager, Sainsbury Laboratory.

A rare mineral with potential industrial and medical applications has been discovered on alpine plants at Cambridge ̽��ֱ�� Botanic Garden.

Biochemists are working to synthetically manufacture vaterite as it has potential for use in drug delivery, but it is not easy to make

Raymond Wightman

Paul Aston

Saxifraga sempervivum, an alpine plant species discovered to produce "pure vaterite".

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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Cells cling and spiral ‘like vines’ in first 3D tissue scaffold for plants

fpjl2 — Wed, 26 Aug 2015 16:53:41 +0000

Miniscule artificial scaffolding units made from nano-fibre polymers and built to house plant cells have enabled scientists to see for the first time how individual plant cells behave and interact with each other in a three-dimensional environment.

These “hotels for cells” mimic the ‘extracellular matrix’ which cells secrete before they grow and divide to create plant tissue. This environment allows scientists to observe and image individual plant cells developing in a more natural, multi-dimensional environment than previous ‘flat’ cell cultures.

̽��ֱ��research team were surprised to see individual plant cells clinging to and winding around their fibrous supports; reaching past neighbouring cells to wrap themselves to the artificial scaffolding in a manner reminiscent of vines growing.

Pioneering new in vitro techniques combining recent developments in 3-D scaffold development and imaging, scientists say they observed plants cells taking on growth and structure of far greater complexity than has ever been seen of plant cells before, either in living tissue or cell culture.

“Previously, plant cells in culture had only been seen in round or oblong forms. Now, we have seen 3D cultured cells twisting and weaving around their new supports in truly remarkable ways, creating shapes we never thought possible and never seen before in any plant,” said plant scientist and co-author Raymond Wightman.

"We can use this tool to explore how a whole plant is formed and at the same time to create new materials.”

This ability for single plant cells to attach themselves by growing and spiralling around the scaffolding suggests that cells of land plants have retained the ability of their evolutionary ancestors – aquatic single-celled organisms, such as Charophyta algae – to stick themselves to inert structures.

While similar ‘nano-scaffold’ technology has long been used for mammalian cells, resulting in the advancement of tissue engineering research, this is the first time such technology has been used for plant cells – allowing scientists to glimpse in 3-D the individual cell interactions that lead to the forming of plant tissue.

̽��ֱ��scientists say the research “defines a new suite of techniques” for exploring cell-environment interactions, allowing greater understating of fundamental plant biology that could lead to new types of biomaterials and help provide solutions to sustainable biomass growth.

̽��ֱ��research, conducted by a team of scientists from Cambridge ̽��ֱ��’s Sainsbury Laboratory and Department of Materials Science & Metallurgy, is published today in the open access journal BMC Plant Biology.

“While we can peer deep inside single cells and understand their functions, when researchers study a ‘whole’ plant, as in fully formed tissue, it is too difficult to disentangle the many complex interactions between the cells, their neighbours and their behaviour,” said Wightman.

“Until now, nobody had tried to put plant cells in an artificial fibre scaffold that replicates their natural environment and tried to observe their interactions with one or two other cells, or fibre itself,” he said.

Co-author and material scientist Dr Stoyan Smoukov suggests that a possible reason why artificial scaffolding on plant cells had never been done before was the expense of 3D nano-fibre matrices (the high costs have previously been justified in mammalian cell research due to its human medical potential).

However, Smoukov has co-discovered and recently helped commercialise a new method for producing polymer fibres for 3-D scaffolds inexpensively and in bulk. ‘Shear-spinning’ produces masses of fibre, in a technique similar to creating candy-floss in nano-scale. ̽��ֱ��researchers were able to adapt such scaffolds for use with plant cells.

This approach was combined with electron microscopy imaging technology. In fact, using time-lapse photography, the researchers have even managed to capture 4-D footage of these previously unseen cellular structures. “Such high-resolution moving images allowed us to follow internal processes in the cells as they develop into tissues,” said Smoukov, who is already working on using the methods in this plant study to research mammalian cancer cells.

New cost-effective material which mimics natural ‘extracellular matrix’ has allowed scientists to capture previously unseen behaviour in individual plant cells, including new shapes and interactions. New methods highlight potential developments for plant tissue engineering.

Until now, nobody had tried to put plant cells in an artificial fibre scaffold that replicates their natural environment

Raymond Wightman

Luo et al

Plant cells twisting and weaving in 3-D cultures

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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