Illustration Corinna Heumann, Text Bernhard Fischer

Plant products without overexploitation of nature? “Ex Planta and In Vitro

2121: A glance at the clock – where is the dealer for the tropical woods? He should be on time for a sales talk, she thinks to herself.

Her old living room furniture is outdated and worn out. “It’s time for new, elegant furnishings,” she tells the designer, who finally appears together with the dealer. In the sales light of the jungle, she is thrilled by the available range and her anger evaporates. Among the jungle giants, she chooses grenadilla wood for her table, plus zebrano for the chair, a chest of drawers made of bongossi and, to crown it all, a sideboard made of meranti wood. The precious jungle woods will grow and be delivered exactly according to her ideas. The dealer assures her of that. But none of the rare trees will be felled for this. The jungle giants remain untouched except for a small removal of cells.

Furniture made of the best wood, without having to cut down a tree for it. Sufficient plant food and clothing for all? Forests that are not cleared but remain green lungs and habitats for endangered species and insects? A world without DDT, glyphosate and poison against “weeds”: could this vision of the future come true? Yes, this utopia could soon become truth.

2021: Cell research against scarcity

Today, scientists all over the world are working to advance research into biological cells and their reproduction in order to conserve the world’s resources on the one hand and to secure people’s high standard of living on the other.

Currently, agriculture grows whole plants, harvests the usable part – sometimes with only a small yield – and composts or burns the rest. This approach consumes considerable resources and time. The entire life cycle of the plants has to be waited for before the usable part can be harvested or utilised.

For example, for a grain of rice, the seedling grows until the grain can be harvested. After harvesting, the plant is thrown away – except for the rice grain. It is even more serious with trees. It takes years until a tree has grown so much that it can be felled, in the case of tropical trees even many decades. No wonder, then, that their use and utilisation is discussed very controversially.

Renewable raw materials are therefore only theoretically renewable today.

The sad fact is that humanity consumes more than it grows back. From 1990 to 2016, for example, two and a half times the area of France was cleared of forest. It is obvious that this kind of use cannot continue for much longer.

Researchers hope for the vitality of plants

Living plant cells have an impressive ability. They can grow, divide and differentiate like human stem cells. Under particularly favourable circumstances, a single plant cell can even regrow into a whole plant. Recently, a team of researchers has shown that single cells can grow into exactly what is needed: A chair, a table, a chest of drawers or even a sideboard – in adjustable form and quality.

How do you get a wooden cell to grow into an object?

First, suitable growing conditions have to be set up, so-called “ex planta farming”. “Ex planta” because although a mother plant is needed as a cell donor, the mother plant is little affected by this. It will continue to live and grow. The crop grows outside the plant, which is how the term “ex planta” comes about.

The researchers used cells from“Zinnia elegans” because they are easy to isolate. In principle, individual cells can be isolated from all plants and further cultivated. The research team grew the tissue of the“Zinnia elegans” in a grid-like scaffold, the walls of which were also doped with cells. This creates a lattice of plant tissue.

This is how “ex-planta farming” works

First, individual cells are isolated from the mother plant. These are then multiplied in the laboratory. This cell cluster is spread out as a gel in a three-dimensional framework, which contains a nutrient solution and fixes the cell cluster. The cells continue to grow in this until a tunable and shaped plant tissue has formed.What is particularly interesting is that the properties of this gittes can be influenced! What becomes of the isolated cells is in fact determined by many external parameters.

For the proof of concept, the researchers only went through a few parameters: pH value, initial concentration of the cells and two growth hormones. With these alone, they were able to noticeably influence the cell size and the degree of lignification of the material.

Wood from cells – a promising field of research!

The tissue “xylem” is mentioned as a first possible application. In the tree, xylem forms the wood. For wood, trees grow at least 20 years, often much longer. Then the harvester comes and takes the trunk.

Bark, roots, leaves, small twigs etc. remain as “waste”. In the laboratory, only the coveted xylem would grow as tissue. Preferably already in a form that will be needed later. As a board, a log, a chair and so on. Of course, with the optimal properties that are desired for the respective application.

Research has not yet reached the point where a chair, a table and sideboards for the furniture industry can grow. But much seems possible once the process and all the growth parameters have been thoroughly researched one day. But the advantages of this research are already promising and enormous today:

The desired tissue can grow quickly, its shape as well as its quality can be specifically influenced.

A piece of furniture, for example, could grow into any desired shape – depending on climate and season. No part of the plant would be left as waste. Harmful environmental influences, such as over-fertilisation or extensive consumption of fertile land, would also become a thing of the past.

Best of all, the process is not limited to the production of wood.

Any plant tissue would be considered for this kind of production. Perhaps at some point in space, on the moon or on Mars, food will even be produced in this way. Just from a few cells and without any arable land.

Find out more about the study here.