Each year, the world loses about 10 million hectares of forest—an area about the size of Iceland—because of cutting down trees. At that rate, some scientists predict the world's forests could disappear in 100 to 200 years. To handle it, now researchers at Massachusetts Institute of Technology(MIT) have pioneered a technique to generate wood-like plant materials in a lab. This makes it possible to "grow" a wooden product without cutting down trees.
In the lab, the researchers first take cells from the leaves of a young plant. These cells are cultured in liquid medium for two days, then moved to another medium which contains nutrients and two different hormones(激素). By adjusting the hormone levels, the researchers can tune the physical and mechanical qualities of the cells. Next, the researchers use a 3-D printer to shape the cell-based material, and let the shaped material grow in the dark for three months. Finally, the researchers dehydrate(使脱水) the material, and then evaluate its qualities.
They found that lower hormone levels lead to plant materials with more rounded, open cells of lower density(密度), while higher hormone levels contribute to the growth of plant materials with smaller but denser cell structures. Lower or higher density of cell structures makes the plant materials softer or more rigid, helping the materials grow with different wood-like characteristics. What's more, it's to be noted that the research process is about 100 times faster than the time it takes for a tree to grow to maturity!
Research of this kind is ground-breaking. "This work demonstrates the great power of a technology," says lead researcher, Jeffrey Berenstain. "The real opportunity here is to be at its best with what you use and how you use it. This technology can be tuned to meet the requirements you give about shapes, sizes, rigidity, and forms. It enables us to ‘grow' any wooden product in a way that traditional agricultural methods can't achieve."