Plant cells are surrounded by intricately structured protective coats called cell walls. It is made from cellulose microfibrils intertwined with polysaccharides such as hemicellulose and pectin. We know what it looks like without a wall, and what they look like when the walls are fully assembled, but we have never seen the wall construction process work. “We knew where we started and the finish point, but we didn’t know what would happen in the meantime,” says Eric Lamb, a plant biologist at Rutgers University. He is a co-author of the first study to operate wall-building plant cells. And when I saw how cell wall construction works, it didn’t look like how I drew it in the Biology Handbook.
Camera shy builder
Wallless plant cells known as protoplasts were extremely vulnerable and it was difficult to keep them alive under a microscope for the hours required to build the walls. Plant cells are also very light sensitive, and most microscopic techniques require that you point to a strong light source to obtain a good image.
Then there was the issue of tracking their progress. “Cellulose is not fluorescent and cannot be seen in traditional microscopes,” says Sisil Chundawatt, a biologist at Rutgers. “It was one of the biggest issues of the past.” The only way you can see it is if you attach a fluorescent marker to it. Unfortunately, the markers normally used to label cellulose were either bound to other compounds or toxic to plant cells. Given their vulnerability and photosensitiveness, cells were unable to survive even simply toxic markers for very long.
