There is no doubt that this vitamin is key to human health or that people get it from the foods they eat, but researchers at Boyce Thompson Institute for Plant Research Inc. at Cornell University have new information to explain why plants make this important anti-oxidant. Humans are among the few species that do not produce their own vitamin C and must rely on eating the right foods to obtain it. Researchers at the Boyce Thompson Institute created mutant plants that have no capacity to make vitamin C, and they then subjected the plants to strenuous environmental factors such as high levels of ozone and ultraviolet light. We grew our Arabidopsis thaliana plants in elevated levels of ozone. For a normal plant, this is not a problem.
Free radicals are atoms with unpaired electrons that are bad for the human immune system.
But our mutants lacking vitamin C had shriveled leaves. When grown in an ozone-contained environment, those plants, the ones with shriveled leaves, were not able to cope with environmental stress. The research was funded by the National Science Foundation Presidential Young Investigator grant and an American Cancer Society postdoctoral fellowship grant. The way in which plant cells make vitamin C is now the topic of a project funded by the U.S. Dept. of Agriculture. The study of the vitamin C deficient plants also showed that they were hypersensitive to sulfur dioxide and ultraviolet B radiation.