Folke Skoog, pioneering plant cell researcher, dies

Renowned plant physiologist and National Medal of Science recipient Folke Karl Skoog, professor of botany at the university for 32 years, died Feb. 15 after a long illness. He was 92.

Skoog arrived on campus already renowned for his pioneering work with auxin, a plant growth hormone. While at Wisconsin, he discovered a major new class of plant hormones, the cytokinins, which stimulate the division of plant cells, and regulate plant growth and development. His work has had a profound impact on agricultural and horticultural practices around the world.

Skoog’s discovery of cytokinins triggered an international flood of publications that continues to this day. His work showed that a number of cytokinins occur naturally, and that at least one of these compounds occurs in every organism tested, from bacteria to humans.

With colleague Nelson J. Leonard at the University of Illinois, Skoog synthesized and tested hundreds of compounds for cytokinin activity, and established the principles that govern relationships between plant structure and activity. These discoveries are generally held to be one of the major advances made in the plant sciences during the last 50 years.

Skoog was also a pioneer in investigating how to control the formation of roots, stems and leaves from undifferentiated cells in plant tissue cultures. Tissues could be made to develop as undifferentiated masses of cells, or to become roots, stems or a combination of roots and stems, resulting in complete plants. Skoog’s theory that plant development is controlled by hormone levels and other factors led to the realization that whole plants can be generated from cultured cells. This laid the groundwork for the production of transgenic plants and other advances in biotechnology. In 1962 he and graduate student Toshio Murashige published a culture medium for optimal plant tissue growth that remains in use today.

Skoog was born in Halland, Sweden on July 15, 1908. He decided to take up residence in the United States during a visit to California in 1925, and he became a U.S. citizen 10 years later. He received a bachelor of science degree in chemistry from the California Institute of Technology in 1932. He earned his Ph.D. from that institution in 1936. While at the institute, he worked closely with prominent plant physiologists Kenneth Thimann and Fritz Went, with whom he developed lifelong friendships.

Between 1937-1941, Skoog was on staff at Harvard University, and from 1941-1944, at Johns Hopkins University. He served as a chemist and technical representative of the U.S. Army in Europe between 1944-1946. When he retired as the UW–Madison’s C. Leonard Huskins Professor of Botany in 1979, he had trained more than 60 doctoral and 40 postdoctoral students.

“He was held in high regard by his students and colleagues, not only for his scientific acumen, but also for his quick wit and his unfailing interest in their personal well-being,” says colleague Eldon Newcomb, UW–Madison professor emeritus of botany. “Many of his students and colleagues kept in touch with him in later years.”

Looking back on his own career, Skoog observed that his professional successes were due in large part to the capable support he had enjoyed from people in different disciplines helping him. In addition, he said he “had a fairly long nose for smelling out problems and blind perseverance in trying to bring matters to a conclusion.”

Skoog played an active role in a number of biological societies. He served as president of the American Society of Plant Physiologists, the Society of Developmental Biology, the American Society of General Physiologists and the International Plant Growth Substances Association. He was a member of the American Academy of Arts and Sciences, and the National Academy of Sciences. He was awarded the National Medal of Science in 1991 during a ceremony at the White House. In addition, several universities awarded him with honorary degrees.

Skoog is survived by his wife Birgit, his daughter Karin and three grandsons. Memorial arrangements are pending.