Shang Fa Yang

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Shang Fa Yang (Chinese: 楊祥發; November 10, 1932 – February 12, 2007) was an acclaimed plant scientist and a professor at the University of California, Davis.

Birth and education[edit]

Shang Fa Yang was born in 1932 in Taiwan. He earned his bachelor's and master's degrees in agricultural chemistry at the National Taiwan University. After completing his master's degree, he went to the United States and completed his doctoral degree in plant biochemistry from Utah State University.

Academic career[edit]

After completing his PhD, he conducted postdoctoral research at the University of California, Davis, New York Medical School, and University of California, San Diego. After completing his postdoctoral research, he joined the faculty University of California, Davis in 1966.


The Yang cycle

Shang Fa Yang was known for his research that unlocked the key to prolonging freshness in fruits and flowers. His research focused on how plants produce ethylene, which is important in regulating a host of plant functions, ranging from seed germination to fruit ripening. He studied the pathway of ethylene biosynthesis and proved unequivocally the central role of methionine as a precursor of ethylene. He discovers that this process is cyclic and therefore receives the name "Yang Cycle". Ethylene represents one of the five major hormones affecting plant development and maturation.

He was the first scientist to report S-adenosylmethionine as an intermediate in methionine conversion to ethylene. Then, in 1979, he discovered aminocylopropane-1-carboxylic acid (ACC) as an intermediate. His discovery of ACC-synthase opened the way to the understanding of the regulating process of ethylene biosynthesis.

Awards and honours[edit]

Shang Fa Yang received several awards and honours for his research. In 1990, he was inducted into the U.S. National Academy of Sciences. In 1991, he was awarded the Wolf Prize in Agriculture "for his remarkable contributions to the understanding of the mechanism of biosynthesis, mode of action and applications of the plant hormone, Ethylene."[1] In 1992, he was awarded the American Society of Horticultural Science Outstanding Research Award.


Shang Fa Yang died on February 12, 2007 in a Davis hospital from complications of pneumonia.



  • IN MEMORIAM - Shang Fa Yang [1]
  • Plant Scientist Shang Fa Yang Dies [2]
  • The Wolf Prize in Medicine in 1991 (detail)[3]

External links[edit]