Arnon, Daniel I.

Arnon, Daniel I. (Israel) (1910–  ) plant physiologist; born in Warsaw, Poland. Raised in the U.S.A., he spent his career at the University of California: Berkeley (1936–78). His early research (1930s) concerned the role of trace elements in the growth of algae and higher plants. He demonstrated that water (hydroponic) culture of tomatoes, using mineral supplements, produces yields similar to soil crops, but is economically feasible only if the available soil is incapable of supporting growth (1939). His pioneering investigations of photosynthesis began in the late 1940s, when he and colleagues isolated chloroplasts (chlorophyll-containing cell organelles) from spinach cells, and published results of the first photosynthetic process outside the living cell (1954). He also discovered "photosynthetic phosphorylation," which occurs in the absence of carbon dioxide.