THE ABSORPTION OF INORGANIC-PHOSPHATE FROM 32P-LABELED INOSITOL HEXAPHOSPHATE BY ERIOPHORUM-VAGINATUM

A scarcity of available phosphorus often limits plant growth, and organic forms of phosphorus are not generally thought to be important direct sources of phosphate for plants. A dominant arctic tundra plant, Eriophorum vaginatum, is able to hydrolyze and absorb phosphate from a naturally occurring organic phosphorus compound at concentrations as low as those found in soil solution and at rates comparable to its ability to absorb inorganic phosphate. Calculations show that in tundra soils, where organic phosphorus is typically the predominant form of phosphorus in soil solution, E. vaginatum's root surface phosphatases may be capable of providing from organic phosphorus up to 69% of the plant's annual phosphorus demand.