Changes in phosphatase activity in phosphorus-deficient Spirodela

Onset of phosphorus deficiency in Spirodela oligorrhiza was accompanied by a 50-fold increase in phosphatase activity of cell extracts. The enzyme behaved like other plant acid phosphatase, and was both inhibited and repressed by inorganic phosphate. The phosphatase activity comprised at least three isozymes. Two, of low molecular weight, were present only in P-deficient Spirodela; one of high molecular weight was also present, though in smaller amounts, in normal Spirodela. Presence of 2-thiouracil during onset of P-deficiency partly inhibited the development of phosphatase activity. The nature and role of the increased phosphatase activity in P-deficient plants are discussed.