Lower temperature and orthophosphate control of alkaline phosphatase in a cold-requiring plant

The elevated activity of alkaline phosphatase observed in roots and shoots of Verbascum rosettes grown in vitro at 15 degrees C may be the result of a reduced supply of orthophosphate. The rosette reveals greater activities of this enzyme under conditions of lower external phosphate or chilling temperature. Either of these treatments gives lower amounts of endogenous phosphate. The stimulation of phosphatase in tissues having lower levels of phosphate is thus a possible feature of other plant species which also display freezing tolerance.