PHOSPHATASE ACTIVITY OF INTACT YOUNG WHEAT ROOTS UNDER STERILE AND NON-STERILE CONDITIONS.

In assays of acid phosphatase activity with p-nitrophenyl phosphate as substrate, the low activity found in fluids removed from around roots in liquid medium was not affected by the presence of micro-organisms. Most phosphatase activity of intact seedling roots was associated with the root surface and was not increased by micro-organisms in the rhizoplane; in some experiments activity was significantly reduced by soil micro-organisms. Inoculation of roots with pure cultures of bacteria and a fungus known to have phosphatase activity did not increase this activity of the roots. These results are contrasted with those of other workers. Possible application to the soil situation is discussed. [ABSTRACT FROM AUTHOR]