X-RAY MICROANALYTICAL STUDIES ON 2 MODES OF STRONTIUM BINDING IN FRONDS OF LEMNA-MINOR

X-ray microprobe analysis of freeze-fractured Lemna fronds has shown t hat zinc (Zn) and cadmium (Cd) are not incorporated into oxalate cryst als in idioblasts, whereas strontium (Sr) is readily incorporated as a n alternative to calcium (Ca). Ca and Sr are uniformly distributed thr oughout the crystal bundle when both elements are present in the nutri ent solution. However, in neighbouring, non-idioblast cells Sr (but no t Ca) may also be incorporated into globular deposits of less than 1 m u m diameter. These globules contain the mineral elements potassium an d phosphorus and their composition appears to be identical to that of phytate globules which contain Zn or Cd under conditions of Zn or Cd t oxicity.