A Histochemical Study of Phosphatases in Root Apical Meristems

Root apices, representing different types of apical tissue organization,were examined with the techniques of enzyme histochemistry.The distribution of acid phosphatase, adenosine triphosphatase,and glucose 6-phosphatase was determined for the various tissuesof the root apices. Phosphatases demonstrated intense activityin the root cap, protoderm, and cortex of all the roots tested.Moderate phosphatase activity was observed in the procambialstrands and differentiating tracheary elements. No activitywas evident in the promeristem and root cap columella. Theseresults are discussed with regard to the morphology of rootapices, and an attempt is made to elucidate possible physiologicalfunctions in relation to enzyme localization.