ULTRASTRUCTURE AND ELECTRON‐PROBE MICROANALYSIS OF THE METACHROMATIC VACUOLAR GRANULES OCCURRING IN <i>TAXUS</i> MYCORRHIZAS

Abstract

SUMMARY Numerous metachromatic vacuolar granules occur in the hyphae of the fungal symbiont of Taxus baccata mycorrhizas. These granules exist in the trunks and in proliferating arbuscules but they are absent in lysed arbuscules. Direct microanalysis with an electron probe shows that they have a high phosphorus and calcium content. Potassium and magnesium are also present but in lesser quantities. The concentration of phosphorus and calcium is higher in the granules than in the light part of the vacuoles. The concentration of phosphorus also is higher in the granules than in the nuclei of the root cells and the concentrations of calcium are greater than those measured in the pecto‐cellulosic wall of root cells. The role of calcium in the metabolism of phosphorus within the tissues of mycorrhizas still remains unknown.