ENZYMATIC STUDIES ON THE METABOLISM OF VESICULAR–ARBUSCULAR MYCORRHIZAS

Publisher Website
Google Scholar
Abstract
Summary: The ultrastructural localization of ATPase activities was identical in onion and sycamore mycorrhizas. DES‐sensitive ATPase activity was associated with the fungal plasmalemma and paramural bodies whilst a DES‐insensitive ATPase activity was detected within the fungal vacuole. The development of the mycorrhizal fungus within root cells modified the distribution of DES‐sensitive plasmalemma‐bound ATPase activity of the host. This became concentrated around the finer arbuscule branches and appeared to be a specialization of the invaginated host membrane which occurred when arbuscule structure was favourable for nutrient exchange. These observations strengthen the hypothesis that nutrient exchange in VA mycorrhizas must occur across the living host‐fungus interface and that phosphate is transferred from fungus to host by an active transport mechanism in the finer branches of the arbuscule.