ENZYMATIC STUDIES ON THE METABOLISM OF VESICULAR-ARBUSCULAR MYCORRHIZA. III. ULTRASTRUCTURAL LOCALIZATION OF ACID AND ALKALINE PHOSPHATASE IN ONION ROOTS INFECTED BY GLOMUS MOSSEAE (NICOL. & GERD.)

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Summary

The ultrastructural distribution of acid and alkaline phosphatase in 6-week-old onion roots infected by Glomus mosseae has been investigated cytochemically. Significant acid phosphatase activity was only observed in the little vacuolated, immature terminal arbuscule branches of the mycorrhizal fungus whilst strong alkaline α-naphthyl phosphatase and β-glycerophosphatase activities were localized within the vacuoles of the mature arbuscular and intercellular hyphae. In the host cells neither acid nor alkaline phosphatase distribution was modified with vesicular-arbuscular mycorrhiza formation. These results are discussed in relation to previously reported mycorrhiza-specific alkaline phosphatase (Gianinazzi-Pearson and Gianinazzi, 1976, 1978) and the metabolism of phosphorus in vesicular-arbuscular mycorrhizal systems.

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