TRANSLOCATION OF CALCIUM AND PHOSPHATE BY EXTERNAL HYPHAE OF VESICULAR-ARBUSCULAR MYCORRHIZAE

Calcium-45 and 32P were injected into soil 4.5 cm from onion root surfaces at rates designed to label available pools of Ca and P at equivalent specific activities. Both tracers were detected in mycorrhizal but not anonmycorrhizal plants after 5 days. Calcium-45 was detected less frequently and in much lower amounts than 32P, indicating that Ca is not translocated to roots through mycorrhizal hyphae as readily as P.