PHOSPHATE ACCUMULATION IN FAGUS MYCORRHIZAS

S ummary The quantities of polyphosphate formed in beech mycorrhizas during uptake of KH 2 32 PO 4 were estimated after extraction with cold TCA and KOH. Over an absorption period of 19 h the proportion of absorbed phosphate converted into polyphosphate increases with external phosphate concentration from 22% in 0·16 mM to 44% in 0·98 mM KH 2 PO 4 . Uptake from 64 mM phosphate results in 39 % being accumulated as polyphosphate during 2·5 h. Calculations based on the percentage of phosphate accumulated in the sheath, obtained by dissection, show that a large fraction of the phosphate in the fungus is accumulated as polyphosphate.