Phosphate-solubilising abilities of ericoid mycorrhizal endophytes of Woollsia pungens (Epacridaceae)

The ability of 13 mycorrhizal endophytes from Woollsia pungens (Cav.) F.Mue ll. (Epacridaceae) and three Hymenoscyphus isolates to solubilise hydroxyap atite and fluorapatite was assessed in axenic culture under a range of cond itions. All Hymenoscyphus isolates and most of the endophytes from W. punge ns solubilised hydroxyapatite in unbuffered media containing NH4+ as the so le nitrogen source, but were unable to solubilise this substrate in buffere d media or when NO3- was the sole nitrogen source. None of the isolates sol ubilised fluorapatite under any of the conditions tested. The internal phos phorus status of the mycelia had no influence on the ability of the isolate s to solubilise either substrate. The data suggest that the phosphate-solub ilising activities of mycorrhizal endophytes of Epacridaceae in soil may be confined to the less chemically resistant phosphorus sources.