THE BIOLOGY OF MYCORRHIZA IN THE RICACEAE: IX. PEPTIDES AS NITROGEN SOURCES FOR THE ERICOID ENDOPHYTE AND FOR MYCORRHIZAL AND NON-MYCORRHIZAL PLANTS.

The ericoid mycorrhizal endophyte Hymenoscyphus ericae (Read) Korf &Kernan was grown both in pure culture and in mycorrhizal association with the host plant Vaccinium corymbosum L. on media containing peptides of differing chain length as sole nitrogen sources. The ability to utilize the peptide nitrogen was assessed in terms of growth of the fungus and of growth and nitrogen content of the plants. The tripeptide, glutathione, and alanine units of 1-6 amino acid residues in length were all readily utilized by the endophyte, though assimilation was less rapid in the case of the longer chain lengths. Mycorrhizal seedlings showed significantly higher yields and had higher nitrogen contents than non-mycorrhizal seedlings in almost all cases. The physiological and ecological implications of these results are discussed.