The Influence of Nitrogenous Compounds on the Growth of Helminthosporium Gramineum in Culture

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Abstract
Helminthosporium gramineum Rabh. exhibited a marked growth response in culture to barley plant extracts and to products diffusing from germinating barley. The organism utilized the ammonium ion in preference to nitrate ion in early stages of growth. Peptone was found to stimulate growth. The B vitamins present in peptone were not found to increase fungus growth when added to basal medium. Growth in certain amino acids plus ammonium nitrate was much greater than that in ammonium nitrate as the sole nitrogen source. In the presence of L tyrosine, L proline, glycine, DL valine, β-alanine, or DL threonine, fungus growth equalled or exceeded that in peptone and approached that obtained with barley plant extracts. Amino acids were the only nutrients tested that gave this type of response. The possibility of a relationship between the response of H. gramineum to amino acids in culture and the establishment of the fungus in the host is suggested.