Growth responses of ammonia fungi to different concentrations of ammonium-nitrogen

Abstract

In order to elucidate the physiological characteristics of ammonia fungi, we cultured 18 isolates of ammonia fungi in synthetic liquid media with varied NH_4Cl concentrations as nitrogen source. Early phase ammonia fungi (EP fungi; saprotrophic ammonia fungi) Ascobolus denudatus, Pseudombrophila petrakii, Coprinopsis phlyctidospora, Coprinopsis sp. (allied species of C. phlyctidospora in Oceana), and late phase ammonia fungi (LP fungi; ectomycorrhizal ammonia fungi) Hebeloma vinosophyllum and He. aminophilum had optimum vegetative growth at 0.003-0.1 M NH_4Cl. The upper limit for their vegetative growth was 0.6 M NH_4Cl. EP fungus Humaria velenovskyi had optimum growth in a wider range of ammonium chloride concentrations whereas EP fungi Amblyosporium botrytis, Peziza moravecii, and Tephrocybe tesguorum had optimum growth at 0.03-0.3 M NH_4Cl. The upper limits for the vegetative growth of these four ammonia fungi were between 1.1-1.6M NH_4Cl. Results indicate that ammonia fungi can be divided into three groups in terms of tolerance to ammonium ion, namely high ammonium ion adapted species, composed of saprotrophic ammonia fungi, wide range concentrations of ammonium ion adapted species, composed of saprotrophic ammonia fungi, and high ammonium ion non-tolerant species composed of saprotrophic and ectomycorrhizal fungi.