Effect of carbon and nitrogen sources on in vitro growth of Scleroderma sinnamariense Mont., a pantropical ectomycorrhizal fungus

Abstract

The utilisation of a range of carbon sources in the presence of either ammonium or peptone as sole nitrogen source by Scleroderma sinnamariense, an ectomycorhiza fungus isolated from Gnetum africanum was compared with Pisolithus tinctorius. Scleroderma showed significant growth of 17 mg with glucose as carbon source in the presence of peptone-N, whereas growth on the same carbon source in presence of ammonium-N was 8.5 mg. On the contrary, the Pisolithus isolate showed poor growth of 4.5 mg in peptone-N even with glucose as sole carbon source whilst growth on ammonium-N in the same carbon source was 15 mg. Utilisation of glucose, sucrose and starch by both Pisolithus and Scleroderma in ammonium-N led to a decrease in pH of the medium from 5.0 to 3.4, 3.5 and 4.8 respectively for Pisolithus and 3.2, 3.8 and 4.8 respectively for Scleroderma, whilst incubation on cellulose caused an increase in pH from 5.0 to 5.2. The decrease in pH was significant for both isolates when the carbon source was sucrose or glucose. Incubation of both fungi, on all carbon sources except glucose, in presence of peptone-N led in an increase in pH.

Keywords: Ammonium-N, Peptone-N, carbon utilisation, Pisolithus tinctorius