Interaction between arbuscular mycorrhizal fungi and cellulose in growth substrate

Plantago lanceolata was grown in a two-factor experiment with and without arbuscular mycorrhizal fungi (AMF) and with and without the addition of 2 g cellulose per litre of a sand-soil based cultivation substrate. Results showed a significant change in plant growth and development of arbuscular mycorrhiza represented by a mixed population of three symbiotic fungi: (1) Glomus claroideum; (2) Glomus geosporum; and (3) Glomus mosseae in cellulose amended substrate. Higher AMF colonization of roots after I I months of cultivation in the cellulose amended treatment was found compared to the unamended treatment. Sporulation of AMF was inhibited by cellulose at the first harvest (5-month-old plants), but it was substantially stimulated at the second harvest (I I-month-old plants). A positive effect of cellulose on the total length of extraradical mycorrhizal mycelium at the second harvest was observed. Significant changes in amounts of bacterial CFU and of the saprophytic fungus Penicillium pinophilum in the substrate amended with cellulose were recorded after I I months of cultivation. No significant changes in total and oxidizable carbon in AMF-inoculated substrate were found. The contribution of AMF extraradical mycelium to the total content of organic matter in the substrate represented less than 2%. The study showed the importance of cellulose, a common organic material in the soil, for development of AMF and saprophytic microfloral population in soil-based cultivation substrate poor in organic carbon. (C) 2002 Elsevier Science B.V. All rights reserved.