THE PROLIFERATION OF FUNGAL HYPHAE IN SOILS SUPPORTING MYCORRHIZAL AND NONMYCORRHIZAL PLANTS

This study investigated the impact of mycorrhizal plants, non-mycorrhi zal plants and soil organic matter on the relative abundance of soil h yphae perceived to belong to indigenous arbuscular mycorrhizal (AM) pl ants. The mycorrhizal plants corn (Zea mays L.) and barley (Hordeum vu lgare L.) and a non-mycorrhizal plant, canola (Brassica napus L.), wer e grown in unsterilized soil in pots inoculated with mycorrhizal corn root fragments. The abundance of hyphae was measured after 5 weeks and the response of fungal growth to the addition of corn residues in the absence of plants was assessed. The abundance of hyphae was higher in the presence of the mycorrhizal plants than in the other treatments. AM hyphae present under mycorrhizal plants accounted for more than 83% of the measured hyphae. The levels of root colonization of 32% in cor n and 27% in barley confirmed the mycorrhizal status of the experiment al plants. Only a few points of entry were observed in canola, the non -host plant. The percentage of mycorrhizal colonization was positively related (R(2) = 0.85) to the abundance of soil hyphae, indicating tha t AM hyphae were the major component of the soil hyphae in the presenc e of mycorrhizal plants in this study.