RELATIONSHIP BETWEEN HYPHAL AND ARBUSCULAR COLONIZATION AND SPORULATION IN A MYCORRHIZA OF PASPALUM-NOTATUM FLUGGE

Experiments were conducted to determine correlation between sporulation by an arbuscular mycorrhizal (AM) fungus to proliferation of arbuscules or intercellular hyphae. Paspalum notatum Flugge seedlings were inoculated with the AM fungus Gigaspora margarita Becker & Hall and treated with either tap water, nutrient solution without P, or nutrient solution with P to manipulate colonization levels. Plants receiving the nutrient solution without P tended to have greater colonization than plants receiving water only (e.g. 62 vs 54%, respectively at week 7) but lesser percentage root length with arbuscules (e.g. 27 vs 38%, respectively at week 7). Mycorrhizas receiving the nutrient solution without P sporulated sooner (week 7) than the water only treatment and had larger spore populations (e.g. 20.9 vs 14.2 spores cm(-3) at week 13). Nutrient solution with P did not completely inhibit colonization, and though these plants had total colonized loot lengths similar to those of the water treatment, spore populations were much less (2.9 cm(-3) at week 13). Spore populations correlated equally well with total root length as with root length colonized and root length with arbuscules in the water and nutrient solution without P treatments. Populations were not correlated to these measures for the nutrient solution with P, indicating that the host may have limited the ability of a unit length of colonization to produce spores in this treatment.