DEVELOPMENT OF VESICULAR-ARBUSCULAR MYCORRHIZAE IN SUGAR MAPLE (ACER-SACCHARUM) AND EFFECTS OF BASE-CATION AMENDMENT ON VESICLE AND ARBUSCULE FORMATION

The development, condition, and incidence of vesicular-arbuscular myco rrhizae of Acer saccharum (sugar maple) seedlings grown in the greenho use in natural sugar maple forest soil substrate were examined. The ef fects of the addition of a cation mixture containing calcium, magnesiu m, and potassium were also studied. The mycorrhizal structures observe d were similar to those found in natural field conditions. Mycorrhizae developed intracellularly via hyphal coils, and arbuscules usually de veloped from these coils, forming arbusculate coils. This development is different from that observed in most annual crop plants. Vesicular- arbuscular mycorrhizal structures appeared within 30 days. The rate of mycorrhizal infection decreased, along with plant health, as the quan tity of the added cations was increased, but the amendment did not aff ect the morphology of the infection. More vesicles were observed in th e lowest level of application than in controls, suggesting a stress re sponse and possible relationship between plant health and condition of the mycorrhizal association.