Growth and root colonization of mycorrhizal maize grown on acid and alkaline soil

Abstract

Arbuscular mycorrhizal fungi often have wide adaptability over many soil environments. We have determined the effects of the AM fungi Glomus etunicatum WV579A (Ge), G. diaphanum WV579B (Gd) and G. intraradices WV894 (Gi) on growth and root colonization of maize ( Zea mays L.) grown on two acid (pH 4.2 and 4.5) and two alkaline (pH 7.8 and 8.0) soils. Shoot and root dry matter (DM), leaf area (LA), and root length (RL) were higher for mycorrhizal (AM) than for nonmycorrhizal (nonAM) plants grown on all soils, and plants grown on alkaline soil had higher DM than plants grown on acid soil. Shoot and root DM followed a sequence of Ge > Gd≥Gi > nonAM for plants grown on the alkaline soil. The AM isolates enhanced DM of plants grown on acid soil, and differences among isolates were minor. Differences between AM and nonAM plants for total LA and RL were greater than for DM. Specific LA values for AM plants were consistently higher than for nonAM plants, while specific RL values for AM plants were only slightly higher than nonAM plants. Roots with arbuscules or vesicles was nil to low for plants grown on acid soil and relatively high for plants grown on alkaline soil. Roots with hyphal infection varied with type of soil and AM isolate, and was considerably higher than arbuscules or vesicles for plants grown on acid soil. Root hyphal infection appeared to be more important than arbuscules for growth enhancement of plants on acid soil. The AM isolates used were effective in enhancing growth of plants on both acid and alkaline soils showing wide adaptability to broad soil pH conditions.