Soy Research Today is a free monthly online journal that collates and summarizes the latest research about Soy, including details on soy milk, soy protein, soya bean, benefits, dangers.

Effect of two AMF life strategies on the tripartite symbiosis with Bradyrhizobium japonicum and soybean.

Antunes PM, Deaville D, Goss MJ

Department of Land Resource Science, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.

This study is the first in assessing the effect of soil disturbance on the contribution of arbuscular mycorrhizal fungi (AMF) with different life-history strategies to the tripartite symbiosis with soybeans and Bradyrhizobium japonicum (Kirchner) Jordan. We hypothesized that Gigaspora margarita Becker and Hall would be more affected by soil disturbance than Glomus clarum Nicol. and Schenck, and consequently, the tripartite symbiosis would develop more rapidly and lead to greater N(2) fixation in the presence of the latter. Soil pasteurization allowed the establishment of treatments with individual AMF species and soil disturbance enabled the development of contrasting root colonization potentials. In contrast, the colonization potential of B. japonicum was kept the same in all treatments. Soil disturbance significantly reduced root colonization by both AMF, with Gi. margarita being considerably more affected than G. clarum. Furthermore, the tripartite symbiosis progressed faster with G. clarum, and at 10 days after plant emergence, there was 30% more nodules when G. clarum was present compared to that when the bacterial symbiont alone was present. At flowering, the absence of soil disturbance stimulated N(2) fixation by 17% in mycorrhizal plants. However, this response was similar for both AMF.

Published 19 May 2006 in Mycorrhiza, 16(3): 167-73.
Full-text of this article is available online (may require subscription).

© 2004-2008 Soy Research Today. All Rights Reserved.