2018 Volume 100 Issue 1 Pages 3-7
In order to examine the seasonal changes in the colonization rates of arbuscular mycorrhizal (AM) fungi in the roots of Cryptomeria japonica, we collected roots from mature trees and seedlings in Takakuma Experimental Forest of Kagoshima University from January 2012 to November 2013. We stained sample fine root segments and observed AM fungi by microscopy. As a result, all the individuals of C. japonica examined in this study were colonized by AM fungi. Colonization rates were low from January to May for both mature trees and seedlings. They drastically increased in June and then decreased until August. They recovered after summer from September till November for mature trees and till October for seedlings, and decreased again. Colonization rates showed quite similar patterns of seasonal change between the two years both for mature trees and seedlings, but were generally higher in mature trees than in seedlings. Colonization rates showed significant positive correlation with mean air temperature in total, but more precisely, they increased with the increase in temperature below 22℃, but decreased above that temperature. Precipitation also showed significant positive correlation with colonization rates, but this seem to be an indirect relationship reflecting the relationship between colonization rate and air temperature.
