Final Report - Center for Invasive Plant Management

exudates in soil. Perhaps root production in the current study (represented here by root length)seln*'ed as a priming etlect fbr the microbial community by producing abr-rndant exudates andenhancing the environrnent for decomposers. As a result, these abundant decomposers degradedthe more readily available EEG and IREEG fractions, decreasing their adsorption to soilparticles. Hence. an increase in root length may have resulted in an increase in either of thesefractions. as observed with the IRHEG l'i'action.The sampling schedule for this study was quite intense (soil cores extracted bi-weeklyfrom N{ay through November 2001 , I3 time points) compared to other iield studies on AM10hyphal dvnamics, partioularly those that measured external hyphal lengfh (four time points;Miller et al. 1995, Kabir et al. 1997). Our sampling frequency allowed for a more detailedresolution of the seasonal patterns of AM hyphal dvnamics and glornalin pools.Although glomalin has a slow turnover time in soil, it appears that some _elomalin15fractions can fluctuate through a growing season" Changes in AM fungal and root parametersdid not exactlv niatch changes observed in glomalin concentrations, However, the decline inIREEG concentration in November is comparable to the general decrease in AN{ fungal and rootparameters in late sumnler through the end of the sampling period. The overall lack ofcorrelation betrveen AM fungal parameters and glomalin is important. as it points out tlrat20glomalin fractions, as cuffently detined, may not be useful as indicators of AMF hyphal lengthand fungal activity in general.l5