Final Report - Center for Invasive Plant Management

study to study, due to varying fungal species and different geographic areas (Smith andGianinazi-Pearson i988). Hor.vever, external hyphal iengths from this study are consistent withhyphal lengths measured in a diflbrent intermountain grassland in westem Montana (Lutgen andRillig submitted). where hyphal lengths reached 45 m -c-rsoil.Percent AM and non-AIVI hyphal colonization in roots decreased in November, similar tothe decrease in AM hyphal length. However, the decrease in fungal hyphal colonization beginsearlier in the sampling period. during August. A dramatic decline in percent AM arbusculecolonization also oceurs at this time. It is likely that plants were stres$ed from the drought10 conditions during the sampling period" and the carbon allocation from plant to fungus may havebeen diminished as a consequence. Because AM arbuscules are the structures involved innutrient exchange r.vith plants, the drought response in plants could be reflected quitedramatically in percent arbuscule colonization.15 Root length parameters measured did not exhibit much significant change through time,with only the fine root length (>0.25 mm diameter) parameter changing through time. Themajority of root iength measured was found in the very fine root length (