Final Report - Center for Invasive Plant Management

oot length: SRL) over a season in two temperate grassland communities (n:4). SRL wasstrongly associated with external hyphal lengths, where root systems with low SRL had greaterlengths of external hyphae. From these studies it is clear that important seasonal patterns inextraradical hyphal length may exist, but the database is far too small to draw firm conclusions.Seasonal dynamics of AMF hyphal products, such as glomalin, in the soil are unknown.The field study described herein examines the seasonality of AMF extraradical hyphaeand glomalin in a spotted knapweed invaded grassland. To relate these parameters to intraradicalcolonization, we also measured AMF root colonization. Total root length and the root length ofl0 two root diameter size classes were also measured to examine the relationship of hyphae andtheir products to plant root morphology.Materials and Methods15Site descriptionThis research site was located in a grassland with an initial invasion of spotted knapweedapproximately I km north of Missoula, Montana, in the North Hills area" The plant communityof this area is an Idaho fescue/bluebunch wheatgrass community type (b'estucaidahoenisislAgropyroft spicatam) (Mueggler and Stuart 1980). The soil at this site is a sandy20loam with pH 6.6 (Table l).Field experiment and samplingSoil cores (2 cm diameter) were extracted systematically along a 5-meter transect, with 3-4 soilsamples taken within a l5 x l5 cm area and pooled every meter (n=5) Samples were taken