PARENT SESSION
Poster Session #41: Plant Demography.
Thursday, August 9, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall
108
Morphological variation in populations of Festuca arundinacea in England.
Gibson, David1, Taylor, Ian2, 1 2
ABSTRACT- The native grass Festuca arundinacea Schreber (tall fescue) is widespread in grasslands across the U.K., and is considered to be highly variable and represented by a number of strains and ecotypes. Analysis of 8 morphological traits, canopy cover, and the number of vegetative and flowering tillers of 151 individuals from 16 populations across southern and central England confirmed this variability. Principal Components Analysis showed that among-population variability in size exceeded within-population variability. Nevertheless, a strong, principal gradient of variability reflected a continuum of mean individual size among populations. Populations in the most productive habitats (e.g, mesotrophic grasslands and roadside verges) had the largest individuals (e.g., >100 vegetative tillers and > 40 flowering tillers per individual) while stressful habitats (e.g., coastal strand) supported relatively small individuals (e.g., 11 and 3 vegetative and flowering tillers, respectively). There was no evidence of geographic structuring of populations with respect to morphological variability or any relationship to associate species composition among sites. Endophyte infection was uncorrelated with plant size, but showed a positive trend towards a relationship with the ratio of flowering/vegetative tillers (P = 0.06). F. arundinacea exhibits extremely high levels of phenotypic plasticity in response to the environmental conditions occurring in the habitat in which it occurs.
KEY WORDS: endophytes, grasslands, plasticity, tall fescue