Genetic diversity in Arum maculatum from two urban forests

An allozyme analysis was conducted on 220 Arum maculatum L. plants in 11 su bpopulations of the Sonian forest (Rood Klooster / Rouge Cloitre) and of th e Terkamerenbos / Bois de la Cambre near the urban environment of Brussels. The II subpopulations could be pooled as 6 populations from 2 forests. Six loci out of twenty studied were found to be polymorphic (adh-1, adh-2, pgm-1, lap-1, 6pgd-1 and 6pgd-2). The mean percentage of polymorphic loci ( P) was 30% for ten subpopulations and only one marginal population was foun d to have 25% (RC/RK5). The mean number of alleles per locus (A) was 1,3 fo r all populations and the mean observed heterozygosity ranged from 0,12 to 0,19. Analysis of fixation indices indicated that in general there is an excess o f heterozygotes. Genetic distances ranged from 0.000 to 0.023. Overall resu lts on the genetic structure of Arum maculatum populations suggested that t here is a considerable interpopulational gene flow, which explains the main tenance of high levels of variability within populations and similarity amo ng populations.