Germination data were arcsine transformed before statistical analysis to ensure homogeneity of variance (Badger and Ungar, 1989). Data were analysed using SPSS 11.5 (SPSS, 2002). A two-way analysis of variance (ANOVA) was carried out to test effects of the main factors and their interaction on the rate and final percentage of germination. Student–Newman–Keuls test was used to estimate least significant range between means.