Table 5.

Results of the tetrazolium (TZ) test (with the frequency of viable seeds as a target variable)

Effect	F	df	p
Species	1.69	9	0.230
Population age	0.22	9	0.651
Species × Population age	0.15	9	0.704
Floating ability	0.00	9	0.987
Species × Floating ability	0.01	9	0.923
Population age × Floating ability	0.03	9	0.874
Species × Population age × Floating ability	8.43	9	0.020

The model compared the non-invasive alien species (‘NIAS’) I. balfourii and the invasive alien species (‘IAS’) I. glandulifera from populations differing in age and included their seed floating ability. The data for the seeds previously used in the still water experiment were used in the model