Germination of Calluna vulgaris (L.) Hull in vitro under different pH-conditions

Seeds, collected from a stock of Calluna vulgaris (L.) Hull appeared to be polymorphic and four types could be distinguished: large-ribbed, small-ribbed, large-smooth, small-smooth. The seed types differ in germination response at pH = 5,6, Moreover, germination of Calluna seeds appears to be pH-dependent; pH = 3.2 is the critical value, at lower values germination decreases significantly. Surface-sterilisation of the seeds also influences their germination percentage. The distribution pattern of Calluna seedlings in the field is explained in connection with the pH.