The Water Relations of Certain Heath Plants with Reference to their Ecological Amplitude: I. Introduction: Germination and Establishment

Abstract

The germination and establishment of three ericaceous heath plants, Calluna vulgaris, Erica cinerea and E. tetralix, were examined under greenhouse conditions with respect to soil type (mineral, humus and peat soils) and water regime(wetter than field capacity, around field capacity and drier than field capacity). Calluna showed the best performance over the whole range of moisture regimes and soil types. A greater number of seeds germinated, a greater proportion of these became successfully established, the seedlings showed better root development, a greater dry matter production and more branching than the other two species. The performance of Calluna in the experiment was considered to be a reasonable explanation of its wide distribution in the field. Erica cinerea, typical of the drier mineral sites in the field, and E. tetralix, typical of the wetter peaty sites, grew taller than Calluna on both mineral soil and wet regimes. Consequently factors other than germination and establishment alone were thought to have a bearing on their distribution in nature.