Temperature Effects on the Seed-Germination of 10 Kwongan Species From Eneabba, Western-Australia

Abstract

The germination responses of 10 species (Acacia blakelyi, A. pulchella, Allocasuarina humilis, Beaufortia elegans, Conostylis neocymosa, Eucalyptus tetragona, Kennedia prostrata, Leptospermum spinescens, Melaleuca acerosa and Xanthorrhoea drummondii) to constant temperatures ranging from 5 to 35º C were studied. These Western Australian perennial species had optimum germination percentages between 15 and 20ºC, except Eucalyptus tetragona which had an optimum at 25ºC and Leptospermum spinescens which had an optimum at 10°C. Seeds were transferred from high and low temperatures to 15ºC to determine whether high or low temperatures induced dormancy. Low temperatures tended not to affect subsequent germination but high temperature decreased subsequent germination for some species. Wetting and drying stimulated the germination of Acacia blakelyi, A. pulchella and Kennedia prostrata seeds.