Interaction of soil burial and smoke on germination patterns in seeds of selected Australian native plants

Patterns of dormancy and smoke responsiveness in artificially buried seeds were investigated in eight native plant species from the species-rich medit erranean-type climate zone of south-western Australia. A comparison was mad e between germination and viability behaviour of shelf- and field-soil-stor ed seed, with and without smoke treatment, at least every 3 months. These c omparisons corresponded with each of the four seasons. The species chosen g erminated with the aid of smoke under field or glasshouse conditions (terme d 'dormant'; n = 4) or produced low and variable germination under glasshou se conditions with smoke (termed 'deeply dormant'; n = 4). Three trends wer e observed in viability of soil-stored seeds over 450 d: no decline, gradua l decline or late-onset decline. In addition, various germination responses to soil burial and aerosol smoke were observed. Burial was not required fo r optimal germination in Anigozanthos manglesii. However, for all other spe cies tested, maximum germination was observed only following a period of bu rial. This was manifested in a germination response without smoke after a s hort period of burial (Stylidium affine and Conospermum triplinervium) or a longer period of burial (Conostylis neocymosa, Hibbertia commutata, Leucop ogon conostephioides, Stirlingia latifolia and Stylidium crossocephalum). S moke treatment led to high germination in buried seed of S. affine, S. cros socephalum and H. commutata. The patterns of germination detected in this l imited number of species indicate that a variety of mechanisms may exist, b oth temporally and spatially, in south-western Australian species, and supp ort further research of this type for horticulture and land restoration.