Fire-elevated nutrients can easily be washed out of the burned habitats, and smoke-derived germination cues can waft into neighboring unburned areas, as can anthropogenic emissions containing nitrogen oxides (the components of smoke that germinate Emmenanthe penduliflora; Keeley and Fotheringham 1997), and may "trick" seeds into maladaptive seed germination.
For example, exposure of Emmenanthe penduliflora to oxidizing gases does not increase the water permeability of the seed and, therefore, is not a simple scarification of the seed coat (Keeley and Fotheringham 1997).
Charred wood was first shown to stimulate germination in the postfire annual Emmenanthe penduliflora (Wicklow 1977, Jones and Schlesinger 1980) and also reported for many other species in western North America (Keeley et al.
On the other hand, Thanos and Rundel (1995), reported germination of Emmenanthe penduliflora in response to 10 mol/[m.
1994) and of Emmenanthe penduliflora (Keeley and Fotheringham 1997a) support the second hypothesis.
micrantha Annual Brassicaceae Caulanthus heterophyllus Annual Caryophyllaceae Silene multinervia Annual Hydrophyllaceae Emmenanthe penduliflora Annual Eucrypta chrysanthemifolia Annual Phacelia grandiflora Annual P.
Although an exhaustive study of the effect of wood type was not included, we did test smoke from pine "sawdust" on Emmenanthe and Romneya and found that it was equally as effective as smoke from Adenostoma wood.
3] in water [ILLUSTRATION FOR FIGURES 2 AND 3 OMITTED], Emmenanthe exhibited substantial germination in KN[O.
15-min exposure was lethal to Emmenanthe germination but optimum for Romneya germination [ILLUSTRATION FOR FIGURE 2 OMITTED].
Germination (%) pH 3 pH 4 pH 5 pH 6 pH 7 Emmenanthe Control 0 0 0 0 0 KN[O.
Lethal chemicals are also water soluble as these solutions inhibited the germination of some species such as Emmenanthe [ILLUSTRATION FOR FIGURE 5 OMITTED] - water exposed to 10-min smoke completely inhibited germination (in both populations tested), but 1/10 and 1/20 dilutions of 10-min smoke-treated water gave high germination [ILLUSTRATION FOR FIGURE 5 OMITTED]; in addition, highly significant germination was still recorded with 1/50 dilution (not shown).
Gaseous transfer of smoke chemicals is apparent from the high germination induced in both Emmenanthe and Romneya seeds when untreated moist seeds were exposed indirectly to vapors emitted from moistened smoked sand (or filter paper) [ILLUSTRATION FOR FIGURE 4C OMITTED].