Smoke as a germination cue: a review

Slow combustion or burning of dry or green plant material from many sources produces volatile compounds that are water soluble and that stimulate the germination of many seeds with different dormancy strategies. The active principals are apparently produced around 160ndash;200 deg;C and are volatilized at higher temperatures. Once dissolved in water the active compounds also stimulate rooting, seedling growth and flowering. The positive effects of smoke have resulted in it being used as a seed pre-treatment for enhancing conservation of threatened or rare species, the horticultural exploitation of desirable plants and in the reclamation of mine spoils and disturbed land. Presently the identity of the active molecules is unknown but their remarkable effect on seed germination is, already widely utilized.