embryo dormancy. (3'14'17) High-temperature desiccation of the seed coat could break coat-imposed
dormancy, (41 while ethylene and ammonia present
in smoke may break embryo dormancy. (17/
Recently, it has been shown that plant-derived
smoke extracts or smoke stimulate the germination
ofmany plant species,/7/both fire-dependent, (5'6~and
non-fire-dependent. (9'16/ Active extracts have been
subjected to many chromatographic purification
steps, but as yet the active principal(s) remains