Cc. Baskin et Jm. Baskin, ROLE OF TEMPERATURE AND LIGHT IN THE GERMINATION ECOLOGY OF BURIED SEEDS OF WEEDY SPECIES OF DISTURBED FORESTS .2. ERECHTITES HIERACIFOLIA, Canadian journal of botany, 74(12), 1996, pp. 2002-2005
At maturity in September, about half the seeds (achenes) of Erechtites
hieracifolia (Asteraceae) collected in Kentucky were dormant (did not
germinate at any test condition), whereas the others were conditional
ly dormant (germinated only at a narrow range of test conditions). See
ds sown on top of soil in an unheated greenhouse in September failed t
o germinate in autumn because temperatures were below those required f
or germination; however, they germinated at comparable temperatures th
e following spring. Seeds buried in soil in September 1987 and exposed
to natural seasonal temperature changes were nondormant (germinated o
ver full range of test conditions) by April 1988, but they entered con
ditional dormancy by October 1988. Each October through 1995, exhumed
seeds exhibited conditional dormancy. Since 89% of the seeds were viab
le after 8 years of burial, it appears that although seeds of this spe
cies are wind dispersed, they also have the potential to form a long-l
ived seed bank. Thus, soil disturbance at any time from May to Septemb
er could result in establishment of plants from seeds in the seed bank
.