TITLE:
Efficient, Season-Independent Seed Germination in Black Cohosh (Actaea racemosa L.)
AUTHORS:
Bhavneet Kaur, Joe-Ann McCoy, Edward Eisenstein
KEYWORDS:
Actaea racemosa; Seed Germination; Morphophysiological Dormancy; Stratification; Radicle
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.4 No.5A,
May
30,
2013
ABSTRACT: Seed
germination in black cohosh was systematically examined in eighteen populations
including 15 USDA accessions with an effective protocol for the consistent,
season independent germination of this valuable alternative specialty crop. Two in vitro approaches were investigated for breaking the complex double
dormancy of black cohosh seeds for yearround germination of
plants for increased cultivation and laboratory studies. The first approach was
a two-step alternating temperature stratification in which surface
sterilized seeds were incubated in darkness at 25?C for two weeks followed by
incubation at alternating temperatures of 20?C and 8?C for 12-hour periods with
a 16-hour photoperiod for 12 months. The second was a three-step-approach that
involved initial stratification of seeds in darkness at 25?C for two weeks,
followed by incubation at 4?C in darkness for 3 -4 months and then
cultivation at 25?C with a 16-hour photoperiod to generate
seedlings. Although both approaches broke double dormancy for black cohosh seed
germination, the three-step-stratification technique yielded higher percentage
seed germination in less time when compared to the two-step scheme, including
for seeds stored over two years. Additional factors of critical importance for
efficient germination included the selection of healthy and viable
seeds, as well as thorough but non-excessive surface sterilization to control
bacterial and fungal contamination. The in
vitro approach for black cohosh germination allowed year-round cultivation
and culture of a number of different genotypic accessions to enable laboratory
based studies on cell culture and transformation approaches to aid in
deciphering gene-metabolite relationships in this important medicinal plant.