Digitalis species callus cultures were initiated from seeds that
were germinated in vitro. Seeds were collected around the Ankara-
Kızılcahamam (N4037.7090, E03226.2650) in August to
September, 2010 and voucher specimens (IEker-2694) were
deposited at the Abant Izzet Baysal University Herbarium (Bolu,
Turkey). Seeds of Digitalis species were disinfected in with 20% (v/
v) sodium hypochlorite solutions and cultured in petri dishes
containing 30 mL MS medium (Murashige and Skoog, 1962) containing
3% (w/v) sucrose and 0.8% (w/v) agar. Seedlings were
grown until they have attained 3e5 cm of length. Callus was
induced from 5 to 8 mm length of hypocotyl segments excised
from 1 month old seedlings when cultured on MS medium containing
0.5 mg L1 TDZ and 0.25 mg L1 IAA. After 30 days of
culture, callus was transferred to MS medium with 0.0 and 10 mM
H2O2 for creating oxidative stress for 6 h. All cultures were incubated
under a 16 h light:8h dark photoperiod from cool white
fluorescent lamps.