Abstract:
Natural regeneration of
Taxus baccata L. is constrained due to the
depth of seed dormancy requirements
(often taking two or more years) and low
seed germination. Further, the
conventional method of vegetative
propagation by cuttings is associated with
difficulties in rooting. Hence, for the first
time, this study describes an efficient and
reproducible in vitro protocol for breaking
the dormancy of seeds from the
endangered forest tree T. baccata L. via
zygotic embryo culture. Embryos isolated
from 100% sterile seeds were cultured on
DCR medium that contains sucrose (30 g/l),
agar (8 g/l), and activated charcoal (5 g/l),
fortified with different concentrations of
Plant Growth Regulators (PGRs), and
held at a temperature of 25 ± 2 ºC in a
growth room. The results revealed that the
in vitro embryo germination percentage
was mostly affected by gibberellic acid
(GA3) and thidiazuron (TDZ). Among the
nine treatments, the treatments with
0.5 mg/l TDZ and 1 mg/l GA3 showed
the highest germination (100%), while the
other treatments all increased the
germination percentages significantly
compared to the control (37.5%). The 1/2
DCR medium with the addition of 0.1
mg/l indole-3-butyric acid (IBA) resulted
in the highest rooting ratio (94%).
However, the greatest root and hypocotyl
elongation (59.37 ± 3.77 and 62.75 ±
4.43 mm, respectively) occurred when
seedlings were cultured on 1/2 DCR
medium containing 0.5 mg/l BA. Plantlets
were transplanted into plastic pots
containing an autoclaved garden soil,
sand, and vermiculite mixture (1:1:1) and
held at a temperature of 25 ± 2 ºC in a
growth room for 4 weeks before being
transplanted into the greenhouse. These
results indicated that the protocol
developed during the current study will be
useful to overcome seed dormancy and
for multiplication and conservation of the
species T. baccata L.
