Liquid cultures were initiated dire

Liquid cultures were initiated directly from primary
explants of sterile seedlings by isolating vegetative
shoot apices about 1.5 mm long. Each ten
shoot apices were placed in 100 ml of liquid
medium in a 350 ml Erlenmeyer flask. A modified
liquid Murashige and Skoog [17] was used, to
which macroelements and iron were added at half
concentration, and microelements and vitamins at
full concentration. The medium was also supplemented
with 250 mg l1 edamine, 40 g l1 sucrose,
5 g l1 glucose. 2,4D was added at a
concentration of 1 mg l1as a sole source of
growth regulators. The pH of the medium was
adjusted to 5.6 before autoclaving (17 min,
121°C). The nitrogen content [NH4
][NNO3
] was
approximately 10:19.5. The explants developing in
liquid media were transferred to fresh media every
2–3 weeks, each time about 300 mg of tissue as
the inoculum per 100 ml of mediumsuspension was formed by the separation of cells
from the explant and their division. At 8–10
months a stable suspension culture (counting from
the moment of initiation) was used for the
experiment.