Shoot clumps developed from leaf explants (10–12 explants) of P. dryas cultured on TDZ supplemented media
were transferred aseptically to liquid MSO (125 mL) contained in sterile Liquid Lab™ culture vessels (Southern Sun Biosystems, Hodges, SC). The mouth of the bioreactor vessel was sealed properly with Parafilm to prevent contamination and placed on Liquid Lab™ Rocker to provide gentle agitation by side to side tilting movements (30 s at 1.2 min interval).
Growth of the shoots was monitored periodically and the growth medium was replenished with fresh MSO after 2–3 weeks or when the liquid medium appeared depleted.
The bioreactors were returned to the rocker and the growth of the cultures were assessed for 3 months after which the shoot clumps were removed from the bioreactor and individual shoots were separated and weighed.