A temporary immersion bioreactor (10) for in vitro production of differentiated plant biomass comprises a growth chamber (12) having one or more transparent side walls (14) and a mesh bottom (16). The bioreactor includes a flexible bag (20) formed from a transparent material, the flexible bag having a sealable opening and being dimensioned to receive the growth chamber together with a liquid medium (22). The bioreactor also includes an outer chamber (24) having one or more transparent side walls (26). The outer chamber is dimensioned to receive the growth chamber within the flexible bag so that the mesh bottom of the growth chamber faces a bottom (28) of the outer chamber. The bioreactor further includes a driving mechanism (30) arranged to selectively drive movement of the growth chamber along a single axis (A) between a first lowered position in which the bottom of the growth chamber is located towards the bottom of the outer chamber and a second raised position in which the bottom of the growth chamber is lifted from the bottom of the outer chamber. The driving mechanism can be a lifting arm or electromagnetic.
