This article illustrates some methods and approaches which improve the performances of plant cell culture processes and relevant bioreactors. The focus is placed on the promotion of cell growth and enhancement of secondary metabolite production. Production of L-DOPA (3,4-dihydroxyphenylalanine) by Stizolobium hassjoo is the primary cell culture system encountered in this article. For suspension cell cultures, the key points for inductions of pertinent callus and cell line are described. Hydrodynamic effects on cell aggregate and secondary metabolite production are demonstrated. Strategy for elicitation, control of gaseous composition in a reactor, measurements of power consumption in shake flasks laboratory-scale agitated reactor are exemplified. For transgenic hairy roots, the medium optimization through statistical experimental design is employed to promote the hairy root weight, L-DOPA content in the roots and L-DOPA productivity. The results show that the root weight, L-DOPA content and L-DOPA productivity promoted 1.8-, 2.2- and 2.8 folds of basal B5 medium control runs. Mist trickling reactor (MTR) is promising for proliferating the hairy roots. The features of hairy root growth on a Petri-dish suggested that the bridging of the lateral roots and exertion of an appropriate hindrance to root tips are favorable to the profuse growth of roots and L-DOPA production. The mode of replenishment of nutrients, especially the nitrogen and carbon sources in the late of the cultures is justified.