Culture characteristics of genetically transformed Mentha citrata shooty teratomas were studied in liquid Murashige and Skoog and Gamborg’s B5 media. Based on calculated kinetic and yield parameters, a stoichiometric equation was developed to describe growth in media containing both nitrate and ammonia. Measurements of oxygen uptake rate showed that delivery of adequate oxygen to completely submerged shoots depends on the elimination of hydrodynamic boundary layers at high external liquid velocity.