Mass propagation of plants by tissue culture is labour intensive and costly. Gelling agents have many drawbacks: they are not inert medium components and do not enable easy automation for commercial mass propagation. So liquid culture systems are considered to have advantages, e.g. culture conditions are much more uniform, media can be changed easily. The use of liquid medium for in vitro culture has many advantages and has been the subject of many studies over many years. It has also frequently been considered an ideal technique for mass production as it reduces manual labor and facilitates changing the medium composition. Techniques and culture vessels of varying complexity have been developed as a result of studies. The major disadvantage of a liquid medium is hyperhydricity, which is a severe physiological disorder. So we considered that to compensate for this problem it would be necessary to expose the plant to the liquid medium intermittently rather than continuously. For this the bioreactors previously developed are not suitable as they are mainly adapted to bacterial culture and do not take into account the specific requirements of plant cells and tissues, such as sensitivity to shear forces, mechanical damages or foam formation in bubble aerated bioreactors. So temporary immersion systems for plant micropropagation have been described and grouped into 4 categories according to operation: i) tilting and rocker machines, ii) complete immersion of plant material and renewal of nutrient medium, iii) partial immersion and a liquid nutrient renewal mechanism, iiii) complete immersion by pneumatic driven transfer of liquid medium and without nutrient medium renewal. The positive effects of temporary immersion on micropropagation are indicated for shoot proliferation and microcuttings, microtuberization and somatic embryogenesis. Immersion time, i.e. duration or frequency, is the most critical parameter for system efficiency. Optimizing the volume of nutrient mediu