Types of Open Cultures - Chemostat and Turbidostat - Basically there are two major types of open cultures; namely, chemostat and turbidostat. The cell growth in chemostat cultures is maintained steady by a constant inflow of fresh medium consisting of nutrients (nitrogen, phosphorous, glucose) at a concentration so as to be growth limiting. Other constituents of such a medium are present at concentrations higher than required.

Increase or decrease in the concentration of the growth limiting factor is correspondingly expressed by increase or decrease in the growth rate of cells.

b) less detrimental effects during mechanical failures,

c) a degree of automation, and

d) versatility with regard to growth speed, illumination, nutrient and growth regulator levels.

In spite of these advantages, plant tissue culturists refrain from using continuous cultures, probably because they require constant attention and specially designed equipment.