ESTIMATION OF CELL BIOMASS IN PLANT-CELL SUSPENSIONS BY THE OSMOTIC-PRESSURE MEASUREMENT OF CULTURE BROTH

A method for estimating plant cell growth in suspension cultures was d eveloped on the basis of changes in osmotic pressure of the medium. Du ring cultivation of Nicotiana tabacum and Wasabia japonica cells in Mu rashige-Skoog (MS) medium using sucrose as the carbon source, sucrose was hydrolyzed to glucose and fructose by invertase with a resultant i ncrease in both the molarity and osmotic pressure of the medium. Under this condition, there was no linear relationship between the increase in cell concentration and the changes in osmotic pressure. When gluco se was used as the carbon source, the increase in osmotic pressure of the medium was not observed. A linear relationship between cell concen tration increase (Delta X [g/l]) and osmotic pressure decrease (Delta P [atm]) was obtained during cultivation of N. tabacum and W. japonica . In suspension cultures of N. tabacum, W. japonica, Catharanthus rose us and Oryza sativa cells, the dry cell concentrations calculated from the osmotic pressure changes coincided well with those obtained by th e gravimetric method.