OSMOLARITY AS A MEASURE OF GROWTH OF PLANT-CELLS IN SUSPENSION-CULTURES

Biomass estimation in cell suspension cultures of Capsicum frutescens and Daucus carota was correlated with the conductivity and osmolarity of the medium. The medium conductivity was influenced by nitrates, CaC l2, and minor and major elements. The addition of organic constituents such as vitamins did not substantially alter the conductivity. The ad dition of sucrose resulted in decreased conductivity of the culture me dium. Changes in conductivity during the growth cycle were less sensit ive to measurement regarding the small changes in biomass levels, beca use conductivity was contributed by electrolytes and not by the sugars that are the major components in the nutrient medium. In both C. frut escens and D. carota, the osmolarity sharply increased as a result of the rapid hydrolysis of sucrose into glucose and fructose, and then li nearly decreased with the increase in biomass. Because all of the medi um constituents contribute to the osmolarity value, its measurement co rrelated well with the increase in biomass in both cultures. Small cha nges in the biomass resulted in relatively wide osmolarity changes, th ereby enhancing the sensitivity over conductivity measurement.