A new micro-method for testing plant growth retardants in cell suspension cultures.

A microtest sytem for detecting the growth retarding potential of chemosynthetic compounds in cell suspension cultures is presented. The new screening technique involves the cultivation of one millilitre of suspension in small sterile test tubes and indirect monitoring of growth by measuring conductivity changes in the medium. Highly significant correlations were obtained in experiments comparing the effects of a broad range of plant growth retardants on the growth of different suspensions in erlenmeyer flasks measured by cell counting and in test tubes with growth recorded by conductivity changes in the medium. The method described is suitable for all suspension cultures hitherto studied.