Rapid determination of free proline for water-stress studies

Proline, which increases proportionately faster than other amino acids in plants under water stress, has been suggested as an evaluating parameter for irrigation scheduling and for selecting drought-resistant varieties. The necessity to analyze numerous samples from multiple replications of field grown materials prompted the development of a simple, rapid colorimetrie determination of proline. The method detected proline in the 0.1 to 36.0 µmoles/g range of fresh weight leaf material.