Stress Metabolism II. Changes in Proline Concentration in Excised Plant Tissues

Shoot apices and excised root systems and sections of the lamina and leaf sheath of the first leaf of to-day barley (cv. Prior) plants were incubated on aerated polyethylene glycol solution (osmotic potential -20 bars) or distilled water. The imino acid proline accumulated rapidly in the leaf lamina sections subjected to osmotic stress and less rapidly, after a delay of 16 hr, in those floated on water.