INVOLVEMENT OF ABSCISIC ACID DURING WATER STRESS AND RECOVERY IN PETUNIA FLOWERS.
In response to stress a rise in abscisic acid was observed, and upon rehydration the level of free abscisic acid declined. The extent of reduction in abscisic acid brought on by rehydration was more pronounced in young flowers than in mature flowers. We therefore conclude that the capacity to metabolize abscisic acid to inactive forms is larger in young flowers and that consequently they are less affected by water stress than the mature flowers.
Application of abscisic acid to cut petunia flowers accelerated their senescence, as reflected by higher ion leakage and development of blueing off colour in the petals.