Levels of Free Proline in Ornamental Plants: I. Influence of Plant Age, leaf Age, and Leaf Region in Saintpaulia and Chrysanthemum

Summary In six experiments the effect of endogenous factors on the level of free proline in Saintpaulia and Chrysanthemum was investigated. Data showed a significant influence of plant and leaf age and of leaf region in Saintpaulia . Young plants showed the highest proline contents. The results of the leaf age study were unequivocal and seem to be dependent on plant age and cultivar, respectively. A clear concentration gradient of proline was seen within the leaf blades, with the maximal amounts on the edges and the top. In Chrysanthemum , the influence of leaf age on the levels of proline was more clearly evident. Samples collected showed a 96% decrease in the proline content in the range from the 5th leaf down to the 32nd leaf.