Is the biochemical mechanism of petal senescence similar within a genus? A case study of Dianthus.

Physiological and biochemical changes were documented during various stages (I-VI) of flower development and senescence in Dianthus barbatus L. and Dianthus chinensis L. A comparison between various biochemical parameters revealed that different biomolecules show different trends during senescence in these two species. Although floral diameter, fresh mass, dry mass and water content showed a positive relationship with flower opening and a sharp decline with senescence in both species; soluble proteins, alpha-amino acids and phenols showed a significant increase towards opening and a decrease towards senescence in D. chinensis but a reverse trend was observed in D. barbatus. Specific protease activity in D. chinensis showed a decrease towards flower opening and an increase towards senescence, but in D. barbatus, specific protease activity increased continuously from bud formation to senescence. Total sugars increased with flower opening and decreased as senescence progressed in both species. Reducing sugars increased as the flowers of D. chinensis opened and declined towards senescence, but in D. barbatus, reducing sugars remained almost constant from flower opening to senescence. To summarize, the various physiological and biochemical changes that execute senescence vary within a genus.