Role of Plant Growth Regulators in Petal Senescence of Calendula Officinalis L. and Coreopsis Lanceolata L.

Freshly cut flowers of Calendula as a detached system and flowers of Coreopsis in an intact system were taken to carry out a comparative study of petal senescence. Changes in proteins, amount of sugars and MDA (Malondialdehyde) content were estimated with the advancement of flower senescence. Activities of peroxidase and protease registered a steady increase during 0 to 8-day and 0 to 16-day in C. officinalis and C. lanceolata respectively. Higher concentration of each plant growth substance was effective to slow down the enzymatic activity and reduced the degradation of various metabolites. The distribution pattern of sugars and degree of effectiveness of growth regulators were not identical in these two flowers. The overall order of effectiveness among the applied plant growth regulators was KN> SA> MOR in both the flowers.