Physiological Studies of Senescence and Abscission in Rosa Indica : Senescence Physiology

Senescence and Abscission both are biological phenomenon.It is directly under the control of environmental and internal biology of the plant.The main internal factors are plant growth regulators .Auxins,gibbrellins,cytokinnins ,abscissic acid and ethylene are well known plant growth regulators .Usually auxins ,gibberellins and cytokinnins are growth promoters and rest twoare growth retardent.Auxins,gibbrellins and cytokinnins retards the senescence as well as abscission by delaying losses in chlorophyll, protein and sugars degradation. However abscissic acid and ethylene are to be considered as promoters of senescence and abscission by increasing the losses losses in chlorophyll, protein and sugars degradation.Among the three tested growth promoters cytokinnins is the best retardent and out of two tested retardent ethylene is the highest promoter of senescence and abscission.