Physiological and biochemical aspects of flower development and senescence in Nicotiana plumbaginifolia Viv.

Healthy buds of Nicotiana plumbaginifolia growing in the Kashmir University Botanic Garden were selected for the present study. Flower development and senescence was divided into seven stages, viz., tight bud stage (I), mature bud stage (II), pencil stage (III), partially open stage (IV), open stage (V), partially senescent stage (VI) and senescent stage (VII). Various physiological and biochemical changes were recorded at each stage of flower development and senescence. Floral diameter, fresh mass, dry mass and water content showed an increase up to flower opening (stage V) and thereafter a significant decrease was recorded as the flower development progressed towards senescence through stages VI and VII. An increase in α-amino acids, total phenols and sugars was registered towards anthesis (stage V) and a decrease in these parameters was recorded with senescence. Protease activity showed a significant increase towards senescence with a concomitant decrease in soluble proteins. Based on the quantitative analysis of various biochemical parameters, the flower opening in N. plumbaginifolia seems to be accompanied by an increase in the water content, soluble proteins, α‑amino acids and phenols. A decrease in these parameters, besides an increase in protease activity induces senescence in the beautiful flowers of N. plumbaginifolia. Understanding flower senescence may help in improving the postharvest performance of this beautiful ornamental flower to make it a potential material for the floriculture industry.