Combined kinetin-morphactin application delays petal senescence in cut flower sticks of Polianthes tuberosa

Abstract: To assess the role of kinetin (KN) and morphactin (MOR) separately and also in combination in the regulation of petal senescence, cut flower sticks of Polianthes tuberosa were placed in various holding (vase) solutions like sucrose (0.1M), kinetin (KN, 20 pM), morphactin (MOR, 20 pM), KN (20 pM) + MOR (20 pM) and sucrose (0.1M) + KN (20 pM) + MOR (20 pM). Holding solutions were taken in sterilized conical flasks and the whole set up was placed under fluorescent tubes (40 Lux light intensity). A combination of sucrose + KN + MOR was the best followed by KN + MOR in partly controlling the loss of moisture content and flower turgidity, as well as a rapid decline in the fresh weight of flower sticks during 4-day as witnessed in treated and control sets. It was also noticed that both plant growth regulators (PGRs) when applied together and when sucrose was included, became more effective in maintaining relatively higher values of flower diameter. Investigation on selected biochemical changes revealed a sharp increase in reducing and total sugars of petals of untreated flower sticks, and KN treatment was found to be the best in arresting sugar accumulation. For the retention of protein, holding solution having sucrose + KN + MOR was the best while lipid peroxidation was arrested by KN+MOR but sucrose application alone was more effective in reducing this process. This study revealed a sharp increase in proline content in untreated tuberose petals, while reduced to some extent by sucrose and further reduction by MOR and KN. Sucrose was found to be the least effective in lowering the proline level.