Polyamines and ethylene action blocker (STS) effectively augment longevity and postharvest attributes in isolated flowers of Digitalis purpurea L.

Abstract: The present investigation focused on the study of the exogenous inclusion of anti-senescence biogenic polyamines (putrescine, spermidine and spermine) and ethylene antagonist silver thiosulphate on flower longevity and postharvest performance in excised flowers of Digitalis purpurea L. At one day before anthesis stage, isolated buds of Digitalis purpurea were transported to the laboratory in distilled water. The samples were divided into five sets with one set of flower buds (i.e., control) held in distilled water. The remaining four sets were respectively supplied with 0.5, 1 and 1.5 mM of putrescine (PUT), 0.1, 0.2 and 0.3 mM of spermidine (SPD), 0.2, 0.4 and 0.6 mM of spermine (SPM), 0.1, 0.2 and 0.3 mM of silver thiosulphate (STS). The inclusion of polyamines and STS in holding solutions enhanced the flower longevity of D. purpurea significantly compared to the control. The results indicated that the flower longevity of 14 days was recorded in 0.4 mM of spermine, followed by 13 days in 1 mM PUT, 12.5 days in 0.2 mM SPD and 12 days in 0.2 mM STS. This enhanced flower longevity corroborated with the higher values of soluble proteins, total sugars, floral diameter and membrane stability index. The improved flower longevity was also found to be positively associated with increased activities of various antioxidant enzymes viz., superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) and reduced activity of lipoxygenase (LOX). The flowers supplemented with different treatments retained a lower phenolic content than the control. This research concluded that polyamines and STS have a profound impact on the flower longevity of Digitalis flowers. SPM was found to be a more potential polyamine in augmenting the postharvest performance in isolated flowers of D. purpurea.