Treatments to prolong the postharvest life of Heliconia wagneriana Petersen

Abstract

Tropical flowers have a growing market due to their exotic appearance and thus postharvest techniques are necessary to prolong their shelf life. The objective of this study was to evaluate the effectiveness of wax and salicylic acid (1 mM) in reducing chilling injury and increase the vase life in stems of Heliconia wagneriana stored at low temperature. For that, 120 stems were harvested in a commercial area. From these, 60 stems were waxed and air-dried; while 60 unwaxed stems served as controls. Then 2 groups of 48 stems from both treated and control were cold-stored at 13 °C and 84 % RH for 5 and 10 days. After storage, the stems were placed either in salicylic acid solution (1 mM) or tap water. The remaining stems (12 waxed and 12 control) were kept at room emperature. The variables evaluated were anatomical characteristics, fresh weight loss, solution uptake, vase life, enzymatic activity (polyphenol oxidase and peroxidase), and membrane integrity. The wax coating maintained the fresh weight and extended the vase life of the stored stems under room temperature for up to 2 more days. The vase life of the cold-stored stems of 5 and 10 days was extended by 3 and 2 more days respectively, as compared to the control. No significant effect was observed for the use of salicylic acid (1 mM). The bracts tissue of the waxed stems showed lower enzymatic activity, reflected in lower oxidative stress compared to the control. Tropical species as heliconia present a very low water absorption, then the use of wax coating is recommended to preserve the turgidity and shelf life of the stems