Effect of waxing, cold storage and salicylic acid on the quality and vase life of Heliconia wagneriana

Abstract

The species of Heliconia that are most commercialized in Mexico are H. stricta, H. bihai, H. caribea, H. psittacorum and H. wagneriana, among others. The bracts of Heliconias can be hanging and erect. The growing demand for these floral stems is attributed to their exotic beauty and longevity of the floral stem. Although the use of preservative solutions and storage at low temperature, improve vase life for most flowers of temperate climate, these do not have the same effectiveness in tropical flowers. For example, while temperate climate flowers are stored at temperatures above the freezing point, for Heliconia species, the recommended temperature for transport and storage is around 10°C, as they are sensitive to chilling injury. Therefore, in this work we evaluated the quality changes in H. wagneriana with the application of wax in the bracts and the use of salicylic acid (SA at 1 mM) in preservative solution at room temperature and under cold storage (10°C/10 days). The variables evaluated were: vase life, water absorption, membrane integrity, enzymatic activity and stomatal functionality. The results showed a low consumption of solution (less than 6% w/v). In Heliconias, there are no vascular connections between the floral peduncle and the leaves, which contributes to low water absorption after harvest. The transpiration evaluation had a non-typical circadian rhythm, which suggests that the stomata located in the bracts are not functional and do not respond to environmental factors. The control stems stored at room temperature had 9 d of vase life, while the waxed ones 12 d; the control stems stored under refrigeration had an additional 4.3 d of vase life and the waxed ones 6.2 d. The use of SA solution did not improve the quality of Heliconia stems. The activity of polyphenol oxidase and peroxidase was lower in the waxed stems as well as the chilling injury damage.