Eco-friendly or flower killer? Understanding the negative effects of essential oil on calla lily postharvest

Abstract There is a demand for the development of sustainable postharvest conservation technologies for flowers, utilizing eco-friendly products to promote sustainability and reduce the production of toxic residues, such as essential oils. Although essential oils have been reported as effective for some species, in calla lily, some negative effects, such as stem strangulation, have been observed. Thus, the objective was to evaluate the effect of preservative solutions prepared with eucalyptus (Eucalyptus citriodora) essential oil on the postharvest quality of calla lily (Zantedeschia aethiopica), analyzing the biochemical and enzymatic processes of senescence. Flower stems, 50 cm in length, were placed in solutions prepared with pure water and various concentrations (0.1%, 0.25%, 0.75%, and 1.0%) of eucalyptus essential oil, with pure water as the control. The stems remained in contact with the solution in a cold chamber at 10 °C for 2, 4, 6, 8, and 10-h. Evaluations were carried out every 2 h, totaling 10-h. At each evaluation, samples were collected from three stem lengths (5, 10, and 15 cm) to determine the sucrose content. After 5 h, a stem section 10 cm in length was collected for electron microscopy analyses. The negative effects observed included the destruction of the conducting system, causing the death if all floral stems. The blockage in the stem limited sucrose absorption and stimulated the activity of antioxidant enzymes, leading to lipid peroxidation (MDA) and an increase in the activity of superoxide dismutase (SOD) and catalase (CAT).