Control of Postharvest Performance of the Lilacs ‘Andenken an Ludwig Spaeth’ Induced to Flower in Spring

Common lilac ( Syringa vulgaris ) is an important cut flower on the flower market. The process of forcing shrub is crucial for lilac availability for floristry for six months of the year: from November to April. In this study, the vase life and certain biochemical processes occurring during senescence of cut lilacs ‘Andenken an Ludwig Spaeth’ induced to flower between March and May were investigated. Additionally, the effect of standard preservative (8-HQC + 2% S) and biocide (8-HQC) was analyzed. The vase life in water was relatively short (4 d), although it lengthened with the season and the standard preservative improved it. This solution enhanced florets’ fresh weight, water uptake, and transpiration rate, also caused an increase in the electroconductivity of the cell sap. Several other senescence-associated parameters such as carbohydrate, soluble protein and free proline contents were affected by the preservative whose effects were comparable to those found earlier in the winter forced lilacs. A highly efficient antioxidant enzyme system including catalase (CAT), peroxidases (POX) and superoxide dismutase (SOD) was present in developing inflorescences but the enzyme activity decreased in senescing florets. The hydrogen peroxide content and catalase activity were the highest in the biocide-treated flowers. Generally, in cut lilacs induced to bloom in April the changes in senescence-associated phenomena under study were occurring as in the flowers forced for November–December sales. Research shows the significant importance of sugar as a component of the cut flower preservatives whose use was essential for a proper bud development and good postharvest quality of cut lilacs.