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Cut lily flowers are very popular but their longevity is not satisfactory. The quality of cut lily flowers is determined by two factors: the longevity of the flowers and the general appearance of the entire cut stem during its vase life. The aim of this work was to evaluate the effects of gibberellic acid (GA3), standard preservative (8HQC and 2% sucrose) and commercial preservatives Chrysal Professional 2 and Chrysal sachet as well as Floralife 200 and Floralife 300 on the quality of ‘Rialto’ cut oriental lily, a white blooming cultivar very popular on the Polish market. The contents of reducing sugars, soluble proteins, free amino acids and free proline were also determined in the senescing flowers. As a major problem in the postharvest handling of lilies is leaf yellowing, the effects of postharvest treatments on the quality of leaves and their chlorophyll contents were also studied. Conditioning (24 h) with GA3 (500 mg d.m.−3) immediately after harvest delayed chlorophyll loss in leaves. When combined with the standard preservative and commercial preparations Chrysal Professional 2 and Chrysal sachet as well as Floralife 200 and Floralife 300, GA3 prolonged flower vase life. The most effective method was using GA3 and Floralife products, which prolonged the vase life of flowers to 23 days, 43% longer relative to the untreated flowers, and maintained the decorative value of the leaves (53 days). During the senescence of flowers held in water, the contents of reducing sugars, free amino acids and proline increased. However, the holding solutions modified changes in these parameters relative to the control.

The effects of a 24 hrs pulse conditioning with GA3 or BA on the lipoxygenase activity and the expression of the lipoxygenase gene were studied in senescing cut leaves of Zantedeschia aethiopica Spr. and Hosta ‘Undulata Erromena’, respectively. The GA3 treatment in Zantedeschia and the BA treatment in Hosta prevented increases the activity of lipoxygenase in senescing cut leaves. No effects of growth regulators on the lipoxygenase gene expression were observed in cut leaves of both species. [ABSTRACT FROM AUTHOR]

Treatments with BA or GA3 are known to extend the foliage display life of Hosta ‘Undulata Erromena’ and Zantedeschia aethiopica Spr., respectively. The effects of a 24hrs pulse conditioning with BA or GA3 on the protein content, proteolytic activity and the expression of the cysteine protease gene were studied in senescing cut leaves of both species. A decrease in the soluble protein content in the untreated leaves was accompanied by an increased total proteolytic activity and the activity of the cysteine protease. The BA treatment in Hosta prevented such increases thereby preventing total protein loss. In Z. aethiopica, the GA3 treatment delayed protein degradation but to a lesser extent than the BA treament of H. ‘Undulata Erromena’ leaves. No expression of the cysteine protease gene was observed in the freshly cut leaves of both species. The presence of the gene transcript was detectable in the senescing leaves of both species kept in water where significant increase in the cysteine protease activity was observed. No increase in the level of the cysteine protease mRNA was detected in the BA - conditioned leaves of Hosta but a slight increase in the transcript level was observed in Z. aethiopica regardless of whether the leaves were conditioned with GA3 or were kept in water. Different reaction of the two species for two plant growth regulators inhibiting senescence suggest different mechanism of this process. [ABSTRACT FROM AUTHOR]