Auxin involvement in tepal senescence and abscission in Lilium: a tale of two lilies.

Petal wilting and/or abscission terminates the life of the flower. However, how wilting and abscission are coordinated is not fully understood. There is wide variation in the extent to which petals wilt before abscission, even between cultivars of the same species.

Expression and localisation of a senescence-associated KDEL-cysteine protease from Lilium longiflorum tepals.

Senescence is a tightly regulated process and both compartmentalisation and regulated activation of degradative enzymes is critical to avoid premature cellular destruction. Proteolysis is a key process in senescent tissues, linked to disassembly of cellular contents and nutrient remobilisation. Cysteine proteases are responsible for most proteolytic activity in senescent petals, encoded by a gene family comprising both senescence-specific and senescence up-regulated genes.

Changes in ultrastructure, protease and caspase-like activities during flower senescence in Lilium longiflorum.

The last phase of flower development is senescence during which nutrients are recycled to developing tissues. The ultimate fate of petal cells is cell death. In this study we used the ethylene-insensitive Lilium longiflorum as a model system to characterize Lily flower senescence from the physiological, biochemical and ultrastructural point of view.