Potential vase life of cut roses: Seasonal variation and relationships with growth conditions, phenotypes, and gene expressions

In this work, we identified the interrelationships between gene expression levels, environmental factors, phenotypic characteristics, and vase life of cut rose 'Lovely Lydia' between seasons and across years. We also determined the contribution of each factor to potential vase life (PVL) of cut roses. The vase life of the cut flowers was longest in spring (12.2 d), followed by summer (11.3 d), autumn (10.0 d), and winter (9.2 d). The environmental conditions in winter were characterized by high relative humidity (RH) and low vapor pressure deficit, and cut flowers grown under these conditions had less-functional stomata and consequently excessive water loss after harvest, resulting in shortened vase life. Leaf brix was not significantly correlated with PVL, but it was strongly correlated with flower diameter, indicating that congenital sucrose may be more important for providing the substances required for flower opening than for determining the longevity of cut roses. Correlation analysis revealed that initial transcript levels of the ethylene receptor RhETR4 and the signaling component RhEIN3-2 are very important factors in determining PVL of cut roses, as are preharvest RH conditions, stomatal function, and transpiration. The transcript levels of these genes were significantly modified by growth environment, including high RH and low temperature. Importantly, we show that RH conditions during cultivation not only determine stomatal characteristics but also modify the initial transcript levels of the ethylene responsive genes, thereby modifying the PVL. Understanding the interrelationships of genetic variation with other factors in the modulation of PVL will greatly help to improve growth environments and postharvest treatments across seasons as well as to develop techniques for guaranteeing the longevity of cut flowers.