Genotypic Variation in Senescence and Water Relations in Cut Flowers of Anthurium andraeanum (Hort.)

Abstract

The role of water status in determining vase life was investigated in three Anthurium andraeanum Hort. cultivars: Spirit, Success, and Honduras. The cultivars were selected based on their vase life in previous studies and designated as ‘Vshort’, ‘Vmed’ and ‘Vlong’ respectively. A timeline experiment observing spadix necrosis (bloom degradation) under controlled conditions determined end of vase life as 15, 18, and 36 days for Vshort, Vmed and Vlong respectively. Spathe relative water content (RWC) was closely associated with bloom degradation with all three cultivars reaching end of vase life at ≈75% spathe RWC. Membrane integrity of the spathe showed no association with bloom degradation before the end of vase life with increased ion leakage found only after spadix necrosis was visible, indicating that bloom degradation was driven by spathe water status rather than senescence induced by other factors. RWC of the peduncle base and apex showed no association with bloom degradation in any of the cultivars. In fact, base and apex RWC remained high throughout the experiment despite the consistent loss of spathe RWC. This suggests that the reduced water content of the spathe was not induced by reduced hydraulic conductance of the peduncle. Stomatal conductance (gS) was highest in Vshort (approximately twice that of Vlong) and likely contributed to the rapid loss of spathe RWC in this cultivar. However, Vmed and Vlong had similar gS rates and water uptake rates despite large differences in spathe RWC. Thus, the two cultivars differed in their ability to retain water within the spathe tissue. In all three cultivars, end of vase life was determined by spathe water status. Genotypic variation in vase life was not driven by differences in the hydraulic conductance of the peduncle as previously thought. Differences in spathe water status were partially explained by differences in gS but other factors were also involved.