Bacteria in vase solution affect water uptake and postharvest quality of cut lilies

• Longer exposure to bacterial water reduces cut lily water uptake more. • Flower lifespan/diameter correlates with uptake. • Bacteria distribution in stems is inversely proportional to base distance. • Vascular differences affect tolerance to bacterial water. • Bacterial proliferation was possible with low initial concentrations. Water is important for maintaining the postharvest quality of cut flowers. Throughout the cut flower industry, the best practice is to maintain high cleanliness levels in the handling chain. Lily growers have questioned the need to keep careful sanitation because lilies are anecdotally thought to be less susceptible to “microbially contaminated water” than other flowers (e.g., gerbera). To check this plausible idea, Lilium ‘Sorbonne’ and ‘Nashville’ stems were exposed to increasing populations of bacteria (0 to 2 × 10 7 cfu·mL -1 ) in the vase solution. We also investigated the effects of exposure time in 2 × 10 7 cfu·mL -1 bacterial water (BW). The average individual flower life and flower diameter were positively correlated to the cumulative water uptake in the vase, which in turn was negatively affected by the initial population of bacteria and the duration of exposure to BW. When bacteria populations were greater than 10 6 cfu·mL -1 , water uptake and flower life were reduced remarkably. As BW exposure time increased, water uptake was decreased for both cultivars. By 1 d, BW reduced total water uptake by 45% compared to controls in ‘Sorbonne’. In other experiments, stems were held in 10 7 cfu·mL -1 BW for 24 h, then dissected into 3-cm segments. Bacteria were mainly distributed in the lower 15 cm of the stem. ‘Nashville’ was less affected by bacterial-induced xylem occlusion and had greater cumulative water uptake than ‘Sorbonne’. While individual vessel diameters of the two cultivars were similar, ‘Nashville’ had more vascular bundles per stem cross-section and more vessels per bundle. Together, increasing bacterial population and exposure time reduce water uptake, flower diameter, and flower life in cut Lilium . Further investigation into whether the differential resistance to bacterial-induced xylem occlusion between cultivars is consistently correlated with vascular bundle density across a abroader range of Lilium cultivars could provide insights for breeding programs focused on resistant cultivars for bacterial-induced xylem occlusion.