Plant Acoustics for Evaluating Vase Life in Chrysanthemums: A Novel and Noninvasive Method

Vase life is a key determinant of cut flower quality and market value. Conventional vase life assessment relies on visual inspection and physiological monitoring over several days to weeks, making it labor- and time-intensive. This study introduces a rapid and noninvasive approach using plant acoustics to assess postharvest vase-life-related variation in cut chrysanthemum flowers. Six chrysanthemum cultivars were grown under two supplemental lighting treatments (Hybrid and LED) and two planting densities (54 and 74 plants m^-2). Acoustic monitoring was compared with optical microscopy for the assessment of xylem vessel diameter, while conventional vase-life testing was performed in parallel. Optical microscopy validated the acoustic measurements, with both methods consistently identifying vessel radii around 10 μm. The acoustic radius ( $r_a$ ), derived from pulse settling time measurements, showed cultivar- and planting-density-specific variation. Linear mixed-effects modelling demonstrated that the relationship between acoustic radius and vase life differed significantly among cultivars, indicating that a universal relationship across cultivars is not supported. These findings show that acoustic monitoring provides a meaningful noninvasive proxy for vase-life-associated stem traits and may serve as a useful cultivar-calibrated tool for evaluating postharvest longevity in cut chrysanthemums.