Comparison of shelf life and quality of potted hydrangea ‘speedy red’ under different abscisic acid spray concentrations

This study compared the shelf life and quality of potted hydrangea (‘Speedy Red’) treated with different abscisic acid (ABA) spray concentrations and investigated the associated physiological changes. Plants were treated with 0 (control), 1,000, 2,000, or 2,500 mg·L^-1 ABA, which was applied by spraying. Treatment with 2,000 and 2,500 mg·L^-1 ABA extended the hydrangea shelf life by 2 days compared to the control, and the 2,000 mg·L^-1 treatment attenuated change in sepal color and wilting compared to other treatments, suggesting quality control in potted plants. Additionally, the 2,000 mg·L^-1 ABA spray treatment increased stomatal closure up to day 5 post-treatment, corresponding to the end of the shelf life for treated plants, indicating that ABA spray decreased transpiration-induced water loss. The 2,000 mg·L^-1 ABA spray treatment resulted in the highest maximum quantum yield of PSII among the treatments, and the normalized difference vegetation index and the simple ratio index values were also higher than those obtained with other treatments. Thus, 2,000 mg·L^-1 ABA spray treatment mitigated water stress by inducing stomatal closure in potted hydrangea (‘Speedy Red’). Overall, the ABA spray treatment controlled stomatal closure and effectively inhibited transpiration, which minimized water loss and preserved plant moisture levels, thereby extending shelf life and quality. Our study also assessed the potential use of nondestructive measurements (e.g., chlorophyll fluorescence and vegetation indices) to monitor the quality of potted hydrangea, which may facilitate the evaluation of potted flower quality on site. ABA spray treatment at 2,000 mg·L^-1 effectively extends the shelf life and improves the quality of potted hydrangea (‘Speedy Red’). These results are useful for the postharvest management of potted hydrangeas.