Viburnum lantanoides (Adoxaceae): Leveraging Epicotyl Seed Dormancy Characterization to Optimize Seedling Regeneration Protocols

Efficient seed regeneration of woody plants is of practical importance for horticulture and conservation practitioners. Seeds of the genus Viburnum are known to be difficult to germinate, as mechanisms of morphophysiological dormancy breaking can vary significantly among species, necessitating unique treatments to promote embryo growth and overcome physiological dormancy barriers. In this study, our objectives were (1) to characterize the class of seed dormancy for V. lantanoides, and (2) to optimize a protocol for seed-based regeneration for the species. Specifically, we evaluated warm and cold stratification treatments of increasing length and assessed the effectiveness and timing of seed germination. Results indicate that V. lantanoides seeds exhibit deep simple epicotyl morphophysiological dormancy (MPD), for which a sequence of warm–cold–warm temperatures is required to complete germination processes. We further assessed probability and time to emergence for radicles, cotyledons, and true leaves, and found that the combination of 12-week warm stratification followed by 12-week cold stratification resulted in the fastest and most effective method for seedling regeneration. This study represents an initial exploratory report on seed dormancy and regeneration in Viburnum section Pseudotinus and is intended to enhance physiological understanding of V. lantanoides seeds in support of conservation and horticultural efforts.