Seed collection, storage, and germination practices may affect Viola reintroduction outcomes

Abstract

Numerous factors can influence the ability to successfully procure and use seeds to support plant reintroductions, including challenges with seed collection, storage, and germination. Viola species (Violaceae) are often missing from regional restoration activities because of such obstacles. Using 6 Viola species native to prairie and woodland habitats in the Midwestern United States, we investigated how timing of seed collection, seed storage conditions and duration, and seed germination pretreatment influences seed viability and germination. Specific germination pretreatments tested were cold stratification length, priming with polyethylene glycol, and gibberellic acid. Our results indicate that very short-term seed storage, from 1 d to 4 mo, can influence the depth of primary dormancy in violet seeds, significantly affecting subsequent germination. Cold stratification was the most effective seed pretreatment in breaking dormancy across the 6 species studied, whereas responses to other pretreatments (for example, gibberellic acid and priming) were largely species-specific. Even though cold stratification was consistently the most effective pretreatment, responses significantly differed among and within species. We provide a “best practices” checklist and recommend more detailed record-keeping when seeds are collected, stored, and pretreated for use in restoration.