The effect of timing of gibberellic acid application and concentrations on seed germination characteristics in red osier dogwood, Canadian buffaloberry, and green alder

Abstract

This study investigated the germination responses of red osier dogwood (Cornus sericea L. [Cornaceae]), Canadian buffaloberry (Shepherdia canadensis (L.) Nutt. [Elaeagnaceae]), and green alder (Alnus viridis (Chaix) DC. [Betulaceae]) seeds to exogenous gibberellic acid (GA3) concentrations (0, 300, 500, and 900 mg/l) and their application timing, before and after cold stratification. Positive responses, particularly with extended cold stratification, confirmed intermediate physiological dormancy in red osier dogwood and Canadian buffaloberry, while green alder exhibited non-deep physiological dormancy. Our findings emphasize the role of GA3, especially when applied prior to cold stratification, in promoting more consistent and uniform germination among dogwood seeds. On the contrary, Canadian buffaloberry responded more pronouncedly to post-cold stratification GA3 application. Green alder showed no cold stratification effect, but 2 higher GA3 concentrations reduced germination time. Optimal GA3 concentrations and their application methods varied between species, emphasizing the need for tailored approaches and further investigations for each native species for successful reclamation.