Gibberellic acid and light effects on seed germination in the seagrass Zostera marina

Abstract

O_LISeagrass meadows have been heavily affected by human activities, with Zostera marina being one of the most impacted species. Seed-based methods are currently the preferred approach for their restoration. However, low germination rates and seedling establishment often affect the success rate and feasibility of restoration projects. C_LIO_LIWe tested, for the first time, the combined effect of light spectra (white and red light and darkness), photoperiod, and gibberellic acid (GA3) on seed germination rates in Z. marina, by means of an incubation experiment with a fully crossed design, employing penalised logistic regression and Cox proportional hazards analysis. Seedling development was subsequently monitored to assess the potential side-effects of the priming agents on morphometric growth. C_LIO_LILight priming positively affects germination, with germination probability being substantially increased when red light and darkness treatments were combined with GA3. Time to germination was reduced at mid- to high- GA3 concentrations. Morphometric analysis of the cotyledonary and leaf tissue development did not indicate a posteriori side-effects of seed priming on growth. C_LIO_LILight and GA3 priming favour germination probability and release from dormancy in Z. marina seeds. Seed priming can reduce stress- or manipulation-induced dormancy and can be considered in contexts where on-demand germination is required. C_LI