Seagrass restoration, every seed counts: increasing restoration success by improved germination

Description

Coastal aquatic plants such as seagrasses play an important role in maintaining biodiversity and ecosystem functions in the marine environment. Seagrass meadows provide a wide range of ecosystem services: contributing to reduce climate change by carbon sequestration; water filtration by reducing nutrients and pollutants in the water; erosion protection by promoting sedimentation and stabilization; and biodiversity support by providing shelter and nursery habitat to marine organisms. Zostera marina is the most wide-ranging seagrass species in the northern hemisphere and is widespread along the European coastline. Unfortunately, seagrasses have drastically declined worldwide, with Z. marina being one of the most impacted species. Causes of decline are related to poor water quality, coastal development, mooring, dredging, and pathogens. Restoration of Z. marina has been focusing on seed-based methods, as they represent a cost-effective technique that facilitates upscaling while conserving genetic diversity. However, low germination rates and low seedling establishment pose major challenges to the success of restoration actions, with an overall success rate that ranges between 5% and 25% of the total amount
of broadcasted seeds. Therefore, understanding the physiological processes governing germination is necessary to substantially raise restoration success rates. Seed germination is a critical step in the life cycle of flowering plants to ensure successful plant establishment. However, seed manipulation,
during collection and processing can negatively influence seed viability and increase levels of dormancy. Dormancy is a physiological stage that allows seed maturation and prevents germination under unfavorable conditions. Germination is regulated by both environmental and endogenous factors. Temperature, salinity, and light are key triggers of germination. Additionally, light quality and photoperiodism influence seed development and dormancy through endogenous regulation of hormones such as gibberellins (GAs) and abscisic acid (ABA). In this study, Z. marina seeds were exposed to different priming agents: three light spectra, two photoperiods, and five levels of GAs; and their effects on the
germination rate and time and on seedling development were assessed. Exogenous application of GAs significantly improved germination success (40.6%) and mean germination time (1.6 days) compared to untreated seeds (respectively 26.7% and 9.3 days). Synergistic effects of the light spectrum and GAs concentrations were also observed to significantly increase germination success. Our findings aim to improve the restoration practices of aquatic marine vegetation to ensure their success and the effective use of seed stocks.

Periode	13 nov. 2023 → 17 nov. 2023
Evenementstitel	16th International Symposium on Aquatic Plants
Evenementstype	Conference
Conferentienummer	16
Locatie	Antwerp, BelgiumToon op kaart
Mate van erkenning	International