Improving seagrass production for transplants - micropropagation, adventitious root development, and artificial substrates

• Main Author: O´Brien, Dannie
• Other Authors: Serrão, Ester, Engelen, Ashwin
• Format: Master Thesis
• Language: English
• Published: 2019
• Subjects: Sistemas Marinhos e Costeiros; Zostera marina; Zostera noltii; Cymodocea nodosa; Trabalho de restauração; Transplante; Micropropagação; in vitro propagação; Desenvolvimento de raízes; Substratos artificiais; Domínio/Área Científica::Ciências Naturais::Outras Ciências Naturais; North Atlantic
• Online Access: http://hdl.handle.net/10400.1/13676

Degradation of seagrass meadows is countered by restoration to secure the important ecosystem services they provide. Restoration outcomes are highly variable, and there are many failures. Restoration methods frequently require harvesting from remnant meadows, with associated ecological risks. In the temperate North Atlantic, Zostera marina, Cymodocea nodosa, and Zostera noltii are the most important seagrass species, and targets for restoration. I tested different transplant approaches to understand and improve seagrass restoration initiatives for these species. Zostera shoots were treated with 0.5 % NaOCl and successfully initiated into the in vitro growth environment for micropropagation. Z. noltii was maintained on enriched seawater media for up to 60 days, but Z. marina survived only 22 days. Mortality was likely related to yeast-like contamination. Cytokinin 6-benzylaminopurine (BAP) in five concentrations between 0.001 mg/L and 3 mg/L did not enhance shoot development in either species, but did maintain health. To assess the impact of transplantation on root development, health, and survival, seagrass shoots were transplanted with roots either removed or intact. This did not affect survival or health. Both Zostera species regrew adventitious root length and mass in only three weeks, but regrowth was almost completely absent in C. nodosa. Auxin Indole-3-butyric (IBA) did not enhance adventitious root development, but rather inhibited root development above 5 mg/L. Two tested seagrass transplant methods, sod and textile substrate, were equally successful and shoots demonstrated similar survival, height, leaf turnover and relative photosynthetic capacity. Sod methods, while popular and successful, are not possible without large donor populations, and their harvest threatens remnant meadows. The successful initiation of Zostera spp. provides high potential to micropropagate shoots for future restoration. Non-rooted shoots can survive transplantation and rapidly establish roots, and these can be integrated with ...