The black mangrove (Avicennia germinans) is native to the subtropical coasts of Florida and the Gulf Coast, and can tolerate moderate to high salinity environments. Of the three mangrove species in Florida, A. germinans is the most cold-tolerant and has experienced a range expansion into temperate salt marshes in recent years. One possible mechanism for both salt and cold tolerance in halophytes is related to their ability to produce glycine betaine (GB), a compatible solute known to function as an osmoprotectant. The presence of GB production in A. germinans was recently confirmed by our lab. We hypothesize the presence of GB, and that GB production is positively related to exposure to salinity and cold temperatures in the black mangrove. We conducted a series of experiments on seedlings of A. germinans to demonstrate the relationship between salt and temperature tolerance ,and GB production. We also made observations of GB production in native plants in estuaries exposed to cold weather events along the Gulf Coast of Florida in December, 2017-January, 2018
Results/Conclusions
Results suggest that GB production increases with exposure to euhaline conditions and cold temperatures, and thus may play a role in the northward range expansion of this species.