Cryopreservation studies are being conducted to conserve and restore populations of Macrocystis pyrifera and Eisenia arborea, two key brown algae species distributed along the Pacific coast of Baja California, which are impacted by climate change. Studies to determine the optimal cryoprotectant agents (CPAs) before cryopreservation are essential due to CPAs reduce ice formation in cryogenics temperatures. However, high concentrations of CPAs can produce toxicity and osmotic imbalance, potentially lethal to nonfrozen cells. Therefore, this study explores the cytotoxic effects of 3 cryoprotectant agents (dimethyl sulfoxide, ethylene glycol, and glycerol) at 2 concentrations (10% and 5%) and equilibration time for 10, 15, 30, and 50 minutes on the spores viability.
Before treatment, the percentage of spore survival and development into gametophytes and early sporophytes were recorded. Also, initial viability and oxidative stress was determined by flow cytometry. The results showed that some cryoprotectant concentrations affected spore development in both species. Spores of Eisenia arborea suspended in 5% glycerol remained in the spore germinate stage for 32 days, making them not viable for reproduction. However, 10% of dimethyl sulfoxide and ethylene glycol delayed the transition between stages and induced oxidative stress in the spores but did not affect the development of early sporophytes in both species. These findings underscore the potential toxicity of cryoprotectants and highlight the need for optimizing cryopreservation protocols for these important seaweed species.