Seaweeds in the upper intertidal zone experience extreme desiccation during low tide, followed by rapid
rehydration during high tide. Porphyra sensu lato are typical upper intertidal seaweeds. Therefore, it is valuable to investigate the adaptive mechanisms of seaweed in response to
dehydration-
rehydration stress.
RESULTS: A reduction in photosynthetic capacity and cell shrinkage were observed when N. haitanensis was dehydrated, and such changes were ameliorated once rehydrated. And the rate and extent of
rehydration were affected by the air flow speed, water content before
rehydration, and storage temperature and time. Rapid
dehydration at high air-flow speed and storage at - 20 °C with water content of 10% caused less damage to N. haitanensis and better-protected cell activity. Moreover, proteomic and metabolomic analyses revealed the abundance members of the differentially expressed
proteins (DEPs) and differentially abundant metabolites (DAMs) mainly involved in
antioxidant system and osmotic regulation. The
ascorbic acid-
glutathione coupled with
polyamine antioxidant system was enhanced in the
dehydration response of N. haitanensis. The increased soluble
sugar content, the accumulated polyols, but hardly changed (iso)
floridoside and insignificant amount of
sucrose during
dehydration indicated that polyols as energetically cheaper organic osmolytes might help resist desiccation. Interestingly, the recovery of DAMs and DEPs upon
rehydration was fast.
CONCLUSIONS: Our research results revealed that rapid
dehydration and storage at - 20 °C were beneficial for recovery of N. haitanensis. And the strategy to resist
dehydration was strongly directed toward
antioxidant activation and osmotic regulation. This work provided valuable insights into physiological changes and adaptative mechanism in desiccation, which can be applied for seaweed farming.