Exploring priming strategies to improve stress resilience of Posidonia oceanica seedlings

Abstract

Seagrasses' ability to store information after exposure to stress (i.e. stress memory) and to better respond to further stress (i.e. priming) have recently been observed, although the temporal persistence of the memory and the mechanisms for priming induction remain to be defined. Here, we explored three priming strategies in Posidonia oceanica seedlings, each inducing a different level of stress, for temperature and salinity. We investigated changes in morphometry, growth rate and biomass between primed and non-primed seedlings. The results showed similar behaviour of seedlings when exposed to an acute stress event, regardless of whether they had been primed or not and of the priming strategy received. This opens the debate on the level of stress necessary for inducing a priming status and the persistence of the stress memory in P. oceanica seedlings. Although no priming-induced stress resistance was observed, seedlings showed unexpectedly high resilience to extreme levels of both abiotic stressors.

Keywords: Priming; Salinity stress; Seagrass; Seedling; Thermal stress.