title: Physiological and molecular evidence of differential short-term heat tolerance in Mediterranean seagrasses.
abstract: The increase in extreme heat events associated to global warming threatens seagrass ecosystems, likely by affecting key plant physiological processes such as photosynthesis and respiration. Understanding species' ability to acclimate to warming is crucial to better predict their future trends. Here, we study tolerance to warming in two key Mediterranean seagrasses, Posidonia oceanica and Cymodocea nodosa. Stress responses of shallow and deep plants were followed during and after short-term heat exposure in mesocosms by coupling photo-physiological measures with analysis of expression of photosynthesis and stress-related genes. Contrasting tolerance and capacity to heat acclimation were shown by shallow and deep P. oceanica ecotypes. While shallow plants acclimated through respiratory homeostasis and activation of photo-protective mechanisms, deep ones experienced photosynthetic injury and impaired carbon balance. This suggests that P. oceanica ecotypes are thermally adapted to local conditions and that Mediterranean warming will likely diversely affect deep and shallow meadow stands. On the other hand, contrasting mechanisms of heat-acclimation were adopted by the two species. P. oceanica regulates photosynthesis and respiration at the level of control plants while C. nodosa balances both processes at enhanced rates. These acclimation discrepancies are discussed in relation to inherent attributes of the two species.
authors.affiliation: Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
authors.forename: Lazaro
authors.initials: L
authors.lastname: Marín-Guirao
authors.affiliation: Seagrass Ecology Group, Oceanographic Center of Murcia, Spanish Institute of Oceanography C/Varadero, 30740 San Pedro del Pinatar, Murcia, Spain.
authors.forename: Juan M
authors.initials: JM
authors.lastname: Ruiz
authors.affiliation: Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Dattolo
authors.affiliation: Seagrass Ecology Group, Oceanographic Center of Murcia, Spanish Institute of Oceanography C/Varadero, 30740 San Pedro del Pinatar, Murcia, Spain.
authors.forename: Rocio
authors.initials: R
authors.lastname: Garcia-Munoz
authors.affiliation: Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Napoli, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Procaccini
mesh_terms: D000064:Acclimatization / Q000502:physiology; D035961:Alismatales / Q000378:metabolism* / Q000502:physiology*; D002244:Carbon / Q000378:metabolism; D017753:Ecosystem; D057232:Global Warming; D006706:Homeostasis / Q000502:physiology; D006358:Hot Temperature; D010788:Photosynthesis / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology; D000071436:Thermotolerance / Q000502:physiology*
chemical_list: D002244:Carbon