Format: ORAL

Melanie Morales1,2, Sergi Munn Bosch1,2

1 Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Barcelona, Spain 2 Institut de Recerca en Biodiversitat (IRBio), Universitat de Barcelona, Barcelona, Spain

Montane plant communities like those growing in the Pyrenees must face multiple and contrasting abiotic stresses throughout their life cycle. Particularly, during winter and cloudless sunny days, these species have to cope harsh low temperatures combined to high solar radiation, both promoting photo-oxidative damage. Extreme temperatures are a main factor limiting plant growth in montane habitats, besides the high risk of frost damage especially in open sites where wind may have a severe drying effect, often in snow-free sites. Here, we studied the cold stress tolerance mechanisms of four diverse perennial herbs inhabiting the Pyrenees: Anthyllis vulneraria L, Leontodon hispidus L, Plantago lanceolata L. and Scabiosa columbaria, with an emphasis on photoprotective and antioxidant, and their association with stress-related phytohormonal responses. The study was performed in a Pyrenean plant community located in a south-facing slope near Sispony (Andorra, Spain) at 1660 m.a.s.l., and a set of functional traits, including leaf gas exchange, photosynthetic pigments and photo- and antioxidant molecules (anthocyanins, carotenoids and a-tocopherol) were measured together with stress-related phytohormones (ABA, salicylic acid and jasmonates), during autumn (before), winter (during) and spring (after cold stress). All species studied were efficient in the prevention of photoinhibition during winter, as indicated by values of the maximum efficiency of PSII (Fv/Fm) above 0.75 during winter. However, they distinctly respond to cold-induced desiccation stress, as indicated by reductions in the relative water content (RWC), which could recover during spring in A. vulneraria and L. hispidus, but not in P. lanceolata and S. columbaria. ABA and jasmonates confirmed the differential behavior and increased stress sensitivity of A. vulneraria and L. hispidus. compared to that of P. lanceolata and S. columbaria. This knowledge is very valuable for predicting how global warming may impact the Pyrenean plant communities.