Physiological Plasticity as a Strategy to Cope with Harsh Climatic Conditions: Ecophysiological Meta-Analysis of the Cosmopolitan Moss Ceratodon purpureus in the Southern Hemisphere

Determining the physiological tolerance ranges of species is necessary to comprehend the limits of their responsiveness under strong abiotic pressures. For this purpose, the cosmopolitan moss Ceratodon purpureus (Hedw.) Brid. is a good model due to its wide geographical distribution throughout different biomes and habitats. In order to disentangle how this species copes with stresses such as extreme temperatures and high radiation, we designed a meta-analysis by including the main photosynthetic traits obtained by gas exchange measurements in three contrasting habitats from the Southern Hemisphere. Our findings highlight that traits such as respiration homeostasis, modulation of the photosynthetic efficiency, adjustment of the optimal temperature, and switching between shade and sun-adapted forms, which are crucial in determining the responsiveness of this species. In fact, these ecophysiological traits are in concordance with the climatic particularities of each habitat. Furthermore, the photosynthetic trends found in our study point out how different Livingston Island (Maritime Antarctica) and Granite Harbour (Continental Antarctica) are for plant life, while the population from the Succulent Karoo Desert (South Africa) shares traits with both Antarctic regions. Altogether, the study highlights the high resilience of C. purpureus under abrupt climate changes and opens new perspectives about the wide spectrum of physiological responses of cryptogams to cope with climate change scenarios.